 
التقييس لدول مجلس التعاون لدول الخليج العربية هيئة  
GCC STANDARDIZATION ORGANIZATION (GSO) 
 
 
مشروع مواصفة أولي 
Draft of Standard DS 
 
 
 
TC05اعداد اللجنة الخليجية رقم  
 
Prepared by GSO Technical Committee No. TC05  
 
 
 
GSO   /2019 
 
الملوثات والسموم في الأغذية والأعلاف 
Contaminants and toxins in food and feed 
 
 
 
 
هذه الوثيقة مشروع لمواصفة قياسية خليجية تم 
توزيعها لإبداء الرأي والملحوظات بشأنها، لذلك 
فإنها عرضة للتغيير والتبديل، ولا يجوز الرجوع 
إليها كمواصفة قياسية خليجية إلا بعد اعتمادها من 
الهيئة. 
 
 
 This document is a draft GSO Standard 
circulated for comments. It is, therefore ,  
subject to alteration and modification and 
may not be referred to as a GSO Standard 
until approved by GSO .  
 
 
ICS: 6 7.040 
 
 
  GSO STANDARD   GSO  /2019  
 
 
2 
 
 Foreword 
 
GCC Standardization Organization (GSO) is a regional Organization which  consists of the 
National Standards Bodies of GCC member States. One of GSO main functions is to issue 
Gulf Standards /Technical regulations through specialized technical committees (TCs).  
GSO through the technical program of committee TC No.( 5) " Technica l committee for 
standards of food and agriculture products " has prepared the GSO Technical regulation  . 
The Draft Technical regulation  has been prepared by Kingdom of Saudi Arabia . 
This Technical regulation  has been approved by GSO Board of Directors  in its meeting No. 
( ), held on   ( ) .     
 
* The limits of food contaminants in this regulation replaced all the food contaminants limits 
in the approved GSO food technical regulations and standards - if no limits or contaminants 
are listed for certain food products in this regulation, the food contaminants limits in food 
product regulation shall be applied.  
Gulf Standard No. GSO 1807:2007 “Maximum level for cadmium in food” shall hereby be 
repealed and superseded by the abovementioned Regulation.  
 
 GSO STANDARD   GSO  /2019  
 
 
3 
 
 Contamin ants and toxins in food and feed  
 
1.  Scope  
 This Standard contains maximum levels of contaminants and toxicants in food 
and feed, This Standard includes only maximum levels of contaminants and 
natural toxicants in feed in cases where the contaminant in feed can be 
transferred to food of animal origin and can be relevant for public health.  
2.  Definition of Terms  
 When reference is made to foods, this also applies to animal feed, in those cases 
where this is appropriate.  
2.1 Contaminant  
 Any substance not  intentionally added to food or feed for food producing 
animals, which is present in such food or feed as a result of the production 
(including operations carried out in crop husbandry, animal husbandry and 
veterinary medicine), manufacture, processing, pr eparation, treatment, packing, 
packaging, transport or holding of such food or feed, or as a result of 
environmental contamination. The term does not include insect fragments, 
rodent ha irs and other extraneous matter .  
This Standard applies to any substanc e that meets the terms for a contaminant, 
including contaminants in feed for food -producing animals, except:  
1) Contaminants having only food and feed quality significance (e.g. copper), 
but no public health significance.  
2) Pesticide residues .  
3) Residues of veterinary drugs, and residues of feed additives1.  
4) Microbial toxins, such as botulinum toxin and staphylococcus ente rotoxin .  
5) Residues of processing aids2.  
2.2 Natural toxins included in this Standard  
 The definition of a contaminant implicitly includes naturally occurring toxicants 
including toxic metabolites of certain microfungi that are not intentionally added 
to food and feed (mycotoxins).  
Toxins that are produced by algae and that may be accumulat ed in edible aquatic 
organisms such as shellfish (phycotoxins) are also included in this Standard. 
Mycotoxins and phycotoxins are both subclasses of contaminants.  
                                                           
1 Feed additives: “Any intentionally added ingredient not normally consumed as feed by itself, whether or not 
it has nutritional value, which affects the characteristics of feed or animal products.  
Residues of feed additives include the parent compounds and /or their metabolites in any edible portion of the 
animal product, and include residues of associated impurities of the feed additive concerned.  
2 Processing aids are any substance or material, not including apparatus or utensils, and not consumed as a 
food ingredient by itself, intentionally used in the processing of raw materials, foods or its ingredients, to 
fulfil a certain technological purpose during treatment or processing and which may result in the non -
intentional but unavoidable presence of residu es or derivatives in the final product.  
 GSO STANDARD   GSO  /2019  
 
 
4 
 
 Endogenous natural toxicants, such as e.g. Solanine in potatoes, that are implicit 
constituen ts of food and feed resulting from a genus, species or strain ordinarily 
producing hazardous levels of a toxic metabolite(s), i.e. phytotoxins are not 
generally considered within the scope of this Standard. They are, however, 
within the terms of reference of CCCF and will be dealt with on a case -by-case 
basis.  
2.3      Maximum level and related terms1 
The maximum level (ML)  for a contaminant in a food or feed commodity is the 
maximum concentration of that substance recommended by this standard  to be 
legally permitted in that commodity.  
 
3.  Principles Regarding Contaminants in Food and Feed  
3.1 General  
 Contamination of food and feed may pose a risk to human (and/or animal health). 
Moreover in some cases they may also have a negative impact on the quality of 
the food or feed. Food and feed can become contaminated by various causes and 
processes.  
Contamin ant levels in food and feed shall be as low as reasonably achievable 
through best practice such as Good Agricultural Practice (GAP) and Good 
Manufacturing Practice (GMP) following an appropriate risk assessment. The 
following actions may serve to prevent o r to reduce contamination of feed and 
food2:  
• Preventing food and feed contamination at the source, e.g. by reducing 
environmental pollution.  
• Applying appropriate technology control measure(s) in food and feed 
production, manufacture, processing, prep aration, treatment, packing, 
packaging, transport or holding.  
• Applying measures aimed at decontamination of contaminated feed or food 
and measures to prevent contaminated feed or food to be marketed for 
consumption.  
 
To ensure that adequate action is t aken to reduce contamination of food and feed 
a Code of Practice shall be elaborated comprising source related measures and 
Good Manufacturing Practice as well as Good Agricultural Practice in relation 
to the specific contamination problem.  
                                                           
1 For the contaminants methylmercury, radionuclides, acrylonitrile and vinylchloride monomer a Codex 
guideline level (GL) has been established.  
A Codex guideline level (GL) is the maximum level of a substance in a food or feed commodity which is 
recommended by the Codex Alimentarius Commission to be acceptable for commodities moving in 
international trade.    
2 In addition, reference is made to the Code of Practice for source Directed measures to reduce 
contamination  of food with chemicals (CXC 49 -2001) and the Code of Practice on Good Animal Feeding 
(CXC 54 -2004).  GSO STANDARD   GSO  /2019  
 
 
5 
 
 The degree of contamination of food and feed and the effect of actions to reduce 
contamination shall be assessed by monitoring, survey programs and more 
specialized research programs, where necessary.  
3.2 Principles for establishing maximum levels in food and feed  
 MLs  shall only be set for food in which the contaminant may be found in 
amounts that are significant for the  total exposure of the consumer .  
3.3 Specific criteria  
 The following criteria should (not preventing the use of other relevant criteria) 
be considere d when developing MLs and/or other measures in connection with 
the General Standard for Contaminants and Toxins in Food and Feed.  
Toxicological information  
• identification of the toxic substance(s);  
• metabolism by humans and animals, as appropriate;  
• toxicokinetics and toxicodynamics including information on possible carry -
over of the toxic substance from feed to edible animal tissue/products;  
• information about acute and long term toxicity and other relevant toxicity 
data; and  
• integrated toxico logical expert advice regarding the acceptability and safety 
of intake levels of contaminants, including information on any population 
groups which are especially vulnerable.  
 
Analytical data  
• validated qualitative and quantitative data on representativ e samples; and  
• appropriate sampling procedures.  
 
Intake data  
• presence in food of dietary significance for the contaminant;  
• presence in food that are widely consumed;  
• presence in feed and feed components;  
• food intake data for average and most exposed/high consumer groups;  
• results from total diet studies;  
• calculated contaminant intake data from food consumption models;  
• data on intake by susceptible groups; and  
• data on intake by food producing a nimals.  
 
Technological considerations  GSO STANDARD   GSO  /2019  
 
 
6 
 
 • Information about contamination processes, technological possibilities, 
production and manufacturing practices and economic aspects related to 
contaminant level management and control.  
 
Risk assessment and risk ma nagement considerations  
• risk management options and considerations;  
• consideration of possible maximum levels in food and feed based on the 
criteria mentioned above; and  
• consideration of alternative solutions.  
 
 GSO STANDARD   GSO  /2019  
 
 
7 
 
 AFLATOXINS, TOTAL  
Reference to JECFA:  31 (1987), 46 (1996), 49 (1997), 68 (2007)  
Toxicological guidance value:  Carcinogenic potency estimates for aflatoxins B, G, M (1997, Intake 
should be reduced to levels as low as reasonably possible)  
Contaminant definition:  Aflatoxins total (B1 + B2 + G1 + G2)  
Synonyms:  Abbreviations, AFB, AFG, with numbers, to designate specific 
compounds  
Related code of practice:  Code of Practice for the Prevention and Reduction of Aflatoxin 
Contamination in Peanuts (CXC 55 -2004)  
Code of Practice for the Prevention and Reduction of Aflatoxin 
Contamination in Tree Nuts (CXC 59 -2005)  
Code of Practice for the Reduction of Aflatoxin B1 in Raw Materials and 
Supplemental Feedingstuffs for Milk Producing Animals (CXC 45 -1997)  
Code of Pr actice for the Prevention and Reduction of Aflatoxin 
Contamination in Dried Figs (CXC 65 -2008)  
Commodity/Product  
Name  Maximum 
Level (ML)  
μg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Almonds  10 Whole commodity after 
removal of shell.  The ML applies to almonds “ready -to-
eat” (**)  
For sampling plan, see Annex 2 . 
Almonds  15 Whole commodity after 
removal of shell.  The ML applies to almonds intended 
for further processing (*)  
For sampling plan, see Annex 2.  
Brazil nuts  10 Whole commodity  The ML applies to shelled Brazil nuts 
ready -to-eat (**).  
For sampling plan, see Annex 2.  
Brazil nuts  15 Whole commodity  The ML applies to shelled Brazil nuts 
intended for further processing (*)  
For sampling plan, see Annex 2.  
Hazelnuts  10 Whole commodity after 
removal of shell.  The ML applies to hazelnuts, also 
known as filberts, “ready to eat” (**)  
For sampling plan, see Annex 2.  
Hazelnuts  15 Whole commodity after 
removal of shell.  The ML applies to hazelnuts, also 
known as filberts, intended for further 
processing (*)  
For sampling plan, see Annex 2.  
Peanuts  15 Unless specified, seed 
or kernels, after emoval 
of shell or husk.  The ML applies for peanuts, also 
known as groundnuts, intended for 
further processing (*).  
For sampling plan, see Annex 1.  
Pistachios  10 Whole commodity after 
removal of shell.  The ML applies to pistachios “ready to 
eat” (**).  
For sampling plan, see Annex 2.  
Pistachios  15 Whole commodity after 
removal of shell.  The ML applies to pistachios intended 
for further processing (*)  
For sampling plan, see Annex 2.  
Dried figs  10 Whole commodity  The ML applies to dried figs “ready -
to-eat” (**)  
For sampling plan see Annex 3.  GSO STANDARD   GSO  /2019  
 
 
8 
 
 (*)   “destined for further processing” means intended to undergo an additional processing/treatment that 
has proven to reduce levels of aflatoxins before being used as an ingredient in foodstuffs, otherwise 
processed or offered for human consumption. Proc esses that have proven to reduce levels of 
aflatoxins are shelling, blanching followed by colour sorting, and sorting by specific gravity and colour 
(damage). There is some evidence that roasting reduces aflatoxins in pistachios but for other nuts the 
evidence is still to be supplied.  
(**)   “ready -to-eat” means “not intended to undergo an additional processing/treatment that has proven to 
reduce levels of aflatoxins before being used as ingredient in foodstuffs, otherwise processed or 
offered for human consumption.  
Foods 20 Whole commodity With the exception of foodstuffs 
listed in  table. 
Nuts with exception 
mentioned  10 Whole commodity Nuts with exception mentioned , to 
be subjected to sorting, or other 
physical treatment, before human 
consumption or use as an 
ingredient in foodstuffs   
Nuts with exception 
mentioned  4 Whole commodity Nuts with exception mentioned , 
intended for direct human 
consumption or use as an 
ingredient in foodstuffs  
Dried fruit  and dried 
fruit products  10 Whole commodity Dried fruit, other than dried figs, to 
be subjected to sorting, or other 
physical treatment, before human 
consumption or use as an 
ingredient in foodstuffs  
Dried fruit  and dried 
fruit products  4 Whole commodity Dried fruit, other than dried figs, 
and processed products thereof, 
intended for direct human 
consumption or use as an 
ingredient in foodstuffs  
Cereals and all 
products derived 
from cereals  4 Whole commodity All cereals and all products 
derived from cereals, including 
processed cereal products, with 
the exception of foodstuffs listed 
in table. 
Maize and rice  10 Whole commodity Maize and rice  to be subjected to 
sorting or other physical treatment GSO STANDARD   GSO  /2019  
 
 
9 
 
 before human consumption or use 
as an ingredient in foodstuffs  
Spices 10 Whole commodity Following species of  spices:  
Capsicum  spp. (dried fruits 
thereof, whole or ground, 
including chillies, chilli powder, 
cayenne and paprika)  
Piper spp. (fruits thereof, including 
white and black pepper)  
Myristica fragrans  (nutmeg)  
Zingiber officinale  (ginger)  
Curcuma longa  (turmeric)  
Mixtures of spices containing one 
or more of the abovementioned 
spices  
Animal Feeds  - 
Corn and peanut 
products  300 Whole commodity Corn and peanut products 
intended for finishing (i.e., feedlot) 
beef cattle  
Animal Feeds - 
Cottonseed meal  300 Whole commodity Cottonseed meal intended for 
beef, cattle, swine, or poultry 
(regardless of age or breeding 
status  
Animal Feeds - 
Corn and peanut 
products  100 Whole commodity Corn and peanut products 
intended for breeding beef cattle, 
or mature poultry  
Animal Feeds - 
Corn, peanut 
products, and other 
animal feeds  20 Whole commodity Corn, peanut products, and other 
animal feeds and feed ingredients 
but excluding cottonseed meal, 
intended for immature animals  
Animal Feeds - 
Corn, peanut 
products, cottonseed 
meal, and other 
animal feed  20 Whole commodity Corn, peanut products, cottonseed 
meal, and other animal feed 
ingredients intended for dairy 
animals, for animal species or GSO STANDARD   GSO  /2019  
 
 
10 
 
 uses not specified above, or when 
the intended use is not known  
 GSO STANDARD   GSO  /2019  
 
 
11 
 
 AFLATOXIN M 1 
Reference to JECFA:  56 (2001)  
Toxicological guidance value:  Cancer potency estimates at specified residue levels (2001, Using 
worst -case assumptions, the additional risks for liver cancer predicted 
with use of proposed maximum levels of aflatoxin M 1 of 0.05 and 0.5 
μg/kg are very small. The potency of aflatoxin M 1 appears to be so low 
in HBsAg - individuals that a carcinogenic effect of M 1 intake in those 
who consume large quantities of milk and milk products in comparison 
with non -consume rs of these products would be impossible to 
demonstrate. Hepatitis B virus carriers might benefit from a reduction 
in the aflatoxin concentration in their diet, and the reduction might also 
offer some protection in hepatitis C virus carriers).  
Contaminant  definition:  Aflatoxin M 1 
Synonyms:  AFM 1 
Related code of practice:  Code of Practice for the Reduction of Aflatoxin B 1 in Raw Materials and 
Supplemental Feedingstuffs for Milk Producing Animals (CXC 45 -1997)  
Commodity/Product  
Name  Maximum 
Level (ML)  
μg/kg Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Milks  0.5 
 Whole commodity.  Milk is the normal mammary 
secretion of milking animals obtained 
from one or more milkings  without 
either addition to it or extraction from 
it, intended for consumption as liquid 
milk or for further processing.  
A concentration factor applies to 
partially or wholly dehydrated milks.  
 GSO STANDARD   GSO  /2019  
 
 
12 
 
 DEOXYNIVALENOL (DON)  
Reference to JECFA:  56 (2001), 72 (2010)  
Toxicological guidance value:  Group PMTDI 0.001 mg/kg bw (2010, for DON and its acetylated 
derivates)  
Group ARfD 0.008 mg/kg bw (2010, for DON and its acetylated 
derivates)  
Contaminant definition:  Deoxynivalenol  
Synonyms:  Vomitoxin; Abbreviation, DON  
Related code of practice:  Code of Practice for the Prevention and Reduction of Mycotoxin 
Contamination in Cereals (CXC 51 -2003)  
Commodity/Product  
Name  Maximum 
Level (ML)  
μg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Cereal -based foods for 
infants and young 
children  200 ML applies to the 
commodity on a dry 
matter basis.  All cereal -based foods intended for 
infants (up to 12 months) and young 
children (12 to 36 months)  
Flour, meal, semolina 
and flakes derived from 
wheat, maize or barley  1000    
Cereal grains (wheat, 
maize and barley) 
destined for further 
processing  2000   “Destined for further processing” 
means intended to undergo an 
additional processing/treatment that 
has proven to reduce levels of DON  
before being used as an ingredient in 
foodstuffs, otherwise processed or 
offered for human consumption. 
Codex members may define the 
processes that have been shown to 
reduce levels  
Pasta (dry)  750   
Bread, pastries, 
biscuits, cereal snacks 
and breakfast  cereals  500  Bread (including small bakery wares), 
pastries, biscuits, cereal snacks and 
breakfast cereals  
 GSO STANDARD   GSO  /2019  
 
 
13 
 
 FUMONISINS (B 1 + B 2) 
Reference to JECFA:  56 (2001), 74 (2011)  
Toxicological guidance value:  PMTDI 0.002 mg/kg bw (2001, 2011)  
Contaminant definition:  Fumonisins (B 1+ B 2) 
Synonyms:  Several related compounds have been described, notably fumonisin B 1, 
B2 and B 3 (abbreviation: FB 1 etc.) 
Related code of practice:  Code of Practice for the Prevention and Reduction of Mycotoxin 
Contamination in Cereals (CXC 51 -2003)  
Commodity/Product  
Name  Maximum 
Level (ML)  
μg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Raw maize grain  4000  Whole commodity   
Maize flour and maize 
meal  2000  Whole commodity   
Maize  1000   for direct human consumption  
Maize -based breakfast 
cereals and maize -
based snacks  800   
Processed maize -
based foods and baby 
foods for infants and 
young children  200   
Maize-based foods for 
direct human 
consumption  1000   for direct human consumption  
 GSO STANDARD   GSO  /2019  
 
 
14 
 
 OCHRATOXIN A  
Reference to JECFA:  37 (1990), 44 (1995), 56 (2001), 68 (2007)  
Toxicological guidance value:  PTWI 0.0001 mg/kg bw (2001)  
Contaminant definition:  Ochratoxin A  
Synonyms:  (The term “ochratoxins ” includes a number of related mycotoxins (A, B, 
C and their esters and metabolites), the most important one being 
ochratoxin A)  
Related code of practice:  Code of Practice for the Prevention and Reduction of Mycotoxin 
Contamination in Cereals (CXC 51-2003)  
Code of Practice for the Prevention and Reduction of Ochratoxin A 
Contamination in Wine (CXC 63 -2007)  
Code of Practice for the Prevention and Reduction of Ochratoxin A 
Contamination in Coffee (CXC 69 -2009)  
Code of Practice for the Prevention and R eduction of Ochratoxin A 
contamination in Cocoa (CXC 72 -2013)  
Commodity/Product  
Name  Maximum 
Level (ML)  
μg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Wheat  5 Whole commodity  The ML applies to raw common 
wheat, raw durum  wheat, raw spelt 
and raw emmer.  
Barley  5 Whole commodity  The ML applies to raw barley.  
Rye 5 Whole commodity  The ML applies to raw rye.  
Unprocessed cereals  5  Unprocessed cereals  
Products derived from 
unprocessed cereals, 
including processed 
cereal products and 
cereals  3  All products derived from 
unprocessed cereals, including 
processed cereal products and 
cereals intended for direct human 
consumption with the exception of 
foodstuffs listed in table.  
Dried vine fruit  10  Dried vine fruit (currants,  raisins and 
sultanas)  
Roasted coffee beans 
and ground roasted 
coffee  5  excluding soluble coffee  
Soluble coffee  10   
Grape juice  and 
concentrated grape 
juice 2  Grape juice, concentrated grape juice 
as reconstituted, grape nectar, grape 
must and concentrated grape must as 
reconstituted, intended for direct 
human consumption  
Processed cereal -
based foods and baby 
foods for infants and 
young children  0.5   
Dietary foods for 
special medical 
purposes intended 
specifically for infants  0.5   
Spices, including dried 
spices  15  Piper  spp (fruits thereof, including 
white and black pepper)  GSO STANDARD   GSO  /2019  
 
 
15 
 
 Myristica fragrans  (nutmeg)  
Zingiber officinale  (ginger)  
Curcuma longa  (turmeric)  
Pepper   15  Capsicum spp. (dried fruits thereof, 
whole or ground, including chillies , 
chilli powder, cayenne and paprika)  
Mixtures of spices  15  Mixtures of spices containing one of 
the abovementioned spices  
Liquorice root  20  Liquorice root, ingredient for herbal 
infusion  
Liquorice extract  80  For use in food in particular 
beverages and confectionary  
Wheat gluten  8  not sold directly to the consumer  
 
 
 
 GSO STANDARD   GSO  /2019  
 
 
16 
 
 PATULIN  
Reference to JECFA:  35 (1989), 44 (1995)  
Toxicological guidance value:  PMTDI 0.0004 mg/kg bw (1995)  
Contaminant definition:  Patulin  
Related code of practice:  Code of Practice for the Prevention and Reduction of Patulin 
Contamination in Apple Juice and Apple Juice Ingredients in Other 
Beverages (CXC 50 -2003)  
Commodity/Product  
Name  Maximum 
Level (ML)  
μg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Apple juice  50 Whole commodity (not 
concentrated) or 
commodity 
reconstituted to the 
original juice 
concentration.  Relevant Codex commodity standard 
include CXS 247 -2005 (apple 
products only).  
The ML applies also to apple juice 
used as an ingredient in other 
beverages.  
Solid apple pro ducts 
and apple puree  25  Solid apple products, including apple 
compote, apple puree intended for 
direct consumption with  exception 
mentioned  
Apple juice and solid 
apple products  10  Apple juice and solid apple products, 
including apple compote and apple 
puree, for infants and young children 
and labelled and sold as such  
Baby foods other than 
processed cereal -
based foods for infants 
and young c hildren  10   
 GSO STANDARD   GSO  /2019  
 
 
17 
 
 ARSENIC  
Reference to JECFA:  5 (1960), 10 (1967), 27 (1983), 33 (1988), 72 (2010)  
SFDA  Inorganic Arsenic in Rice and Rice Products Risk assessment   
Toxicological guidance value:  At the 72nd meeting of JECFA (2010), the inorganic arsenic lower 
limit on the benchmark dose for a 0.5% increased incidence of lung 
cancer (BMDL 0.5) was determined from epidemiological studies to be 
3.0 μg/kg bw/day (2 –7 μg/kg bw/day based on the range of  estimated 
total dietary exposure) using a range of assumptions to estimate total 
dietary exposure to inorganic arsenic from drinking -water and food. 
The JECFA noted that the provisional tolerable weekly intake (PTWI) 
of 15 μg/kg bw (equivalent to 2.1 μg/k g bw/day) is in the region of the 
BMDL 0.5 and therefore was no longer appropriate. The JECFA 
withdrew the previous PTWI.  
Contaminant definition:  Arsenic: total (As -tot) when not otherwise mentioned; inorganic 
arsenic (As -in); or other specification  
Synonyms:  As 
Related code of practice:  Code of Practice for Source Directed Measures to Reduce 
Contamination of Foods with Chemicals (CXC 49 -2001)  
Code of Practice for the Prevention and Reduction of Arsenic 
Contamination in Rice (CXC 77 -2017)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Edible fats and oils  0.1 Whole commodity  Relevant Codex commodity 
standards are CXS 19 -1981, CXS 33 -
1981, CXS 210 -1999, CXS 211 -1999 
and CXS 329 -2017  
For fish oils covered by CXS 329 -
2017, the ML is for fish oils (As -in).  
Countries or importers may decide to 
use their own screening when 
applyin g the ML for As -in in fish oils 
by analysing total arsenic (As -tot) in 
fish oils. If the As -tot concentration is 
below the ML for As -in, no further 
testing is required and the sample is 
determined to be compliant with the 
ML. If the As -tot concentration is  
above the ML for As -in, follow -up 
testing shall be conducted to 
determine if the As -in concentration is 
above the ML.  
Fat spreads and 
blended spreads  0.1  Relevant Codex commodity standard 
is CXS 256 -2007.  
Natural mineral waters  0.01  Relevant Codex commodity standard 
is CXS 108 -1981.  
Calculated as total As in mg/l.  
Rice, husked  0.25 Whole commodity  Determined as inorganic Arsenic  
Rice, polished  0.08 Whole commodity  Determined as inorganic Arsenic  
Salt, food grade  0.5  Relevant Codex commodity standard 
is CXS 150 -1985.  GSO STANDARD   GSO  /2019  
 
 
18 
 
 Rice Products  0.2  Determined as inorganic Arsenic  
Rice pies, rice flakes and rice cakes  
Rice for baby and 
infant food  0.05  Determined as inorganic Arsenic  
Rice for baby and infant food  
 GSO STANDARD   GSO  /2019  
 
 
19 
 
 CADMIUM  
Reference to JECFA:  16 (1972), 33 (1988), 41 (1993), 55 (2000), 61 (2003), 64 (2005), 73 
(2010)  
Toxicological guidance value:  In view of the long half -life of cadmium, daily ingestion in food has a 
small or even a negligible effect on overall exposure. In order to ass ess 
long- or short -term risks to health due to cadmium exposure, dietary 
intake should be assessed over months, and tolerable intake should be 
assessed over a period of at least 1 month. To encourage this view, at 
the 73rd meeting (2010) the JECFA decided to express the tolerable 
intake as a monthly value in the form of a provisional tolerable 
monthly intake (PTMI) and established a PTMI of 25 μg/kg bw.  
Contaminant definition:  Cadmium, total  
Synonyms:  Cd 
Related code of practice:  Code of Practice for Source Directed Measures to Reduce 
Contamination of Foods with Chemicals (CXC 49 -2001)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Brassica vegetables  0.05 Head cabbages and 
kohlrabi: whole 
commodity as 
marketed, after 
removal of obviously 
decomposed or 
withered leaves.  
Cauliflower and 
broccoli: flower heads 
(immature 
inflorescence only).  
Brussels sprouts: 
“buttons” only.  The ML does not apply to Brassica 
leafy vegetables.  
Bulb vegetables  0.05 Bulb/dry onions and 
garlic: whole 
commodity after 
removal of roots and 
adhering soil and 
whatever parchment 
skin is easily detached.   
Fruiting vegetables  0.05 Whole commodity after 
removal of stems.  
Sweet corn and fresh 
corn: kernels plus cob 
without husk.  The ML does not apply to tomatoes 
and edible fungi.  
Leafy vegetables  0.2 Whole commodity as 
usually marketed, after 
removal of obviously 
decomposed or 
withered leaves.  The ML also applies to Brassica leafy 
vegetables.  
Legume vegetables  0.1 Whole commodity as 
consumed. The 
succulent forms may 
be consumed as whole  GSO STANDARD   GSO  /2019  
 
 
20 
 
 pods or as the shelled 
product.  
Pulses  0.1 Whole commodity  The ML does not apply to soya bean 
(dry).  
Root and tuber 
vegetables  0.1 Whole commodity after 
removing tops. 
Remove adhering soil 
(e.g. by rinsing in 
running water or by 
gentle brushing of the 
dry commodity).  
Potato: peeled potato.  The ML does not apply to celeriac.  
Stalk and stem 
vegetables  0.1 Whole commodity as 
marketed  after removal 
of obviously 
decomposed or 
withered leaves.  
Rhubarb: leaf stems 
only.  
Globe artichoke: flower 
head only.  
Celery and asparagus: 
remove adhering soil.   
Cereal grains  0.1 Whole commodity  The ML does not apply to buckwheat, 
cañihua , quinoa, wheat and rice.  
Rice, polished  0.4 Whole commodity   
Wheat  0.2 Whole commodity  The ML applies to common wheat, 
durum wheat, spelt and emmer.  
Marine bivalve 
molluscs  2 Whole commodity after 
removal of shell.  The ML applies to clams, cockles and 
mussels but not to oysters and 
scallops.  
Cephalopods  2 Whole commodity after 
removal of shell.  The ML applies to cuttlefishes, 
octopuses and squids without viscera  
Natural mineral waters  0.003   Relevant Codex commodity standard 
is CXS 108 -1981.  
The ML is expressed in mg/l.  
Salt, food grade  0.5  Relevant Codex commodity standard 
is CXS 150 -1985.  
Chocolate containing 
or declaring ≥ 50% to < 
70% total cocoa solids 
on a dry matter basis  0.8 Whole commodity as 
prepared for wholesale 
or retail distribution  Including sweet chocolate, Gianduja 
chocolate, semi – bitter table 
chocolate, Vermicelli chocolate / 
chocolate flakes, and bitter table 
chocolate.  
Chocolate containing 
or declaring ≥ 70% 
total cocoa solids on a 
dry matter basis  0.9 Whole commodity as 
prepared for wholesale 
or retail distribution  Including sweet chocolate, Gianduja 
chocolate, semi – bitter table 
chocolate, Vermicelli chocolate / 
chocolate flakes, and bitter table 
chocolate.  
Vegetables and fruit, 
with exception 
mentioned  0.05  with exception mentioned  
Mushroom   0.2   
Fungi  with exception 
mentioned  1  with exception mentioned  
Soy beans  0.2   
Cocoa powder 
(drinking chocolate)  0.6  Cocoa powder sold to the final 
consumer or as an ingredient in GSO STANDARD   GSO  /2019  
 
 
21 
 
 sweetened cocoa powder sold to the 
final consumer (drinking chocolate)  
Milk chocolate with < 
30 % total dry cocoa 
solids  0.1   
Chocolate with < 50 % 
total dry cocoa solids; 
milk chocolate with ≥ 
30 % total dry cocoa 
solids  0.3   
Meat of bovine 
animals, sheep and 
poultry  0.05  excluding offal  
Horsemeat  0.2  excluding offal  
Liver of bovine 
animals, sheep, poultry 
and horse  0.5   
Kidney of bovine 
animals, sheep, poultry 
and horse  1   
Muscle meat of fish: 
Mackerel,  tuna and 
bichique  0.1 Muscle meat   
Muscle meat of fish: 
bullet tuna  0.15 Muscle meat   
Muscle meat of fish: 
Anchovy, swordfish 
and sardine  0.25 Muscle meat   
Muscle meat of Fish  
with exception 
mentioned  0.05 Muscle meat   
Crustaceans  0.5 Muscle meat  Excluding  brown mea t (offal) 
Powdered  formulae 
manufac - tured from 
cows' milk proteins or 
protein hydrolysates  0.01   
Liquid  formulae 
manufactured from 
cows' milk proteins or 
protein hydrolysates  0.005    
Powdered  formulae 
manufac -tured from 
soya protein isolates, 
alone or in a mixture 
with cows' milk proteins  0.02   
Liquid  formulae 
manufactured from 
soya protein isolates, 
alone or in a mixture 
with cows' milk proteins  0.01   
Processed cereal -
based foods and baby 
foods for infants and 
young children  0.04   
Food supplements  
consisting exclusively 
or mainly of dried 
seaweed, products 3   GSO STANDARD   GSO  /2019  
 
 
22 
 
 derived from seaweed, 
or of dried bivalve 
molluscs  
Food supplements  with 
exception mentioned  1   
 
  GSO STANDARD   GSO  /2019  
 
 
23 
 
 LEAD  
Reference to JECFA:  10 (1966), 16 (1972), 22 (1978), 30 (1986), 41 (1993), 53 (1999), 73 
(2010)  
Toxicological guidance value:  Based on the dose –response analyses, at the 73rd meeting (2010), 
JECFA estimated that the previously established PTWI of 25 μg/kg bw  
is associated with a decrease of at least 3 intelligence quotient (IQ) 
points in children and an increase in systolic blood pressure of 
approximately 3 mmHg (0.4 kPa) in adults. While such effects may be 
insignificant at the individual level, these change s are important when 
viewed as a shift in the distribution of IQ or blood pressure within a 
population. The JECFA therefore concluded that the PTWI could no 
longer be considered health protective and withdrew it.  
Contaminant definition:  Lead, total  
Synon yms:  Pb 
Related code of practice:  Code of Practice for the Prevention and Reduction of Lead 
Contamination in Foods (CXC 56 -2004)  
Code of Practice for Source Directed Measures to Reduce 
Contamination of Foods with Chemicals (CXC 49 -2001)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product to 
which the ML applies  Notes/Remarks  
Berries and other small 
fruits  0.1 Whole commodity after 
removal of caps and 
stems.  The ML does not apply to cranberry, 
currant and elderberry.  
Cranberry  0.2 Whole commodity after 
removal of caps and 
stems.   
Currants  0.2 Fruit with stem.   
Elderberry  0.2 Whole commodity after 
removal of caps and 
stems.   
Fruits  0.1 Whole commodity.  
Berries and other small 
fruits: whole 
commodity after 
removal of caps and 
stems.  
Pome fruits: whole 
commodity after 
removal of stems.  
Stone fruits, dates and 
olives: whole 
commodity after 
removal of stems and 
stones, but the level 
calculated and 
expressed on the 
whole commodity 
without stem.  
Pineapple: whole 
commodity after 
removal of crown.  The ML does not apply to cranberry, 
currant and elderberry.  GSO STANDARD   GSO  /2019  
 
 
24 
 
 Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product to 
which the ML applies  Notes/Remarks  
Avocado, mangos and 
similar fruit with hard 
seeds: whole 
commodity after 
removal of stone but 
calculated on whole 
fruit. 
Brassica vegetables  0.1 Bulb/dry o nions and 
garlic: whole 
commodity after 
removal of roots and 
adhering soil and 
whatever parchment 
skin is easily detached.  The ML does not apply to kale and 
leafy Brassica vegetables.  
Bulb vegetables  0.1 Bulb/dry onions and 
garlic: whole 
commodity after 
removal of roots and 
adhering soil and 
whatever parchment 
skin is easily detached.   
Fruiting vegetables  0.05 Whole commodity after 
removal of stems  
Sweet corn and fresh 
corn: kernels plus cob 
without husk.  The ML does not apply to fungi and 
mushrooms.  
Leafy vegetables  0.3 Whole commodity as 
usually marketed, after 
removal of obviously 
decomposed or 
withered leaves.  The ML applies to leafy Brassica 
vegetables but does not apply to 
spinach.  
Legume vegetables  0.1 Whole commodity as 
consumed. The 
succulen t forms may 
be consumed as whole 
pods or as the shelled 
product.   
Fresh farmed 
mushrooms (common 
mushrooms (Agaricus 
bisporous), shiitake 
mushrooms (Lentinula 
edodes), and oyster 
mushrooms (Pleurotus 
ostreatus))  0.3 Whole commodity  Relevant Codex commodity standard 
is CXS 38 -1981  
Pulses  0.1 Whole commodity   
Root and tuber 
vegetables  0.1 Whole commodity after 
removing tops. 
Remove adhering soil 
(e.g. by rinsing in 
running water or by 
gentle brushing of the 
dry commodity).  
Potato: peeled potato.   GSO STANDARD   GSO  /2019  
 
 
25 
 
 Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product to 
which the ML applies  Notes/Remarks  
Canned fruits  0.1 The ML applies to the 
product as consumed.  Relevant Codex commodity standards 
are CXS 242 -2003, CXS 254 -2007, 
CXS 78 -1981, CXS 159 -1987, CXS 
42-1981, CXS 99 -1981, CXS 60 -
1981, CXS 62 -1981  
Jams, jellies and 
marmalades  0.4  Relevant Codex commodity standard 
is CXS 296 -2009 (for jams and jellies 
only).  
Mango chutney  0.4  Relevant Codex commodity standard 
is CXS 160 -1987.  
Canned vegetables  0.1 The ML applies to the 
product as consumed.  Relevant Codex commodity standard 
is CXS 297 -2009.  
Preserved tomatoes  0.05  Relevant Codex commodity standard 
is CXS 13 -1981.  
In order to consider the concentration 
of the product, the determination of 
the maximum levels for contaminants 
shall take into account the natural 
total soluble solids, the reference 
value being 4.5 for fresh fruit.  
Table olives  0.4  Relevant Codex comm odity standard 
is CXS 66 -1981.  
Pickled cucumbers  
(cucumber pickles)  0.1  Relevant Codex commodity standard 
is CXS 115 -1981.  
Canned chestnuts and 
canned chestnuts 
puree  0.05  Relevant Codex commodity standard 
is CXS 145 -1985.  
Fruit juices  0.03 Whole commodity (not 
concentrated) or 
commodity 
reconstituted to the 
original juice 
concentration, ready to 
drink.  
The ML applies also to 
nectars, ready to drink.  The ML does not apply to juices 
exclusively from berries and other 
small fruit.  
Relevant Codex comm odity standard 
is CXS 247 -2005.  
Fruit juices obtained 
exclusively from 
berries and other small 
fruits  0.05 Whole commodity (not 
concentrated) or 
commodity 
reconstituted to the 
original juice 
concentration, ready to 
drink. The ML applies 
also to nectars, ready 
to drink.  The ML does not apply to grape juice.  
Relevant Codex commodity standard 
is CXS 247 -2005.  
Grape juice  0.04 Whole commodity (not 
concentrated) or 
commodity 
reconstituted to the 
original juice 
concentration, ready to 
drink. The ML applies 
also to nectars, ready 
to drink.  Relevant Codex commodity standard 
is CXS 247 -2005.  GSO STANDARD   GSO  /2019  
 
 
26 
 
 Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product to 
which the ML applies  Notes/Remarks  
Cereal grains  0.2 Whole commodity  The ML does not apply to buckwheat 
cañihua and quinoa.  
Infant formula, formula 
for special medical 
purposes intended for 
infants and follow -up 
formula  0.01 Whole commodity  Relevant Codex commodity standards 
are CXS 72 -1981 and CXS 156 -1987.  
The ML applies to formula as 
consumed.  
Fish 0.3 Whole commodity (in 
general after removing 
the digestive tract)   
Meat of cattle and 
sheep  0.1 Whole commodity 
(without bones)  The ML also applies to fat from the 
meat.  
Meat and fat of poultry  0.1 Whole commodity 
(without bones)   
Cattle, edible offal of  0.5 Whole commodity   
Poultry, edible offal of  0.5 Whole commodity   
Edible fats and oils  0.08 Whole commodity as 
prepared for wholesale 
or retail distribution.  Relevant Codex commodity standards 
are CXS 19 -1981, CXS 33 -1981, CXS 
210-1999, CXS 211 -1999 and CXS 
329-2017  
Fat spreads and 
blended spreads  0.04 Whole commodity as 
prepared for wholesale 
or retail distribution.  Relevant Codex commodity standard 
is CXS 256 -2007.  
Milk 0.02 Whole commodity  Milk is the normal mammary secretion 
of milking animals obtained from one 
or more milkings  without either 
addition to it or extraction from it, 
intended for consumption as liquid 
milk or for further processing.  
A concentration factor applies to 
partially or wholly dehydrated milks  
Secondary milk 
products  0.02 Whole commodity  The ML applies to the food as 
consumed.  
Natural mineral waters  0.01  Relevant Codex commodity standard 
is CXS 108 -1981.  
The ML is expressed in mg/l.  
Salt, food grade  1 Whole commodity as 
prepared for wholesale 
or retail distribution  Relevant Codex commodity standard 
is CXS 150 -1985.  
Excluding salt from marshes  
Concentrated fruit 
juices and fruit nectars  0.05   
Infant formulae and 
follow -on formulae  0.02   
Crustaceans   0.5 Muscle  meat   
Bivalve molluscs  1.5   
Cephalopods  1  Without  viscera  
Food supplements  3   
 
  GSO STANDARD   GSO  /2019  
 
 
27 
 
 MERCURY  
Reference to JECFA:  10 (1966), 14 (1970), 16 (1972), 22 (1978), 72 (2010)  
Toxicological guidance value:  At the 72rd meeting (2010), JECFA established a PTWI for inorganic 
mercury of 4 μg/kg bw. The previous PTWI of 5 μg/kg bw  for total 
mercury, established at the sixteenth meeting, was withdrawn. The new 
PTWI for inorganic mercury was considered applicable to dietary 
exposure to total mercury from foods other than fish and shellfish. For 
dietary exposure to mercury from these foods the previously 
established PTWI for methyl mercury should be applied.  
Contaminant definition:  Mercury, Total  
Synonyms:  Hg 
Related code of practice:  Code of Practice for Source Directed Measures to Reduce 
Contamination of Foods with Chemicals (CXC 49-2001)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product to 
which the ML applies  Notes/Remarks  
Natural mineral waters  0.001   Relevant Codex commodity standard 
is CXS 108 -1981.  
The ML is expressed in mg/l.  
Salt food grade  0.1  Relevant Codex commodity standard 
is CXS 150 -1985.  
Tuna  1.2 Whole commodity after 
removing the digestive 
tract  
Alfonsino  1.5 Whole commodity after 
removing the digestive 
tract  
Marlin  1.7 Whole commodity after 
removing the digestive 
tract  
Shark  1.6 Whole commodity after 
removing the digestive 
tract  
Fishery products  and 
muscle meat of fish  
with exception 
mentioned , 
Crustaceans  and crabs  1   
Food supplements  0.1   
Wheat pink kernels  1  Pink kernels only  
 
  GSO STANDARD   GSO  /2019  
 
 
28 
 
 METHYLMERCURY IN CERTAIN FISH SPECIES  AND CRUSTACEANS  
Reference to JECFA:  22 (1978), 33 (1988), 53 (1999), 61 (2003), 67 (2006)  
Toxicological guidance value:  PTWI 0.0016 mg/kg bw (2003, confirmed in 2006)  
Contaminant definition:  Methylmercury  
Related code of practice:  Code of Practice for Source Directed Measures to Reduce 
Contamination of Foods with Chemicals (CXC 49 -2001)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product to 
which the ML applies  Notes/Remarks  
Tuna  1.2 
Whole commodity 
fresh or frozen (in 
general after removing 
the digestive tract)  The ML also applies to fresh or frozen 
fish intended for further processing.  Alfonsino  1.5 
Marlin  1.7 
Shark  1.6 
Crustaceans and crabs  1   
 
  GSO STANDARD   GSO  /2019  
 
 
29 
 
 TIN 
Reference to JECFA:  10 (1966), 14 (1970), 15 (1971), 19 (1975), 22 (1978), 26 (1982), 33 
(1988), 55 (2000), 64 (2005)  
Toxicological guidance value:  PTWI 14 mg/kg bw (1988, expressed as Sn; includes tin from food 
additive uses; maintained in 2000)  
Contaminant definition:  Tin, total (Sn -tot) when not otherwise mentioned; inorganic tin (Sn -in); 
or other specification  
Synonyms:  Sn 
Related code of practice:  Code of Practice for the Prevention and Reduction of Inorganic Tin 
Contamination in Canned Foods (CXC 60 -2005)  
Code of Practice for Source Directed Measures to Reduce 
Contamination of Foods with Chemicals (CXC 49 -2001)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Canned foods (other 
than beverages)  250  The ML does  not apply to non -tinplate 
canned cooked cured chopped meat, 
cooked cured ham, cooked cured 
pork shoulder, corned beef and 
luncheon meat.  
Relevant Codex commodity 
standards include CXS 62 -1981, CXS 
254-2007, CXS 296 -2009, CXS 242 -
2003, CXS 297 -2009, CXS 78 -1981, 
CXS 159 -1987, CXS 42 -1981, CXS 
60-1981, CXS 99 -1981, CXS 160 -
1987, CXS 66 -1981, CXS 13 -1981, 
CXS 115 -1981, CXS 57 -1981, CXS 
145-1981, CXS 98 -1981, CXS 96 -
1981, CXS 97 -1981, CXS 88 -
1981,CXS 89 -1981.  
Canned beverages  150  Relevant Codex commodity 
standards include CXS 247 -2005.  
Cooked cured chopped 
meat  50  The ML applies to products in 
containers other than tinplate 
containers.  
Relevant Codex commodity standard 
is CXS 98 -1981.  
Corned beef  50  The ML applies to products in 
containers other than tinplate 
containers.  
Relevant Codex commodity standard 
is CXS 88 -1981.  
Luncheon meat  50  The ML applies to products in 
containers other than tinplate 
containers.  
Relevant Codex commodity standard 
is CXS 89 -1981.  
Canned baby foods 
and processed cereal -
based foods for infants 
and young children, 50   GSO STANDARD   GSO  /2019  
 
 
30 
 
 excluding dried and 
powdered products  
Canned infant f ormulae 
and follow -on formulae , 
excluding dried and 
powdered products  50   
Canned dietary foods 
for special medical 
purposes  intended 
specifically for infants, 
excluding dried and 
powdered products  50   
 
  GSO STANDARD   GSO  /2019  
 
 
31 
 
 RADIONUCLIDES  
Commodity/Product  
Name  Guideline 
Level (GL)  
(Bq/kg)  Representative 
radionuclides  Portion of the 
Commodity/Product 
to which the GL 
applies  Notes/Remarks  
Infant foods  1 Pu-238, Pu -239, 
Pu-240, Am -241  The GL applies to foods 
intended for consumption 
by infants.  
Infant foods 
100 Sr-90, Ru -106, I -
129, I -131, U -235  The GL applies to foods 
intended for consumption 
by infants.  
Infant foods  
1000  S-35 (*), Co -60, Sr -
89, Ru -103, Cs -
134, Cs -137, Ce -
144, Ir -192  The GL applies to foods 
intended for consumption 
by infants.  
Infant foods 
1000  H-3(**), C -14, Tc -
99  The GL applies to foods 
intended for consumption 
by infants.  
Foods other than 
infant foods  10 Pu-238, Pu -239, 
Pu-240, Am -241   
Foods other than 
infant foods  100 Sr-90, Ru -106, I -
129, I -131, U -235   
Foods other than 
infant foods  1000  S-35 (*), Co -60, Sr -
89, Ru -103, Cs -
134, Cs -137, Ce -
144, Ir -192   
Foods other than 
infant foods  10000  H-3(**), C -14, Tc -
99   
 )*(This represents the value for organically bound sulphur  
 )**(This represents the value for organically bound tritium  
Scope : The Guideline Levels apply to radionuclides contained in foods destined for human 
consumption and traded internationally, which have been contaminated 
following a nuclear or radiological emergency1. These guideline levels apply to 
food after reconstitution or as prepared for consumption, i.e., not to dried or 
concentrated foods, and are based on an int ervention exemption level of 1 mSv 
in a year . 
Application : As far as generic radiological protection of food consumers is concerned, when 
radionuclide levels in food do not exceed the corresponding Guideline Levels, 
the food should be considered as safe fo r human consumption. in the case of 
wide -spread radioactive contamination. For foods that are consumed in small 
quantities, such as spices, that represent a small percentage of total diet and 
hence a small addition to the total dose, the Guideline Levels m ay be increased 
by a factor of 10.  
Radionuclides: The Guideline Levels do not include all radionuclides. Radionuclides 
included are those important for uptake into the food chain; are usually contained 
in nuclear installations or used as a radiation source  in large enough quantities 
to be significant potential contributors to levels in foods, and; could be 
accidentally released into the environment from typical installations or might be 
                                                           
1 For the purposes of this document, the term “emergency” includes both accidents and malevolent actions.  GSO STANDARD   GSO  /2019  
 
 
32 
 
 employed in malevolent actions. Radionuclides of natural origin are gen erally 
excluded from consideration in this document.  
In the Table, the radionuclides are grouped according to the guideline levels 
rounded logarithmically by orders of magnitude. Guideline levels are defined for 
two separate categories “infant foods” and “other foods”. This is because, for a 
number of radionuclides, the sensitivity of infants could pose a problem. The 
guideline levels have been checked against age -dependent ingestion dose 
coefficients defined as committed effective doses per unit intake fo r each 
radionuclide, which are taken from the “International Basic Safety Standards” 
(IAEA, 1996)1.  
Multiple radionuclides in foods : The guideline levels have been developed with the 
understanding that there is no need to add contributions from radionucli des in 
different groups. Each group should be treated independently. However, the 
activity concentrations of each radionuclide within the same group should be 
added together2. 
 
                                                           
1 Food and Agriculture Organization of the United  Nations, International Atomic Energy Agency, 
International Labour Office, OECD Nuclear Energy Agency, Pan American Health Organization, World 
Health Organization (1996) International Basic Safety Standards for Protection against Ionizing Radiation 
and for  the Safety of Radiation Sources, IAEA, Vienna.  
2 For example, if 134Cs and 137Cs are contaminants in food, the guideline level of 1 000 Bq/kg refers to the 
summed activity of both these radionuclides.  GSO STANDARD   GSO  /2019  
 
 
33 
 
 Annex A 
SCIENTIFIC JUSTIFICATION FOR THE GUIDELINE LEVELS FOR 
RADIONUCLIDES IN  FOODS CONTAMINATED FOLLOWING A 
NUCLEAR OR RADIOLOGICAL EMERGENCY  
Infants and adults: The levels of human exposure resulting from consumption of foods 
containing radionuclides listed in Table 1 at the suggested guideline levels have been 
assessed both for infants and adults and checked for compliance with the appropriate dose 
criterion.  
In order to assess public exposure and the associated health risks from intake of radionuclides 
in food, estimates of food consumption rates and ingestion dose coefficients  are needed. It 
is assumed that 550 kg of food is consumed by an adult in a year. The value of infant food 
and milk consumption during first year of life used for infant dose calculation equal to 200 
kg is based on contemporary human habit assessments. The  most conservative values of the 
radionuclide -specific and age -specific ingestion dose coefficients, i.e. relevant to the 
chemical forms of radionuclides which are most absorbed from the gastro -intestinal tract and 
retained in body tissues, are taken from the IAEA.  
Radiological criterion : The appropriate radiological criterion, which has been used for 
comparison with the dose assessment data below, is a generic intervention exemption level 
of around 1 mSv for individual annual dose from radionuclides in ma jor commodities, e.g. 
food, recommended by the International Commission on Radiological Protection as safe for 
members of the public.  
Naturally occurring radionuclides: Radionuclides of natural origin are ubiquitous and as 
a consequence are present in all foodstuffs to varying degrees. Radiation doses from the 
consumption of foodstuffs typically range from a few tens to a few hundreds of microsieverts 
in a year. In essenc e, the doses from these radionuclides when naturally present in the diet 
are unamenable to control; the resources that would be required to affect exposures would 
be out of proportion to the benefits achieved for health. These radionuclides are excluded 
from consideration in this document as they are not associated with emergencies.  
One-year exposure assessment: It is conservatively assumed that during the first year after 
major environmental radioactive contamination caused by a nuclear or radiological 
emergency it might be difficult to readily replace foods imported from contaminated regions 
with foods imported from unaffected areas. According to FAO statistical data the mean 
fraction of major foodstuff quantities imported by all the countries worldwide i s 0.1. The 
values in Table 1 as regards foods consumed by infants and the general population have been 
derived to ensure that if a country continues to import major foods from areas contaminated 
with radionuclides, the mean annual internal dose of its inha bitants will not exceed around 
1 mSv (see Annex B). This conclusion might not apply for some radionuclides if the fraction 
of contaminated food is found to be higher than 0.1, as might be the case for infants who 
have a diet essentially based on milk with little variety.  
Long -term exposure assessment: Beyond one year after the emergency the fraction of 
contaminated food placed on the market will generally decrease as a result of national 
restrictions (withdrawal from the market), changes to other produce, agricultural 
countermeasures and decay.  
Experience has shown that in the long term the fraction of imported contaminated food will 
decrease by a factor of a hundred or more. Specific food categories, e.g. wild forest products, 
may show persistent or even increasing levels of contamination. Other categories of food GSO STANDARD   GSO  /2019  
 
 
34 
 
 may gradually be exempted from controls. Nevertheless, it must be anticipated that it may 
take many years before levels of individual exposure as a result of contaminated food could 
be qualified as negligible.  GSO STANDARD   GSO  /2019  
 
 
35 
 
 Annex B 
ASSESSMENT OF HUMAN INTERNAL EXPOSURE WHEN THE GUIDELINE 
LEVELS ARE APPLIED  
For the purpose of assessment of the mean public exposure level in a country caused by the 
import of food products from foreign areas with residual radioact ivity, in implementing the 
present guideline levels the following data should be used: annual food consumption rates 
for infants and adults, radionuclide - and age -dependent ingestion dose coefficients and the 
import/production factors. When assessing the m ean internal dose in infants and adults it is 
suggested that due to monitoring and inspection the radionuclide concentration in imported 
foods does not exceed the present guideline levels. Using cautious assessment approach it is 
considered that all the fo odstuffs imported from foreign areas with residual radioactivity are 
contaminated with radionuclides at the present guideline levels.  
Then, the mean internal dose of the public, E (mSv), due to annual consumption of imported 
foods containing radionuclides  can be estimated using the following formula:  
E = GL(A) M(A) eing(A) IPF  
where:  
GL(A ) is the Guideline Level (Bq/kg)  
M(A ) is the age -dependent mass of food consumed per year (kg)  
eing(A ) is the age -dependent ingestion dose coefficient (mSv/Bq)  
IPF is the import/production factor1 (dimensionless)  
Assessment results presented in Table 2 both for infants and adults demonstrate that for all 
the twenty radionuclides doses from consumption of imported foods during the 1st year after 
major radioactive conta mination do not exceed 1 mSv. It should be noted that the doses were 
calculated on the basis of a value for the IPF equal to 0.1 and that this assumption may not 
always apply, in particular to infants who have a diet essentially based on milk with little 
variety.  
It should be noted that for 239Pu as well as for a number of other radionuclides the dose 
estimate is conservative. This is because elevated gastro -intestinal tract absorption factors 
and associated ingestion dose coefficients are applied for the whole first year of life whereas 
this is valid mainly during suckling period recently estimated by ICRP to be as average first 
six months of life. For the subsequent six months of the first year of life the gut absorption 
factors are much lower. This is no t the case for 3H, 14C, 35S, iodine and caesium isotopes.  
As an example, dose assessment for 137Cs in foods is presented below for the first year after 
the area contamination with this nuclide.  
For adults: E = 1 000 Bq/kg 550 kg 1.3 10-5 mSv/Bq 0.1 = 0.7  mSv;  
For infants: E = 1 000 Bq/kg 200 kg 2.1 10-5 mSv/Bq 0.1 = 0.4 mSv  
                                                           
1 The import/production factor ( IPF) is defined as the  ratio of the amount of foodstuffs imported per year 
from areas contaminated with radionuclides to the total amount produced and imported annually in the region 
or country under consideration.  GSO STANDARD   GSO  /2019  
 
 
36 
 
 TABLE 2  
ASSESSMENT OF EFFECTIVE DOSE FOR INFANTS AND ADULTS FROM 
INGESTION OF IMPORTED FOODS IN A YEAR  
Radionuclide  Guideline Level (Bq/kg)  Effective dose (mSv)  
Infant foods  Other  foods  year after major st1 
contamination  
Infants  Adults  
238Pu  
1 10 0.08 0.1 
239Pu  0.08 0.1 
240Pu  0.08 0.1 
241Am  0.07 0.1 
90Sr  
100 100 0.5 0.2 
106Ru  0.2 0.04 
129I  0.4 0.6 
131I  0.4 0.1 
235U  0.7 0.3 
35S*  
1000  1000  0.2 0.04 
60Co  1 0.2 
89Sr  0.7 0.1 
103Ru  0.1 0.04 
134Cs  0.5 1 
137Cs  0.4 0.7 
144Ce  1 0.3 
192Ir  0.3 0.08 
3H**  
1000  10000  0.002  0.02 
14C  0.03 0.3 
99Tc  0.2 0.4 
 
* This represents the value for organically bound sulphur  
** This represents the value for organically bound tritium  
  GSO STANDARD   GSO  /2019  
 
 
37 
 
 ACRYLONITRILE  
Reference to JECFA:  28 (1984)  
Toxicological guidance value:  Provisional Acceptance (1984, the use of food -contact materials from 
which acrylonitrile may migrate is provisionally accepted on condition 
that the amount of the substance migrating into food is reduced to the 
lowest level technologically attainable)  
Contaminant definition:  acrylonitrile (monomer)  
Synonyms:  2-Propenenitrile; vinyl cyanide (VCN); cyanoethylene; abbreviations, 
AN, CAN.  
Related code of practice:  Code of Practice for Source Directed Measures to Reduce 
Contamination of Foods with Chemicals (CXC 49 -2001)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product to 
which the ML applies  Notes/Remarks  
Food  0.02   
 
  GSO STANDARD   GSO  /2019  
 
 
38 
 
 CHLOROPROPANOLS  
Reference to JECFA:  41 (1993; for 1,3 -dichloro -2-propanol only), 57 (2001), 67 (2006)  
Toxicological guidance value:  PMTDI 0.002 mg/kg bw  (2001, for 3 -chloro -1,2-propanediol); 
maintained in 2006. Establishment of tolerable intake was considered 
to be inappropriate for 1,3 -dichloro -2-propanol because of the nature of 
the toxicity (tumorogenic in various organs in rats and the contaminant 
can interact with chromosomes and/or DNA) . 
BMDL 10 cancer, 3.3 mg/kg bw/day (for 1,3 -dichloro -2-propanol); 
MOE, 65 000 (general population), 2 400 (high level intake, including 
young children).  
Contaminant definition:  3-MCPD  
Synonyms:  Two substances are the  most important members of this group: 3 -
monochloropropane -1,2-diol (3 -MCPD, also referred to as 3 -
monochloro -1,2-propanediol) and 1,3 -dichloro -2-propanol (1,3 -DCP).  
Related code of practice:  Code of Practice for the Reduction of 3-Monochloropropane -1,2-diol 
(3-MCPD) during the production of Acid -Hydrolyzed Vegetable 
Proteins (Acid -HVPs) and Products that Contain Acid -HVPs (CXC 64 –
2008).  
Technical Regulations SFDA.FD 26:2018 “Soy sauce”  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Liquid condiments 
containing acid 
hydrolyzed vegetable 
proteins  0.4  The ML does not apply to naturally 
fermented soy sauce.  
Soy sauce  0.02   
 
  GSO STANDARD   GSO  /2019  
 
 
39 
 
 HYDROCYANIC ACID  
Reference to  JECFA:  39 (1992), 74 (2011)  
Toxicological guidance value:  ARfD 0.09 mg/kg bw as cyanide (2011, this cyanide -equivalent ARfD 
applies only to foods containing cyanogenic glycosides as the main 
source of cyanide)  
PMTDI 0.02 mg/kg bw as cyanide (2011)  
Contaminant definition:  See explanatory notes in the column “Notes/Remarks”  
Synonyms:  HCN  
Related code of practice:  Code of Practice for the Reduction of Hydrocyanic Acid (HCN) in 
Cassava and Cassava products (CXC 73 -2013)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product to 
which the ML applies  Notes/Remarks  
Gari 2 Whole commodity  The ML is expressed as free 
hydrocyanic acid.  
Relevant Codex commodity standards 
include CXS 151 -1989.  
Cassava flour  10  The ML is expressed as total 
hydrocyanic acid  
Relevant Codex commodity standards 
include CXS 176 -1989.  
 
  GSO STANDARD   GSO  /2019  
 
 
40 
 
 MELAMINE  
Reference to JECFA:  FAO/WHO Expert Meeting (2008)  
Toxicological guidance value:  TDI 0.2 mg/kg bw (2008)  
Contaminant definition:  Melamine  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Food (other than infant 
formulae) and feed  2.5  The ML applies to food other than 
infant formula.  
The ML applies to levels of melamine 
resulting from its non -intentional and 
unavoidable presence in feed and 
food.  
The ML does not apply to feed and 
food for which it can be proven that 
the level of melamine higher than 2.5 
mg/kg is the consequence of:  
• Authorised use of cyromazine as 
insecticide. The melamine level shall 
not exceed the level of cyromazine.  
• Migration from food contact 
materials taking account of any 
nationally authorised migration limit.  
 
The ML does not apply to melamine 
that could be present in the following 
feed ingredients / additives: guanidine 
acetic acid (GAA), urea and biuret, as 
a result of normal production 
processes.  
Powdered infant 
formula  1   
Liquid infant formula  0.15  The ML applies to liquid infant 
formula as consumed.  
Powdered infant 
formulae and follow -on 
formulae  1   
 GSO STANDARD   GSO  /2019  
 
 
41 
 
 VINYL CHLORIDE MONOMER  
Reference to JECFA:  28 (1984)  
Toxicological guidance value:  Provisional Acceptance (1984, the use of food -contact materials from 
which vinyl chloride may migrate is provisionally accepted, on 
condition that the amount of the substance migrating into food is 
reduced to the lowest level technologically achievable.  
Contaminant definition:  Vinylchloride monomer  
Synonyms:  Monochloroethene, chloroethylene; abbreviation VC  or VCM  
Related code of practice:  Code of Practice for Source Directed Measures to Reduce 
Contamination of Foods with Chemicals (CXC 49 -2001)  
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Food  0.01  The GL in food packaging material is 
1.0 mg/kg.  
 GSO STANDARD   GSO  /2019  
 
 
42 
 
 TUTIN  
Reference to JECFA:   
Toxicological guidance value:   
Contaminant definition:  Tutin   
Synonyms:  Tutin   
Related code of practice:  Food Standards Australia New Zealand (Food Standard: Tutin in 
Honey 2016 ) 
Commodity/Product  
Name  Maximum 
Level (ML)  
mg/kg  Portion of the 
Commodity/Product 
to which the ML 
applies  Notes/Remarks  
Honey comb  0.7  Honey bees in honeycomb cell  
Honey  0.7   
 GSO STANDARD   GSO  /2019  
 
 
43 
 
 Annex 1  
SAMPLING PLAN FOR TOTAL AFLATOXINS IN PEANUTS INTENDED FOR 
FURTHER PROCESSING  INTRODUCTION  
 
1. The sampling plan calls for a single 20 kg laboratory sample of shelled peanuts (27 kg of 
unshelled peanuts) to be taken from a peanut lot (sub -lot) and tested against a maximum 
level of 15 μg/kg total aflatoxins.  
2. This sampling plan has been designed for enforcement and controls concerning total 
aflatoxins in bulk consignments of peanuts traded in the export market. To assist member 
countries in implementing the sampling plan, sampl e selection methods, sample 
preparation methods and analytical methods required, to quantify aflatoxin in bulk peanut 
lots are described in this document.  
A. DEFINITIONS  
Lot  An identifiable quantity of a food commodity delivered at one time and 
determin ed by the official to have common characteristics, such as 
origin, variety, type of packing, packer, consignor or markings.  
Sublot  Designated part of a large lot in order to apply the sampling method on 
that designated part. Each sublot  must be physically separate and 
identifiable.  
Sampling plan  It is defined by an aflatoxin test procedure and an accept/reject limit. An 
aflatoxin test procedure consists of three steps: sample selection, sample 
preparation and aflatoxin quantification.   
Incremental 
sample  A quantity of material taken from a single random place in the lot or 
sublot.  
Aggregate sample  The combined total of all the incremental samples taken from the lot or 
sublot . The aggregate sample has to be at least as large as the 20 kg 
laboratory sample.  
Laboratory sample  The smallest quantity of peanuts comminuted in a mill. The laboratory 
sample may be a portion of or the entire aggregate sample. If the 
aggregate sample is larger than 20 kg, a 20 kg laboratory sample should 
be removed in a random manner from the aggregate  sample. The 
sample should be finely ground and mixed thoroughly using a process 
that approaches as complete a homogenisation as possible.  
Test portion  A portion of the comminuted laboratory sample. The entire 20 kg 
laboratory sample should be comminuted in a mill. A portion of the 
comminuted 20 kg sample is randomly removed for the extraction of 
the aflatoxin for chemical analysis. Based upon grinder cap acity, the 20 
kg aggregate sample can be divided into several equal sized samples, if 
all results are averaged.  
  
B. SAMPLING  
Material to be sampled  
3. Each lot, which is to be examined,must be sampled separately. Large lots should be 
subdivided into s ublots to be sampled separately. The subdivision can be done following 
provisions laid down in Table 1 below.  GSO STANDARD   GSO  /2019  
 
 
44 
 
 4. Taking into account that the weight of the lot is not always an exact multiple of the weight 
of the sublots, the weight of the sublot may exce ed the mentioned weight by a maximum 
of 20%.  
 
Table 1. Subdivision of large lots into sublots for sampling  
Commodity  Lot weight – 
tonne (T)  Weight or 
number of 
sublots  Number of 
incremental 
samples  Laboratory 
sample 
weight (kg)  
Peanuts  ≥ 500  
> 100 and < 500  
≥ 25 and ≤ 100  
> 15 and <= 25  100 tonnes  
5 sublots  
25 tonnes  
--1 sublot  100  
100  
100  
100  20  
20  
20  
20 
 
Number of incremental samples for lots of less than 15 tonnes  
5. The number of incremental samples to be taken depends on the weight of the lot, with a 
minimum of 10 and a maximum of 100. The figures in the following Table 2 may be used 
to determine the number of incremental samples to be taken. It is necessary that the total 
sample weight of 20 kg is achieved.  
 
Table 2. Number of incremental samples to be taken depending on the weight 
of the lot  
Lot weight tonnes – (T)  N° of incremental samples  
T ≤ 1  10 
1 < T ≤ 5  40 
5 < T ≤ 10  60 
10 < T < 15  80 
 
Incremental sample selection  
6. Procedures used to take incremental samples from a peanut lot are extremely important. 
Every individual peanut in the lot should have an equal chance of being chosen. Biases 
will be introduced by the sample selection method s if equipment and procedures used to 
select the incremental samples prohibit or reduce the chances of any item in the lot from 
being chosen.  
7. Since there is no way to know if the contaminated peanut kernels are uniformly dispersed 
throughout the lot, i t is essential that the aggregate sample be the accumulation of many 
small portions or increments of the product selected from different locations throughout 
the lot. If the aggregate sample is larger than desired, it should be blended and subdivided 
until the desired laboratory sample size is achieved.  
 
Static lots  
8. A static lot can be defined as a large mass of peanuts contained either in a single large 
container such as a wagon, truck, or railcar or in many small containers such as sacks or 
boxes and  the peanuts are stationary at the time a sample is selected. Selecting a truly GSO STANDARD   GSO  /2019  
 
 
45 
 
 random sample from a static lot can be difficult because the container may not allow 
access to all peanuts.  
9. Taking a aggregate sample from a static lot usually requires the  use of probing devices to 
select product from the lot. The probing devices used should be specially designed for the 
type of container. The probe should (1) be long enough to reach all product, (2) not restrict 
any item in the lot from being selected, and  (3) not alter the items in the lot. As mentioned 
above, the aggregate sample should be a composite from many small increments of 
product taken from many different locations throughout the lot.  
10. For lots traded in individual packages, the sampling freq uency (SF), or number of 
packages that incremental samples are taken from, is a function of the lot weight (LT), 
incremental sample weight (IS), aggregate sample weight (AS) and the individual 
packing weight (IP), as follows:  
Equation 1: SF = (LT x IS) / (AS x IP)  
The sampling frequency (SF) is the number of packages sampled. All weights should be in 
the same mass units such as kg.  
Dynamic lots  
11. True random sampling can be more nearly achieved when selecting an aggregate sample 
from a moving stream of peanuts as, the lot is transferred, for example, by a conveyor 
belt from one location to another. When sampling from a moving stream, take small  
increments of product from the entire length of the moving stream; composite the 
peanuts to obtain an aggregate sample; if the aggregate sample is larger than the required 
laboratory sample, then blend and subdivide the aggregate sample to obtain the desi red 
size laboratory sample.  
12. Automatic sampling equipment such as cross -cut samplers are commercially available 
with timers that automatically pass a diverter cup through the moving stream at 
predetermined and uniform intervals. When automatic equipment is not available, a 
person can be assigned to manually pass a cup though the stream at periodic intervals to 
collect incremental samples. Whether using automatic or manual methods, small 
increments of peanuts should be collected and composited at frequent and uniform 
intervals throu ghout the entire time peanuts flow past the sampling point.  
13. Cross -cut samplers should be installed in the following manner: (1) the plane of the 
opening of the diverter cup should be perpendicular to the direction of flow; (2) the 
diverter cup should pass through the entire cross sectional area of the stream; and (3) 
the opening of the diverter cup should be wide enough to accept all items of interest in 
the lot. As a general rule, the width of the diverter cup opening should be about three 
times the l argest dimensions of the items in the lot.  
14. The size of the aggregate sample (S) in kg, taken from a lot by a cross cut sampler is:  
Equation 2: S = (D x LT) / (T x V)  
D is the width of the diverter cup opening (in cm), LT is the lot size (in kg), T i s interval 
or time between cup movement through the stream (in seconds), and V is cup velocity 
(in cm/sec).  
15. If the mass flow rate of the moving stream, MR (kg/sec), is known, then the sampling 
frequency (SF), or number of cuts made by the automatic sa mpler cup is:  
Equation 3: SF = (S x V) / (D x MR)  GSO STANDARD   GSO  /2019  
 
 
46 
 
 16. Equation 2 can also be used to compute other terms of interest such as the time between 
cuts (T). For example, the required time (T) between cuts of the diverter cup to obtain a 
20 kg aggregate sample  from a 30 000 kg lot where the diverter cup width is 5.08 cm (2 
inches), and the cup velocity through the stream 30 cm/sec. Solving for T in Equation 
2.  
T = (5.08 cm x 30 000 kg) / (20 kg x 30 cm/sec) = 254 sec  
17. If the lot is moving at 500 kg per min ute, the entire lot will pass through the sampler in 
60 minutes and only 14 cuts (14 incremental samples) will be made by the cup through 
the lot. This may be considered too infrequent in that too much product passes through 
the sampler between the time th e cup cuts through the stream.  
Weight of the incremental sample  
18. The weight of the incremental sample should be approximately 200 g or greater, 
depending on the total number of increments, to obtain an aggregate sample of 20 kg.  
Packaging and transmi ssion of samples  
19. Each laboratory sample shall be placed in a clean, inert container offering adequate 
protection from contamination and against damage in transit. All necessary precautions 
shall be taken to avoid any change in composition of the labor atory sample which might 
arise during transportation or storage.  
Sealing and labelling of samples  
20. Each laboratory sample taken for official use shall be sealed at the place of sampling and 
identified. A record must be kept of each sampling, permitting  each lot to be identified 
unambiguously and giving the date and place of sampling together with any additional 
information likely to be of assistance to the analyst.  
C. SAMPLE PREPARATION  
Precautions  
21. Daylight should be excluded as much as possible during the procedure, since aflatoxin 
gradually breaks down under the influence of ultra -violet light.  
Homogenisation – Grinding  
22. As the distribution of aflatoxin is extremely non -homogeneous, samples should be 
prepared - and especially homogenised - with extreme care. All laboratory sample 
obtained from aggregate sample is to be used for the homogenisation/grinding of the 
sample .  
23. The sample should be finely ground and mixed thoroughly using a process that 
approaches as complete a homogenisation as possible.  
24. The use of a hammer mill with a #14 screen (3.1 mm diameter hole in the screen) has 
been proven to represent a com promise in terms of cost and precision. A better 
homogenisation (finer grind – slurry) can be obtained by more sophisticated equipment, 
resulting in a lower sample preparation variance.  
Test portion  
25. A minimum test portion size of 100 g taken from the  laboratory sample.  
D. ANALYTICAL METHODS  GSO STANDARD   GSO  /2019  
 
 
47 
 
 Background  
26. A criteria -based approach, whereby a set of performance criteria is established with 
which the analytical method used should comply, is appropriate. The criteria -based 
approach has the advantage t hat, by avoiding setting down specific details of the method 
used, developments in methodology can be exploited without having to reconsider or 
modify the specified method. The performance criteria established for methods should 
include all the parameters that need to be addressed by each laboratory such as the 
detection limit, repeatability coefficient of variation, reproducibility coefficient of 
variation, and the percent recovery necessary for various statutory limits. Utilising this 
approach, laboratori es would be free to use the analytical method most appropriate for 
their facilities. Analytical methods that are accepted by chemists internationally (such 
as AOAC) may be used. These methods are regularly monitored and improved 
depending upon technology.  
Performance criteria for methods of analysis  
Table 3. Specific requirements with which methods of analysis should comply  
Criterion  Concentration Range  Recommended Value  Maximum Permitted 
Value  
Blanks  All  Negligible  - 
Recovery -Aflatoxins 
Total  1 – 15 μg/kg  70 to 110%   
 > 15 μg/kg  80 to 110%   
Precision RSD R All  As derived from 
Horwitz Equation  2 x value derived from 
Horwitz Equation  
Precision RSDr may be calculated as 0.66 times Precision RSD R at the concentration of interest  
 
 
• The detection limits of the methods used are not stated as the precision values are given at 
the concentrations of interest;  
• The precision values are calculated from the Horwitz equation, i.e.:  
RSD R = 2(1-0.5logC)  
 
 
where:  
∗ RSD R is the relative standard deviation calculated from results generated under 
reproducibility conditions [(S r / x) x 100]  
∗ C is the concentration ratio (i.e. 1 = 100 g/100 g, 0.001 = 1 000 mg/kg)  
27. This is a generalised precision equation, which has bee n found to be independent of 
analyte and matrix but solely dependent on concentration for most routine methods of 
analysis.  GSO STANDARD   GSO  /2019  
 
 
48 
 
 Annex 2  
SAMPLING PLANS FOR AFLATOXIN CONTAMINATION IN READY -TO-EAT 
TREENUTS AND TREENUTS DESTINED FOR FURTHER PROCESSING: 
ALMONDS , HAZELNUTS, PISTACHIOS AND SHELLED BRAZIL NUTS  
DEFINITIONS  
Lot  An identifiable quantity of a food commodity delivered at one time and 
determined by the official to have common characteristics, such as origin, 
variety, type of packing, packer, consignor, or markings.  
Sublot  Designated part of a larger lot in order to apply the sampling method on that 
designated part. Each sublot must be physically separate and identifiable.  
Sampling plan  It is defined by an aflatoxin test procedure and an accept/reject limit. An 
aflatoxin test procedure consists of three steps: sample selection, sample 
preparation and aflatoxin quantification. The accept/reject limit is a tolerance 
usually equal to the Cod ex maximum level.  
Incremental 
sample  The quantity of material taken from a single random place in the lot or sublot.  
Aggregate sample  The combined total of all the incremental samples that is taken from the lot 
or sublot. The aggregate sample has to be at least as large as the laboratory 
sample or samples combined.  
Laboratory 
sample  The smallest quantity of tree nuts comminuted in a mill. The laboratory 
sample may be a portion of or the entire aggregate sample. If the aggregate 
sample is larger than the laboratory sample(s), the laboratory sample(s) 
should be removed in a random manne r from the aggregate sample.  
Test portion  A portion of the comminuted laboratory sample. The entire laboratory 
sample should be comminuted in a mill. A portion of the comminuted 
laboratory sample is randomly removed for the extraction of the aflatoxin f or 
chemical analysis.  
Ready -to-eat 
treenuts  Nuts, which are not intended to undergo an additional processing/treatment 
that has proven to reduce levels of aflatoxins before being used as an 
ingredient in foodstuffs, otherwise processed or offered for human 
consumption.  
Treenuts destined 
for furthe r 
processing  Nuts, which are intended to undergo an additional processing/treatment that 
has proven to reduce levels of aflatoxins before being used as an ingredient 
in foodstuffs, otherwise processed or offered for human consumption. 
Processes that have proven to reduce levels of aflatoxins are shelling, 
blanching followed by colour sorting, and sorting by specific gravity and 
colour (damage). There is some evidence that roasting reduces aflatoxins in 
pistachios but for other nuts the evidence is still to  be supplied.  
Operating 
characteristic 
(OC) curve  A plot of the probability of a accepting a lot versus lot concentration when 
using a specific sampling plan design. The OC curve provides an estimate of 
good lots rejected (exporter’s risk) and bad lots accepted (importer’s risk) by 
a specific aflatoxin sa mpling plan design.  
SAMPLING PLAN DESIGN CONSIDERATIONS  GSO STANDARD   GSO  /2019  
 
 
49 
 
 1. Importers may commercially classify treenuts as either “ready -to-eat” (RTE) or “destined 
for further processing” (DFP). As a result, maximum levels and sampling plans are 
proposed for both commercial types of treenuts. Maximum levels need to be defined for 
treenuts destined for further processing and ready -to-eat treenuts before a final decision 
can be made about a sampling plan design.  
2. Treenuts can be marketed either as in -shell or shell ed nuts. For example, pistachios are 
predominately marketed as in -shell nuts while almonds are predominately marketed as 
shelled nuts.  
3. Sampling statistics, shown in Annex, are based upon the uncertainty and aflatoxin 
distribution among laboratory sampl es of shelled nuts. Because the shelled nut count per 
kg is different for each of the treenuts, the laboratory sample size is expressed in number 
of nuts for statistical purposes. However, the shelled nut count per kg for each treenut, 
shown in Annex, can be used to convert laboratory sample size from number of nuts to 
mass and vice versa.  
4. Uncertainty estimates associated with sampling, sample preparation, and analysis, shown 
in Annex, and the negative binomial distribution are used to calculate operati ng 
characteristic (OC) curves that describe the performance of the proposed aflatoxin -
sampling plans.  
5. In Annex, the analytical variance reflects a reproducibility relative standard deviation of 
22%, which is based upon Food Analysis Performance Assessm ent Scheme (FAPAS) 
data. A relative standard deviation of 22% is considered by FAPAS as an appropriate 
measure of the best agreement that can be reliably obtained between laboratories. An 
analytical uncertainty of 22% is larger than the within laboratory v ariation measured in 
the sampling studies for the four treenuts.  
6. The issue of correcting the analytical test result for recovery is not addressed in this 
document. However, Table 2 specifies several performance criteria for analytical methods 
including  suggestions for the range of acceptable recovery rates.  
AFLATOXIN TEST PROCEDURE AND MAXIMUM LEVELS  
7. An aflatoxin -sampling plan is defined by an aflatoxin test procedure and a maximum level. 
A value for the maximum level and the aflatoxin test procedu re are given below in this 
section.  
8. The maximum levels for total aflatoxins in treenuts (almonds, hazelnuts, pistachios and 
shelled Brazil nuts) “ready -to-eat” and “destined for further processing” are 10 and 15 
μg/kg, respectively.  
9. Choice of the n umber and size of the laboratory sample is a compromise between 
minimizing risks (false positives and false negatives) and costs related to sampling and 
restricting trade. For simplicity, it is recommended that the proposed aflatoxin sampling 
plans use a 2 0 kg aggregate sample for all four treenuts.  
10. The two sampling plans (RTE and DFP) have been designed for enforcement and 
controls concerning total aflatoxins in bulk consignments (lots) of treenuts traded in the 
export market.  
Treenuts destined for f urther processing  
Maximum level    –  15 μg/kg total aflatoxins  
Number of laboratory samples –  1  GSO STANDARD   GSO  /2019  
 
 
50 
 
 Laboratory sample size  –  20 kg  
Almonds –  shelled nuts  
Hazelnuts –  shelled nuts  
Pistachios –  in-shell nuts (equivalent to about 10 kg shelled nuts that is calculated 
on the basis of the actual edible portion in the sample)  
Brazil nuts –  shelled nuts  
Sample preparation - sample shall be finely ground and mixed thoroughly 
using a process, e.g., d ry grind with a vertical cutter 
mixer type mill, that has been demonstrated to 
provide the lowest sample preparation variance. 
Preferably, Brazil nuts should be ground as slurry.  
Analytical method    –  performance based (see Table 2)  
Decision rule   If the aflatoxin test result is less than or equal to 15 
μg/kg total aflatoxins, then accept the lot. Otherwise, 
reject the lot.  
Ready -to-eat treenuts  
Maximum level   –  10 μg/kg total aflatoxins  
Number of laboratory samples –  2 
Laboratory sample size  –  10 kg  
Almonds –  shelled nuts  
Hazelnuts –  shelled nuts  
Pistachios –  in-shell nuts (equivalent to about 5 kg shelled nuts per test sample 
that is calculated on the basis of the actual edible portion in the 
sample)  
Brazil nuts –  shelled nuts  
Sample preparation   sample shall be finely ground and mixed thoroughly 
using a process, e.g., dry grind with a vertical cutter 
mixer type mill, that has been demonstrated to 
provide the lowest sample preparation variance. 
Preferably, Brazil nuts should be  ground as slurry.  
Analytical method   –  performance based (see Table 2)  
Decision rule  if the aflatoxin test result is less than or equal to 10 
μg/kg total aflatoxin in both test samples, then accept 
the lot. Otherwise, reject the lot.  
 
 
11. To assist member countries implement these two sampling plans, sample selection 
methods, sample preparation methods, and analytical methods required to quantify 
aflatoxin in laboratory samples taken from bulk treenut lots are described in the 
following sections.  GSO STANDARD   GSO  /2019  
 
 
51 
 
 SAMPLE SELECTION  
MATERIAL TO BE SAMPLED  
12. Each lot, which is to be examined for aflatoxin, must be sampled separately. Lots larger 
than 25 tonnes should be subdivided into sublots to be sampled separately. If a lot is 
greater than 25 tonnes, the number o f sublots is equal to the lot weight in tonnes divided 
by 25 tonnes. It is recommended that a lot or a sublot should not exceed 25 tonnes. The 
minimum lot weight should be 500 kg.  
13. Taking into account that the weight of the lot is not always an exact m ultiple of 25 tonne 
sublots, the weight of the sublot may exceed the mentioned weight by a maximum of 
25%.  
14. Samples should be taken from the same lot, i.e. they should have the same batch code or 
at the very least the same best before date. Any changes , which would affect the 
mycotoxin content, the analytical determination or make the aggregate samples 
collected unrepresentative should be avoided. For example do not open packaging in 
adverse weather conditions or expose samples to excessive moisture or sunlight. Avoid 
cross -contamination from other potentially contaminated consignments nearby.  
15. In most cases any truck or container will have to be unloaded to allow representative 
sampling to be carried out.  
INCREMENTAL SAMPLE SELECTION  
16. Procedure s used to take incremental samples from a treenut lot are extremely important. 
Every individual nut in the lot should have an equal chance of being chosen. Biases will 
be introduced by sample selection methods if equipment and procedures used to select 
the incremental samples prohibit or reduce the chances of any item in the lot from being 
chosen.  
17. Since there is no way to know if the contaminated treenut kernels are uniformly dispersed 
throughout the lot, it is essential that the aggregate sample be th e accumulation of many 
small incremental samples of product selected from different locations throughout the 
lot. If the aggregate sample is larger than desired, it should be blended and subdivided 
until the desired laboratory sample size is achieved.  
NUM BER OF INCREMENTAL SAMPLES FOR LOTS OF VARYING 
WEIGHT  
18. The number and size of the laboratory sample(s) will not vary with lot (sublot) size. 
However, the number and size of the incremental samples will vary with lot (sublot) 
size.  
19. The number of incremental samples to be taken from a lot (sublot) depends on the weight 
of the lot. Table 1 shall be used to determine the number of incremental samples to be 
taken from lots or sublots of various sizes below 25 tonnes. The number of incremental 
samples varies from a minimum of 10 and to a maximum of 100.  
Table 1. Number and size of incremental samples composited for an aggregate sample 
of 20 kga as a function of lot (orsublot) weight  
Lot or sublot weight b 
(T in tonnes)  Minimum number 
of incremental 
samples  Minimum 
incremental sample 
size c (g) Minimum aggregate 
sample size (Kg)  GSO STANDARD   GSO  /2019  
 
 
52 
 
 T < 1  10  2 000  20  
1 ≤ T < 5  25  800  20  
5 ≤ T < 10  50  400  20  
10 ≤ T < 15  75  267  20  
15 ≤T  100  200  20  
a / Minimum aggregate sample size  = laboratory sample size of 20 kg  
b / 1 Tonne     = 1 000 kg  
c / Minimum incremental sample size = laboratory sample size (20 kg) / minimum number 
of incremental samples, i.e. for 0.5 < T < 1 tonne, 
2 000 g = 20 000/10  
WEIGHT OF THE INCREMENTAL SAMPLE  
20. The suggested minimum weight of the incremental sample should be approximately 200 
g for lots of 25 metric tonnes (25000 kg). The number and/or size of incremental samples 
will have to be larger than that suggested in Table 1 for lots sizes below 25000  kg in 
order to obtain an aggregate sample greater than or equal to the 20 kg laboratory sample.  
STATIC LOTS  
21. A static lot can be defined as a large mass of treenuts contained either in a large single 
container such as a wagon, truck or railcar or in many small containers such as sacks or 
boxes and the nuts are stationary at the time a sample is selected. Selecting a truly 
random sample from a static lot can be difficult because all containers in the lot or sublot 
may not be accessible.  
22. Taking inc remental samples from a static lot usually requires the use of probing devices 
to select product from the lot. The probing devices should be specifically designed for 
the commodity and type of container. The probe should (1) be long enough to reach all 
products, (2) not restrict any item in the lot from being selected, and (3) not alter the 
items in the lot. As mentioned above, the aggregate sample should be a composite from 
many small incremental samples of product taken from many different locations 
throu ghout the lot.  
23. For lots traded in individual packages, the sampling frequency (SF), or number of 
packages that incremental samples are taken from, is a function of the lot weight (LT), 
incremental sample weight (IS), aggregate sample weight (AS) and t he individual 
packing weight (IP), as follows:  
Equation 1: SF = (LT x IS) / (AS x IP)  
24. The sampling frequency (SF) is the number of packages sampled. All weights should be 
in the same mass units such as kg.  
DYNAMIC LOTS  
25. Representative aggregate samples can be more easily produced when selecting 
incremental samples from a moving stream of treenuts as the lot is transferred from one 
location to another. When sampling from a moving stream, take small incremental 
samples of product from the entire le ngth of the moving stream; composite the 
incremental samples to obtain an aggregate sample; if the aggregate sample is larger GSO STANDARD   GSO  /2019  
 
 
53 
 
 than the required laboratory sample(s), then blend and subdivide the aggregate sample 
to obtain the desired size laboratory sample (s).  
26. Automatic sampling equipment such as a cross -cut sampler is commercially available 
with timers that automatically pass a diverter cup through the moving stream at 
predetermined and uniform intervals. When automatic sampling equipment is not 
avail able, a person can be assigned to manually pass a cup through the stream at periodic 
intervals to collect incremental samples. Whether using automatic or manual methods, 
incremental samples should be collected and composited at frequent and uniform 
interva ls throughout the entire time the nuts flow past the sampling point.  
27. Cross -cut samplers should be installed in the following manner: (1) the plane of the 
opening of the diverter cup should be perpendicular to the direction of the flow; (2) the 
diverter  cup should pass through the entire cross sectional area of the stream; and (3) 
the opening of the diverter cup should be wide enough to accept all items of interest in 
the lot. As a general rule, the width of the diverter cup opening should be about two t o 
three times the largest dimensions of items in the lot.  
28. The size of the aggregate sample (S) in kg, taken from a lot by a cross cut sampler is:  
Equation 2: S = (D x LT) / (T x V)  
where D is the width of the diverter cup opening (cm), LT is the lot  size (kg), T is 
interval or time between cup movement through the stream (seconds), and V is cup 
velocity (cm/sec).  
29. If the mass flow rate of the moving stream, MR (kg/sec), is known, then the sampling 
frequency (SF), or number of cuts made by the aut omatic sampler cup can be computed 
from Equation 3 as a function of S, V, D, and MR.  
Equation 3: SF = (S x V) / (D x MR)  
30. Equations 2 and 3 can also be used to compute other terms of interest such as the time 
between cuts (T). For example, the time (T ) required between cuts of the diverter cup to 
obtain a 20 kg aggregate sample from a 20000 kg lot where the diverter cup width is 5.0 
cm and the cup velocity through the stream 30 cm/sec. Solving for T in Equation 2.  
T = (5.0 cm x 20 000 kg) / (20 kg x 2 0 cm/sec) = 250 sec.  
31 If the lot is moving at 500 kg per minute, the entire lot will pass through the sampler in 
40 minutes (2 400 sec) and only 9.6 cuts (9 incremental samples) will be made by the 
cup through the lot (Equation 3). This may be considere d too infrequent, in that too 
much product (2 083.3 kg) passes through the sampler between the time the cup cuts 
through the stream.  
PACKAGING AND TRANSPORTATION OF SAMPLES  
32. Each laboratory sample shall be placed in a clean, inert container offering a dequate 
protection from contamination, sunlight, and against damage in transit. All necessary 
precautions shall be taken to avoid any change in composition of the laboratory sample, 
which might arise during transportation or storage. Samples should be stor ed in a cool 
dark place.  
SEALING AND LABELLING OF SAMPLES  
33. Each laboratory sample taken for official use shall be sealed at the place of sampling and 
identified. A record must be kept of each sampling, permitting each lot to be identified GSO STANDARD   GSO  /2019  
 
 
54 
 
 unambiguously and giving the date and place of sampling together with any additional 
information likely to be of assistance to the analyst.  
SAMPLE PREPARATION  
PRECAUTIONS  
34. Sunlight should be excluded as much as possible during sample preparation, sin ce 
aflatoxin gradually breaks down under the influence of ultra -violet light. Also, 
environmental temperature and relative humidity should be controlled and not favour 
mould growth and aflatoxin formation.  
HOMOGENISATION - GRINDING  
35. As the distributio n of aflatoxin is extremely non -homogeneous, laboratory samples 
should be homogenized by grinding the entire laboratory sample received by the 
laboratory. Homogenization is a procedure that reduces particle size and disperses the 
contaminated particles eve nly throughout the comminuted laboratory sample.  
36. The laboratory sample should be finely ground and mixed thoroughly using a process 
that approaches as complete homogenization as possible. Complete homogenization 
implies that particle size is extremely small and the variability associated with sample 
preparation (Annex I) approaches zero. After grinding, the grinder should be cleaned to 
prevent aflatoxin cross -contamination.  
37. The use of vertical cutter mixer type grinders that mix and comminute the l aboratory 
sample into a paste represent a compromise in terms of cost and fineness of grind or 
particle size reduction. A better homogenization (finer grind), such as a liquid slurry, 
can be obtained by more sophisticated equipment and should provide the l owest sample 
preparation variance.  
TEST PORTION  
38. The suggested weight of the test portion taken from the comminuted laboratory sample 
should be approximately 50 g. If the laboratory sample is prepared using a liquid slurry, 
the slurry should contain 5 0 g of nut mass.  
39. Procedures for selecting the 50 g test portion from the comminuted laboratory sample 
should be a random process. If mixing occurred during or after the comminution 
process, the 50 g test portion can be selected from any location throug hout the 
comminuted laboratory sample. Otherwise, the 50 g test portion should be the 
accumulation of several small portions selected throughout the laboratory sample.  
40. It is suggested that three test portions be selected from each comminuted laborator y 
sample. The three test portions will be used for enforcement, appeal, and confirmation 
if needed.  
ANALYTICAL METHODS  
BACKGROUND  
41. A criteria -based approach, whereby a set of performance criteria is established with 
which the analytical method used s hould comply, is appropriate. The criteria -based 
approach has the advantage that, by avoiding setting down specific details of the method 
used, developments in methodology can be exploited without having to reconsider or 
modify the specific method. The per formance criteria established for methods should 
include all the parameters that need to be addressed by each laboratory such as the GSO STANDARD   GSO  /2019  
 
 
55 
 
 detection limit, repeatability coefficient of variation (within lab), reproducibility 
coefficient of variation (among lab),  and the percent recovery necessary for various 
statutory limits. Analytical methods that are accepted by chemists internationally (such 
as AOAC, ISO) may be used. These methods are regularly monitored and improved 
depending upon technology.  
PERFORMANCE C RITERIA FOR METHODS OF ANALYSIS  
42. A list of criteria and performance levels are shown in Table 2. Utilizing this approach, 
laboratories would be free to use the analytical method most appropriate for their 
facilities.  
Table 2. Specific requirements with  methods of analysis should comply with  
Criterion  Concentration 
range (ng/g)  Recommended value  Maximum permitted 
value  
Blanks  All  Negligible  n/a  
Recovery  1 to 15  70 to 100%  n/a  
> 15 80 to 110%  n/a  
Precision or relative 
standard deviation 
RSD R 
(Reproducibility)  1 to 120  Equation 4  2 x value derived from 
Equation 4  
> 120  Equation 5  2 x value derived from 
Equation 5  
Precision or relative 
standard deviation 
RSDr (Repeatability)  1 to 120  Calculated as 0.66 
times Precision RSD R  n/a  
> 120  Calculated as 0.66 
times Precision RSDr  n/a  
n/a = not applicable  
43. The detection limits of the methods used are not stated. Only the precision values are 
given at the concentrations of interest. The precision values are calculated from 
equations 4 and 5.  
Equation 4: RSD R = 22.0 (for C ≤ 120 μg/kg or c ≤ 120 x 10-9)  
Equation 5: RSD R = 2 (1-0.5logc) (for C > 120 μg/kg or c > 120 x 10-9)  
where:  
• RSD R  = the relative standard deviation calculated from results generated under 
reproducibility conditions  
• RSDr  = the relative standard deviation calculated from results generated under 
repeatability conditions = 0.66 RSD R  
• c  = the aflatoxin concentration ratio (i.e. 1 = 100 g/100 g, 0.001 = 1 000 
mg/kg)  
• C  = aflatoxin concentration or mass of aflatoxin to mass of treenuts (i.e. 
μg/kg)  
 GSO STANDARD   GSO  /2019  
 
 
56 
 
 44. Equations 4 and 5 are gen eralized precision equations, which have been found to be 
independent of analyte and matrix but solely dependent on concentration for most 
routine methods of analysis.  
45. Results should be reported on the edible portion of the sample.  GSO STANDARD   GSO  /2019  
 
 
57 
 
 Uncertainty, as measured by the variance, associated with sampling, sample 
preparation, and analytical steps of the aflatoxin test procedure used to estimate 
aflatoxin in almonds, hazelnuts, pistachios and shelled Brazil nuts.  
 
Sampling data for almonds, hazelnuts, pistac hios and shelled Brazil nuts were supplied by 
the United States, Turkey, Iran and Brazil, respectively.  
Sampling, sample preparation, and analytical variances associated with testing almonds, 
hazelnuts, pistachios and shelled Brazil nuts are shown in Tabl e 1 below.  
Table 1. Variancesa associated with the aflatoxin test procedure for each treenut  
Test procedure  Almonds  Hazelnuts  Pistachios  Shelled Brazil 
nuts 
Samplingb,c  S2s = (7 730/ns) 
5.759C1.561  S2s = (10 000/ns) 
4.291C1.609  S2s = 8 000/ns) 
7.913C1.475  ss2 = (1 850/ns) 
4.8616C1.889  
Sample Prepd  S2sp = (100/nss) 
0.170C1.646  S2sp = (50/nss) 
0.021C1.545  S2sp = (25/nss) 
2.334C1.522  sss2 = (50/nss) 
0.0306C0.632  
Analyticale  S2a = (1/na) 
0.0484C2.0  S2a = (1/na) 
0.0484C2.0  S2a = (1/na) 
0.0484C2.0  experimental s a2 = 
(1/n) 0.0164C1.117 
or FAPAS s a2 = 
(1/n) 0.0484C2.0  
Total variance  S2s + S2sp + S2a  S2s + S2sp + S2a  S2s + S2sp + S2a  S2s + S2sp + S2a  
a/ Variance = S2 (s, sp, and a denote sampling, sample preparation, and analytical steps, 
respectively, of aflatoxin test procedure)  
b/ ns = laboratory sample size in number of shelled nuts, nss =test portion size in grams, na 
= number of aliquots quantified by HPLC, and  C = aflatoxin concentration in μg/kg total 
aflatoxin.  
c/ Shelled nut count/kg for almonds, hazelnuts, pistachios and Brazil nuts is 773, 1 000, 1 
600 and 185, respectively.  
d/ Sample preparation for almonds, hazelnuts, and pistachios reflect Hobart, Rob ot Coupe, 
Marjaan Khatman and Turrax type mills, respectively. Laboratory samples were dry 
ground into a paste for each treenut except for Brazil nut that were prepared as a slurry 
Brazil nut/water 1/1 w/w.  
e/ Analytical variances reflect FAPAS recommenda tion for upper limit of analytical 
reproducibility uncertainty. A relative standard deviation of 22%, which is based upon 
FAPAS data, is considered, as an appropriate measure of the best agreement that can be 
obtained between laboratories. An analytical un certainty of 22% is larger than the within 
laboratory uncertainty measured in the sampling studies for the four treenuts.  GSO STANDARD   GSO  /2019  
 
 
58 
 
 Annex 3  
SAMPLING PLAN FOR AFLATOXIN CONTAMINATION IN DRIED FIGS  
DEFINITIONS  
Lot  An identifiable quantity of a food commodity delivered at one time 
and determined by the official to have common characteristics, such 
as origin, variety, type of packing, packer, consignor, or markings.  
Sublot  Designated part of a larger lot in order t o apply the sampling method 
on that designated part. Each sublot must be physically separate and 
identifiable.  
Sampling plan  It is defined by an aflatoxin test procedure and an accept/reject level. 
An aflatoxin test procedure consists of three steps: sample selection 
of sample(s) of a given size, sample preparation and aflatoxin 
quantification. The accept/reject level is a toler ance usually equal to 
the Codex maximum level.  
Incremental sample  The quantity of material taken from a single random place in the lot 
or sublot.  
Aggregate sample  The combined total of all the incremental samples that is taken from 
the lot or sublot. The aggregate sample has to be at least as large as 
the laboratory sample or samples combined.  
Laboratory sample  The smallest quantity of dried figs comminuted in a mill. The 
laboratory sample may be a portion of or the entire aggregate 
sample. If the aggregate sample is larger than the laboratory 
sample(s), the laboratory sample(s) should be removed in a random 
manner from the aggregate sample.  
Test portion  A portion of the comminuted laboratory sample. The entire 
laboratory sample should be comminuted in a mill. A portion of the 
comminuted laboratory sample is randomly removed for the 
extraction of the aflatoxin for chemical analysis.  
Ready -to-eat dried 
figs  Dried figs, which are not intended to undergo an additional 
processing/treatment that have proven to reduce levels of aflatoxin 
before being used as an ingredient in foodstuffs, otherwise 
processed or offered for human consumption.  
Operating 
characte ristic (OC) 
curve  A plot of the probability of accepting a lot versus lot concentration 
when using a specific sampling plan design. The OC curve also 
provides an estimate of good lots rejected (exporter’s risk) and bad 
lots accepted (importer’s risk) by a  specific aflatoxin sampling plan 
design.  
 
SAMPLING PLAN DESIGN CONSIDERATIONS  
1. Importers commercially classify dried figs mostly as “ready -to-eat” (RTE). As a result, 
maximum levels and sampling plans are established only for ready -to-eat dried figs.   GSO STANDARD   GSO  /2019  
 
 
59 
 
 2. The performance of the sampling plan was computed using the variability and aflatoxin 
distribution among laboratory samples of dried figs taken from contaminated lots. 
Because the dried fig count per kg is different for different varieties of dried fi gs, the 
laboratory sample size is expressed in number of dried figs for statistical purposes. 
However, the dried fig count per kg for each variety of dried figs can be used to convert 
laboratory sample size from number of dried figs to mass and vice versa.   
3. Uncertainty estimates (variances) associated with sampling, sample preparation, and 
analysis and the negative binomial distribution are used to calculate operating 
characteristic (OC) curves that describe the performance of the aflatoxin -sampling plan s 
for dried figs.  
4. The analytical variance measured in the sampling study reflects within laboratory variance 
and was replaced with an estimate of analytical variance reflects a reproducibility relative 
standard deviation of 22%, which is based upon Food Analysis Performance Assessment 
Scheme (FAPAS) data. A relative standard deviation of 22% is considered by FAPAS as 
an appropriate measure of the best agreement that can be reliably obtained between 
laboratories. An analytical uncertainty of 22% is la rger than the within laboratory 
variation measured in the sampling studies for dried figs.  
5. The issue of correcting the analytical test result for recovery is not addressed in this 
document. However, Table 2 specifies several performance criteria for ana lytical methods 
including suggestions for the range of acceptable recovery rates.  
AFLATOXIN TEST PROCEDURE AND MAXIMUM LEVELS  
6. An aflatoxin sampling plan is defined by an aflatoxin test procedure and a maximum level. 
A value for the maximum level and t he aflatoxin test procedure are given below in this 
section.  
7. The maximum level for “ready -to-eat” dried figs is 10 ng/g total aflatoxins.  
8. Choice of the number and size of the laboratory sample is a compromise between 
minimizing risks (false positiv es and false negatives) and costs related to sampling and 
restricting trade. For simplicity, it is recommended that the aflatoxin sampling plan uses 
three 10 kg aggregate samples of dried figs.  
9. The RTE sampling plan has been designed for enforcement an d controls concerning total 
aflatoxins in bulk consignments (lots) of dried figs traded in the export market.  
Maximum level   – 10 μg/kg total aflatoxins  
Number of laboratory samples  – 3  
Laboratory sample size   – 10 kg  
Sample preparation   – water -slurry grind and a test portion that represents 
55 g mass of dried figs  
Analytical method   – performance based (see Table 2)  
Decision rule  – If the aflatoxin test result is less than or equal to 10 
μg/kg total aflatoxins for all three 10 kg laboratory 
samp les, then accept the lot. Otherwise, reject the lot.  
10. To assist member countries implement the above sampling plan, sample selection 
methods, sample preparation methods, and analytical methods required to quantify GSO STANDARD   GSO  /2019  
 
 
60 
 
 aflatoxin in laboratory samples taken f rom bulk dried fig lots are described in the 
following sections.  
SAMPLE SELECTION  
MATERIAL TO BE SAMPLED  
11. Each lot, which is to be examined for aflatoxin, must be sampled separately. Lots larger 
than 15 tonnes should be subdivided into sublots to be sampled separately. If a lot is 
greater than 15 tonnes, the number of sublots is equal to the lot weight in tonnes divided 
by 15 tonnes. It is recommended that a lot or a sublot should not exceed 15 tonnes.  
12. Taking into account that the weight of the l ot is not always an exact multiple of 15 tonnes, 
the weight of the sublot may exceed the mentioned weight by a maximum of 25%.  
13. Samples should be taken from the same lot, i.e. they should have the same batch code or 
at the very least the same best befo re date. Any changes, which would affect the 
mycotoxin content, the analytical determination or make the aggregate samples 
collected unrepresentative should be avoided. For example do not open packaging in 
adverse weather conditions or expose samples to ex cessive moisture or sunlight. Avoid 
cross -contamination from other potentially contaminated consignments nearby.  
14. In most cases any truck or container will have to be unloaded to allow representative 
sampling to be carried out.  
INCREMENTAL SAMPLE SELE CTION  
15. Procedures used to take incremental samples from a dried fig lot are extremely important. 
Every individual fig in the lot should have an equal chance of being chosen. Biases will 
be introduced by sample selection methods if equipment and procedu res used to select 
the incremental samples prohibit or reduce the chances of any item in the lot from being 
chosen.  
16. Since there is no way to know if the contaminated figs are uniformly dispersed 
throughout the lot, it is essential that the aggregate s ample be the accumulation of many 
small incremental samples of product selected from different locations throughout the 
lot. If the aggregate sample is larger than desired, it should be blended and subdivided 
until the desired laboratory sample size is ach ieved.  
17. For lots less than 10 tonnes, the size of the aggregate sample is reduced so that the 
aggregate sample size doesn’t exceed a significant portion of the lot or sublot size.  
NUMBER AND SIZE OF INCREMENTAL SAMPLES FOR LOTS OF VARYING 
WEIGHT  
18. The number of incremental samples to be taken from a lot (sublot) depends on the weight 
of the lot. Table 1 shall be used to determine the number of incremental samples to be 
taken from lots or sublots of various sizes. The number of incremental sample s varies 
from 10 to 100 for lots or sublots of various sizes.  
Table 1. Number and size of incremental samples composited for an aggregate sample 
of 30 kga as a function of lot (or sublot) weight  
 GSO STANDARD   GSO  /2019  
 
 
61 
 
 Lot or sublot 
weightb (T in 
tonnes)  Minimum 
number of 
incre mental 
samples  Minimum 
incremental 
sample sizec 
(g) Minimum 
aggregate 
sample size 
(Kg)  Laboratory 
sample size 
(Kg)  Number of 
laboratory 
samples  
15.0 ≥T > 10.0  100 300 30 10 3 
10.0 ≥T > 5.0  80 300 24 8 3 
5.0 ≥T > 2.0  60 300 18 9 2 
2.0 ≥T > 1.0  40 300 12 6 2 
1.0 ≥T > 0.5  30 300 9 9 1 
0.5 ≥T > 0.2  20 300 6 6 1 
0.2 ≥T > 0.1  15 300 4.5 4.5 1 
0.1 ≥T  10 300 3 3 1 
a/ Minimum aggregate sample size   = laboratory sample size of 30 kg for lots above 10 tonnes  
 b/ 1 Tonne  = 1 000 kg  
c/ Minimum incremental sample size  = laboratory sample size (30 kg)/minimum number of 
incremental samples,  
 i.e. for 10 < T ≤ 15 tonnes, 300 g = 30 000/100  
 
19. The suggested minimum weight of the incremental sample is 300 g for lots and sublots 
of various sizes.  
STATIC LOTS  
20. A static lot can be defined as a large mass of dried figs contained either in a large single 
container such as a wagon, truck or ra ilcar or in many small containers such as sacks or 
boxes and the dried figs are stationary at the time a sample is selected. Selecting a truly 
random sample from a static lot can be difficult because all containers in the lot or sublot 
may not be accessibl e.  
21. Taking incremental samples from a static lot usually requires the use of probing devices 
to select product from the lot. The probing devices should be specifically designed for 
the commodity and type of container. The probe should (1) be long enoug h to reach all 
products, (2) not restrict any item in the lot from being selected, and (3) not alter the 
items in the lot. As mentioned above, the aggregate sample should be a composite from 
many small incremental samples of product taken from many differe nt locations 
throughout the lot.  
22. For lots traded in individual packages, the sampling frequency (SF), or number of 
packages that incremental samples are taken from, is a function of the lot weight (LT), 
incremental sample weight (IS), aggregate sample  weight (AS) and the individual 
packing weight (IP), as follows:  
Equation 1: SF = (LT x IS) / (AS x IP)  
23. The sampling frequency (SF) is the number of packages sampled. All weights should be 
in the same mass units such as kg.  GSO STANDARD   GSO  /2019  
 
 
62 
 
 DYNAMIC LOTS  
24. Represe ntative aggregate samples can be more easily produced when selecting 
incremental samples from a moving stream of dried figs as the lot is transferred from 
one location to another. When sampling from a moving stream, take small incremental 
samples of produc t from the entire length of the moving stream; composite the 
incremental samples to obtain an aggregate sample; if the aggregate sample is larger 
than the required laboratory sample(s), then blend and subdivide the aggregate sample 
to obtain the desired si ze laboratory sample(s).  
25. Automatic sampling equipment such as a cross -cut sampler is commercially available 
with timers that automatically pass a diverter cup through the moving stream at 
predetermined and uniform intervals.  
When automatic sampling eq uipment is not available, a person can be assigned to 
manually pass a cup through the stream at periodic intervals to collect incremental 
samples. Whether using automatic or manual methods, incremental samples should be 
collected and composited at frequent  and uniform intervals throughout the entire time 
the figs flow past the sampling point.  
26. Cross -cut samplers should be installed in the following manner: (1) the plane of the 
opening of the diverter cup should be perpendicular to the direction of the f low; (2) the 
diverter cup should pass through the entire cross sectional area of the stream; and (3) 
the opening of the diverter cup should be wide enough to accept all items of interest in 
the lot. As a general rule, the width of the diverter cup opening should be about two to 
three times the largest dimensions of items in the lot.  
27. The size of the aggregate sample (S) in kg, taken from a lot by a cross cut sampler is:  
Equation 2: S = (D x LT) / (T x V)  
where D is the width of the diverter cup openin g (cm), LT is the lot size (kg), T is 
interval or time between cup movement through the stream (seconds), and V is cup 
velocity (cm/sec).  
28. If the mass flow rate of the moving stream, MR (kg/sec), is known, then the sampling 
frequency (SF), or number of  cuts made by the automatic sampler cup can be computed 
from Equation 3 as a function of S, V, D, and MR.  
Equation 3: SF = (S x V) / (D x MR)  
29. Equations 2 and 3 can also be used to compute other terms of interest such as the time 
between cuts (T). For  example, the time (T) required between cuts of the diverter cup to 
obtain a 30 kg aggregate sample from a 20000 kg lot where the diverter cup width is 5.0 
cm and the cup velocity through the stream 20 cm/sec. Solving for T in Equation 2.  
T = (5.0 cm x 20  000 kg) / (30 kg x 20 cm/sec) = 167 sec.  
30. If the lot is moving at 500 kg per minute, the entire lot will pass throu gh the sampler in 
40 minutes (2 400 sec) and only 14.4 cuts (14 incremental samples) will be made by the 
cup through the lot (Equation 3) . This may be considered too infrequent, in that too 
much product (1 388.9 kg) passes through the sampler between the time the cup cuts 
through the stream.  
PACKAGING AND TRANSPORTATION OF SAMPLES  GSO STANDARD   GSO  /2019  
 
 
63 
 
 31. Each laboratory sample shall be placed in a clean, iner t container offering adequate 
protection from contamination, sunlight, and against damage in transit. All necessary 
precautions shall be taken to avoid any change in composition of the laboratory sample, 
which might arise during transportation or storage. Samples should be stored in a cool 
dark place.  
SEALING AND LABELLING OF SAMPLES  
32. Each laboratory sample taken for official use shall be sealed at the place of sampling and 
identified. A record must be kept of each sampling, permitting each lot to be i dentified 
unambiguously and giving the date and place of sampling together with any additional 
information likely to be of assistance to the analyst.  
SAMPLE PREPARATION  
PRECAUTIONS  
33. Sunlight should be excluded as much as possible during sample preparation, since 
aflatoxin gradually breaks down under the influence of ultra -violet light. Also, 
environmental temperature and relative humidity should be controlled and not favour 
mould growth and aflatoxin formation.  
HOMOGENISATION - GRINDING  
34. As the distribution of aflatoxin is extremely non -homogeneous, the laboratory samples 
should be homogenized by grinding the entire laboratory sample received by the 
laboratory. Homogenization is a procedure that reduces particle size and disperses the 
contaminated particles evenly throughout the comminuted laboratory sample.  
35. The laboratory sample should be finely ground and mixed thoroughly using a process 
that approaches as complete homog enization as possible. Complete homogenization 
implies that particle size is extremely small and the variability associated with sample 
preparation approaches zero. After grinding, the grinder should be cleaned to prevent 
aflatoxin cross -contamination.  
36. The use of vertical cutter mixer type grinders that mix and comminute the laboratory 
sample into a paste represent a compromise in terms of cost and fineness of grind or 
particle size reduction. A better homogenization (finer grind), such as a liquid slu rry, 
can be obtained by more sophisticated equipment and should provide the lowest sample 
preparation variance.  
TEST PORTION  
37. The suggested weight of the test portion taken from the comminuted laboratory sample 
should be approximately 50 g. If the labo ratory sample is prepared using a liquid slurry, 
the slurry should contain 50 g of fig mass.  
38. Procedures for selecting the 50 g test portion from the comminuted laboratory sample 
should be a random process. If mixing occurred during or after the commin ution 
process, the 50 g test portion can be selected from any location throughout the 
comminuted laboratory sample. Otherwise, the 50 g test portion should be the 
accumulation of several small portions selected throughout the laboratory sample.  
39. It is suggested that three test portions be selected from each comminuted laboratory 
sample. The three test portions will be used for enforcement, appeal, and confirmation 
if needed.  GSO STANDARD   GSO  /2019  
 
 
64 
 
 ANALYTICAL METHODS  
BACKGROUND  
40. A criteria -based approach, whereby a set o f performance criteria is established with 
which the analytical method used should comply, is appropriate. The criteria -based 
approach has the advantage that, by avoiding setting down specific details of the method 
used, developments in methodology can be exploited without having to reconsider or 
modify the specific analytical method. The performance criteria established for 
analytical methods should include all the parameters that need to be addressed by each 
laboratory such as the detection limit, repeata bility coefficient of variation (within lab), 
reproducibility coefficient of variation (among lab), and the percent recovery necessary 
for various statutory limits. Analytical methods that are accepted by chemists 
internationally (such as AOAC) may be used . These methods are regularly monitored 
and improved depending upon technology.  
PERFORMANCE CRITERIA FOR METHODS OF ANALYSIS  
41. A list of criteria and performance levels are shown in Table 2. Utilizing this approach, 
laboratories would be free to use th e analytical method most appropriate for their 
facilities.  
Table 2. Specific requirements with which methods of analysis should comply with  
Criterion  Concentration 
range (ng/g)  Recommended value  Maximum permitted 
value  
Blanks  All  Negligible  n/a  
Recovery  1 to 15  70 to 100%  n/a  
> 15 80 to 110%  n/a  
Precision or relative 
standard deviation 
RSD R 
(Reproducibility)  1 to 120  Equation 4  2 x value derived from 
Equation 4  
> 120  Equation 5  2 x value derived from 
Equation 5  
Precision or relative 
standard deviation 
RSDr (Repeatability)  1 to 120  Calculated as 0.66 
times Precision RSD R  n/a  
> 120  Calculated as 0.66 
times Precision RSDr  n/a  
n/a = not applicable  
42. The detection limits of the methods used are not stated. Only the precision values are 
given at the concentrations of interest. The precision values (expressed as a%) are 
calculated from equations 4 and 5.  
Equation 4: RSD R = 22.0  
Equation 5: RSD R = 45.25C-0.15  
where:  
• RSD R = the relative standard deviation calculated from results generated under 
reproducibility conditions  GSO STANDARD   GSO  /2019  
 
 
65 
 
 • RSD r = the relative standard deviation calculated from results generated under 
repeatability conditions = 0.66RSD R  
• C = afla toxin concentration or mass of aflatoxin to mass of dried figs (i.e. ng/g)  
43. Equations 4 and 5 are generalized precision equations, which have been found to be 
independent of analyte and matrix but solely dependent on concentration for most 
routine metho ds of analysis.  
44. Results should be reported on the sample.  
UNCERTAINTY, AS MEASURED BY THE VARIANCE, ASSOCIATED WITH 
THE SAMPLING, SAMPLE PREPARATION, AND ANALYTICAL STEPS OF 
THE AFLATOXIN TEST PROCEDURE USED TO DETECT AFLATOXIN IN 
DRIED FIGS  
45. The sampling, sample preparation, and analytical variances associated with the aflatoxin 
test procedure for dried figs are shown in Table 3.  
Table 3. Variancesa associated with the aflatoxin test procedure for dried figs  
------------------------------------------------------------   
Test Procedure Variances for Dried Figs  
------------------------------------------------------------   
Samplingb,c  S2s = (590/ns) 2.219C1.433  
Sample Prepd  S2sp = (55/nss) 0.01170C1.465  
Analy ticale  S2a = (1/na) 0.0484C2.0  
Total   S2t = S2s + S2sp + S2a  
-------------------------------------------------------------   
a / Variance = S2 (t, s, sp, and a denote total, sampling, sample preparation, and analytical 
steps, respectively, of aflatoxin test procedure)  
b / ns = laboratory sample size in number of dried figs, nss =test portion size in grams of fig 
mass, na = number of aliquots qu antified by HPLC, and C = aflatoxin concentration in 
ng/g total aflatoxins  
c / Count/kg for dried figs averaged 59/kg  
d / Sample preparation variance reflects a water -slurry method and a test portion that reflects 
55 g fig mass  
e / Analytical variances reflect FAPAS recommendation for upper limit of analytical 
reproducibility uncertainty. A relative standard deviation of 22% is based upon FAPAS 
data and considered as an appropriate measure of the best agreement that can be obtained 
between laboratories. An analytical uncertainty of 22% is larger than the within 
laboratory uncertainty measured in the sampling studies for the three dried figs.  
 GSO STANDARD   GSO  /2019  
 
 
66 
 
 Annex 4 
SAMPLING PLANS AND PERFORMANCE CRITERIA FOR 
DEOXYNIVALENOL (DON) IN CEREAL -BASED FOODS FOR INFANTS 
AND YO UNG CHILDREN; IN FLOUR, MEAL, SEMOLINA AND FLAKES 
DERIVED FROM WHEAT, MAIZE OR BARLEY; AND IN CEREAL GRAINS 
(WHEAT, MAIZE AND BARLEY) DESTINED FOR FURTHER PROCESSING  
Cereal grains (wheat, maize and barley) destined for further processing  
Maximum level  2000 μg/kg DON  
Increments  increments of 100 g, depending on the lot weight (≥ 0.5 tonnes)  
Sample preparation  dry grind with a suitable mill (particles smaller than 0.85 mm - 
20 mesh)  
Laboratory sample weight  ≥ 1 kg  
Number of laboratory 
samples  1  
Test portion  25 g test portion  
Method  HPLC  
Decision rule  If the DON -sample test result for the laboratory samples is equal 
or less than 2000 μg/kg, accept the lot. Otherwise, reject the lot.  
Cereal -based foods for infants and young children  
Maximum level  200 μg/kg DON  
Increments  10 x 100 g  
Sample preparation  None  
Laboratory sample weight  1 kg  
Number of laboratory samples  1  
Test portion  25 g test portion  
Method  HPLC  
Decision rule  If the DON sample test result is equal or less than 
200 μg/kg, accept the lot. Otherwise, reject the lot.  
Flour, semolina, meal and flakes derived from wheat, maize or barley  
Maximum level  1000 μg/kg DON  
Increments  10 x 100 g  
Sample preparation  None  
Laboratory sample weight  1 kg  
Number of laboratory samples  1  
Test portion  25 g test portion  
Method  HPLC  GSO STANDARD   GSO  /2019  
 
 
67 
 
 Decision rule  If the DON sample test result is equal or less than 
1000 μg/kg, accept the lot. Otherwise, reject the lot.  
DEFINITIONS  
Lot  An identifiable quantity of a food commodity delivered at one time and 
determined by the official to have common characteristics, such as origin, 
variety, type of packing, packer, consignor, or markings.  
Sublot  Designated part of a larger lot in order to apply the sampling method on 
that designated part. Each sublot must be physically separate and 
identifiable.  
Sampling plan  It is defined by a DON test procedure and an accept/reject level. A DON 
test procedure  consists of three steps: sample selection, sample preparation 
and analysis or DON quantification. The accept/reject level is a tolerance 
usually equal to the Codex maximum level (ML).  
Incremental 
sample  The quantity of material taken from a single random place in the lot or 
sublot.  
Aggregate sample  The combined total of all the incremental samples that is taken from the 
lot or sublot. The aggregate sample has to be at least as large as the 
laboratory s ample or samples combined.  
Laboratory 
sample  The smallest quantity of shelled cereal comminuted in a mill. The 
laboratory sample may be a portion of or the entire aggregate sample. If 
the aggregate sample is larger than the laboratory sample(s), the lab oratory 
sample(s) should be removed in a random manner from the aggregate 
sample in such a way to ensure that the laboratory sample is still 
representative of the sublot sampled.  
Test portion  A portion of the comminuted laboratory sample. The entire laboratory 
sample should be comminuted in a mill. A portion of the comminuted 
laboratory sample is randomly removed for the extraction of the DON for 
chemical analysis.  
 
 
SAMPLING PLAN DESIGN CONS IDERATIONS  
MATERIAL TO BE SAMPLED  
1. Each lot of cereal, which is to be examined for DON, must be sampled separately. Lots 
larger than 50 tonnes should be subdivided into sublots to be sampled separately. If a lot 
is greater than 50 tonnes, the lot should be subdivided into sublots accordi ng to Table 1.  
 
 
 
Table 1. Subdivision of cereal sublots according to lot weight  GSO STANDARD   GSO  /2019  
 
 
68 
 
 Lot weight (t)  Maximum Weight 
or minimum 
number of sub lots  Number of 
incremental sample  Minimum 
laboratory Sample 
Weight (kg)  
≥ 1500  500 tonnes  100 1 
> 300 and < 1500  3 sublots  100 1 
≥ 100 and ≤ 300  100 tonnes  100 1 
≥ 50 and < 100  2 sublots  100 1 
< 50  - 3-100*  1 
* see table 2  
2. Taking into account that the weight of the lot is not always an exact multiple of the weight 
of sublots, the weight of the sublot may exceed the mentioned weight by a maximum of 
20%.  
 
INCREMENTAL SAMPLE  
3. The suggested minimum weight of the increment al sample should be 100 grams for lots 
≥ 0.5 tonnes.  
4. For lots less than 50 tonnes, the sampling plan must be used with 3 to 100 incremental 
samples, depending on the lot weight. For very small lots (≤ 0.5 tonnes) a lower number 
of incremental samples m ay be taken, but the aggregate sample uniting all incremental 
samples shall be also in that case at least 1 kg. Table 2 may be used to determine the 
number of incremental samples to be taken.  
 
Table 2. Number of incremental samples to be taken depending o n the weight of the lot of  
Lot weight (t)  Number of incremental 
sample  Minimum Laboratory 
Sample Weight (kg)  
≤ 0.05  3 1 
> 0.05 - ≤ 0.5  5 1 
> 0.5 - ≤ 1  10 1 
> 1 - ≤ 3  20 1 
> 3 - ≤ 10  40 1 
> 10 - ≤ 20  60 1 
> 20 - < 50  100 1 
STATIC LOTS  
5. A static lot can be defined as a large mass of shelled cereal contained either in a large 
single container such as a wagon, truck or railcar or in many small containers such as 
sacks or boxes and the cereal is stationary at the time a sample is selected. Se lecting a 
truly random sample from a static lot can be difficult because all containers in the lot or 
sublot may not be accessible.  GSO STANDARD   GSO  /2019  
 
 
69 
 
 6. Taking incremental samples from a static lot usually requires the use of probing devices 
to select product from the lot. The probing devices should be specifically designed for the 
commodity and type of container. The probe should (1) be long enough to reach all 
products, (2) not restrict any item in the lot from being selected, and (3) not alter the items 
in the lot. As men tioned above, the aggregate sample should be a composite from many 
small incremental samples of product taken from many different locations throughout the 
lot. 
7. For lots traded in individual packages, the sampling frequency (SF), or number of 
packages th at incremental samples are taken from, is a function of the lot weight (LT), 
incremental sample weight (IS), aggregate sample weight (AS) and the individual packing 
weight (IP), as follows:  
SF = (LT x IS)/(AS x IP).  
8. The sampling frequency (SF) is the nu mber of packages sampled. All weights should be 
in the same mass units such as kg.  
DYNAMIC LOTS  
9. Representative aggregate samples can be more easily produced when selecting 
incremental samples from a moving stream of shelled cereal as the lot is transfer red from 
one location to another. When sampling from a moving stream, take small incremental 
samples of product from the entire length of the moving stream; composite the 
incremental samples to obtain an aggregate sample; if the aggregate sample is larger than 
the required laboratory sample(s), then blend and subdivide the aggregate sample to 
obtain the desired size laboratory sample(s).  
10. Automatic sampling equipment such as a cross -cut sampler is commercially available 
with timers that automatically pas s a diverter cup through the moving stream at 
predetermined and uniform intervals. When automatic sampling equipment is not 
available, a person can be assigned to manually pass a cup through the stream at periodic 
intervals to collect incremental samples. Whether using automatic or manual methods, 
incremental samples should be collected and composited at frequent and uniform 
intervals throughout the entire time the cereal flow past the sampling point.  
11. Cross -cut samplers should be installed in the follow ing manner: (1) the plane of the 
opening of the diverter cup should be perpendicular to the direction of the flow; (2) the 
diverter cup should pass through the entire cross sectional area of the stream; and (3) 
the opening of the diverter cup should be wid e enough to accept all items of interest in 
the lot. As a general rule, the width of the diverter cup opening should be about two to 
three times the largest dimensions of items in the lot.  
12. The size of the aggregate sample (S) in kg, taken from a lot by  a cross cut sampler is:  
S=(D x LT) / (T x V),  
where D is the width of the diverter cup opening (cm), LT is the lot size (kg), T is 
interval or time between cup movement through the stream (seconds), and V is cup 
velocity (cm/sec).  
13. If the mass flow rat e of the moving stream, MR (kg/sec), is known, then the sampling 
frequency (SF), or number of cuts made by the automatic sampler cup can be computed 
as a function of S, V, D, and MR.  
SF = (S x V) / (D x MR).  GSO STANDARD   GSO  /2019  
 
 
70 
 
 PACKAGING AND TRANSPORTATION OF SAMPLES  
14. Each  laboratory sample shall be placed in a clean, inert container offering adequate 
protection from contamination, sunlight, and against damage in transit. All necessary 
precautions shall be taken to avoid any change in composition of the laboratory sample, 
which might arise during transportation or storage. Samples should be stored in a cool 
dark place.  
15. Each laboratory sample taken for official use shall be sealed at the place of sampling and 
identified. A record must be kept of each sampling, permitting each lot to be identified 
unambiguously and giving the date and place of sampling together with any additional 
information likely to be of assistance to the analyst.  
SAMPLE PREPARATION  
16. Sunlight should be excluded as much as possible during sample prepa ration, since DON 
may gradually break down under the influence of ultra -violet light. Also, environmental 
temperature and relative humidity should be controlled and not favour mould growth 
and DON formation.  
17. As the distribution of DON is extremely non -homogeneous, laboratory samples should 
be homogenised by grinding the entire laboratory sample received by the laboratory. 
Homogenisation is a procedure that reduces particle size and disperses the contaminated 
particles evenly throughout the comminuted la boratory sample.  
18. The laboratory sample should be finely ground and mixed thoroughly using a process 
that approaches as complete homogenisation as possible. Complete homogenisation 
implies that particle size is extremely small and the variability assoc iated with sample 
preparation approaches zero. After grinding, the grinder should be cleaned to prevent 
DON cross -contamination.  
TEST PORTION  
19. The suggested weight of the test portion taken from the comminuted laboratory sample 
should be approximately  25 g  
20. Procedures for selecting the test portion from the comminuted laboratory sample should 
be a random process. If mixing occurred during or after the comminuting process, the 
test portion can be selected from any location throughout the comminuted laboratory 
sample. Otherwise, the test portion should be the accumulation of several small portions 
selected throughout the laboratory sample.  
21. It is suggested that three test portions be selected from each comminuted laboratory 
sample. The three test portions will be used for enforcement, appeal, and confirmation 
if needed.  
ANALYTICAL METHODS  
22. A criteria -based approach, whereby a set of performance criteria is established with 
which the analytical method used should comply, is appropriate. The criteria -based 
approach has the advantage that, by avoiding setting down specific details of the me thod 
used, developments in methodology can be exploited without having to reconsider or 
modify the specific method. A list of possible criteria and performance levels are shown 
in Table 3). Utilising this approach, laboratories would be free to use the ana lytical 
method most appropriate for their facilities.  
 GSO STANDARD   GSO  /2019  
 
 
71 
 
 Table 3. Proposed method criteria for DON in cereals . 
Commodity  ML (mg/kg)  LOD 
(mg/kg)  LOQ 
(mg/kg)  Precision 
on HorRat  Minimum 
applicable 
range 
(mg/kg)  Recovery  
Cereal grains 
(wheat, maize 
and barley) 
destined for 
further 
processing  2.0  ≤ 0.2  ≤ 0.4  ≤ 2  1-3  80 - 110%  
Cereal -based 
foods for infants 
and young 
children  0.2  ≤ 0.02  ≤ 0.04  ≤ 2  0.1 – 0.3  80 – 110%  
Flour, semolina, 
meal and flakes 
derived from 
wheat, maize or 
barley  1.0  ≤ 0.1  ≤ 0.2  ≤ 2  0.5 – 1.5  80 – 110%  
 
  GSO STANDARD   GSO  /2019  
 
 
72 
 
 Annex 5 
SAMPLING PLANS AND PERFORMANCE CRITERIA FOR FUMONISINS (FB1 + 
FB2) IN MAIZE GRAIN AND MAIZE FLOUR AND MAIZE MEAL  
Maize grain, unprocessed  
Maximum level  4 000 μg/kg FB1 + FB2  
Increments  increments of 100 g, depending on the lot weight (≥ 0.5 
tonnes)  
Sample preparation  dry grind with a suitable mill (particles smaller than 0.85 mm 
- 20 mesh)  
Laboratory sample weight  ≥ 1 kg  
Number of laboratory samples  1  
Test portion  25 g test portion  
Method  HPLC  
Decision rule  If the fumonisin -sample test result for the laboratory samples 
is equal or less than 4 000 μg/kg, accept the lot. Otherwise, 
reject the lot.  
Maize flour and maize meal  
Maximum level  2 000 μg/kg FB1 + FB2  
Increments  10 x 100 g  
Sample preparation  None  
Laboratory sample weight  ≥ 1 kg  
Number of laboratory samples  1  
Test portion  25 g test portion  
Method  HPLC  
Decision rule  If the fumonisin -sample test resu lt is equal or  less than 2 000 
μg/kg, accept the lot. Otherwise, reject the lot.  
DEFINITION  
Lot  An identifiable quantity of a food commodity delivered at one time 
and determined by the official to have common characteristics, such 
as origin, variety, type of packing, packer, consignor, or markings.  
Sublot  The designated part of a larger lot in order to apply the sampling 
method on that designated part. Each sublot must be physically 
separate and identifiable.  
Sampling plan  It is defined by a fumonisin test procedure and an accept/reject level. 
A fumonisin test procedure consists of three steps: sample selection, 
sample preparation and analysis or fumonisin quantification. The 
accept/reject level is a tolerance usually equal to the Codex maximum 
level (ML).  GSO STANDARD   GSO  /2019  
 
 
73 
 
 Incremental sample  The quantity of material taken from a single random place in the lot 
or sublot.  
Aggregate sample  The combined total of all the incremental samples that is taken from 
the lot or sublot. The aggregate sample has to be at least as large as 
the laboratory sample or samples combined.  
Laboratory sample  The smallest quantity of shelled maize comminuted in a mill. The 
laboratory sample may be a portion of or the entire aggregate sample. 
If the aggregate sample is larger than the laboratory sample(s), the 
laboratory sample(s) should be removed in a random m anner from the 
aggregate sample in such a way to ensure that the laboratory sample 
is still representative of the sublot sampled.  
Test portion  A portion of the comminuted laboratory sample. The entire laboratory 
sample should be comminuted in a mill. A portion of the comminuted 
laboratory sample is randomly removed for the extraction of the 
fumonisin for chemical analysis.  
 
SAMPLING PLAN DESIGN CONSIDERATIONS  
MATERIAL TO BE SAMPLED  
1. Each lot of maize, which is to be examined for fumonisin, must be sampled separately. 
Lots larger than 50 tonnes should be subdivided into sublots to be sampled separately. If 
a lot is greater than 50 tonnes, the lot should be subdivided into sublots according to Table 
1. 
Table 1. Subdivision of maize sublots according t o lot weight  
Lot weight (t)  Maximum weight 
or minimum 
number of sub lots  Number of 
incremental sample  Minimum 
laboratory sample 
weight (kg)  
≥ 1500  500 tonnes  100 1 
> 300 and < 1500  3 sublots  100 1 
≥ 100 and ≤ 300  100 tonnes  100 1 
≥ 50 and < 100  2 sublots  100 1 
< 50  - 3-100*  1 
* see table 2  
2. Taking into account that the weight of the lot is not always an exact multiple of the weight 
of sublots, the weight of the sublot may exceed the mentioned weight by a maximum of 
20%.  
INCREMENTAL SAMPLE  
3. The suggested minimum weight of the incremental sample should be 100 grams for lots 
≥0.5 tonnes.  
4. For lots less than 50 tonnes, the sampling plan must be used with 3 to 100 incremental 
samples, depending on the lot weight. For very small lots (≤ 0.5 tonn es) a lower number 
of incremental samples may be taken, but the aggregate sample uniting all incremental GSO STANDARD   GSO  /2019  
 
 
74 
 
 samples shall be also in that case at least 1 kg. Table 2 may be used to determine the 
number of incremental samples to be taken.  
Table 2. Number of in cremental samples to be taken depending on the weight of the lot  
Lot weight (t)  Number of 
incremental 
sample  Minimum 
laboratory sample 
weight (kg)  
≤ 0.05  3 1 
> 0.05 - ≤ 0.5  5 1 
> 0.5 - ≤ 1  10 1 
> 1 - ≤ 3  20 1 
> 3 - ≤ 10  40 1 
> 10 - ≤ 20  60 1 
> 20 - < 50  100 1 
 
STATIC LOTS  
5. A static lot can be defined as a large mass of shelled maize contained either in a large 
single container such as a wagon, truck or railcar or in many small containers such as 
sacks or boxes and the maize is stationary at the time a sample is selected. Selecting a 
truly random sample from a static lot can be difficult because all containers in the lot or 
sublot may not be accessible.  
6. Taking incremental samples from a static lot usually requires the use of probing devices 
to select product from the lo t. The probing devices should be specifically designed for the 
commodity and type of container. The probe should (1) be long enough to reach all 
products, (2) not restrict any item in the lot from being selected, and (3) not alter the items 
in the lot. As mentioned above, the aggregate sample should be a composite from many 
small incremental samples of product taken from many different locations throughout the 
lot.  
7. For lots traded in individual packages, the sampling frequency (SF), or number of 
package s that incremental samples are taken from, is a function of the lot weight (LT), 
incremental sample weight (IS), aggregate sample weight (AS) and the individual packing 
weight (IP), as follows:  
SF = (LT x IS)/(AS x IP).  
8. The sampling frequency (SF) is t he number of packages sampled. All weights should be 
in the same mass units such as kg.  
DYNAMIC LOTS  
9. Representative aggregate samples can be more easily produced when selecting 
incremental samples from a moving stream of shelled maize as the lot is transferred from 
one location to another. When sampling from a moving stream, take small incremental 
samp les of product from the entire length of the moving stream; composite the 
incremental samples to obtain an aggregate sample; if the aggregate sample is larger than GSO STANDARD   GSO  /2019  
 
 
75 
 
 the required laboratory sample(s), then blend and subdivide the aggregate sample to 
obtain t he desired size laboratory sample(s).  
10. Automatic sampling equipment such as a cross -cut sampler is commercially available 
with timers that automatically pass a diverter cup through the moving stream at 
predetermined and uniform intervals. When automati c sampling equipment is not 
available, a person can be assigned to manually pass a cup through the stream at periodic 
intervals to collect incremental samples. Whether using automatic or manual methods, 
incremental samples should be collected and composite d at frequent and uniform 
intervals throughout the entire time the maize flow past the sampling point.  
11. Cross -cut samplers should be installed in the following manner: (1) the plane of the 
opening of the diverter cup should be perpendicular to the dire ction of the flow; (2) the 
diverter cup should pass through the entire cross sectional area of the stream; and (3) 
the opening of the diverter cup should be wide enough to accept all items of interest in 
the lot. As a general rule, the width of the diverte r cup opening should be about two to 
three times the largest dimensions of items in the lot.  
12. The size of the aggregate sample (S) in kg, taken from a lot by a cross cut sampler is:  
S=(D x LT) / (T x V),  
where D is the width of the diverter cup openi ng (cm), LT is the lot size (kg), T is 
interval or time between cup movement through the stream (seconds), and V is cup 
velocity (cm/sec).  
13. If the mass flow rate of the moving stream, MR (kg/sec), is known, then the sampling 
frequency (SF), or number o f cuts made by the automatic sampler cup can be computed 
as a function of S, V, D, and MR.  
SF = (S x V) / (D x MR).  
PACKAGING AND TRANSPORTATION OF SAMPLES  
14. Each laboratory sample shall be placed in a clean, inert container offering adequate 
protection from contamination, sunlight, and against damage in transit. All necessary 
precautions shall be taken to avoid any change in composition of the laboratory s ample, 
which might arise during transportation or storage. Samples should be stored in a cool 
dark place.  
15. Each laboratory sample taken for official use shall be sealed at the place of sampling and 
identified. A record must be kept of each sampling, pe rmitting each lot to be identified 
unambiguously and giving the date and place of sampling together with any additional 
information likely to be of assistance to the analyst.  
SAMPLE PREPARATION  
16. Sunlight should be excluded as much as possible during s ample preparation, since 
fumonisin may gradually break down under the influence of ultra -violet light. Also, 
environmental temperature and relative humidity should be controlled and not favor 
mold growth and fumonisin formation.  
17. As the distribution of  fumonisin is extremely non -homogeneous, laboratory samples 
should be homogenised by grinding the entire laboratory sample received by the 
laboratory. Homogenisation is a procedure that reduces particle size and disperses the 
contaminated particles evenly throughout the comminuted laboratory sample.  GSO STANDARD   GSO  /2019  
 
 
76 
 
 18. The laboratory sample should be finely ground and mixed thoroughly using a process 
that approaches as complete homogenisation as possible. Complete homogenisation 
implies that particle size is extremely sma ll and the variability associated with sample 
preparation approaches zero. After grinding, the grinder should be cleaned to prevent 
fumonisin cross -contamination.  
TEST PORTION  
19. The suggested weight of the test portion taken from the comminuted laborat ory sample 
should be approximately 25 g  
20. Procedures for selecting the test portion from the comminuted laboratory sample should 
be a random process. If mixing occurred during or after the comminuting process, the 
test portion can be selected from any l ocation throughout the comminuted laboratory 
sample. Otherwise, the test portion should be the accumulation of several small portions 
selected throughout the laboratory sample.  
21. It is suggested that three test portions be selected from each comminuted laboratory 
sample. The three test portions will be used for enforcement, appeal, and confirmation 
if needed.  
ANALYTICAL METHODS  
22. A criteria -based approach, whereby a set of performance criteria is established with 
which the analytical method used shou ld comply, is appropriate. The criteria -based 
approach has the advantage that, by avoiding setting down specific details of the method 
used, developments in methodology can be exploited without having to reconsider or 
modify the specific method. A list of possible criteria and performance levels are shown 
in Table 3). Utilising this approach, laboratories would be free to use the analytical 
method most appropriate for their facilities.  
Table 3. Performance criteria for Fumonisin B1+ B2.  
Maize Grain  
Analyte  ML (mg/Kg)  LOD (mg/Kg)  LOQ (mg/Kg)  RSD R  Recovery (%)  
FB1 + FB2  4.0  -  -  -  -  
FB1   ≤ 0.3*  ≤ 0.6*  HorRat ≤ 2  
(< 27%)  80 - 110  
FB2  ≤ 0.15*  ≤ 0.3*  HorRat ≤ 2  
(< 32%)  80 - 110  
* - The LOD and LOQ were derived based upon typical B1:B2 ratio of 5:2 in naturally -
contaminated samples  
Maize Flour/Meal  
Analyte  ML (mg/Kg)  LOD (mg/Kg)  LOQ (mg/Kg)  RSDR  Recovery (%)  
FB1 + FB2  2.0  -  -  -  -  
FB1   ≤ 0.15*  ≤ 0.3*  HorRat ≤ 2  
(< 30%)  80 – 110  GSO STANDARD   GSO  /2019  
 
 
77 
 
 FB2  ≤ 0.06*  ≤ 0.15*  HorRat ≤ 2  
(< 34%)  80 – 110  
* - The LOD and LOQ were derived based upon typical B1:B2 ratio of 5:2 in naturally -
contaminated samples  
 GSO STANDARD   GSO  /2019  
 
 
78 
 
 Reference:  
- General Standard For Contamina nts And Toxins In Food And Feed Codex Stan 193 -
1995  
- Commission Regulation (EC) No 1881/2006 of 19 December 2006 setting 
maximum levels for certain contaminants in foodstuffs  
 
 