sushi and sashimi are traditional japanese food , though in recent years they attracted a large number of european consumers .
it was formerly used for carps , that were caught , gutted , salted and preserved between two stones , and left to ferment for a period ranged from one to three years .
sushi is prepared with cold cooked rice acidified with vinegar , and it is shaped into bite - sized pieces and topped with raw or cooked fish , or formed into a roll with fish , eggs or vegetables , and wrapped in seaweed ( nori ) ( atanassova et al . , 2008 ) .
the sashimi , instead , is characterised by the use of fish and shellfish , which are cut into thin slices and served with several sauces ( e.g. wasabi , soy sauce or ponzu sauce ) , and accompanied with daikon roots ( food and environmental hygiene department hksar , 2000 ) .
sushi and sashimi are ready - to - eat ( rte ) food and regarded as a potentially hazardous . frequently , indeed , foodborne diseases related to sushi e sashimi consumption have been reported ( adams et al .
, 2004 ; food and environmental hygiene department hksar , 2000 ; masotti et al . , 2004 ; millard and rockliff , 2003 ; nsw food authority , 2006 ) .
, staphylococcus aureus , vibrio parahaemolyticus , vibrio cholerae , listeria monocytogenes , bacillus cereus can occur in materials used for their preparation such as fish , seafood products , vegetables and rice . in the light of the significant increase of consumption of traditional japanese foods in italy and due to the attention of ec reg .
( european commission , 2005 ) , the aim of this study was to investigate the microbiological quality of sushi and sashimi sold in messina and catania ( southern sicily , italy ) .
the study was carried out on 38 samples of sushi and 12 of sashimi collected from restaurants , sushi bar and take - away outlets of messina and catania .
in addition to rice and nori seaweed , they were made with smoked fish ( salmon , tuna and swordfish ) , canned tuna in oil , surimi , fish eggs , cream cheese , cucumbers , carrots , avocado , sesame or poppy seeds .
all samples , transported to the laboratory under refrigerated condition , were analysed for the following bacteriological determinations : aerobic mesophilic bacteria ( amb ) ( iso 4833:2004 ; uni , 2004 ) , psychrophilic bacteria ( pb ) ( iso 17410:2001 ; iso , 2001 ) , specific spoilage organisms ( ssos ) ( lyngby iron agar at 25c for 5 days ) , enterobacteriaceae ( iso 21528 - 2:2004 ; iso , 2004 ) , pseudomonas spp .
( pseudomonas agar base with cfc supplement at 30c for 48 h ) , quantitative and qualitative determination of vibrio spp .
( thiosulphate citrate bile salt sucrose agar at 37c for 24 h ) , coagulase - positive staphylococci and micrococci ( iso 6888 - 2:1999 ; iso , 1999 ) , bacillus cereus ( iso 7932:2005 ; uni , 2005a ) , listeria monocytogenes ( iso 11290 - 1:2005 and iso 11290 - 2:2005 ; uni , 2005b , 2005c ) and salmonella spp .
colonies of enterobacteriaceae , isolated from tuna sashimi , were identified by api 20 e ( biomrieux , marcy letoile , france ) .
then , they were cultured on niven medium , in order to evaluate their istidino - decarboxylase activity .
in sushi samples , the amb ranged from 5.00 to 8.18 log cfu / g , and pb from 4.70 to 7.13 log cfu / g ( table 1 ) .
the highest percentage of samples for amb ( 44.74% ) and pb ( 47.37% ) were from 6.00 to 7.00 log cfu / g , while for enterobacteriaceae ( 44.74% ) from 4.00 to 5.00 log cfu / g .
specific spoilage organisms and pseudomonas spp . ranged from 3.49 to 7.72 log cfu / g and from 3.26 to 8.00 log cfu / g respectively .
coagulase - positive staphylococci were isolated in 16 samples ( 42.11% ) with values from 2.00 to 3.60 log cfu / g .
bacillus cereus was detected in 3 samples ( 7.89% ) , with values between 1.70 and 4.00 log cfu / g and vibrio spp .
were observed in 15 samples ( 39.47% ) ranging from 1.70 to 3.70 log cfu / g . in all sushi samples , no salmonella spp . and
the ph of the rice ranged from 4.6 to 6.6 ( mean 5.6 ) , while the ph of fish from 5.06 to 8.4 ( mean 6.06 ) . in sashimi samples , the amb , pb and ssos were higher than 7.00 log cfu / g ( table 2 ) .
the enterobacteriaceae and pseudomonas spp . were from 6.00 to 8.00 log cfu / g .
were observed in 6 samples ( 50% ) ( 2.00 log cfu / g ) , while in all 12 samples ( 100% ) no salmonella spp . and
twenty - five colonies of enterobacteriaceae , isolated from tuna sashimi , were identified as citrobacter freundii , klebsiella oxytoxa , serratia liquefaciens , rahnella aquatilis and raoultella ornithinolytica .
the ph of sashimi samples examined ranged from 5.86 to 8.4 ( mean 6.98 ) .
the microbiological limits for rte foods such as sushi and sashimi are defined by ec reg .
sushi and sashimi characterised by shelf - life less than five days are rte foods unable to support the growth of l. monocytogenes . for this reason
, l. monocytogenes must be less than 100 cfu / g during the shelf - life of these products .
all samples examined in this study were in accordance with the microbiological criteria of ec reg .
( 2000 ) , hong kong ( food and environmental hygiene department hksar , 2000 , 2007 ) and food standards australia ( food standards australia new zealand , 2001 ; anzfa , 2001 ) , 6 sushi samples ( 21.05% ) examined were considered unsatisfactory for amb criteria ( table 3 ) .
thirty - one samples ( 81.58% ) were unsatisfactory for enterobacteriaceae and 6 ( 15.79% ) for coagulase - positive staphylococci .
seventeen samples resulted borderline for amb ( 44.74% ) , 6 for enterobacteriaceae ( 15.79% ) , 3 for b. cereus ( 7.90% ) and 11 for coagulase - positive staphylococci ( 28.95% ) , as showed in table 3 .
high bacterial charges as well as potentially pathogen microorganisms were observed in sushi and sashimi examined as previously reported by several authors ( adams et al . , 1994 ;
, 2008 ; barralet et al . , 2004 ; millard and rockliff , 2003 ) . in this
( 2008 ) described average amb values of 6.3 log cfu / g in fresh sushi samples .
l. monocytogenes were found in 1.6 and 1.2% of samples respectively , while staphylococcus aureus showed a charge of 2.2 to 4.7 log cfu / g ( atanassova et al . , 2008 ) .
the microbiological status of sushi and sashimi reflects the microbiology of materials used for their preparation .
is indeed related to the fish and shellfish products used ( giuffrida and panebianco , 2008 ) , while b. cereus has been reported in plant foods ( especially rice ) ( eglezos et al . , 2010 ) .
l. monocytogenes can occur in vegetables and dairy products ( cheese ) , while the finding of s. aureus is an evidence of human contact during the preparation of food ( nogara et al . , 2004 ) .
this study confirms that the production of sushi and sashimi of good quality obviously depends on the choice of raw materials , as also reported by atanassova et al .
a good rice acidification ( ph of the rice must be less than 4.6 ) and the maintaining of cold chain during preparation and storage are also essential to obtain products of good microbiological status .
finally , a proper training of personnel who manipulates this easily perishable food is desirable .
further bio - molecular investigations will be necessary to confirm the istidino - decarboxylase activity of enterobacteriaceae strains isolated from tuna sashimi as suggested by mancusi et al .
the presence of hista - mine - producing bacteria on sashimi could also represent a potential toxicological hazard .
 sushi and sashimi are traditional japanese food , mostly consisting of raw seafood alone or in combination with rice . eating sushi and sashimi 
 has become popular in many countries even outside japan . 
 this food is not free from health risks such as ingestion of pathogenic bacteria or parasite . 
 the aim of this study was to investigate on hygienic - sanitary quality of sushi and sashimi sold in the cities of messina and catania , southern italy . 
 fifty samples ( 38 sushi and 12 sashimi ) were analysed to determinate the aerobic mesophilic bacteria ( amb ) , psycrophilic bacteria ( pb ) , enterobacteriaceae , specific spoilage organisms ( ssos ) , pseudomonas spp . 
 , coagulase - positive staphylococci , micrococci , vibrio spp . , bacillus cereus , salmonella spp . and listeria monocytogenes . in sushi , 
 amb ranged from 5.00 to 8.18 log cfu / g , pb from 4.70 to 7.13 log cfu / g , enterobacteriaceae from 1.41 to 6.67 log cfu / g , while ssos and pseudomonas spp . from 3.49 to 7.72 and from 3.36 to 8.00 log cfu / g , respectively . 
 micrococci ranged from 3.53 to 5.03 log cfu / g and coagulase positive staphylococci were found in 16 samples ( 2.00 to 3.60 log cfu / g ) . 
 bacillus cereus was found in 3 samples ( 1.70 to 4.00 log cfu / g ) , while vibrio spp . 
 was found in 15 of the sushi samples ( 1.70 to 3.70 log cfu / g ) . in sashimi , the amb , pb and ssos values were higher than 7.00 log cfu / g , pseudomonas spp . 
 and enterobacteriaceae were from 6.00 to 8.00 log cfu / g , while vibrio spp . were found in six samples with means of 2.00 log cfu / g . 
 no salmonella spp . and 
 listeria monocytogenes were detected in all sushi and sashimi samples . 
Introduction
Materials and Methods
Results
Discussion
Conclusions