for food labelling as a standard relating to the labelling of products as gluten-free. it only applies to foods that would normally contain gluten. gluten-free is defined as 20 ppm (= 20 mg/kg) or less. it categorizes gluten-free food as: food that is gluten-free by composition food that has become gluten-free through special processing. reduced gluten content, food which includes food products with between 20 and 100 ppm of gluten reduced gluten content is left up to individual nations to more specifically define. the codex standard suggests the enzyme-linked immunoassay (elisa) r5 mendez method for indicating the presence of gluten, but allows for other relevant methods, such as dna. the codex standard specifies that the gluten-free claim must appear in the immediate proximity of the name of the product, to ensure visibility. there is no general agreement on the analytical method used to measure gluten in ingredients and food products. the elisa method was designed to detect w-gliadins, but it suffered from the setback that it lacked sensitivity for barley prolamins. the use of highly sensitive assays is mandatory to certify gluten-free food products. the european union, world health organization, and codex alimentarius require reliable measurement of the wheat prolamins, gliadins rather than all-wheat proteins. australia the australian government recommends that: food labelled gluten-free include no detectable gluten (<3ppm ) oats or their products, cereals containing gluten that have been malted or their products food labelled low gluten claims such that the level of 20 mg gluten per 100 g of the food brazil all food products must be clearly labelled whether they contain gluten or they are gluten-free. since april 2016, the declaration of the possibility of cross-contamination is mandatory when the product does not intentionally add any allergenic food or its derivatives, but the good manufacturing practices and allergen control measures adopted are not sufficient to prevent the presence of accidental trace amounts. when a product contains the warning of cross-contamination with wheat, rye, barley, oats and their hybridised strains, the warning "contains gluten" is mandatory. the law does not establish a gluten threshold for the declaration of its absence. canada health canada considers that foods containing levels of gluten not exceeding 20 ppm as a result of contamination, meet the health and safety intent of section b.24.018 of the food and drug regulations when a gluten-free claim is made. any intentionally added gluten, even at low levels must be declared on the packaging and a gluten-free claim would be considered false and misleading. labels for all food products sold in canada must clearly identify the presence of gluten if it is present at a level greater than 10 ppm. european union the eu european commission delineates the categories as: gluten-free: 20 ppm or less of gluten very low gluten foodstuffs: 20-100ppm gluten. all foods containing gluten as an ingredient must be labelled accordingly as gluten is defined as one of the 14 recognised eu allergens. united states until 2012 anyone could use the gluten-free claim with no repercussion. in 2008, wellshire farms chicken nuggets labelled gluten-free were purchased and samples were sent to a food allergy laboratory where they were found to contain gluten. after this was reported in the chicago tribune, the products continued to be sold. the manufacturer has since replaced the batter used in its chicken nuggets. the u.s. first addressed gluten-free labelling in the 2004 food allergen labeling and consumer protection act (falcpa). the alcohol and tobacco tax and trade bureau published interim rules and proposed mandatory labelling for alcoholic products in 2006. the fda issued their final rule on august 5, 2013. when a food producer voluntarily chooses to use a gluten-free claim for a product, the food bearing the claim in its labelling may not contain: an ingredient that is a gluten-containing grain an ingredient that is derived from a gluten-containing grain that has not been processed to remove gluten an ingredient that is derived from a gluten-containing grain, that has been processed to remove gluten but results in the presence of 20 ppm or more gluten in the food. any food product claiming to be gluten-free and also bearing the term "wheat" in its ingredient list or in a separate "contains wheat" statement, must also include the language "*the wheat has been processed to allow this food to meet the fda requirements for gluten-free foods," in close proximity to the ingredient statement. any food product that inherently does not contain gluten may use a gluten-free label where any unavoidable presence of gluten in the food bearing the claim in its labelling is below 20 ppm gluten.