Division 1.5 Allergenicity

Food allergy is an adverse reaction to food and represents an important public health problem. Food allergy is different from toxic reactions and intolerance. Allergy is a pathological deviation of the immune response to a particular substance, which affects only some individuals where a combined effect of variations in the environment and genetic predisposition has resulted in allergic sensitisation.

In allergic individuals, sometimes minute amounts of a food that is well tolerated by the vast majority of the population can cause serious symptoms and death. It is not the allergen per se, but the allergic person’s abnormal reaction to the allergen that causes the adverse health effect.

Food allergy can be caused by various immune mechanisms. However, IgE-mediated food allergy represents the main form of food allergy, that causes the most severe reactions and the only form causing life-threatening reactions. This IgE-mediated food allergy has been the focus in the risk assessment of allergenicity of GMOs. Importantly, food allergy consists of two separate phases: first sensitisation where no symptoms occur while the capacity of the immune system to react increases dramatically, and later elicitation (provocation) with clinical manifestations.

When ingested, the allergen(s), that is to say, the sensitising food or food constituent is to some extent degraded by digestive enzymes, absorbed by the gut mucosa (small amounts even by the oral mucosa), processed in specialised cells of the immune system and then presented to the reactive immune cells that produce an immune response. Sensitisation can also occur if the food allergen comes into contact with the skin or is inhaled.

The majority of the constituents that are responsible for allergenicity of foods, as well as of pollens, are proteins. Some protein breakdown products, that is to say, peptide fragments, may conserve part of the allergenicity of the native protein and thus can also be considered as allergens.

The specific allergy risk of GMOs is associated with: (i) exposure to newly expressed protein(s) that can be present in edible parts of the plants or in the pollen; this point is related to the biological source of the transgene; and (ii) alterations to the allergenicity of the whole plant and its products, for example, due to over-expression of natural endogenous allergens as an unintended effect of the genetic modification; this point is related to the biology of the recipient plant itself.

More detailed guidance for the application of the requirements of this Section is available F1from the Food Safety Authority.