Handbook of Food Allergen
Detection and Control

Food allergy is defi ned as an immunological reaction resulting from consumption or
other contact with food. It only affects susceptible people who are sensitive, or
‘sensitised’, to the specifi c food allergen, which would otherwise normally be well
tolerated by the rest of the population. For those affected by food allergy, consumption
of normally nutritious foodstuffs, even in small quantities, can produce life-threatening
adverse reactions. Food allergy is a type of food hypersensitivity. Defi nitions of food
allergy have recently been published by the European Academy of Allergy and
Clinical Immunology (Johansson et al ., 2001 ) and by the US National Institutes of
Allergy and Infectious Diseases (NIAID) (Boyce et al ., 2010 ). Figure 1.1 summarises
their defi nitions in an overview of different types of adverse reactions to food. Food
hypersensitivity can be divided in clinical terms into food allergy and non-allergic
food hypersensitivity such as lactose intolerance. Food allergy can then be further
subdivided into IgE-mediated food allergy to foods such as milk, egg or peanuts, and
non-IgE-mediated food allergy such as gluten intolerance (coeliac disease) and
systemic allergic contact dermatitis.