There has been significant increase in food allergy incidents in the past few decades and food allergies are becoming an important public health concern and a major food safety issue globally. Public health systems, food safety authorities and the food industry can play a key role in helping individuals with certain food allergies avoid exposure to such food. Recognizing a true food allergy that a consumer is experiencing is critical to recommending avoidance of a particular food, since some individuals have very low threshold levels for these foods.
Adverse food reactions
Adverse food reactions can be defined as any abnormal reaction caused by the ingestion of food. Adverse reactions to foods can be broadly divided into immune (IgE) mediated food allergies or nonimmune (non-IgE) mediated food intolerances. Food allergies and food intolerances are different from other food-borne diseases caused by foodborne pathogens that cause illness in humans by either infection or intoxication. Food-borne infections are caused by consuming live pathogens like bacteria, molds, viruses, and parasites that grow in the body, usually in the intestinal tract, and cause illness. Food-borne intoxications are caused by consuming toxins produced by certain bacteria like Staphylococcus aureus after they have grown in the food and ingestion of chemical substances like aflatoxins produced by certain molds. Food-borne infections and intoxications can affect all the individuals who consume the contaminated food, but the degree of susceptibility may vary between individuals. In contrast to foodborne infections and intoxications, food allergies and food intolerances cause adverse reactions in only certain individuals in the population and the majority of the population can consume that food without any adverse reactions. A classification scheme for different types of adverse reactions to foods is provided in Figure 1 on page 62.
Food allergy vs food intolerance
Food allergy is defined as ‘‘an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food, usually a naturally occurring protein’’. Depending on the involvement of antibody called immunoglobulin E (IgE), the immune response in food allergy can be classified into IgE-mediated, non-IgE-mediated or a mixture of both (Figure 1). In IgE-mediated response, symptoms of food allergy usually start within minutes of exposure (immediate hypersensitivity reactions) to the trigger food and occur within few hours. Non-IgEmediated food allergy (delayed hypersensitivity reactions) are cell-mediated reactions with symptoms developing 48-72 hours after ingestion of the trigger food.
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OCTOBER 2019