Serious attempts to estimate the impact of allergic reactions to foods on public health did not begin until the 1980s. Until about 15 years ago, food allergy was considered a minor aspect of food safety. Two developments probably prompted a radical re-appraisal of that situation. The first was the apparently inexorable rise in the prevalence of atopic diseases, of which food allergy forms a part, with its possible consequences highlighted by some well publicized severe reactions. The second was the growth of genetic modification technology, manifested by the commercialization of transgenic crops. Each of these developments impacted on the food industry in distinct ways. On the one hand, food-allergic consumers had to be enabled to avoid specific allergens in products formulated with existing ingredients. Food manufacturers therefore had to identify those specific allergens down to trace amounts in all the ingredients forming the product, and label or remove them. On the other hand, the introduction of products using ingredients from novel sources required an assessment of the allergenicity of these ingredients as an integral part of safety assurance. The approaches used by the food industry to protect existing allergic consumers and those at potential risk of sensitization by novel proteins will be illustrated, emphasizing how they need to be built into every stage of the life cycle of a product.