Allergen labelling for food manufacturers | Food Standards Agency 14 allergens. If your product contains any of the main 14 allergens as an ingredient or processing aid, it must be included on the label. The 14 main allergens are: celery. cereals containing gluten - including wheat (such as spelt and Khorasan), rye, barley and oats. crustaceans - such as prawns, crabs and lobsters.