Food Allergens and the 14 Named Allergens
What an allergen is
A food allergen is normally a protein (or protein-bound substance) that triggers an abnormal immune response in susceptible people. The UK recognises 14 named allergens that must always be declared when used as ingredients: celery (including celeriac); cereals containing gluten (wheat, rye, barley, oats and their hybridised strains); crustaceans; eggs; fish; lupin; milk; molluscs; mustard; peanuts; sesame; soybeans; sulphur dioxide/sulphites above 10 mg/kg or 10 mg/L; and tree nuts (almond, hazelnut, walnut, cashew, pecan, Brazil, pistachio, macadamia/Queensland).
Concepts to understand
Distinguish allergy (immune-mediated, often immediate, small doses can trigger) from intolerance (e.g. lactose, dose-related, not immune) and coeliac disease (autoimmune response to gluten). Recognise that peanut is a legume, not a tree nut, and that coconut is not a tree nut for labelling purposes. Understand hidden allergens: wheat in soy sauce, milk in butter or ghee, egg in mayonnaise, sulphites in dried fruit and wine, mustard in dressings, celery in stock.
Traps in questions
- Sulphites have a threshold (10 mg/kg or 10 mg/L); other allergens do not.
- Gluten cereals cover oats separately because of cross-contamination risk in growing/processing.
- Lupin flour appears in some imported baked goods and is easy to miss.
- Molluscs (squid, mussels) and crustaceans (prawns, crab) are separate allergens.
Rule of thumb
If a candidate ingredient is a protein-containing plant or animal food, assume it could be one of the 14 until checked against the list; only sulphites have a numeric trigger level.