The Big 9 Allergens
Since January 2023, US food labeling law requires disclosure of nine major allergens that cause over 90% of all food allergic reactions. These must be declared on the label either in the ingredient list (in parentheses after the ingredient name) or in a separate "Contains" statement immediately following the ingredient list. The nine allergens are: milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, soybeans, and sesame. Sesame was added as the ninth major allergen under the FASTER Act of 2021.
Hidden Sources of Major Allergens
| Allergen | Obvious Sources | Hidden Sources |
|---|---|---|
| Milk | Cheese, butter, yogurt, ice cream | Casein, whey, lactose, ghee, nougat, some medications |
| Eggs | Omelets, mayonnaise, meringue | Albumin, lysozyme, globulin, pasta, some vaccines |
| Wheat | Bread, pasta, cereal, crackers | Soy sauce, modified food starch, hydrolyzed protein, couscous |
| Soy | Tofu, edamame, soy milk | Lecithin, vegetable oil, textured vegetable protein, miso |
| Peanuts | Peanut butter, trail mix | Arachis oil, some sauces (satay, mole), hydrolyzed peanut protein |
| Tree nuts | Almonds, walnuts, cashews | Marzipan, praline, pesto, nut oils, some granola bars |
| Sesame | Sesame seeds, tahini, hummus | Halvah, some bread toppings, Asian sauces, spice blends |
| Fish | Salmon, tuna, cod | Worcestershire sauce, Caesar dressing, some supplements |
| Shellfish | Shrimp, lobster, crab | Glucosamine, surimi (imitation crab), some broths |
Reading Labels for Allergen Safety
For individuals with food allergies, label reading is a critical safety practice. Always check the "Contains" statement at the end of the ingredient list — this is the quickest way to identify major allergens. However, the "Contains" statement only covers the Big 9; other allergens (corn, mustard, celery) may be present but not highlighted. For these, you must read the full ingredient list. Be aware that "May contain" or "produced in a facility that processes" statements are voluntary — they indicate cross-contamination risk but are not required by law. Their absence does not guarantee the product is free from cross-contamination.
Cross-Contamination Risks
Manufacturing cross-contamination occurs when shared equipment or facilities transfer allergen proteins between products. For highly sensitive individuals, even trace amounts (measured in parts per million) can trigger reactions. Look for products with dedicated allergen-free production lines — some manufacturers explicitly state "made in a peanut-free facility" or carry third-party certifications like GFCO (Gluten-Free Certification Organization). Restaurants present additional cross-contamination risks through shared fryers, preparation surfaces, and utensils.
Emergency Response
Severe allergic reactions (anaphylaxis) require immediate epinephrine injection followed by calling 911. Symptoms include difficulty breathing, throat swelling, rapid pulse, dizziness, and loss of consciousness. Antihistamines (Benadryl) are insufficient for anaphylaxis — they may help mild symptoms but cannot stop a severe reaction. Every person with a diagnosed food allergy should carry two epinephrine auto-injectors and have an anaphylaxis action plan. Search for specific allergens in common food products using our ingredient profiles.