What Are the Major Food Allergens? The Big 9 Explained (2026)

The Big 9 food allergens

Together, these nine foods account for roughly 90% of all food-allergic reactions in the U.S. Here's the full list, with common examples of where each hides:

• Milk — dairy, butter, cheese, whey, casein, and many baked goods.
• Eggs — mayonnaise, baked goods, some sauces, and egg washes.
• Fish — tuna, cod, salmon, and hidden sources like Worcestershire and Caesar dressing.
• Crustacean/Shellfish — shrimp, crab, lobster, and crawfish.
• Tree nuts — almonds, walnuts, cashews, pecans, pistachios, and more.
• Peanuts — a legume, tracked separately from tree nuts because reactions are so common.
• Wheat — breads, pastas, batters, and many thickeners and sauces.
• Soybeans — soy sauce, tofu, edamame, and countless processed ingredients.
• Sesame — seeds, tahini, hummus, and many breads, spice blends, and dressings.

Why these nine?

The federal government designates major allergens based on how frequently they cause reactions and how severe those reactions tend to be. Because these foods are the most common triggers of dangerous, sometimes life-threatening reactions, U.S. law (the Food Allergen Labeling and Consumer Protection Act, expanded by the FASTER Act) requires them to be clearly declared on packaged food labels.

Sesame: the newest addition

For years the list was the “Big 8.” That changed when the FASTER Act added sesame as the ninth major allergen, effective January 1, 2023. Sesame can be difficult to spot because it appears in so many breads, sauces, and spice blends, which is exactly why regulators singled it out for clearer labeling and greater awareness.

Allergy vs. intolerance — an important distinction

A food allergy involves the immune system and can be life-threatening, triggering symptoms from hives to anaphylaxis. A food intolerance (such as lactose intolerance) is a digestive issue — uncomfortable, but not life-threatening. For food establishments, the safe assumption is always to treat a stated allergy as serious.

Why this matters for food businesses

For anyone in food service, knowing the Big 9 is only the starting point. The real risk is cross-contact — when an allergen is unintentionally transferred to a food that's supposed to be safe, through shared equipment, utensils, gloves, or fryer oil. A single overlooked ingredient or a shared cutting board can send a guest to the emergency room.

That's why allergen awareness has become a core part of food safety training. Staff who understand where allergens hide, how to prevent cross-contact, and how to respond confidently to a guest's allergy question are what stand between a great meal and a medical emergency.

The bottom line

The nine major food allergens — milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, and sesame — drive the overwhelming majority of serious food reactions, and every food business is responsible for identifying and controlling them. Training your team to recognize and manage them isn't just good compliance, it's how you protect your customers and your reputation.