The FDA recognizes nine major food allergens: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, and sesame. These nine foods and food groups account for the most serious allergic reactions in the United States, and federal law requires that every one of them be clearly identified on packaged food labels.
The Nine Major Food Allergens
The original eight allergens were established by the Food Allergen Labeling and Consumer Protection Act (FALCPA) in 2004. Sesame became the ninth in January 2023, when the FASTER Act took effect. Here is the complete list:
- Milk
- Eggs
- Fish (the specific species must be named, such as bass, flounder, or cod)
- Crustacean shellfish (the specific species must be named, such as crab, lobster, or shrimp)
- Tree nuts (the specific type must be named, such as almonds, pecans, or walnuts)
- Peanuts
- Wheat
- Soybeans
- Sesame
About 6.7% of U.S. adults have a diagnosed food allergy, according to 2024 data from the National Center for Health Statistics. Women are more likely to have one (8.3%) than men (5.1%), and the rate is highest among younger adults ages 18 to 44 at 7.4%. An estimated 90,000 emergency department visits occur each year in the U.S. for food-related anaphylaxis, which is the severe, potentially life-threatening reaction these labeling rules are designed to prevent.
How Allergens Must Appear on Labels
Federal law gives manufacturers two ways to declare a major allergen on packaged food. The first is a “Contains” statement printed immediately after the ingredient list. You’ll see something like “Contains: milk, wheat, soy.” The text must be at least the same size as the ingredient list itself.
The second option is to call out the allergen in parentheses within the ingredient list. For example, a label might read “casein (milk)” or “lecithin (soy).” If the common name of an ingredient already makes the allergen source obvious, like “milk” or “egg,” no extra clarification is needed.
These rules apply even when an allergen shows up in unexpected places. Flavorings, colorings, and incidental additives that contain a major allergen are not exempt. If a natural flavoring is derived from wheat, it must be disclosed.
Tree Nuts: Not Every Nut Counts
The FDA maintains a specific list of which tree nuts qualify as major food allergens. Not every nut you’d find in a grocery store makes the cut. The agency recently updated its guidance and removed several nuts from the list, including coconut, chestnut, hickory nut, beech nut, butternut, ginkgo nut, cola nut, palm nut, pili nut, shea nut, and lichee nut. These were dropped because the scientific evidence didn’t support classifying them alongside higher-risk tree nuts like almonds, cashews, walnuts, and pecans.
Nuts removed from the list should not appear in a “Contains” statement, because that statement is legally reserved for the nine major allergens. This distinction matters if you have a tree nut allergy: the label will name the specific nut used, so you can identify exactly which ones to avoid rather than steering clear of all products that mention “tree nuts” generically.
What the Rules Don’t Cover
Allergen labeling requirements apply to packaged foods regulated by the FDA, not to raw agricultural commodities like fresh fruits and vegetables. They also don’t apply to foods regulated by the USDA, such as most meat and poultry products (though many meat processors voluntarily disclose allergens).
Highly refined oils derived from major allergens are specifically excluded. Highly refined soybean oil, for instance, does not need to be labeled as a soy allergen because the refining process removes the allergenic proteins. Any manufacturer can petition the FDA with scientific evidence showing that an ingredient derived from a major allergen no longer contains allergenic protein. If the FDA doesn’t object within 90 days, that ingredient is exempt from labeling.
“May Contain” Warnings Are Voluntary
You’ve probably seen statements like “may contain traces of peanuts” or “produced in a facility that processes tree nuts.” These precautionary advisory labels are entirely voluntary. The FDA does not require them, and there is no standardized format or threshold for when a manufacturer should use one. This means their absence on a package doesn’t guarantee the product is free from cross-contact with an allergen. It also means two products with identical manufacturing conditions might handle advisory labels differently.
Allergens Recognized in Other Countries but Not the U.S.
If you travel or buy imported foods, it’s worth knowing that other countries require labeling for allergens the FDA does not recognize. The European Union, for example, mandates labeling for mustard, celery, lupin, molluscan shellfish (like clams, oysters, and mussels), and sulfites. Other jurisdictions around the world also flag buckwheat, beef, peach, and even latex-related allergens. These foods can still cause serious reactions, but they are not part of the FDA’s list and won’t necessarily appear in a “Contains” statement on products sold in the U.S.
Crustacean shellfish (shrimp, crab, lobster) is on the FDA list, but molluscan shellfish (clams, mussels, oysters, scallops) is not. This is a gap that catches some people off guard, especially those with broad shellfish allergies.