Under US federal law, packaged foods must clearly declare the presence of a defined set of "major food allergens." The list started at eight under the Food Allergen Labeling and Consumer Protection Act (FALCPA) of 2004 and became nine when sesame was added by the FASTER Act, effective January 1, 2023. These nine are responsible for the large majority of serious allergic reactions to food in the US. Knowing the list — and the many alternative names each allergen appears under — is the difference between reading a label confidently and guessing.
The 9 major allergens
The FDA's major allergens are: milk, egg, peanut, tree nut, soy, wheat, fish, shellfish (crustacean shellfish), and sesame. For each, federal labeling rules require the food source to be named in plain language — either inside the ingredient list or in a separate "Contains" statement directly after it. That means a label can't just say "casein"; it must make clear that casein is milk.
Why the names are the hard part
The allergen is rarely listed by its common name. Milk appears as casein, caseinate, whey, lactose, or ghee. Egg shows up as albumin, globulin, lysozyme, or ovalbumin. Wheat hides in semolina, durum, spelt, farina, and bulgur. Soy appears as lecithin, edamame, miso, or textured vegetable protein. The legal requirement to name the source helps, but precautionary phrases and processing aids still trip people up — which is why a decoder that maps each term back to its allergen is useful.
What the label is — and isn't — telling you
A required "Contains" statement is reliable: if a major allergen is in the product, it must be there. A voluntary "may contain" or "made in a facility with" statement is different — it's an unregulated, optional warning about possible cross-contact, not a declared ingredient. Its absence does not guarantee safety, and its presence doesn't always mean meaningful risk. When the stakes are high, the safest move is to read the full ingredient list and contact the manufacturer.
FDA Top-9 Allergen Reference
Look up any allergen or label word
Open FDA Top-9 Allergen Reference →Memorize the nine, but don't try to memorize the hundreds of derivative names — that's what the Hidden Allergen Names decoder and the Top-9 reference are for. Always confirm against the full label and the "Contains" statement.