Tool · United States
Allergen checker — US “Contains” statement
Paste an ingredients list. The checker marks the allergens it finds and then does the step that matters for a US label: it shows what a “Contains” statement under 21 U.S.C. § 343(w) would say — and which allergens drop out because the United States has nine where Europe has fourteen. Free, no sign-up, everything stays in your browser.
A first pass based on word patterns, not a legally binding declaration. An empty result is no guarantee that a product is free from allergens. Before you print a label, have the list verified against the actual recipe by a qualified person.
Nine, not fourteen — and that is the trap
The default text above is deliberate: it contains celery salt and mustard powder. Both are allergens in the European Union. Neither is one in the United States, and a label that declares them is not wrong so much as misleading about what the law requires — while the reverse, a US list taken to Europe, is simply incomplete.
| Allergen | United States | European Union |
|---|---|---|
| Milk, egg, fish, crustaceans, tree nuts, peanuts, soy, sesame | ✅ | ✅ |
| Cereals containing gluten | wheat only | wheat, rye, barley, oats, spelt, kamut |
| Celery | — | ✅ |
| Mustard | — | ✅ |
| Sulphites ≥ 10 mg/kg | —* | ✅ |
| Lupin | — | ✅ |
| Molluscs | — | ✅ |
*Sulphites are regulated in the United States, but not through § 321(qq): 21 CFR 101.100(a)(4) requires them in the ingredient list at or above 10 ppm. A different duty, a different threshold, and not part of the “Contains” statement — which is why the checker keeps them out of it.
Two ways to declare, and the checker shows one
§ 343(w)(1) gives a choice, and either is complete on its own: a “Contains” statement immediately after or adjacent to the ingredient list, or the food source in parentheses inside it. The box above shows the first, because it is the one that can be written out in a single line. Whichever you pick, it has to name every major food allergen in the food.
The full working-through, including the three species that need naming and the flavouring rule that overrides the flavouring rule, is in the Big 9 guide.
What the checker cannot see
- A carrier inside a flavouring. § 343(w)(4) catches it — “notwithstanding … any other law” — but the word “natural flavors” in your text does not say what is in it.
- A processing aid. It may not appear in the ingredient list at all and can still carry protein.
- Cross-contact. Nothing in the text reveals what else runs on the line. Precautionary statements are voluntary and are not part of § 343(w).
- Whether an oil is highly refined. § 321(qq)(2)(A) excludes highly refined oils and anything derived from them; “soybean oil” in a text does not say which it is.
Frequently asked questions
How many allergens does a US label declare?
Nine — § 321(qq)(1). The EU requires fourteen, and five of them are not US allergens.
Is “Contains: Tree nuts” enough?
No — § 343(w)(2) wants the species, for tree nuts, fish and crustaceans.
Does gluten count as an allergen in the US?
Not as such — wheat is named, gluten-containing cereals are not.
Can I use the checker output as my label?
No. It is a first pass over word patterns and has to be verified against the recipe.
Why does it show the EU allergens at all?
Because the difference is the point — those five are what a translation carries over by mistake.
Does a “Contains” statement have to list every allergen?
Yes, if you use one. It is an alternative to the parentheses route, not a supplement to it.
Wording quoted from 21 U.S.C. § 321(qq) and § 343(w) (US Code, 2023 edition, govinfo.gov) and 21 CFR 101.100(a)(4). The detection works on word patterns in the text you paste and makes no statement about your product; whether an ingredient carries a major food allergen is a question about that ingredient. This page is information, not legal advice — the responsibility for a label stays with the business that puts the food on the market.