The 9 Major Allergens Under US Federal Law

Since the addition of sesame under the FASTER Act in January 2023, US federal law requires declaration of nine major food allergens on all packaged food products. Understanding exactly what each allergen covers — and what counts as a "major food allergen" — is critical for any food business selling in the United States.

The Nine Major Allergens

Milk covers all forms including dried, condensed, evaporated, and butter. Eggs includes eggs from chickens and other poultry. Fish must be declared with the specific type (e.g. "salmon", "tuna") rather than just "fish". Shellfish likewise requires the specific type (e.g. "shrimp", "lobster"). Tree nuts must be declared by specific nut variety — almond, cashew, walnut, and so on. Peanuts are declared separately from tree nuts. Wheat covers wheat in all forms. Soybeans covers soy in all its forms. Sesame is the newest addition, added in January 2023.

How to Declare Them

FALCPA allows two methods. First, within the ingredient list itself — using the common name of the allergen (e.g. listing "whey (milk)" or "flour (wheat)"). Second, in a "Contains" statement immediately following the ingredient list, such as "Contains: milk, wheat, soy". Both methods are legally acceptable; many food businesses use the "Contains" statement for clarity.

Tree Nuts: The Specific Name Requirement

One area where food businesses frequently get it wrong is tree nuts. FALCPA requires that the specific type of tree nut be named — "almonds" rather than "tree nuts". If your product contains multiple tree nuts, each must be listed individually. Review your labels and Shopify product pages to ensure specificity.

Sesame: What the FASTER Act Changed

Sesame became the ninth major allergen on 1 January 2023 under the FASTER Act — Food Allergy Safety, Treatment, Education, and Research Act — signed into law in April 2021. Before this change, sesame was not federally recognised as a major allergen, meaning manufacturers were not legally required to call it out by name. It could appear under vague terms like "natural flavours" or "spices" without triggering a declaration requirement. That is no longer permitted. Any product containing sesame must now explicitly declare it, regardless of how it was historically labelled.

The practical impact on food businesses has been significant. Many manufacturers had to reformulate products or update labels within a relatively short compliance window. Some businesses that had been using sesame in small quantities as a flavouring agent — never prominently disclosed — found themselves facing a choice between reformulation and full allergen disclosure. For Shopify merchants selling packaged food in the US market, this means any product description or digital ingredient list on your store also needs to reflect sesame where it is present, not just the physical label.

One further complication with sesame is cross-contact. Because sesame is so widely used in international cuisines and processed in shared facilities, cross-contact risk is high even for products that do not include sesame as a deliberate ingredient. The FDA's guidance on sesame cross-contact and voluntary advisory statements continues to evolve. Food businesses should monitor FDA updates closely and ensure their digital product information on Shopify stays current whenever their physical labels or formulations change. Allergen Matrix can help you keep that information consistent across your entire catalogue.

Fish and Shellfish: Why the Specific Name Matters

Fish and shellfish are two separate allergen categories under FALCPA, and each carries its own specific-name requirement that trips up many food businesses. For fish, you cannot simply write "fish" in your Contains statement or ingredient list — you must name the species. So a product containing anchovies must say "anchovies", not "fish". This matters clinically because fish allergies can be species-specific; a person allergic to salmon may tolerate tuna, and vice versa, so the specific name gives consumers the information they need to make safe choices.

Shellfish is similarly divided into crustaceans and molluscs, though FALCPA's major allergen definition focuses primarily on crustacean shellfish — shrimp, lobster, crab, and related species. Molluscs such as oysters, clams, scallops, and mussels are not currently classified as major allergens under federal law, though some states have introduced their own requirements. If your product contains both shrimp and lobster, both must be declared individually. Writing "shellfish" alone is not compliant, just as writing "tree nuts" alone is not compliant for products containing multiple nut varieties.

For Shopify merchants selling seafood products, sauces, or any prepared food containing fish or shellfish derivatives — including fish sauce, Worcestershire sauce, and certain stocks — it is worth auditing every ingredient source carefully. Fish derivatives can appear in unexpected places, and the specific-name requirement means you need to trace each one back to its species. Maintaining a clear and up-to-date allergen record for each product in your Shopify catalogue is not just good practice; it is a legal requirement for products sold into the US market.

Milk and Eggs: Broader Than You Might Expect

Milk as a major allergen under FALCPA covers far more than a carton of fresh dairy. It includes all derivatives — casein, whey, lactose, lactalbumin, lactulose, and ghee, among others. Butter, cream, cheese, yoghurt, and powdered milk are all covered. This breadth catches out food businesses that assume a small quantity of whey protein powder in a sports supplement or baked good does not require a milk declaration. It does. Any ingredient derived from milk must trigger a declaration, regardless of how processed or refined it is, unless it meets a very narrow exemption for highly refined oils.

Eggs present a similar challenge. The allergen covers eggs from chickens and other poultry, and includes derivatives such as albumin, globulin, lysozyme, and mayonnaise. Eggs can appear in unexpected formulations — certain wines and beers use egg-based fining agents, some pasta products use dried egg, and many baked coatings contain egg-derived ingredients. Food businesses sometimes overlook egg derivatives because they do not resemble the whole ingredient. Reviewing supplier specifications for each ingredient in your formulation is the most reliable way to identify hidden egg sources before they cause a labelling problem.

For Shopify merchants, the practical takeaway is that your digital product pages need to reflect the same level of detail as your physical labels. If your label declares milk because of whey, your online product description should not simply list the marketing highlights of your product while omitting that information. Customers with milk or egg allergies rely on digital information when deciding whether to add something to their cart. Keeping your allergen declarations consistent and accurate across both physical and digital touchpoints is not only a legal consideration — it is a basic matter of consumer safety.

What "Major Food Allergen" Does Not Cover

Understanding what is not on the federal list is just as important as knowing what is. Gluten, for example, is not a major food allergen under FALCPA — wheat is. A product could theoretically contain rye or barley and not trigger a major allergen declaration, even though those grains contain gluten and are a serious concern for people with coeliac disease. The FDA has separate voluntary labelling guidance for gluten-free claims, but that is distinct from the mandatory allergen declaration framework. Food businesses targeting coeliac customers should not rely on the allergen declaration system alone to communicate gluten status.

Similarly, mustard, celery, lupin, sulphur dioxide, and molluscs are major allergens under European food law but are not on the US federal list. If you are a Shopify merchant selling across both markets — or if you are a US-based business sourcing products formulated to EU standards — the two frameworks do not align neatly. A product compliant under EU labelling rules may still be missing declarations required under US law, and vice versa. Managing dual-market compliance requires careful attention to the specific requirements of each jurisdiction rather than assuming that meeting one framework automatically satisfies the other.

It is also worth noting that individual US states can and do introduce requirements beyond federal law. California, for instance, has historically moved ahead of federal standards on food safety and labelling issues. Food businesses selling nationally through Shopify should keep an eye on state-level developments, particularly for allergens like mustard and sesame, which have active advocacy communities pushing for expanded recognition. Federal law sets the floor, not the ceiling, and state requirements can add meaningful compliance obligations depending on where your customers are located.

Keeping Your Shopify Store Compliant

Maintaining allergen compliance across a Shopify store is not a one-time task. Every time a formulation changes, a supplier switches an ingredient, or a new product is added to your catalogue, your allergen information needs to be reviewed and updated. Many food businesses manage physical label updates carefully but overlook their digital product pages, leaving outdated or incomplete allergen information visible to customers. That gap creates both legal risk and genuine safety risk for consumers who rely on your online descriptions to make purchasing decisions.

A practical audit process should include reviewing every product page against the current physical label, checking that all nine major allergens are declared where present, and confirming that specific names are used for fish, shellfish, and tree nuts rather than generic category terms. If your store has dozens or hundreds of products, doing this manually is time-consuming and error-prone. Building a structured allergen record for each SKU — and keeping that record updated whenever anything changes upstream in your supply chain — is the only reliable way to stay on top of your obligations.

SaltAI's Allergen Matrix app supports all nine US major allergens across your Shopify store. Learn more.

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