FDA Allergen Labeling Requirements: A Founder's Guide

Allergen labeling looks like a single short line near the ingredient list. It is one of the most heavily enforced parts of a US food label, and undeclared allergens are consistently the leading cause of FDA food recalls. The rules are specific about which allergens you have to call out, the exact words you can use, and how precise the source name must be. Most of them come from two laws: the Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA) and the FASTER Act of 2021. FALCPA’s allergen labeling rules took effect on January 1, 2006. The FASTER Act, signed April 23, 2021, added sesame as the ninth major allergen, with its requirements applying as of January 1, 2023.

This guide walks through what FDA requires, in plain language, and points out where first-time founders most often get it wrong. It is a starting map, not a substitute for a compliance review. The rules have exceptions, and some of the exceptions matter a lot.

Why allergen labeling is not optional

A packaged food sold at retail in the US has to declare every major food allergen it contains, in the format the law specifies. If a major allergen is present but not declared, or declared the wrong way, the product is “misbranded” under the Federal Food, Drug, and Cosmetic Act. FALCPA amended that Act so that a food is misbranded under section 403(w)(1) when it contains a major food allergen that is not declared as required. Unlike a formatting slip on the Nutrition Facts panel, an undeclared allergen is a safety issue, which is why it so often ends in a recall rather than a quiet correction.

That distinction matters for the stakes. A formatting error usually costs you a reprint. An undeclared allergen can pull product off shelves, trigger a Class I recall, and put a real safety claim on the table. The same reprint range of roughly $5,000 to $50,000 applies, but with allergens the downside does not stop there.

The nine major food allergens

FALCPA defined a list of “major food allergens” that have to be declared by their plain food source name, set out in section 201(qq) of the FD&C Act. For most of the law’s life that list had eight entries. The FASTER Act added sesame as the ninth, effective January 1, 2023. The current list is:

• Milk
• Eggs
• Fish
• Crustacean shellfish
• Tree nuts
• Peanuts
• Wheat
• Soybeans
• Sesame

A few things on this list trip people up. “Crustacean shellfish” means crab, lobster, shrimp, and similar species, but not mollusks like clams, mussels, oysters, or scallops, which are not major allergens under FALCPA. “Wheat” is the allergen, which is a different question from gluten and from the separate “gluten-free” claim rules. And these nine are the federally defined majors, but they are not the only ingredients a sensitive consumer reacts to, which is part of why precautionary statements exist further down.

A note on sesame, because the timing caught a lot of brands out

Sesame became the ninth major allergen on January 1, 2023. Products already in interstate commerce before that date did not have to be removed or relabeled, so any label printed before then may predate the requirement. If you are reusing an older template or a panel from a product printed a few years ago, sesame is the single most likely thing to be missing, because for most of food-labeling history it simply was not on the list. Treat any pre-2023 artwork as something to re-check against the current nine, not as a safe starting point.

The two compliant ways to declare an allergen

FDA gives you two acceptable formats, and you pick one. The food source name has to appear at least once, and you have to follow one of these two routes exactly.

The first is a “Contains” statement placed immediately after or directly adjacent to the ingredient list. It names every major allergen in the product, for example: “Contains: Milk, Wheat, Soy.” If you use a Contains statement, it has to list every major allergen present in the food, not just some of them.

The second is to name the food source inside the ingredient list itself, in parentheses right after the ingredient that contains it. For example, “lecithin (soy)” or “whey (milk).” If the source name is already obvious in the ingredient name (the word “buttermilk” already contains “milk”), you may not need the parenthetical, but the safer pattern is to make the source explicit.

You cannot mix the two to cover different allergens, declaring some in the ingredient list and relying on an absent Contains line for the rest. Whichever route you take, the complete set of major allergens has to be accounted for. Most brands use the Contains statement because it is harder to get wrong and easier to scan.

You have to name the specific source, not just the category

This is the detail that catches the most labels at review. For three of the categories, naming the broad category is not enough. You have to identify the specific food source:

• Tree nuts: declare the specific nut. “Almond,” “walnut,” “pecan,” “cashew,” not just “tree nuts.”
• Fish: declare the species. “Cod,” “salmon,” “bass,” not just “fish.”
• Crustacean shellfish: declare the species. “Shrimp,” “crab,” “lobster,” not just “shellfish.”

So a Contains statement reading “Contains: Tree Nuts” is not compliant on its own. It needs to say which tree nut, for example “Contains: Almond.” The same specificity applies whether you declare in a Contains line or inside the ingredient list.

How allergen declarations interact with the ingredient list

Allergen labeling does not replace the ingredient statement, it sits on top of it. Every ingredient still has to appear in the ingredient list in descending order by weight, and the allergen declaration is an additional safeguard layered over that list.

The place this gets subtle is sub-ingredients. A compound ingredient (a sauce, a seasoning blend, a chocolate coating) can carry an allergen that is easy to miss because it is buried one level down. If your “natural flavor” is carried on a soy base, or your spice blend includes a wheat-derived ingredient, that allergen is present in your product and has to be declared even though “soy” or “wheat” never appears as a top-line ingredient. FALCPA reaches allergens that are components of compound ingredients, so building the declaration correctly means tracing every sub-ingredient, not just reading the front of each component.

”May contain” and other precautionary statements

There is a second kind of allergen language you will see on packages: precautionary or advisory statements like “May contain peanuts,” “Made in a facility that also processes tree nuts,” or “Made on shared equipment with milk.” These address cross-contact, the unintended presence of an allergen that is not a deliberate ingredient, usually from shared lines, equipment, or facilities.

Two things are important here, and founders regularly get both wrong.

First, these statements are voluntary. FALCPA does not require them, and FDA does not define standard wording for them. They are a risk-communication choice, not a mandatory declaration, and they still have to be truthful and not misleading.

Second, a precautionary statement is not a substitute for allergen controls or for the mandatory declaration. You cannot use “may contain milk” to cover an allergen that is actually an ingredient, and you cannot use it as a shortcut around current good manufacturing practices (GMPs) and allergen cross-contact controls in your facility. FDA has been clear that advisory statements should not be used in place of adhering to GMPs, and should never replace declaring an allergen that is genuinely in the recipe. A precautionary line is a backstop for unavoidable cross-contact risk, applied after you have actually assessed and controlled that risk, not a label you slap on to be safe.

Canada’s allergen rules are not the same

If you plan to sell the same product in Canada, do not assume the US allergen declaration carries over. Canada works from its own list of priority allergens, and that list is not identical to the FDA nine. Canada includes mustard as a priority allergen, names both crustaceans and molluscs as shellfish allergens rather than only crustaceans, and requires that priority allergens, gluten sources, and added sulphites be declared in either a “Contains” statement or the ingredient list. On top of that, Canadian labeling is generally bilingual, so allergen information typically has to appear in both English and French. The takeaway is the same as with the Nutrition Facts table differences: a compliant US allergen declaration is a starting point for Canada, not a finished one.

How allergen issues surface at review

When a label comes through review, allergen problems are rarely dramatic. They are the same quiet ones, repeatedly: sesame missing from a pre-2023 template, “tree nuts” or “fish” declared without the specific species, an allergen hiding in a sub-ingredient that never made it into the Contains line, a Contains statement that lists three allergens when the recipe has four, or a “may contain” advisory being used to paper over an allergen that is actually an ingredient. These sit alongside the other common failure modes that get a food label kicked back, and like those, they are easiest to catch before the file goes to a printer, not after.

The shortcut

You can learn all of this. Founders do, usually one rejected proof or one near-miss recall at a time. The faster path is to hand it off.

That is what Complion does. You send us your recipe or product idea, and we build the ingredient statement, the Nutrition Facts panel, the allergen declarations, and the print-ready artwork. Then our food-compliance experts verify the whole thing against FDA, USDA, Health Canada, and CFIA before it reaches you, including tracing every sub-ingredient for hidden allergens. Your only step is sharing what you have.

If you want a compliant allergen declaration without becoming an expert in FALCPA and the FASTER Act, book a free call to start.