Undeclared Allergen
When a food contains a major allergen, such as milk or peanut, that the label fails to list. It is the single most common reason for US food recalls.
An undeclared allergen recall happens when a product contains one of the nine major allergens recognized in the US (milk, egg, fish, shellfish, tree nut, peanut, wheat, soybean, and sesame) but the ingredient label does not declare it.
The cause is usually a process failure rather than a bad ingredient. A supplier swaps a recipe without telling the manufacturer, the wrong label gets printed on a package, or a shared production line carries over residue from a previous run. The food is safe for most people, but for someone with that allergy it can be life-threatening.
This is why undeclared allergens led FDA food recalls in 2026, with milk and soy as the most common offenders. The FDA usually classifies these as Class I or Class II depending on the severity of the allergen and how the product is consumed.
If you have a food allergy, this is the recall reason that matters most to you. Search your regular brands periodically, and pay attention to the lot numbers in each notice, since allergen recalls almost always cover a specific production window rather than the whole product line.
Related terms
Class I Recall
The most serious FDA recall class, used when a product has a reasonable chance of causing serious health harm or death.
Recall Classification (I, II, III)
The FDA's three-level system that ranks how dangerous a recalled product is, from life-threatening (I) to a labeling-only issue (III).
FDA vs USDA Jurisdiction
Two agencies split US food recalls: the FDA covers most packaged foods and produce, while the USDA covers meat, poultry, and egg products.