Are you going by 21 CFR for food or for nutritional supplements?
I'm going by the Food Allergen Labeling and Consumer Protection Act of 2006. that is the statutory mandate to include the specific name of an allergen within the list of ingredients if that ingredient contains the allergen. It mandates that when you say flour, you must have the word "wheat" along with it so people know that there is wheat in it. It specifies the exact name.
The FDA regulations say that all the ingredients must be on the label. So if it's in there, it must say so. Allergen or not allergen, the customer has to know what was put into the box. The FALCPA says that the ingredient name must clearly communicate that an ingredient contains an allergen in a way that the consumer can recoginze. All this is to be part of the list of ingredients (which follows the word "Contains".)
I've attached a guidance document for you.
Guidance for Industry.pdf 215.17KB
It has some FAQ that do a good job of explaining it. But I've read the statute as well, and you are welcome to read it. The text is on the FDA website.
So the original FDA labeling requirements for food always required that all ingredients had to be listed whether they contained an allergen or not. The FALCPA required that the terminology be standardized so that consumers know that a mixture contains an allergen in a recognizable manner. But you don't have to include a statement that a bar that has peanuts in the list of ingredients "may have peanuts." That makes you the fodder for commedians.
Many manufacturers put warning statements if there is a chance that the product has small amounts of an allergen as a contaminant. That's not mandatory, it's done to protect the corporation from lawsuits. The FDA says that if it's in the box, it has to be on the label. If you don't include potential allergens and it is discovered in the box, you are not in compliance. It's very simple, if it's in the box, it has to be on the label.
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