The FDA sets the floor. The people who actually read your label, license the maker, and pull product off a shelf work for a state department of agriculture.
Ask who regulates pet food in America and most people say the FDA. That is half an answer.
The FDA has federal authority over animal food, including pet food. It sets requirements for ingredient legality and food safety, it issues guidance, it inspects, and it can act on adulterated or misbranded product moving in interstate commerce.
But the routine, day-to-day work — reviewing a label before it can be sold, licensing the company, registering the individual product, and inspecting the place where it is made — is done by state feed control officials, in fifty separate departments of agriculture.
The Association of American Feed Control Officials is not a government agency. It has no enforcement power and it does not regulate anything.
It is an association of the officials who do. What it produces is a model bill and model regulations — a template for what a state's feed law could say — plus the Official Publication containing ingredient definitions and the labeling requirements built on them.
States then adopt that model. Most adopt most of it. None are required to adopt any of it.
That is why the phrase "AAFCO approved" is meaningless. AAFCO does not approve products. States register them.
A company that wants to sell pet food in a state generally needs a commercial feed license from that state, and it generally needs to register each individual product with the label the product will actually carry.
Fees are per license and per product. A three-product line is three registrations. A change to a formulation can mean a new registration rather than an amended one, because the label filed is the label sold.
The official reviewing that submission reads the product name against the naming rules, checks the guaranteed analysis, reads the ingredient statement against defined ingredient names, and reads the nutritional adequacy statement. That review is where most label problems get caught, before anything reaches a shelf.
Requirements vary. Fees vary. Timelines vary. Interpretation varies.
AAFCO's own human grade guidance advises manufacturers to contact the feed control officials in each state they intend to distribute into, because the appropriate course of action for a given claim depends on the state.
A national brand deals with this by employing people whose job it is. A company selling in one state deals with one regulator — which is simpler, and which also means that regulator's reading of a rule is, for practical purposes, the rule.
The state layer runs on the Official Publication. State officials enforce ingredient definitions that AAFCO publishes.
That is what made the expiration of the FDA–AAFCO memorandum in October 2024 consequential rather than procedural. The book state regulators use was populated through a process the FDA participated in. When the FDA's role in that process ended, the agency had to issue guidance stating it did not intend to act against ingredients already in the 2024 edition — precisely because so much state enforcement depends on that book.
Federal and state are not separate systems here. They are one system with the federal government at one end and fifty enforcement bodies at the other, connected by a publication produced by a private association.
The last one is the one a small manufacturer talks to. It is also the one almost nobody outside the industry has heard of.
Structure as described in the AAFCO model bill and model regulations and in FDA guidance. AAFCO is a private association of regulatory officials with no enforcement authority. Requirements vary by state.