Aflatoxin in Food: Sources, Health Risks & FDA Action Levels

Aflatoxin is a poison that some molds make. These molds grow on crops such as corn, peanuts, tree nuts, and spices. Aflatoxin can stay in food after processing, and it can cause serious illness in people and animals.

For a food manufacturer, aflatoxin is a chemical hazard. You must identify it, control it, and verify the control. The U.S. Food and Drug Administration (FDA) uses action levels to decide when food with aflatoxin is adulterated.

Aflatoxin can also cause business problems. A contaminated lot can cause a recall, an import refusal, or a lost customer. Many buyers and export markets set limits that are lower than the FDA limits.

This article tells you where aflatoxin comes from and how it affects human health. It gives the FDA action levels for food and feed, and it compares them with other markets. It also gives a procedure to sample, test, and control aflatoxin in your facility.

Aflatoxins are toxic chemicals from two molds: Aspergillus flavus and Aspergillus parasiticus. Aflatoxins are part of a larger group of toxins with the name mycotoxins. Other mycotoxins include ochratoxin A, fumonisins, and deoxynivalenol (DON).

There are four primary types of aflatoxin: B1, B2, G1, and G2. B1 is the most toxic type and the most common type. When a dairy animal eats feed that contains B1, its body changes some B1 into aflatoxin M1. M1 then goes into the milk.

Where Does Aflatoxin Come From?

The molds grow best in hot and humid conditions. Contamination can occur at two points in the supply chain: in the field and in storage.

In the field. Drought and heat make crops weak. Insects make holes in kernels and pods, and the mold goes in through these holes. A late harvest gives the mold more time to grow.

In storage. Mold grows quickly when the crop is not dry. Warm temperatures, condensation, and roof leaks increase the risk. Insects and rodents in a warehouse also damage the product and spread the mold.

The weather changes from year to year, so the risk also changes. A hot and dry season can increase aflatoxin levels across a full region.

Aflatoxin is stable at high temperatures.

Cooking, roasting, and pasteurization do not fully remove it.

Because of this, the best control is to prevent contamination.

You must also reject contaminated lots before they go into your process.

An action level is a limit that FDA uses to decide when to take enforcement action. Action levels are not binding on the courts, the regulated industry, or the agency. But FDA can find food adulterated when the aflatoxin level is above the action level. FDA can also take action below an action level when it has sufficient evidence.

The action levels apply to total aflatoxins (B1 + B2 + G1 + G2). For milk, the action level applies to aflatoxin M1. The unit is parts per billion (ppb). 20 ppb is equal to 20 micrograms in 1 kilogram of food.

Human Food

Animal Feed (CPG Sec. 683.100)

FDA generally does not let you blend corn that contains aflatoxin with clean corn to decrease the level.

How FDA Enforces the Action Levels

FDA collects samples during inspections and at the port of entry. If a sample is above the action level, FDA can take regulatory action. Examples are a recall request, a seizure, or the refusal of an imported lot.

FDA can also put a foreign firm on an import alert. FDA can then detain future shipments from that firm without a physical examination. The importer must then show that each shipment is safe.

How the FDA Limits Compare to Other Markets

The European Union (EU) has stricter limits than FDA. The EU sets one limit for aflatoxin B1 and a second limit for total aflatoxins. The Codex Alimentarius sets international limits that many countries use. For example, the Codex limit for total aflatoxins in almonds, hazelnuts, and pistachios is 10 ppb when ready to eat and 15 ppb for further processing.

If you sell into more than one market, set your specification to the strictest limit that applies. 1 ppb is equal to 1 µg/kg.

• Sampling causes most of the error in an aflatoxin result. Mold grows in small areas, so a small number of kernels can contain most of the toxin in a lot. A small sample can miss these kernels, or it can include too many of them.

To decrease this error, do these steps:

• Take many small portions from different locations in the lot.
• Use a large total sample, as your sampling plan specifies.
• Grind the full sample to a fine particle size before you take the test portion.
• Use a recognized sampling plan, such as the USDA FGIS plan for grain or the Codex plan for nuts.

Test Methods

Rapid methods are fast, but they can give incorrect results in some products, such as spices. Make sure that the method is validated for your product. Use an accredited laboratory (ISO/IEC 17025) for confirmation and for disputes with suppliers.

New Updates for 2026

• FDA levels have not changed. The FDA action level guidance for human food is dated August 2000. The feed guidance, CPG Sec. 683.100, was last issued in March 2019.
• More EU checks on pistachios. On January 28, 2026, the European Commission published a regulation that increased official controls on certain imports. It entered into force on February 18, 2026. The regulation applies 50% aflatoxin checks to Turkish pistachios and to U.S. pistachios that go through Türkiye.
• Enforcement focus on hazard analysis. In a 2023 warning letter, FDA cited a firm that did not show that mycotoxins require a preventive control. The firm also did not provide a preventive control for mycotoxins. A COA alone is not sufficient.

Does cooking remove aflatoxin?

No. Aflatoxin is stable at normal cooking and roasting temperatures. You must control it before the ingredient goes into your process.

What is the FDA action level for aflatoxin in peanut butter?

The FDA action level for peanuts and peanut products is 20 ppb total aflatoxins. Many buyers set a lower limit in their specifications.

Is aflatoxin a hazard under FSMA?

Yes. Aflatoxin is a natural chemical hazard. You must evaluate it in your hazard analysis for each applicable ingredient.

How often must I test for aflatoxin?

FDA does not give a fixed test frequency. Base the frequency on your hazard analysis, the ingredient risk, and the supplier history.

Is aflatoxin in milk a risk for dairy processors?

Yes. Aflatoxin M1 goes into milk when cows eat contaminated feed. The FDA action level for M1 in milk is 0.5 ppb, so dairy farms must control their feed.

Can I blend a contaminated lot with a clean lot?

No. FDA generally does not let you blend lots to decrease the aflatoxin level. Hold the lot and decide on a corrective action, such as rejection or an animal feed use that the FDA levels permit.