Fact Sheets - The Facts about Aflatoxin

What is aflatoxin?

Aflatoxin is a naturally occurring contaminant produced by mold, particularly Aspergillus flavus and A parasiticus. These molds grow on crops, especially peanuts, tree nuts, corn, wheat, and seed oils (i.e., cottonseed) that are stored under conditions of warmth and humidity.

Does aflatoxin cause cancer?

Aflatoxin B1 has been classified as a known human carcinogen and is known to cause liver cancer in animals. Aflatoxins may also be associated with liver cell cancer in humans in Africa and Asia where peanuts are a dietary mainstay. Recent research has shown a strong association between long-term dietary aflatoxin exposure in conjunction with hepatitis B (a viral infectious disease of the liver) and increased rates of liver cancer.

How and where are people exposed?

Aflatoxins are widespread in nature. The Food and Drug Administration permits low levels of exposure to aflatoxin, believing that limited exposures over a lifetime are not dangerous. Humans are exposed to aflatoxins by ingesting contaminated foods. The FDA considers aflatoxin an “unavoidable contaminant.” Even with food supply monitoring of aflatoxins, concern remains over the effects of long-term dietary exposures to this toxin.

Can I still eat peanuts and peanut butter?

The FDA does test for aflatoxins in certain foods but permits low levels because these toxins are thought to be unlikely to cause disease with low-level exposures over a lifetime. Peanut butter and peanuts are more stringently tested and controlled in the U.S., since aflatoxins are commonly found on these food items and their consumption is widespread in this country. Although levels vary, the lowest levels of aflatoxin are found in brand name peanut butters found at grocery stores. Eating peanuts and peanut butter in moderation remains acceptable.

How can I reduce my risk of aflatoxin exposure?

Buy only major brands of nuts and nut butters, such as peanut butter, from reputable distributors. Do not store nuts for prolonged periods of time and throw away nuts that have become moldy, discolored or otherwise irregular.

Where can I get more information?

For more information, please refer to the following documents, which were used as sources for this fact sheet:

• Aflatoxins in Your Food – and the Effect on Your Health, Environmental Health and Safety Online, retrieved February 15, 2005, from http://www.ehso.com/ehshome/aflatoxin.php
• Aflatoxin, USDA Grain Inspection, Packers and Stockyards Administration (GIPSA), retrieved November 2007, from http://www.rma.usda.gov/news/currentissues/aflatoxin/
• Aflatoxins: Occurrence and Health Risks, Cornell University, Department of Animal Science, retrieved February 15, 2005, click here