Why We Get aflatoxin in Our Peanut Butter

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Aflatoxin, found in mold on nuts and grains can cause liver cancer if consumed in large quantities. University California, Irvine researchers for the first time have discovered what triggers the toxin to form, which could lead to methods of limiting its production. Sheryl Tsai, lead author of a study appearing Oct. 22, in the journal Nature that reports the finding. Dr. Tsai is an associate professor of molecular biology & biochemistry, chemistry, and pharmaceutical sciences. "It's shocking how profoundly these molds can affect public health," said Dr. Tsai

Aflatoxin, found in mold on nuts and grains can cause liver cancer if consumed in large quantities. University California, Irvine researchers for the first time have discovered what triggers the toxin to form, which could lead to methods of limiting its production. Dr. Sheryl Tsai, lead author of a study appearing Oct. 22, in the journal Nature that reports the finding. Dr. Tsai is an associate professor of molecular biology & biochemistry, chemistry, and pharmaceutical sciences. "It's shocking how profoundly these molds can affect public health," said Dr. Tsai

Because of lax or nonexistent regulation, 4.5 billion people in developing countries are chronically exposed to vast amounts of aflatoxin — often hundreds of times higher than safe levels. In places such as China, Vietnam and South Africa, the combination of aflatoxin and hepatitis B virus exposure increases the likelihood of liver cancer occurrence by 60 times, and toxin-related cancer causes up to 10 percent of all deaths in those nations.

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Aflatoxin can colonize and contaminate nuts and grains before harvest or during storage. The U.S. Food & Drug Administration considers it an unavoidable food contaminant but sets maximum allowable limits.

The toxin wreaks havoc on a cancer-preventing gene in humans called p53. Without p53 protecting the body, aflatoxin can compromise immunity, interfere with metabolism, and cause severe malnutrition and cancer.

Dr. Tsai, graduate student Tyler Korman and undergraduate Oliver Kamari-Bidkorpeh, along with Johns Hopkins University researchers, found that a protein called PT is critical for aflatoxin to form in fungi. Previously, scientists didn't know what prompted the toxin's growth.

"The protein PT is the key to making the poison," Tsai said. "With this knowledge, perhaps we could kill the PT with drugs, inhibiting the mold's ability to make aflatoxin."

Destroying the mold — rather than just the PT — is the traditional method of decontamination, but it's expensive, costing hundreds of millions of dollars worldwide. 

For more information: http://www.universityofcalifornia.edu/news/article/22174