If you’ve been watching all of the peanut recalls in the news, you may be surprised to know that some of them are due to mold. Of course you’ve heard about the salmonella outbreak (you’d have to be living under a bridge in Kentucky not to have heard about it.)
Peanuts are also subject to aflatoxin. Aflatoxin is a specific mycotoxin produced by Aspergillus flavus and A. parasiticus which has been connected to everything from stunted growth to liver cancer. (Aflatoxins produce acute necrosis, cirrhosis, and carcinoma of the liver–but it rarely occurs in developed countries.) The main point is this–when people in developed countries do get exposed to aflatoxin, it’s usually because they ate it in peanut butter. Roasting the peanuts does not usually kill it all. And as it sits in the jar, it just keeps growing. The problem is worst in organic peanut butter because the mold growth in peanuts is not tested or monitored once it has reached the store. Compared to grocery store peanut butter which is roasted and packaged in sterile–regulated–conditions, organic is probably the most fertile ground for aflatoxin production.