Question: Should I be concerned about aflatoxin in peanuts and peanut butter?
Short answer: Commercial peanuts and peanut products sold through regulated food channels are monitored, so they are not generally considered a significant aflatoxin risk for most consumers. Sensible selection and storage still matter: keep peanuts cool and dry, and discard any that appear moldy, shriveled or discolored.
What aflatoxin is
Aflatoxins are naturally occurring toxins produced by certain molds, especially Aspergillus flavus. These molds can affect peanuts as well as other nuts, legumes, seeds, corn, wheat and some spices. In substantial amounts, aflatoxins can damage the liver; long-term exposure is also associated with liver cancer.
The mold is widespread in soil and decaying vegetation. Crop stress before harvest—particularly severe heat or drought—may increase susceptibility. Warm, moist and humid conditions during storage can also encourage mold growth.
Why commercial products are monitored
Growers, handlers and processors can reduce mold growth through agricultural controls, prompt drying, careful storage and product testing. Food regulators sample peanuts and peanut products and set limits intended to keep aflatoxin concentrations low.
These controls do not mean that aflatoxins never occur. They mean that prevention, inspection and removal of affected lots are built into the regulated food supply. Risk can be greater where crops are poorly dried, stored in humid conditions or not routinely tested.
Visible mold is a reason to discard a food, but the absence of visible mold cannot test for aflatoxin. Consumers should rely on reputable food channels rather than attempting to identify contamination by sight alone.
How to handle peanuts at home
Buy packaged peanuts and peanut butter from established retailers. Check that packaging is intact, observe the use-by guidance on the product and keep dry peanuts in a cool, dry location. In a warm or humid kitchen, refrigeration can help preserve quality after opening.
Do not taste peanuts that smell musty or look moldy, unusually dark, shriveled or discolored. Discard the affected product. If a food has been recalled, follow the recall instructions rather than trying to sort or salvage it.
What about nut butter?
Commercial peanut butter is made from processed peanuts and is subject to the same food-safety controls. Follow the label's storage directions, use clean utensils and discard the product if its appearance or odor suggests spoilage.
The bottom line
For most people buying commercial products, aflatoxin is not a reason to avoid peanuts. Purchase from reliable sources, store products as directed and discard questionable food. Anyone with a peanut allergy must avoid peanuts for a separate and potentially serious reason.
Related reading: See 10 questions about nut butters, learn why peanuts are not botanically nuts, or read Heavy metals in juice: what to know.
