You Ask, I Answer: Aflatoxins

I'm concerned about aflatoxin risk associated with consuming nut butters.

Is there legitimate cause for concern?

Are aflatoxins only present in peanut butter, but not almond, cashew or other nut butters?

-- Tom T.
Boston, MA

For those of you not familiar with aflatoxins, allow me to introduce you. You might not want to shake hands, though.

Aflatoxins are highly poisonous varieties of mycotoxins. In biochemical jargon, we are talking about the metabolic byproduct of a particular fungus.

It just so happens that this fungus has a tendency to grow on certain crops -- especially corn and peanuts.

Like any good fungus, it thrives in damp, warm environments.

Hence, if such conditions present themselves at any point of the transit or storage of these crops you can bet there will be fungal growth -- and high aflatoxin levels.

Yeah, not so ideal.

Apart from providing a funky flavor, aflatoxins can cause a variety of liver disorders, as well as significantly increase liver cancer risk when consumed in high amounts..

No need to start peanut panic just yet, though.

Most countries, particularly the "developed" nations (I put that in quotations because I find that term to be so outdated and elitist) have set limits on just how many parts per billion of aflatoxins can be permitted in crops entering their food supply.

So, if a particular peanut crop registers as too high, it will certainly not end up in your peanut butter.

In the United States, the National Peanut Administrative Committee has taken this issue very seriously. There is no worse PR for a food than intoxication risks.

There is now a certain pesticide that prevents this fungus from ever growing. If you are buying organic, you can not count on that particular barrier.

Again, though, aflatoxins are carefully monitored, so you truly have no reason to worry.

To answer your second question: yes, peanut butter is the only nut butter to contain aflatoxins, but not the only nut. Walnuts and pecans also register teeny, tiny, insignificant amounts.

PS: I know a peanut is technically a legume and not a nut. For simplicity purposes, though, it's a nut. Capiche?