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Wheat affected by the fungus Fusarium culmorum can produce the mycotoxin “deoxynivalenol.” Photo: CORMA

Some fungi are great: they give us cheese, antibiotics and delicious mushrooms. Others sort of suck: they kill plants, they may have doomed the hapless “witches” of Salem, Massachusetts, and to this day they contaminate our food. As part of their metabolism, some fungi produce mycotoxins, “secondary metabolites… that are capable of causing disease and death in humans and other animals.”

Government regulators are well aware of the effects of most common fungi, however, and our exposure to these mycotoxin is controlled. The Canadian government, for instance, limits the contamination of wheat with the mycotoxin “deoxynivalenol” to less than 2.0 milligrams per kilogram of wheat.

 Chemical and Engineering News reports, however, that a new study says some mycotoxins may slip past health regulators, hidden behind chemical masks, put there by the plants on which the mycotoxins grow.

The toxins are harmful to the crops themselves, so, as a defense strategy, the plants neutralize the mycotoxins by tacking on a sugar or sulfate group to the chemicals. Because of this chemical modification, these masked mycotoxins slip past current detection methods used by food safety inspectors.

For example, the scientists found that one mycotoxin, deoxynivalenol (the one regulated by Health Canada), changes when it grows on wheat. The wheat gives the deoxynivalenol a glucose molecule, hampering its toxic effects. Normally, deoxynivalenol can cause “nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and fever,” but without the exact same chemical make-up, the mycotoxin’s effects on the body change.

What the scientists found next, however, is that bacteria living in conditions analogous to a human’s large intestine can take that glucose molecule back off the deoxynivalenol molecule, reverting the mycotoxin back to its original toxic form.

According to Chemical and Engineering News, just because the human body is capable of stripping the mycotoxin of its mask does not necessarily mean that the toxin’s effects on the body are going to be the same as if a person ate the toxin straight. Because the mycotoxin loses its mask in the large intestine, much less may be absorbed into the bloodstream, and the toxic effects could be minimized. Still, the scientists suggest that government regulators should start paying attention to these masked mycotoxins.

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