Aside from some molds growing on “stinky” cheeses, molds are generally not good for human consumption. For example, we all know to stay away from bread with tell-tale green spots or white cottony threads on the slices. And we need to take special measures when black spots of mold appear on damp walls.
Mold can produce poisons called mycotoxins. These toxins can wind up in food either directly because a fungus grew on an ear of corn that a person eats, for example, or indirectly because a cow ate that infected ear of corn, and a person ate a steak from that cow. Mycotoxins also can cause problems if they are released into the air. Farmers can develop “farmers’ lung,” which shows up as flu-like symptoms, from such exposure.
Governments already put limits on the amounts of mold toxins in grain crops. But researchers now say in the ACS journal Chemical Research in Toxicology that these regulations should be expanded to include so-called “masked mycotoxins.” These versions change from harmless to potentially harmful forms once they are in the body.
In the report, Chiara Dall’Asta and colleagues explain some health experts regard mycotoxins as the most serious chronic dietary risk factor, greater than the potential health threats from pesticides and insecticides.
Plants protect themselves by binding or “conjugating” glucose, sulfur or other substances to a mycotoxin, producing conjugated mycotoxins that are not harmful to them. These are called “masked mycotoxins” because they are masked or hidden by that bound substance.
Dall’Asta explains that these masked mycotoxins are not included in current safety regulations because no one was really sure what happened when people and animals ate them.
The new study focused on two of the most widespread mycotoxin contaminants of grain crops — deoxynivalenol (DON) and zearalenone (ZEN). The authors say their results show, for the first time, that bacteria present in the large intestine in people deconjugate or “unmask” DON and ZEN, releasing the original toxic forms. “For this reason, masked mycotoxins should be considered when evaluating population exposure," the study concludes.