The warnings come from researchers based in Italy who explain that ‘masked’ mycotoxins – that change from harmless to potentially harmful forms of moulds when already in the body – are not currently covered by regulations.
Writing in Chemical Research in Toxicology, the team note that many health experts regard mycotoxins as a serious chronic dietary risk factor; ranking them a greater risk than any potential health threats from pesticides or insecticides.
As a result many regulators limit the levels of mycotoxins allowed in food products. However the research team, led by Chiara Dall'Asta from the University of Parma, Italy, noted that many plants protect themselves by binding (or conjugating) glucose, sulphur or other substances to the mycotoxin – so producing conjugated (or masked) mycotoxins that are not directly harmful.
Dall'Asta explained that these masked mycotoxins are not included in current safety regulations because of uncertainty about what happens when people and animals eat them.
However the new study suggests, for the first time, that bacteria present in the large intestine in people deconjugate (or unmask) common mycotoxins including deoxynivalenol (DON) and zearalenone (ZEN) – so releasing the original toxic forms.
"For this reason, masked mycotoxins should be considered when evaluating population exposure," the researchers said.