Mycotoxin (from the
Greek µ???? (mykes, mukos) "fungus") is a
toxin produced by an organism of the
fungus kingdom, which includes
mushrooms,
molds and
yeasts. Most fungi are
aerobic (use oxygen). Fungi are found almost everywhere in extremely small quantities because of their
spores, and are most commonly
microscopically small. They consume
organic matter, wherever
humidity and
temperature are sufficient.
Where conditions are right, fungi proliferate into colonies and mycotoxin levels become high. Toxins vary greatly in their severity. Some fungi produce severe toxins only at specific levels of moisture, temperature or oxygen in the air. Some toxins are lethal, some cause identifiable diseases or health problems, some weaken the immune system without producing symptoms specific to that toxin, some act as allergens or irritants, and some have no known effect on humans. Some mycotoxins generally have more negative impacts on farm animal populations than on humans. Some mycotoxins are harmful to other micro-organisms such as other fungi or even bacteria; penicillin is one example.
Mycotoxins can appear in the food chain as a result of fungal infection of crops, either by being eaten directly by humans, or by being used as livestock feed. Mycotoxins greatly resist decomposition or being broken down in digestion, so they remain in the food chain in meat and dairy products. Even temperature treatments, such as cooking and freezing, do not destroy mycotoxins.
Buildings are another source of mycotoxins. Public concern over mycotoxins increased following multi-million dollar toxic mold settlements in the 1990s. The negative health effects of mycotoxins are a function of the concentration, the duration of exposure and the subject's sensitivities. The concentrations experienced in a normal home, office or school are often too low to trigger a health response in occupants.
