Mycotoxins are toxic secondary metabolites produced by filamentous fungi that contaminate food and feed worldwide. The major mycotoxin-producing genera are Aspergillus, Penicillium, and Fusarium. Mycotoxins are chemically stable and can survive food processing operations including cooking, baking, and extrusion. Chronic exposure to low levels of mycotoxins is associated with carcinogenic, nephrotoxic, hepatotoxic, immunotoxic, and estrogenic effects. Global trade in agricultural commodities necessitates harmonized regulatory limits and reliable testing methods.
Aflatoxins are produced primarily by Aspergillus flavus and A. parasiticus and are among the most potent naturally occurring carcinogens. Aflatoxin B1 is classified as a Group 1 human carcinogen by the IARC. The four major aflatoxins are B1, B2, G1, and G2, with B1 being the most toxic and prevalent. When dairy cows consume aflatoxin B1-contaminated feed, it is metabolized and excreted as aflatoxin M1 in milk, which is also regulated. Aflatoxins contaminate maize, peanuts, tree nuts, cottonseed, and spices, particularly under hot and humid conditions during pre-harvest and storage.
Ochratoxin A is produced by Penicillium verrucosum and several Aspergillus species, contaminating cereals, coffee, dried fruit, wine, and beer. It is nephrotoxic and classified as a possible human carcinogen (Group 2B). Fumonisins, primarily produced by Fusarium verticillioides, contaminate maize and maize-based products and are associated with esophageal cancer and neural tube defects. Deoxynivalenol (DON, vomitoxin), produced by Fusarium graminearum, causes gastroenteritis and feed refusal in animals. Patulin, produced by Penicillium expansum, is found in apples and apple products. Zearalenone has estrogenic effects and causes reproductive disorders in livestock.
Regulatory limits for mycotoxins vary by country and commodity. The EU has some of the most stringent limits: aflatoxin B1 in cereals at 2 µg/kg, total aflatoxins at 4 µg/kg, and aflatoxin M1 in milk at 0.05 µg/kg. Detection methods include HPLC with fluorescence detection (HPLC-FLD) for aflatoxins and ochratoxin A, LC-MS/MS for multi-mycotoxin analysis, and ELISA for rapid screening. Prevention strategies emphasize good agricultural practices, proper drying of grains to moisture levels below 14%, controlled storage conditions, and the use of mold-resistant crop varieties. Mycotoxin-producing molds are related to yeast and mold spoilage organisms, though some molds are used beneficially in mold fermentations. Mycotoxins are classified as chemical contaminants in food safety management.
