Zearalenone is a nonsteroidal oestrogenic mycotoxin biosynthesized through a polyketide pathway by a variety of Fusarium fungi. Fungi-producing ZEA contaminate corn and also colonize, to a lesser extent, barley, oats, wheat, sorghum, millet and rice. In addition, the toxin has been detected in cereals products like flour, malt, soybeans and beer. Fungi of the genus Fusarium infect cereals in the field. Toxin production mainly takes place before harvesting, but may also occurs post harvest if the crop is not handled and dried properly. The ZEA derivatives (α-zearalenol (α-ZEA), β-zearalenol (β-ZEA), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), zearalanone (ZAN)) can be detected in corn stems infected with Fusarium in the field and in rice culture.