Zearalenon

Zearalenone, commonly abbreviated as ZEN, is a non-steroidal estrogenic mycotoxin produced by several Fusarium species, most notably Fusarium graminearum and Fusarium culmorum, during growth on cereal crops. It belongs to the resorcylic acid lactone family and is chemically stable under ordinary processing, enabling partial retention in milled foods and animal feeds.

ZEN occurs widely in grains such as maize, wheat, barley, and oats and is a frequent contaminant of animal feeds. It can be formed post-harvest under warm, humid storage conditions that promote Fusarium growth. Detection relies on chromatographic methods, especially liquid chromatography–tandem mass spectrometry (LC-MS/MS), with immunoassays used for screening.

Estrogenic in nature, zearalenone and its reduced metabolites bind to estrogen receptors, producing hormonal effects. In livestock, exposure can cause reproductive disturbances, notably in young females, including irregular estrous cycles, vulvar swelling, and reduced fertility. Sensitivity varies by species and life stage; pigs are particularly susceptible. In humans, possible estrogenic effects have been discussed, but evidence at typical dietary exposure levels is limited.

To manage risk, authorities set limits in cereals and cereal products and feeds, and producers employ good agricultural and storage practices, grain cleaning, and regular monitoring. Laboratories commonly confirm results by LC-MS/MS, while screening may use immunoassays.