Zearalenone

Zearalenone (ZEN) is a mycotoxin produced by Fusarium species, especially Fusarium graminearum and Fusarium culmorum. It is a nonsteroidal estrogenic compound that commonly contaminates cereals and cereal-based products, including maize, wheat, barley, oats, and sorghum, as well as animal feeds. It is relatively heat-stable, so processing does not reliably eliminate it.

ZEN is metabolized in animals to alpha- and beta-zearalenol, with alpha-zearalenone typically exhibiting stronger estrogenic activity. The estrogenic mechanism underpins most health concerns, as ZEN and its metabolites can bind to estrogen receptors, potentially disrupting reproductive function. In pigs, exposure is associated with vulvar swelling, irregular estrous cycles, reduced fertility, and other reproductive effects. Human data are limited, and risk to consumers is considered low at typical dietary exposures, but regulatory agencies evaluate it as a potential endocrine disruptor.

Exposure occurs primarily through contaminated cereals and cereal products in the human diet and through animal feeds. Regulatory frameworks exist in many regions to limit ZEN levels in foods and feeds. The European Food Safety Authority established a tolerable daily intake of about 0.25 micrograms per kilogram of body weight per day for zearalenone. Monitoring and risk management rely on analytical methods such as LC-MS/MS to detect ZEN and its metabolites at low concentrations.

Prevention focuses on agricultural practices, proper harvest and storage to suppress Fusarium growth, sorting and cleaning of grains, and the use of binders or other feed-management strategies to reduce bioavailability in animals. Decontamination is challenging, so prevention remains the primary control measure.