Zearalenone contamination in corn for human consumption in the state of Tlaxcala, Mexico

Corn from various regions of the state of Tlaxcala, Mexico was sampled to determine whether or not corn which is consumed by humans is contaminated with the estrogenic mycotoxin zearalenone (ZEA). In order to quantify this mycotoxin, a method with adequate sensitivity using solid–liquid extraction and high-performance liquid chromatography (HPLC) with UV diode array detection was optimized. ZEA and zearalanol, used as an internal standard, were extracted from 5 g of a finely ground corn sample with an 85:15 v/v methanol:water solution, cleaned by way of a Florisil column, defatted with n-hexane, and subsequently re-extracted with chloroform. The separation was performed on a reverse phase analytical column. Detection was confirmed by on-line simultaneous UV spectral scanning during the chromatographic run. The method’s limit of detection was 0.7 ng/g and the recovery average was 90%. Analysis of 24 samples indicates that approximately 70% of the monitored samples were contaminated with zearalenone, with levels ranging from 3 to 83 μg/kg of corn kernels.