Occurrence of zearalenone and its major metabolites in cereal flour from Korea

The occurrence of zearalenone (ZEN) and its metabolites (α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), and zearalanone (ZAN)) was investigated in 78 cereal flour from Korea using UHPLC-MS/MS. Among these mycotoxins, ZEN was the most abundant in the analyzed samples at an incidence rate of 41% and concentration range of 0.5-536 µg/kg. The highest contamination and incidence rate of ZEN were found in corn flour samples, while oat flour samples showed the lowest contamination and incidence rate of this mycotoxin. α-ZEL, β-ZEL, and ZAN were detected only in corn flour samples but at lower frequencies of 23%, 17%, and 15%, respectively, while α-ZAL and β-ZAL were not detected in any sample. To the best of our knowledge, this is the first investigation of the simultaneous occurrence of ZEN and its major metabolites in commercially available cereal flour from Korea. Among the tested samples, only four were contaminated with ZEN at levels exceeding the maximum regulatory level established in Korea. The co-occurrence of ZEN, α-ZEL, β-ZEL, and ZAN was observed in 14% of all samples. Although ZEN metabolites were detected at relatively lower levels than ZEN, the relatively high co-occurrence rate of those mycotoxins is of significant concern from a food safety perspective, since they can synergistically contribute to the overall toxicity and estrogenic effects.