Occurrence of regulated, emerging, and masked mycotoxins in Chinese wheat between 2021 and 2022

Wheat is one of three major food crops in China. Wheat grains are prone to contamination with various mycotoxins. The risk of exposure to mycotoxins through the consumption of wheat flour has long been a concern. This study evaluated the occurrence of regulated, marked, and emerging mycotoxins in 304 wheat samples that were randomly sampled from major wheat-producing regions of China. Aflatoxin B₁ (AFB₁) was detected in only 3 wheat samples, with a maximum concentration of 2.37 microg/kg. Deoxynivalenol (DON) was identified as the most prevalent mycotoxin, being present in 94.4 % of the samples with a maximum concentration of 2.84 mg/kg. Additionally, 11.5 % of the positive DON samples exceeded the maximum Chinese limit of 1000 microg/kg. The incidence of zearalenone (ZEN), zearalanone (ZAN), α-zearalenol, and β-zearalenol in wheat samples were 27.96, 2.96, 2.63, and 2.63 %, respectively. Of 304 wheat samples, 86.2 %, 14.5 and 7.24 % were positive for Deoxynivalenol-3-Glucoside (range: 3.58-609 microg/kg), 3-AcDON (range: 2.31-95.97 microg/kg), and 15-AcDON (range: 2.26-76.65 microg/kg), respectively. Beauvericin (BEA) was detected in 89.14 % of wheat samples with the maximum concentrations 114 microg/kg. However, the average concentration of BEA (2.40 microg/kg) in the positive samples was less than 10 microg/kg. Alternariol (AOH) and moniliformin were detected in 48.68 % and 16.78 % of wheat samples, respectively. Most wheat samples (89 %) were simultaneously contaminated with more than one mycotoxin, with an average of approximately five mycotoxins per sample, and up to 15 mycotoxins were detected in individual samples. In conclusion, DON was the most prevalent mycotoxin in wheat samples, followed by D-3-G, BEA, and AOH, and co-contamination of mycotoxins in wheat samples were very common.