Exposure assessment and risk calculations for mycotoxins contaminating coix seed sold in Gansu Province, China

In order to understand the current situation of mycotoxin contamination and risk assessment of dietary exposure of coix seed (Coix lacryma-jobi) sold in Gansu Province, China, a total of 67 coix seed samples were collected from the local markets and supermarkets in 14 prefectures and cities in Gansu Province. Sixteen mycotoxins were determined by isotope dilution liquid chromatography-tandem mass spectrometry. The results showed that 37.3% of coix seed was contaminated by mycotoxins. Among them, fumonisin B₁ (FB1), fumonisin B₂(FB2), fumonisin B₃ (FB3) and zearalenone (ZEN) had the highest prevalence in coix seed, 10.5%, 11.9%, 17.9% and 10.5%, respectively. Coix seed was susceptible to mixed contamination of various mycotoxins, which was often detected in the forms of an FB1, FB2, and FB3 combination (35.7%) and an ZEN-FBs combination (21.5%). In this study, the exposure assessment was evaluated separately according to the use of coix seed for food or clinical use. It was found that the EDI values of ZEN, FB1, FB2, FB3, AME (alternariol monomethyl ether), TeA (tenuazonic acid), and TEN (tentoxin) calculated from the intake of coix seed for both medicinal and edible purposes were less than their TDIs, indicating that the health risk of exposure to the above toxins caused by the consumption of coix seed was within an acceptable range.