Occurrence of deoxynivalenol (DON) in cereal-based food products marketed through e-commerce stores and an assessment of dietary exposure of Chinese consumers to DON

Deoxynivalenol (DON), a mycotoxin produced by various Fusarium species, was analyzed in 200 cereal-based food products collected from e-commerce stores in China. Optimized methods using immunoaffinity column (IAC) clean-up coupled with UV detection were applied. DON was detected in 87.5% (12.5-1920.4 μg/kg) of samples, and 10.5% of tested samples exceeded the legal limit for DON in China (1000 μg/kg). DON was found in 100% of whole wheat flour (51.6-1308.9 μg/kg), Chinese steamed bread (54.5-845.4 μg/kg), and biscuit (40.9-1920.4 μg/kg), samples, and in 85.3% of all-purpose flour (12.5-1285.4 μg/kg), 73.3% of maize flour (26.4-138.2 μg/kg), and 60.0% of oat flake samples (16.8-243.6 μg/kg), with 426.0, 293.0, 419.2, 455.7, 55.4, and 44.0 μg/kg, respectively, representing the mean levels in these products. A chronic intake assessment indicated that estimated daily intake (EDI) of DON through the consumption of wheat flour was 1.0-3.8 and 3.1-11.3 times that of the Provisional Maximum Tolerable Daily Intake (PMTDI) of 1.0 μg/kg body weight/day for adults and children, respectively, at different levels. The EDIs of DON consumed through wheat flour-derived products (Chinese steamed bread and biscuits) for children was 1.7-12.7 times those of the PMTDI at different levels, whereas the EDIs obtained through consumption of maize flour and oat flakes were 0.2 times lower than those of the PMTDI for both adults and children. In a dietary exposure assessment, the acute hazard indexes (aHI) for adults and children were above 100% of Acute Reference Dose (ARfD) of 8.0 μg/kg body weight/day) through the consumption of wheat flour, Chinese steamed bread, and biscuits, and the aHIs were only 16.4% (31.2%) and 5.1% (8.3%) of ARfD for adults (children). Among the cereal-based food products analyzed, both chronic (long-term) and acute (short-term) dietary exposure assessments for DON consumption by adults and children indicated that wheat flour (all-purpose flour and whole wheat flour), Chinese steamed bread, and biscuits have become sources of potential health hazards in the human diet in China. The risk associated with DON contamination in maize flour and oat flakes should also not be ignored.