Critical mycotoxins in Chinese diets: Multidimensional exposure assessment, thermal degradation, and hidden mycotoxin release mechanisms

Abstract

Mycotoxins pose significant global food safety risks, with emerging and hidden forms requiring urgent attention. This study conducted a total diet study covering 15 food categories to assess the contamination of 46 mycotoxins using optimized UHPLC-MS/MS with C₁₈/EMR-Lipid hybrid cleanup. The results revealed that 73.7 % of the samples contained two or more mycotoxins. Alternariol monomethyl ether (hazard quotient 313 %–346 %), aflatoxin B₁, ochratoxin A, and sterigmatocystin (margin of exposure: 65.4–172 < 10,000) were identified as high-risk contaminants. Notably, 2–7 years children exhibited particularly elevated exposure risks, with vulnerability 120 %–250 % higher than that of adults. Significant levels of hidden enniatins were detected and released during thermal/enzymatic processing; digestion increased enniatin B/B₁ levels by over 200 %, revealing substantial matrix-bound reserves. Molecular docking simulations further elucidated the underlying binding mechanisms, confirming that the interactions between enniatins and both amylose and gliadin are primarily mediated by non-covalent bonding, specifically through an extensive hydrogen-bonding network and dominant hydrophobic interactions (ΔG: 5.40 to −6.55 kcal/mol). Thermal treatment (>150 °C) and alkaline conditions (pH > 12) could facilitate the hidden-to-free conversion. These findings underscore the necessity of accounting for hidden mycotoxins in exposure assessments and updating regulations, especially for vulnerable populations and high-risk commodities.