Mycotoxins Co-Exposure Risk Assessment in Coix Seed: Contamination Levels and Safety for Dietary Consumption and Medicinal Intake.

Coix seed, a traditional medicinal and edible crop, is susceptible to mycotoxin contamination posing potential health risks, yet systematic risk assessments for its dual dietary and medicinal pathways remain limited. Fifty batches were collected from five major production regions in China. UPLC-MS/MS was used to quantify eight mycotoxins in raw materials and decoctions. A Monte Carlo simulation model assessed long-term (20-year) health risks via both pathways, and acceptable daily intake (ADI) levels were derived using a combined margin of exposure (MOE) threshold of 10,000. Results indicated that mycotoxins were present in 94% of samples. Zearalenone (ZEN) was the most frequent, with an occurrence of 82% and concentrations of 52.16~1804.43 μg/kg. Dietary exposure indicated potential risks for ZEN (MOE = 259), aflatoxin B1 (AFB1, MOE = 666), and AFB2 (MOE = 8040). Six mycotoxins transferred to decoctions at rates of 0.70~19.73%, with long-term medicinal use indicating potential ZEN-related risk (MOE = 4880). Multi-mycotoxin co-exposure assessment revealed elevated dietary risk (combined MOE = 181), whereas medicinal exposure within a standard 3-month treatment course remained within acceptable limits. Safety intake thresholds are proposed: ≤30 g/day for ≤130 days (dietary) and ≤30 g/day for ≤2000 days (medicinal). This study establishes a risk assessment framework applicable to herbal materials with both dietary and medicinal applications.