Natural occurrence and dietary exposure assessment of Alternaria toxins in commercially available fermented sauce products in China

Fermented sauces are widely consumed condiments in China. This study investigated the natural occurrence, influencing factors, co-occurrence patterns, and dietary exposure of four Alternaria toxins (ALTs) in 192 commercially available fermented sauce products collected from four provinces in China. Results showed that tenuazonic acid (TeA) was the most prevalent toxin, with a positive rate of 90.10% and concentrations ranging from 0.13 to 1970.64 μg/kg. The mean concentrations in descending order were TeA (70.62 μg/kg), monomethyl ether (AME) (6.53 μg/kg), alternariol (AOH) (3.09 μg/kg), and tentoxin (TEN) (2.00 μg/kg). Multiple linear regression analysis revealed that chili pepper substrate was the most influential factor, with TeA ( β =13.34, 95% CI: 5.94–29.99), AOH ( β =3.58, 95% CI: 2.29–5.59), and TEN ( β =3.90, 95% CI: 2.05–7.41) significantly higher than those in legume-based products. Products from southern regions had significantly lower concentrations of AOH ( β =0.33, 95% CI: 0.23–0.47), TEN ( β =0.10, 95% CI: 0.06–0.17), and AME ( β =0.16, 95% CI: 0.09–0.27) compared with northern products. Bulk packaging was independently associated with elevated AOH levels ( β =1.63, 95% CI: 1.17–2.78). Additionally, co-contamination was widespread, with 94.79% of products containing at least two toxins. Partial correlation analysis further revealed that extrinsic confounding factors masked the intrinsic co-occurrence relationships between TeA and the other three toxins. Dietary exposure assessment identified children aged 4 – 6 years as the most vulnerable population subgroup. MOE-based assessment suggested potential genotoxic risks for AOH and AME, though current estimates rely on limited toxicological data and conservative assumptions. TeA intake exceeded the TTC threshold in all age and gender groups; TEN exposure remained under the TTC limit across all subgroups. These findings underscore the necessity of strengthening large-scale and long-term contamination monitoring and risk assessment of Alternaria toxins in fermented sauce products.