Risk screening of mycotoxins and their derivatives in dairy products using a stable isotope dilution assay and LC-MS/MS

An liquid chromatography-tandem mass spectrometry method coupled with a stable isotope dilution assay was established for the simultaneous detection of 17 mycotoxins and their derivatives (aflatoxins B-1, B-2, G(1), G(2), M-1, and M-2; fumonisins B-1 and B-2; ochratoxin A; zearalenone; zearalanone; alpha-zearalanol; alpha-zearalenol; T-2 toxin; deoxynivalenol; deepoxy-deoxynivalenol; and sterigmatocystin) in milk and dairy products. The mycotoxins were extracted with acidified acetonitrile and the lipids were removed using a Captiva EMR-lipid column. The average recoveries of the target compounds from samples spiked at three different concentrations were 67-102%, and the relative standard deviations of the peak areas were less than 10%. Limits of quantification (S/N = 10) of 0.004-1.25 mu g/kg were achieved, which are significantly lower than the maximum levels allowed in various countries and regions for each regulated mycotoxin. Milk and yogurt products from local markets and e-commercial platforms were analyzed using the optimized method. The screening showed that aflatoxin M-1, deoxynivalenol, fumonisins B-1 and B-2, and zearalenone could be found in milk and yogurt products, especially those products also containing grains or jujube ingredients, indicating that there is a risk of mycotoxins in dairy products.