Quantification of aflatoxin and ochratoxin contamination in animal milk using UHPLC-MS/SRM method: a small-scale study.

Mycotoxin contamination in animal milk is an emerging concern around the globe. Here we developed and validated an ultrahigh-performance liquid chromatography and mass spectrometry-selected reaction monitoring (UHPLC/MS-SRM) method to quantify low concentrations of aflatoxins (AFs) and ochratoxins (OTs) in routinely consumed animal milk samples collected from southern India. Stable isotope dilution methodology was applied to quantify AFB1, AFB2, AFG1, AFG2, AFM1, AFM2 and OTA, OTB in n = 38 different milk samples, using 1 mL of milk. Bioanalytical parameters including method accuracy, precision, recovery, regression analysis and stability were assessed. Dynamic ranges for quantification were between 15.6-1000 pg/mL for AFB1, AFB2, AFG1, and OTA; 7.8-500 pg/mL for AFM1, AFM2 and OTB; 78.6-5000 pg/mL for AFG2. Method accuracy ranged between 80-120%, with ± 15% precision. Recoveries for spiked standards were > 88% in water and 75% in milk, with limits of quantification (LOQ) ranging between 31.3 pg/mL for AFB1, AFB2, AFG1 and OTA, 15.6 pg/mL for AFM1, AFM2 and OTB and 156 pg/mL for AFG2. R2 values for regression analyses ranged between 0.9991-0.9999. AFB2 [mean: 38 pg/mL (0.038 µg/kg)] was quantified in goat milk, AFM1 was quantified in cow, goat, pasteurized milk [mean: 331 pg/mL (0.331 µg/kg), 406 pg/mL (0.406 µg/kg), 164 pg/mL (0.164 µg/kg)]. Additionally, 90% of cow, goat and pasteurized milk samples were above European Union (EU) limits of 50 pg/mL (0.05 µg/kg) and 40% of cow and goat milk samples were above the Food Safety Standards Authority of India (FSSAI) limit of 500 pg/mL (0.5 µg/kg). AFM2 was also quantified in cow, goat, and pasteurized milk samples [mean: 249 pg/mL (0.249 µg/kg), 375 pg/mL (0.375 µg/kg), 81 pg/mL (0.081 µg/kg)]. Our dynamic ranges for quantification are lower than other published methods, with need for a smaller volume of milk. This validated method can be applied for routine quantification of mycotoxins in milk. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s13197-021-04986-w). © Association of Food Scientists & Technologists (India) 2021.