Comparison of methods for detecting aflatoxins B1 and M1 in milk

Immunoaffinity column-high performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) methods were adopted to determine aflatoxins (AF) B1 and M1 in milk. The recovery, detection limit, and precision of these two methods were compared in this study. The results showed that, for HPLC, the detection limits of AFB1 and AFM1 were 0.02 and 0.01 μg·L-1, respectively, while for ELISA, the detection limits of AFB1 and AFM1 were 0.05 and 0.02 μg·L-1, respectively. Standard solutions of AFB1 (0.003, 0.006, 0.012, and 0.024 μg·kg-1) and AFM1 (0.005, 0.01, 0.025, and 0.05 μg·kg-1) were added into blank milk samples and the results of recovery experiments indicated that, for HPLC, the recoveries of AFB1 and AFM1 were 77.58%~82.81% and 77.51%~82.23% with relative standard deviations of 1.93% and 3.51%, respectively. For ELISA, the recoveries of AFB1 and AFM1 were 77.28%~79.11% and 75.40%~76.34% with relative standard deviations of 2.20% and 3.80%, respectively. The recovery of AFB1 did not significantly differ between the two methods (P>0.05). However, the recovery of AFM1, when the amount added was more than 0.025 μg·kg-1, was significantly higher by HPLC than by ELISA (P1, the accuracy of HPLC was better than that of ELISA.