Indexed on: 29 Nov '16Published on: 01 Oct '16Published in: Journal of animal science
Aflatoxin M1 (AFM1), a strong carcinogenic derivate of aflatoxin B1 (AFB1), occurs in milk from dairy cows fed an AFB1-contaminated diet and subsequently contaminates dairy products. This survey was conducted to evaluate the occurrence of AFM1 in UHT, pasteurized, and powdered milk available in Hubei province (central China) and to compare these milk AFM1 levels with the maximum AFM1 limits of 50 and 500 ng/L set by the European Commission (EU) and China’s Ministry of Health, respectively. A total of 271 samples, composed of UHT milk (120 samples), pasteurized milk (121), and powdered student formula (30) from two major dairy brands available in Hubei province were collected from November 2014 to February 2015 (winter season). Milk AFM1 was detected by using a commercial ELISA method (RIDASCREEN® Aflatoxin M1 test kit; R-Biopharm AG, Darmstadt, Germany) with the detection limit of 5 ng/L. Differences in the concentration of milk AFM1 were statistically analyzed by Mann–Whitney comparisons using SPSS version 19.0 software. The results showed that the mean of AFM1 concentration in positive samples of pasteurized milk was significantly higher (P < 0.05) than that in UHT milk (133.4 vs. 20.5 ng/L), and there were significant differences (P < 0.05) in AFM1 concentration in milk samples among two dairy brands. In addition, AFM1 was detected in 61 samples of UHT milk (50.8%) with concentrations of 5.5–62.3 ng/L and in 115 samples of pasteurized milk (95.0%) with concentrations between 5.2 and 346.2 ng/L. Moreover, 2 samples of UHT milk (3.4%) and 77 samples of pasteurized milk (63.6%) were found to contain AFM1 above the European tolerance limit, but all samples were below China’s legal limit. All samples of powdered student formula were negative at the AFM1 detection limit. The findings of the study are as follows: 1) the content of AFM1 in all milk samples was below China’s national legal limit though the incidence of AFM1 in UHT and pasteurized milk was high, 2) powdered student formula was free from AFM1 contamination and thus can be considered the safest milk product tested, and 3) the incidence and concentration of AFM1 in pasteurized milk was higher compared to other dairy products. To maintain milk safety, strict monitoring systems are recommended.