Incidence of aflatoxins B1 and M1 in raw milk and some cheeses

A tolal of 150 random samples of market raw cows milk, hard chesse, and processed cheese (50 each) were collected from different groceries and supermarkets at Mansoura city, and investigated for the presence of aflatoxins B1 and/or M1 as well as the thermostability of both toxins against laboratory pasteurization of contaminated milk samples at 63°c for 30 min. One hundred and twenty one (80.66%) of 150 samples were contaminated with aflatxin(s), 35 (23.33%) samples were polluted with AFB1 alone, 33 (22.00%) samples had AFM1 alone, and 53(35.33%) samples contained AFB1 and AFM1. Of all examined samples, 35(70%) milk, 45 (90%) hard chesse, and 41(82%) processed cheese samples were contaminated with aflation (s). The averages of AFBI and AFM1 levels were 1.06±0.23 and 1.16±0.20µg/L of milk, 7.54±1.46 and 3.88±0.90 µg/kg of hard chesse, and 13.11±2.70 and 14.06±2.36 µg/kg of processed chesse samples, respectively. All contaminated cheese samples contained AFB1 and/or AFM1 by levels more than both Egyptian and FDA limits (nil and 0.5 µg/kg for each toxin), while 20 (40%) and 21 (42%) of aflatoxin- contaminated raw milk samples harboured toxin quantities higher than FDA limits for AFB1 and AFM1 consecutively (0.5 µg/L for each toxin. As regards the effect of pasteurization of aflatoxin- contaminated milk samples at 63ºc for 30 min., there were a negligible percentages of reductions ranged from 4.9 to 7.8% for AFB1 and 0.6 to 3.1% for AFM1. Public health significance of recognized aflatoxins as well as a suggested measures for minimizing or resolving such a world wide problem were discussed.