Survey of aflatoxin M1 in cows' milk from free-grazing cows in Abeokuta, Nigeria.

Aflatoxin M1 (AFM1) in milk from 100 different herds of free-grazing cows in Abeokuta, Nigeria, was analysed by immunoaffinity column cleanup and HPLC with fluorescence detection. AFM1 was found in 75% of the samples, the toxin levels in positive samples ranged from 9.0 to 456.0 ng/l. The mean AFM1 level in positive samples was 108.15 ng/l, exceeding, for example, the European Union maximum level by a factor of two. These results indicated that there is an urgent need to more closely control the milk of free-grazing cows for AFM1 in order to protect the health of humans consuming milk and milk products.