Aflatoxin M1 in milk: development of analytical and sampling strategies for quality control in dairy factories.

Nowadays one of the main goals of a factory working with milk and its derivatives is the determination of aflatoxin M 1 level, in order to maintain an high qualitative standard production from the point of view of health risk and legal restrictions. It has been carried out an analytical strategy for a rapid and reliable screening of several farms giving their milk to a factory for milk distribution.The aflatoxin M 1 evaluation was performed by ELISA technique on thirteen milk harvesting points from farms, for three days during the same week. The average level of aflatoxin M 1 in the harvesting points during the three days was 21.7 ng/L with a coefficient of variation (CV%) of 12.7 ng/L, but with a high CV for the different harvesting points in the same day (23.1 ng/L CV 57.3%, first day; 18.5 ng/L CV 38.3%, second day; 23.4 ng/L CV 59.4%, third day) and for the same harvesting point in the three different days. One of the harvesting points was found to be close to the limit of 50 ng/L milk and therefore the four farms collecting the milk were controlled one by one. Only one of them, belonging to this harvesting point, was found to overcome the limit of 50 ng/L for the aflatoxin M 1 , showing an amount, for this analyte, of 132.7 ng/L by ELISA technique. This value was also checked by using HPLC chromatography confirming the ELISA result.