On the occurrence of aflatoxin M1 in milk and dairy products

Aflatoxins are toxic fungal metabolites found in foods and feeds. When ruminants eat AFB1-feedstuffs, they metabolise the toxin and excrete AFM1 in milk. To control AFM1 in foods it is necessary to reduce AFB1 contamination of feeds for dairy cattle by preventing fungal growth and AFB1 formation in agricultural commodities intended for animal use. Corn and corn-based products are one of the most contaminated feedstuffs; therefore risk factor analysis of AFB1 contamination in corn is necessary to evaluate risk of AFM1 contamination in milk and milk products. During the corn silage production, the aflatoxins production is mostly influenced by: harvest time; fertilization; irrigation; pest control; silage moisture; and storage practices. Due to the lower moisture at harvest and to the conservation methods, the corn grain is mostly exposed to the contamination by Aspergillus species. Therefore, it is necessary to reduce the probability of this contaminant through choice of: hybrids; seeding time and density; suitable ploughing and fertirrigation; and chemical or biological control. Grains harvested with the lowest possible moisture and conservation moisture close to or less than 14% are necessary to reduce contamination risks, as is maintaining mass to homogeneous moisture. Kernel mechanical damage, grain cleaning practices and conservation temperature are also factors which need to be carefully controlled.