Aflatoxin M1 distribution during cream separation and butter manufacture from naturally contamined milk

Aflatoxin M-1 (AFM(1)) associated to milk fat constituents is usually considered to be very low, although few scientific studies on this item are available. The aim of this study was to verify the residual amount of AFM(1) in cream and butter obtained from naturally contaminated milk (three levels of contamination: pool 0 = [AFM(1)] < 5 ngkg(-1); pool 1 = [AFM(1)] about 100 ngkg(-1) and pool 2 = [AFM(1)] about 200 ngkg(-1)). The three batches were defatted by applying both natural and centrifuge creaming and cream was then used to produce butter. A commercial competitive enzyme-linked immunosorbent assay (ELISA) was used to determine AFM(1) content. Natural creaming supplied products with a higher toxin content than centrifuge creaming, but in both cases, during butter manufacture, AFM(1) was mainly eliminated with buttermilk. Only butter produced from pool 2 showed a detectable AFM(1) content (28 ngkg(-1)).