DETERMINATION OF FUMONISINS IN MILK

Fumonisin B-1 (FB1) and fumonisin B-2 (FB2) were determined in milk by liquid chromatography (LC) following immunoaffinity column cleanup. Recoveries from milk spiked with 5-50 ng each fumonisin/ml averaged 79-109%. The aminopentol hydrolysis product of FB1 (AP(1)) was determined by LC after cleanup on a C-18 solid phase phase extraction column; mean recoveries were 69-83% at spiking levels of 50-100 ng AP(1)/ml milk. Detection limits were of the order 3-7 ng/ml for FB1 and FB2, and 20-25 ng/ml for AP(1). A stability study showed no losses of FB1 and FB2 in milk under conditions of freezing, refrigeration and boiling. A transmission study using four cows dosed with pure FB1 either orally (1.0 and 5.0 mg FB1/kg b.w.) or by i.v. injection (0.05 and 0.20 mg FB1/kg b.w.) showed no detectable residues of FB1 or AP(1) in the milk, with or without hydrolytic treatment with beta-glucuronidase/sulfatase to liberate any conjugates.