FUMONSIN B-1, B-2, AND B-3 CONTENT OF COMMERCIAL UNPROCESSED MAIZE IMPORTED INTO SOUTH-AFRICA FROM ARGENTINA AND THE USA DURING 1992

The widespread occurence of F. moniliforme and the toxic effects of if s secondary metabolites, the fumonisins B-1(FB1), B-2(FB2) and B-3(FB3 ), make it imperative that fumonisin contamination of maize, a major c onstituent of animal feed as well as the staple diet of many populatio ns, be closely monitored to reduce the risk of fumonisin exposure. Equ ine leukoencephalomalacia and pol cine pulmonary oedema have been asso ciated with the intake of feed heavily contaminated with fumonisins. I n addition, high levels of fumonisins in the maize-based staple diets of cel tain populations have been linked to a high incidence of oesoph ageal cancel in the Transkei region of South Africa and in Linxian and Cixian Counties, China. Bulk shipments of maize imported into South A frica from the USA and Argentina during 1992 were sampled at the port of entry to determine fumonisin levels. Of the 79 samples from two US shipments, all were positive for fumonisins, with FB1 constituting app roximately 71% of the total fumonisins with an overall mean of 2.35 mu g/gFB(1). The maximum FB1 level observed was 3.9 mu g/g. These levels contrast with those obtained from two Argentinian bulk: shipments, wh ich also were all positive for fumonisins, but had a mean FB1 level of 0.31 mu g/g and a maximum observed level of 0.7 mu g/g FB1 measured o ver 47 composite samples.