Natural co-occurrence of fumonisins and zearalenone in cereals and cereal-based foods from Eastern and Southern Africa

The natural co-occurrence of fumonisin B1 (FB1), fumonisin B2 (FB2), fumonisin B3 (FB3), and zearalenone was investigated in 40 randomly selected cereals and cereal-based commodities collected in 1994 from Botswana, Kenya, Malawi, Mozambique, South Africa, Tanzania, Uganda, Zambia, and Zimbabwe. FB1 was detected in 37 of the samples (92.5%) at concentrations ranging from 20 to 1910 ng/g, while total fumonisin (FB1 + FB2 + FB3) concentrations in the same samples ranged from 20 to 2735 ng/g. The highest total fumonisin levels were detected in maize kernels from Zimbabwe (2735 ng/g). In contrast to the high incidence of fumonisins (92.5%), zearalenone was detected in only five samples (12.5%) at concentrations ranging from 40 to 400 ng/g. Linear regression analysis showed no correlation between the occurrence of fumonisins and zearalenone in the samples tested. Although limited in sample numbers, this survey ranks the fumonisins as major contaminants of cereals and cereal-based foods in Eastern and Southern Africa.