Exposure of rural and urban populations in KwaZulu Natal, South Africa, to fumonisin B(1) in maize.

We surveyed households in rural and urban areas of KwaZulu Natal, South Africa, to assess the exposure of the inhabitants to fumonisin B(1) (FB(1)), a mycotoxin produced by Fusarium verticillioides. In southern African regions maize, used as a staple food by the population, is prone to F. verticillioides infection. Furthermore, high levels of FB(1) in maize have been associated with esophageal cancer in South Africa. We assessed exposure of the population to FB(1) at three levels, namely, by analyzing stored maize, plate-ready food, and feces. The positions of participating households in the rural area were recorded using geographic information systems (GIS) for ease and accuracy of follow-up. Of the 50 rural maize samples examined, 32% had levels of FB(1) ranging from 0.1-22.2 mg/kg, whereas 29% of the 28 cooked maize (phutu) samples contained FB(1) ranging from 0.1-0.4 mg/kg. The incidence and levels of FB(1) in feces were 33% and 0.5-39.0 mg/kg, respectively. Of the 49 urban maize samples analyzed 6.1% had a range of 0.2-0.5 mg/kg FB(1), whereas 3 of 44 fecal samples (6%) ranged between 0.6 and 16.2 mg/kg. No FB(1) was detected in urban phutu samples. Because these levels are lower than those published from regions in South Africa with high incidence of esophageal cancer, it may be concluded that the risk of esophageal cancer from FB(1) exposure is lower in the KwaZulu Natal region.