The Effect of Processing Practices On Mycotoxin Reduction in Maize Based Products: Evidence from Lactic Acid Fermentation in Southwest Nigeria

Because aflatoxin, a naturally occurring mycotoxin (fungal toxin) in maize and nuts, is known to cause liver cancer in humans, strategies to reduce aflatoxin in food are critical. Although fumonisin, another mycotoxin in maize, has not been conclusively linked to any human diseases, it can cause multiple adverse effects in other animal species and has been implicated in neural tube defects and growth impairment in human children. In this study, we examined the impact of lactic acid fermentation – a food processing method that has been used for possibly millennia in human populations – to decrease levels of aflatoxin and fumonisin in maize products in Nigeria. Our study showed that the mean total aflatoxin levels in processed maize samples (after lactic acid fermentation) were lower but not significantly different from mean levels in the raw maize product. Furthermore, even after processing, the mean total aflatoxin level in the samples of the final processed product was higher than the maximum acceptable limit shared by Nigeria and the European Union of 4µg/kg. However, we find strong evidence that lactic acid fermentation significantly reduced the mean levels of total fumonisins. Thus, while lactic acid fermentation can improve the food safety profile of maize, other strategies such as low initial levels in maize grain are likely necessary to guarantee a safe final product.