Maize flour contaminated with toxigenic fungi and mycotoxins in Kenya

The majority of the Kenyan human population may be exposed to regular doses of a wide spectrum of highly toxic, carcinogenic, immunosuppressive, mutagenic, and hepatotoxic mycotoxins through the consumption of maizemeal. Maizemeal is consumed in Kenya at the rate of about 0.4kg/person/day, therefore, even the lowest amount of toxins consumed can cause significant effects as some are cumulative. Maize is also a major component in livestock and poultry feed, and the therefore regular indirect human exposure through the consumption of animal products that contain mycotoxin residues could be common. Due to these suspected risks, it is imperative to establish whether consumers in Kenya are actually exposed to dangerous mycotoxins in maize products hence this survey. Forty samples of flour packed in 90kg bags, 58 samples of "Ugali" brand (milled and packed by the Milling Corporation of Kenya Ltd), and 74 samples of "Jogoo" brand ( Unga Maize Millers) were collected from the Nairobi area. The samples were analysed for resident mycoflora, and some mycotoxins associated with key fungal species. Important fungal species isolated from the flour included Aspergillus flavus, A. sulphureus, Fusarium moniliforme, Penicillium stoloniferum, and P. cyclopium. All the three brands of flour were contaminated with Aflatoxins B1 and B2 (0.4-20 ug/kg), Ochratoxin A(50-1,500 ug/kg), and Zearalenone (2,500 - 5,000 ug/kg). Ochratoxin A was the most prevalent mycotoxin. These data provide a warning that the mycotoxin contamination problem in maizemeal is critical and consumers' health is at risk. Therefore, rigorous countrywide monitoring of mycotoxins in this staple food should be pursued. If possible, maize products should be subjected to stiff microbial quality control from the farm gate to the market shelf.