Incidence of Mycotoxin Contamination along the Maize Value Chain in Lusaka Province of Zambia

Aflatoxins and Fumonisins are carcinogenic mycotoxins produced by Aspergillus spp. and Fusarium spp., respectively that frequently contaminate maize and its derivative products when the conditions are ideal. A survey was conducted to establish levels of aflatoxin and fumonisins contamination in maize and maize products in Lusaka Province of Zambia. Sixty-six maize samples comprising grain, samp, maize flour, and popcorn were collected from farms, markets, street vendor and hammer mills. Total fungal forming units were estimated after plating on selective media. and incubating up to 14 days. Quantification of total aflatoxin and fumonisins was done using enzyme-linked immunosorbent assay. The maize grain sourced from farm stores in Lusaka had highest mean number of fungal colonies, 4.18 ± 0.05 log CFU/g while the breakfast maize mealie meal flour from the supermarkets had lowest number, 1.31 ± 0.11 log CFU/g. All the maize products, tested positive for aflatoxin and fumonisins with 54.6% above the Zambian regulatory standard of 10 μg kg-1 for total aflatoxin, while all the samples were significantly higher than the acceptable level of PMTDI of fumonisins, 2 mg kg-1. Significantly higher amounts of aflatoxins were obtained from hammer mill, 11.28 μg kg-1 while the least was in the maize products sold by street vendors, 2.62 μg kg-1. The highest amount of fumonisins was recorded in the maize grain obtained from the farms, 2991 mg kg-1 followed by those from the hammer mill, 1659 mg kg-1. Both aflatoxin and fumonisins were found to coexist in all the maize products analyzed. The high levels of contamination observed in the maize products suggest that both the urban and peri-urban population in Lusaka province were being exposed to high levels of both aflatoxin and fumonisins. However, the high level of fumonisins observed in the maize products merits further investigation