Zonal Evaluation of Aflatoxin Contamination of Local Maize Products in Nigeria

Abstract

Aflatoxin contamination of food and feeds continue to be a worldwide food safety concern due to its health and economic hazards. There is need to maintain a close monitoring of the level of contamination so as to assess the effectiveness of various control strategies and interventions. This study seeks to provide recent data on aflatoxin contamination of local maize products in Nigerian open markets. Maize grains, Ogi/Akamu (a fermented maize condiment), local and industrial maize flour were obtained from the six geo-political zones of Nigeria and assessed for mycological profile and aflatoxin content using standard fungal isolation/identification methods and Enzyme-Linked Immunosorbent Assay respectively. Results showed mean fungal count ranging from 1.10 x 103±0.00 cfu/g to 2.60x107±0.75 cfu/g with no significant difference (p<0.05) in counts across the zones. Fungal genera identified include; Aspergillus, Penicillium, Mucor, Neospora, Choanophora, Cladosporium, Rhizopus, Rhodotorula, Sacharomyces, Fusarium, Botrydoplodia, Helminthosporium, Trichoderma, Cunighamella and Geotricum. Aspergillus genera was most frequently isolated from the maize samples across the zones with an incidence of 28.5% while the least isolated were Cuninghamella and Geotricum spp. with 1.00 % incidence. Aflatoxin levels ranged from -11.24±0.40 ppb to 66.80±2.36 ppb with the southern zones having higher level of aflatoxin contamination. Fifty-six percent (56.00 %) of maize products had greater than 20 ppb maximum allowable limit across the zones. There is need for timely and a more target oriented intervention to prevent the serious health implications of this moderate dose exposures to this carcinogenic toxin.
Key words: Aflatoxin, Contamination, Maize products, Nigeria