Incidence of fungi and aflatoxin contamination of maize in Tolon-Kumbungu district of Ghana
Maize (Zea mays L.) is an important staple food crop and a source of income to farmers, as well as foreign exchange earner in most countries in sub-Saharan Africa. Its production is hampered by fungal diseases, which also cause contamination with mycotoxins, especially aflatoxin and its associated health hazards. This study sought to isolate and identify aflatoxigenic fungi, as well as detect the presence of Aflatoxin B1 (AfB1) in maize samples obtained from farmers in the Tolon-Kumbungu district in the northern region of Ghana. Twenty farming communities were randomly selected for the study in consultation with the district office of the Ministry of Food and Agriculture (MoFA). Samples were collected from 200 randomly selected maize farmers by the composite sampling technique, for isolation of aflatoxigenic fungi by the agar plate method and the detection of aflatoxin. Aflatoxin was detected in maize samples with the Black light, rapid screening and immunoassay methods. Aspergillus flavus had the highest percentage of occurrence (63.7%); followed by A. niger (16.5%), Rhizopus stolonifer (9.3%), Penicillium spp. (6.9%) and Fusarium oxysporum (3.7%). Farm samples had more aflatoxin than those from stores and markets. Samples of maize from farms in Gbirimani community had the highest aflatoxin contamination of +60 ppb. Concentrations of Afb1 at or above +20 ppb were recorded in all the communities, except in Tinguli. Apart from Voggu, all market samples were free from aflatoxin contamination.
Key words: Aflatoxigenic fungi, postharvest, Zea mays