Natural Occurrence of Fungi and Aflatoxins Contamination in Maize, Rice and Sorghum from Gashaka Taraba State, Nigeria

Abstract

This work aimed to determine fungi profile and Aflatoxin levels in maize, rice, and sorghum consumed in Gashaka Local Government, Taraba State, Nigeria. Eighteen samples of maize (6), rice (6), and sorghum (6) from markets and stores were analyzed for fungi profiling and Aflatoxins using the conventional method of identification and Ultra High-Performance Liquid Chromatography (UHPLC) method respectively. Forty-one fungi species were isolated in maize, 36 in rice, and 26 in sorghum. Rice samples collected from the markets had the highest mean fungal load of (12.47 ± 10.01) x 10⁴ CFU/g while sorghum samples from the market had the lowest fungal load of (2.03 ± 1.27) x 10⁴ CFU/g. The predominant genera isolated were Aspergillus sp, Fusarium, and Penicillium sp. Aspergillus flavus (14.63%) and Aspergillus tamarii (14.63%) were the most prevalent species in maize. Aspergillus niger (13.88 %) and Aspergillus flavus (11.11 %) were predominant in rice. Fusarium solani (19.23%) and Fusarium oxysporum (13.79 %) were more prevalent in sorghum. Aflatoxins analysis revealed that 16.66% and 27.77 % of the samples exceeded the 2 µg/Kg and 4 µg/Kg EU maximum regulatory limit for AFB1 and total aflatoxins, respectively, in all cereals intended for direct human consumption. Rice from the market had the highest Aflatoxin B1 contamination (15.52±0.0 µg/kg), followed by maize from the market (4.15±2.28 µg/kg). Aflatoxins G2 (2.09±0.00 µg/kg) and Aflatoxin B1 (1.87±0.18 µg/kg) were most prevalent in stored maize. This study confirms low levels of Aflatoxins contamination in cereals from Taraba State but levels in rice exceed the European Union regulatory levels, raising public health concerns.