Fungal Contamination of Stored Grains in Markets Across Kano Metropolis

Post-harvest fungal contamination of stored grains is a significant economic and public health concern in northern Nigeria, where grain storage practices are frequently suboptimal. This study investigates fungal contamination of stored grains including maize, sorghum, millet, and groundnut sold in five major markets across Kano metropolis, North West Nigeria. Grain samples were collected from 50 market stalls during the post-harvest dry season and processed using standard dilution plating on Sabouraud dextrose agar and potato dextrose agar. Fungal species were identified through cultural and morphological characterisation supplemented by lactophenol cotton blue wet mount microscopy. A total of 18 fungal species were isolated, with Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, and Penicillium citrinum being the most frequently recovered. Aflatoxin-producing potential was screened using ultraviolet fluorescence on coconut cream agar. Aspergillus flavus isolates from 62 percent of maize samples demonstrated aflatoxin-producing fluorescence. Fungal load was highest in samples stored in jute sacks in open market stalls compared to metallic silos. Moisture content analysis correlated positively with fungal load across all grain types (r = 0.78, p < 0.05). The study links high fungal contamination to inadequate drying before storage, poor storage container hygiene, and ambient humidity. Recommendations include improved pre-storage drying, hermetic storage promotion, and aflatoxin monitoring by the Kano State Ministry of Agriculture. Keywords: fungal contamination, stored grains, Aspergillus flavus, aflatoxin, Kano