Fungal biodiversity associated with groundnuts stored in Nasarawa State

Various food commodities such as groundnuts are prone to fungal contamination in favourable environmental conditions. The purpose of this study was to isolate and identify fungi associated with stored groundnuts. A purposeful and random sampling was employed to collect three hundred (300) samples of groundnuts in storage for more than six (6) months from local storage facilities known as ‘rumbun’ from the three agricultural zones (Nasarawa South, Nasarawa North and Nasarawa West) in Nasarawa State. The samples were grounded and cultured in potato dextrose agar (PDA) under sterile conditions, with the aid of a microscope and the fungal flora were determined using taxonomical schemes relying on their morphological and cultural characteristics. The total heterotrophic fungal ranged from 1.4 × 102 to 2.9 × 105 with stored groundnut from Nasarawa South being the most contaminated (4.8 × 104 CFU/g) followed by Nasarawa West (1.6 x 104) and Nasarawa North was the least contaminated (3.3 × 103 CFU/g). Fungal diversity from this study included Rhizopus stolonifer (65.3%), with the highest prevalence followed by Mucor spp (48.5%), Aspergillus niger (43%) and Aspergillus flavus (39 %) while Neosartorya fisheri (0.6 %). The findings of this study suggests that the groundnuts in storage from the three agricultural zones are heavily contaminated by fungi capable of producing mycotoxins which could present a public health challenge to the consumers. It is therefore recommended that groundnuts for long term storage should be properly dried to reduce the attack of fungi with reduced moisture.