Mycoflora and Aflatoxin Producing Fungi from Some Storage Cereal Grains Sold in Darki Market, Wudil Local Government Area, Kano State, Nigeria

Abstract

Aim: The study was aimed at determining the mycoflora and aflatoxin producing fungi in some storage cereals sold at Darki market, Wudil Local Government Area, Kano State. Nigeria. Study Design: A total of thirty samples (ten samples containing 250g each of maize, millet and wheat) were obtained from storage facilities of traders in different location of Darki, market. Place and Duration of Study: Storage facilities of Darki market, Wudil, Kano State, between May 2021 and July 2021. Methodology: Samples were subjected to serial dilution, enumeration of fungal load using pour plate method, inoculation and isolation of fungi using direct plating method, extraction and detection of aflatoxin using thin layer chromatography and molecular analysis using PCR. Result: Total fungal (mold) count on Potato Dextrose Agar recorded the highest count of 6.5103 in wheat sample 4 (WH4) while the least count of 2.2102 was recorded in wheat sample 6 (WH6). The fungal isolates obtained from this study were Aspergillus niger, Aspergillus flavus, Fusarium spp, Mucor spp, and Rhizopus spp. The percentage of occurrence of fungi isolated from the cereal samples was highest in Aspergillus niger (34.43%) and the least (11.48%) was recorded in Mucor spp. Extraction and detection methods revealed a blue fluorescence on the TLC plates indicating the presence of aflatoxin B in the samples. The standard calculated range of Retention factor value was between 0.58 and 0.75. After DNA extraction, the fragment size obtained by PCR reactions with primer pairs ITS1/ITS4 showed 600bp for most of the isolates. All the Aspergillus spp, Fusarium spp. and Rhizopus spp showed positivity for the molecular markers ITS1/ITS4 by having positive bands. Only Mucor spp showed negative results for ITS1/ITS4 primers and showed no band. Conclusion: This study shows that most of the cereals were contaminated with either one or more molds but within the satisfactory and marginal limits. However, aflatoxin contamination is a threatening issue Hence aflatoxins contamination of crops at harvest conditions should be controlled to some extent by the implementation of good agricultural practices and good storage practices.