Isolation and identification of aflatoxin producing fungi from different foodstuffs at Shuwarin Market, Jigawa State, Nigeria

Abstract

Aflatoxin is a word derived from Aspergillus spp toxin which is naturally occurring mycotoxins that is produced by Aspergillus flavus and Aspergillus parasiticus species of fungi. The aim of this study was to isolate and identify aflatoxin producing fungi from four different grains (maize, rice, cowpea, and groundnut). During the research, four (4) different grain samples were obtained from Shuwarin market (Kiyawa L.G.A), Jigawa state. The samples were analyzed for microbial examination through serial dilution, inoculation, incubation, subculture and microscopy. Six (6), fungal species were isolated which included Aspergillus flavus, Rhizopus sp, Penicillium sp, Fusarium sp, Cladosporium sp and Aspergillus niger, where A. niger has the highest number of isolates (16; 40%), Rhizopus sp with 12 (30%) isolates, and A. flavus having 8 isolates (20%), Penicillium sp, 2 (5%), Cladosporium sp has and Fusarium sp has 1(2.5%) having 1 (2.5%), each, having the lowest number of isolate. Furthermore, the samples were also used to detect the presence of aflatoxin using thin layer chromatography technique (TLC). The contamination levels found ranged from the relative factor value (Rf) for maize, the Rf 0.94 registering the highest level of aflatoxin content and groundnut with Rf value of 0.08 registering the lowest level of aflatoxin content. This is due to improper harvesting, handling, processing, storage, and poor hygiene of the farmers and vendors. Therefore, the farmers and vendors have to be trained and enlightened on the method of harvesting, storage, handling, processing, transportation and selling of cereals and legumes so as to reduce the risk of causing health problems to the consumers.