.Isolation and characterization of fungal contaminants associated with five selected fruits offered for sale in Lapai, Niger State Nigeria.

Abstract

The alarming rate of fruit of poisoning caused by microbial contamination is enormous. In view of this, mycotic contaminations of banana, orange, mango, garden egg and apple on sale in Lapai, Niger State, Nigeria were investigated. Fruit samples were collected weekly for a period of five months from vendors. Samples collected were cut into pieces and stock dilutions of 1g of sample per 9ml of sterile distilled water were prepared. Serial dilution of samples (10¬¬¯2) were inoculated on Potato Dextrose Agar (PDA) and incubated for 72hours at 28±2˚C. Pure culture of the fungi isolated were obtained and identified. Percentage rate of occurrence of isolated fungi was determined for each fruit. A total of ten (10) fruits spoilage fungi (Aspergillus niger, A. flavus, A. fumigatus, Mucor hiemails, Candida tropicalis, Penicillium digitatum, Alternaria sp., Fusarium notatum, Rhizopus stolonifera, and Colletotrichum sp.) belonging to seven (7) different genera were isolated and characterized. Rhizopus stolonifera has the highest average frequencies of occurrence in orange (18.72%), banana (17.81%), garden egg (19.16%) and apple (25.03%) which were significantly different (P˂0.05) from other isolates. However, in mango, A. niger has the highest percentage frequency of 21.64%. In all the fruits, A. fumigatus has the least percentage of occurrence except in garden egg. From this study, the presence of fungi contaminants some of which are known to produce mycotoxin that cause serious effects on human health if consumed was established. Therefore, an enforceable safety standard for the production, harvesting and distribution of fruits generally is suggested.