ISOLATION AND IDENTIFICATION OF FUNGI ASSOCIATED WITH SPOILAGE VEGETABLES SOLD IN SELECTED SOKOTO MARKET

Abstract

This study investigated the isolation and identification of fungi responsible for the spoilage of tomatoes (Solanum lycopersicum), pepper (Capsicum frutescens), and bell pepper (Capsicum annuum) sold in major markets within Sokoto State, Nigeria. Vegetable spoilage poses a serious post-harvest challenge that reduces food quality, safety, and market value, particularly under the region’s hot and dry climatic conditions. The research aimed to identify the fungal species associated with spoiled vegetables, determine their frequency of occurrence, and suggest control measures to minimize post-harvest losses. Forty-five samples of tomatoes, peppers, and bell peppers were randomly collected from Sokoto Central Market, Kasuwa Dankure, and Kasuwa Daji. The samples were cultured on Potato Dextrose Agar (PDA) and incubated at 25 ± 2 °C for 5–7 days, while fungal identification was based on macroscopic and microscopic characteristics, and data analyzed using SPSS version 25. The results revealed five dominant fungal species: Aspergillus niger, Aspergillus flavus, Rhizopus oryzae, Rhizopus stolonifer, and Saccharomyces cerevisiae. Among these, S. cerevisiae showed the highest frequency of occurrence (37.1%), followed by R. oryzae (28.6%), while A. flavus had the lowest (8.6%). Tomatoes and peppers recorded the highest overall fungal contamination (40% each), whereas bell peppers showed the lowest (20%). The high occurrence of S. cerevisiae and Rhizopus species suggests that high sugar and moisture content in vegetables, coupled with poor handling and elevated temperature, greatly encourage fungal proliferation. The presence of Aspergillus species, especially A. flavus, also indicates possible health hazards due to mycotoxin production. The study concludes that poor storage conditions, open-air marketing, and lack of cold facilities are major factors promoting fungal contamination in Sokoto markets. It recommends improved hygiene practices, the use of plastic crates instead of woven baskets, adoption of cold or evaporative storage, and awareness campaigns on the dangers of consuming spoiled vegetables. Implementing these measures will help reduce economic losses, enhance food safety, and improve the shelf life of perishable vegetables in Sokoto State.