Assessment of Microorganisms Associated with Spoilage of Fresh Tomatoes in Storage Facilities in Plateau State

Fresh tomato spoilage during storage and transit causes enormous post-harvest losses in Nigeria, reducing food availability and farmer income, particularly in Plateau State where large-scale tomato farming underpins the North Central agricultural economy. This study assesses the microorganisms associated with spoilage of fresh tomatoes in storage facilities in Plateau State, Nigeria. Tomato samples at varying stages of spoilage were collected from cold stores and ambient warehouses in Jos North and Barkin Ladi local government areas. Isolation and identification of bacteria and fungi were performed using standard pour plate, selective media culture, and morphological characterisation techniques. Bacterial isolates included Pectobacterium carotovorum, Pseudomonas fluorescens, and Erwinia species, while fungal isolates were dominated by Rhizopus stolonifer, Aspergillus niger, and Botrytis cinerea. Rhizopus stolonifer was the single most prevalent organism, isolated from 72 percent of spoiled samples, producing characteristic soft rot with extensive mycelial growth. Bacterial soft rot caused by Pectobacterium carotovorum was observed in 48 percent of samples. Cold-stored tomatoes showed significantly lower spoilage rates but were not immune to fungal colonisation at temperatures above 8 degrees Celsius. The study recommends improved cold chain infrastructure, post-harvest fungicide treatment under regulatory guidance, and farmer training in harvest hygiene across tomato-growing LGAs in Plateau State. Keywords: tomato spoilage, Rhizopus stolonifer, post-harvest loss, Plateau State, storage fungi