Spatial Distribution and Isolation of Microbiota Associated with Spoilage of Tomatoes Sold in Selected Markets in Nasarawa State, Nigeria

Abstract

Tomato (Lycopersicum spp) is widely consumed universally because of its high nutritive value, but suffers great post-harvest losses due to microbial attack. This work was carried out to investigate the causative agents of tomato spoilage and the spatial distribution of such causative agents in some selected major markets in Nasarawa State, Nigeria. Sixty tomato fruits from each of the four selected markets (total of 240 fruits) were investigated for the microorganisms responsible for tomato fruit spoilage. Eleven microorganisms, comprising of five bacterial species and six fungal species were isolated from the spoilt tomatoes. The bacterial isolates included Micrococcus varians, Lactobacillus fermenti, Escherichia coli, Salmonella sp and Klebsiella sp. The isolated fungi included Rhizopus stolonifer, Fusarium oxysporium, Aspergillus flavus, Geotrichum candidum, Mucor mucedo, and Candida tropicalis. They were all positive for the pathogenicity test. The isolated organisms were heterogeneously distributed with remarkable levels of severity across the study area. The bacterial load ranged between 2.09 X 109 and 2.56 X 109, while the fungal load ranged between 2.72 X109 and 3.97 X 10 9. The occurrence and magnitude of the spoilage, and hence economic loss due to microbial attack could be attributable to the biologic, ecologic and environmental factors of the study area. Recommendations were, therefore, made for improved personal and environmental hygiene, good agricultural practice and proper treatment of tomato fruits before consumption to avert the imminent health consequences due to the spoilage microorganisms.