Effects of storage methods and duration on the microbial composition and load of tomato (Solanum lycopersicum [L.], Solanaceae) fruits

Abstract

Tomato is a widely cultivated fruit vegetable in Nigeria. They are valued for their fruits, which are consumed fresh or processed. The method and duration of storage have profound effects on the economic value and utilization of the fruits. Therefore, this study was set up to investigate the efficacy of three common storage methods (plastic basket, concrete floor and refrigeration at 4 oC) by conducting microbial assessment. Freshly harvested fruits were sourced from two locations in Benin City, Nigeria and stored for a period of four weeks. Microbial composition and load was determined using standard laboratory techniques initially (on the first day) and every week afterwards. Results showed that the microbial load increased with prolonged storage. Tomato fruits stored in plastic basket had the highest mean total microbial count (132 × 105 CFU/mL), whereas those stored in the refrigerator had the least (3 × 105 CFU/mL). The common microorganisms isolated from the stored fruits include the fungi; Aspergillus niger, A. flavus, Rhizopus, Penicillium spp., and yeast cells as well as the bacteria; Staphylococcus sp. E. coli, Salmonella and Enterobacter spp. These results suggest that refrigeration will extend the shelf life of tomato fruits and minimize the rate of spoilage due to microbial composition and load.