Isolation, identification and characterisation of bacteria from ripe tomatoes grown under different agronomic conditions

Background: Tomatoes are exposed to potential microbial contamination. The objective of the study was to determine the presence of bacteria in and on tomato fruits grown under different agronomic conditions in Lusaka. Methods: Bacteriological survey of 27 samples of fresh tomatoes collected from different sources was carried out and analysed. Analysis was done by culturing the tomatoes on different medias: MacConkey, chocolate, blood and shingella and salmonella agar. Following isolation of pure colonies, biochemical tests were done, SIM, catalase, oxidase, TSI, simmons citrate agar and the urease test. Results: Nine bacteria were identified: Escherichia coli, citrobacter, enterobacter, Vibrio spp, Shigella, Salmonella, Klebsiella and Streptococcus aureus. E. Coli and Staphylococcus aureus were found to be the dominant species. Results indicated that the microbial load in samples from fields near the sewer was higher than in samples from far away from the sewer system. Conclusion: Tomatoes grown near the sewer streams are contaminated with bacteria from entrobactriaceae family