DOI: 10.36347/sajb.2014.v02i07.012

Pages: 459-466

This study investigated the microorganisms associated with the spoilage of fresh fruits of tomato, Lycopersicum esculentum obtained from four markets in Benin City, southern Nigeria. A total of nine species of bacteria isolated and identified were: Bacillus subtilis, B. cereus, B. aureus, Escherichia coli, Klebsiella aerogenes, Pseudomonas aeruginosa, Salmonella typhi, Proteus mirabilis and Staphylococcus aureus. The most prevalent bacterial isolate was Bacillus subtilis with 49.2% and was found in all samples from the four markets. Proteus mirabilis was the least prevalent isolate with 13.1% and was found in samples from Vegetable market only. The fungal isolates were Penicilium sp., Mucor sp., Aspergillus niger, Fusarium sp. and Saccharomyces cerevisae. Whereas Mucor sp. was the most prevalent with 57.7% and was found in fruit samples from all the markets, Saccharomyces cerevisiae had the least prevalence of 9.1% and occurred only in Vegetable and Santana markets. The mean microbial count ranges were: 2.0 x 104 – 35.0 x 104 for New Benin market; 1.0 x 104 – 25 x 104 for Vegetable market; 2.0 x 104 – 23.0 x 104 for Oba market and 1.1 x 104 – 9.3 x 104 for Santana market. The antibiotic susceptibility profile of bacterial isolates obtained from spoilt tomato fruit samples was determined using the disc-diffusion method. Bacillus subtilis was the most sensitive to all the antibiotics used while Pseudomonas aeroginosa and Salmonella typhi showed the highest resistance. The presence of toxin producing fungi Aspergillus niger, which are capable of causing food poisoning as well as some bacterial isolates with multiple antibiotics resistance, raises concern over public health risks that may be associated with the consumption of spoilt tomato fruits.