Bacteriological Quality of Ready to Eat Vegetable Salads Vended in Ilala District Markets and Antibiotic Sensitivity Profiles of Isolated Contaminant Bacteria

Abstract

Aim: To determine level of bacterial contaminants and antibiotic susceptibility profiles of bacteria isolated from read-to-eat salads (RTES). Study Design: An experimental cross-sectional study was conducted in three localities of Ilala District in Dar es Salaam (Tanzania). Methodology: Twenty-four RTES samples were bought from randomly chosen fast food centers. RTE salads were analyzed at the Pharmaceutical Microbiology Laboratory. The total viable counts (TVC) were determined, and the standard procedures for microbial identification were performed and confirmed by physiological tests. The identified microbial contaminants were subjected to antibiotic sensitivity testing (AST) using the Kirby-Bauer disc diffusion method. Six widely used antibiotics: amoxicillin (AX25), sulfamethoxazole/ trimethoprim-(SXT-25), amoxicillin/clavulanic acid (AMC30), gentamicin (CN5), ciprofloxacin (C5), and chloramphenicol (C30) were used for the AST. Results: The TVC of isolated bacterial contaminants ranged from 106 to 108 cfu/g, which was above the acceptable standard limit and unfit for human consumption. Five bacterial species comprised of Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella oxytoca were isolated and subjected to the AST.  All bacteria were resistant to AMC30. Escherichia coli was isolated from 10% of the RTES. Association between bio-burden and antibiotic resistance was observed. Conclusion: The RTES harbored contaminant bacteria beyond acceptable limits. The predominant contaminants were P. aeruginosa and E. coli. One-fifth of the samples contained E. coli, indication of poor sanitation. All the isolated bacteria were resistant to AMC30. Prompt measures are required to curb the spread of antibiotic-resistant microorganisms.