Comparative Microbiological Analysis of Marine Fish Collected from Local Markets and Supermarkets

Abstract

The present study investigated microbial contamination and antibiotic susceptibility of bacteria isolated from marine fish sold in supermarkets and local markets. Two fish species, Rupchanda (Piaractus brachypomus) and Red Poa (Otolithoides pama), along with environmental samples (ice, shopkeeper’s hand swab, and air), were collected from both markets. Microbial loads were measured using conventional culture and biochemical methods, while antibiotic susceptibility was determined with the disc diffusion technique. All fish samples showed high bacterial contamination, with total viable counts ranging from 10⁶ to 10⁸ cfu/g. Supermarket samples had higher microbial loads than those from local markets. Coliforms were detected in all samples; Pseudomonas spp. and Staphylococcus aureus were isolated only from the supermarket Red Poa, whereas Salmonella spp. was common in local market fish. Vibrio spp. was detected in samples from both markets. Environmental samples were also collected, including ice samples from stores, hand swabs of shopkeepers, and air quality, which were also heavily contaminated. Antibiotic susceptibility testing revealed multidrug resistance, with limited effectiveness of common antibiotics such as ciprofloxacin, tetracycline, and gentamicin. These findings demonstrate that both supermarket and local market fish can serve as reservoirs of pathogenic and multidrug-resistant bacteria, posing significant public health risks and underscoring the need for enhanced hygiene practices and stricter monitoring in fish retail environments.

Stam. J. Microbiol. 2025;15(1):40-46