Microbial contaminant trails in Siganus sutor landed by artisanal fishers along the Kenyan coast

Fish is highly susceptible to spoilage and environmental contamination, leading to quality deterioration and significant food safety concerns. Globally, outbreaks of food-borne illnesses linked to fish consumption have prompted strict safety regulations along the value chain.

At the Kenyan coast, untreated or partially treated sewage and other pollutants are frequently discharged into inshore waters, which also serve as artisanal fishing grounds. This study aimed to identify microbial contamination hotspots in Siganus sutor from artisanal fisheries in order to enhance fish safety and inform stakeholders about risks associated with pollution and poor handling practices.

Sampling sites were selected based on a pretested questionnaire covering both North and South Coast of Kenya. Mtwapa and Tudor Creek represented polluted fishing grounds, while Mkunguni and Mayungu were selected as relatively pristine sites. Fish samples were collected immediately after capture, on board, and subsequently tracked along the value chain. Microbial analysis focused on total plate counts, coliforms, and specific pathogens including Escherichia coli, Salmonella spp., and Pseudomonas spp.

Results showed significantly higher microbial loads in fish from polluted sites compared to those from unpolluted areas. However, all tested microorganisms were detected across all fishing grounds and value chain nodes, regardless of handling practices.

Sanitary handling methods were associated with reduced microbial growth, as evidenced by lower counts in fish handled hygienically by fishers and traders. Fried fish samples exhibited the lowest microbial levels due to the high temperatures involved in cooking, which effectively reduce microbial load. The presence of microorganisms in fried fish suggests possible post-processing contamination, likely from frequent handling by consumers during purchase.

The consistent detection of fecal coliforms and pathogenic bacteria such as E. coli, Salmonella, and Enterococcus faecalis highlights potential public health risks. The findings underscore the need for improved hygiene practices and stronger regulatory measures across the fish value chain.