Phenotype and genotype detection of Escherichia coli and Salmonella spp. contamination in fishery commodities in Bali, Indonesia

Abstrak

This study aimed to identify Salmonella spp. and Escherichia coli contamination associated with foodborne diseases in fishery commodities from Bali, Indonesia. A total of 216 samples representing commercially important fish and shrimp species were collected from suppliers, fish processing units, micro, small, and medium enterprises (MSMEs), traditional markets, and modern markets across regencies in Bali. Sampling was proportionally distributed across supply chain loci, with three replicate samples collected for each commodity at each locus to minimize sampling bias and improve prevalence estimates. Phenotypic detection was performed using selective culture media, while positive isolates were confirmed genotypically using specific primers targeting the invA gene for Salmonella spp. and the lacZ gene for E. coli. The results revealed the presence of E. coli contamination in all fishery commodities examined, albeit with varying prevalence across commodity types. Conversely, Salmonella spp. was not detected in any of the samples. The highest prevalence of E. coli contamination by sampling locus was observed in traditional markets (12/36; 33%), whereas lemuru fish exhibited the highest prevalence among commodity types (5/10; 50%). Spatially, Tabanan Regency showed the highest prevalence of E. coli contamination, reaching up to 66% across the surveyed villages. Genotypic confirmation successfully identified E. coli isolates based on amplification of the lacZ gene at 876 bp. These findings highlight the need to implement a One Health approach as an effective framework for controlling foodborne bacterial contamination and its environmental transmission.

Kata kunci

• bacterial contamination
• contaminated fish
• Escherichia coli
• foodborne pathogen
• fishery products