Microbiological Assessment of Escherichia coli Contamination in Vannamei Shrimp (Litopenaeus vannamei)

Whiteleg shrimp (Litopenaeus vannamei) is a globally important aquaculture commodity, including in Indonesia, due to its fast growth and salinity tolerance. Microbiological safety is crucial to protect consumer health and meet food quality standards. One key indicator in microbiological testing is the presence of Escherichia coli (E. coli), which reflects fecal contamination from poor water quality or unhygienic post-harvest handling. This study aimed to detect and characterize E. coli contamination in L. vannamei from two different pond systems with contrasting environmental conditions. Sample Q was collected from a pond relying on rainwater near a goat pen, posing a higher risk of organic contamination. Sample R originated from a pond with a controlled single water gate system and more stable water quality. Microbiological analysis was performed using the Most Probable Number (MPN) method with Lauryl Sulfate Broth (LSB) and EC broth for presumptive tests, L-EMB agar for confirmation, Gram staining, and biochemical IMViC tests (Indole, MR, VP, Citrate). Results showed higher coliform and E. coli contamination in sample Q, detectable up to 10⁻³ dilution, while sample R was positive only at 10⁻¹ to 10⁻² dilutions. All isolates exhibited typical E. coli phenotypic and biochemical characteristics, including Gram-negative short rods and IMViC pattern Indole (+), MR (+), VP (–), Citrate (–). These findings highlight the importance of water quality management and hygienic handling to control microbiological contamination in L. vannamei. Routine testing and strict monitoring are essential to ensure food safety and enhance the competitiveness of Indonesian aquaculture products in global markets.