Year: 2026 | Month: May | Volume: 13 | Issue: 5 | Pages: 199-208
DOI: https://doi.org/10.52403/ijrr.20260516
Isolation and Molecular Identification of Gram-Negative Bacteria in Tuna Sashimi (Thunnus spp.) Products in Manado City
Ayid Rivandi Patuti1, Beivy Jonathan Kolondam2, Saroyo3
Department of Biology, Faculty of Mathematics and Natural Sciences, Sam Ratulangi University, Manado, Indonesia
Corresponding Author: Ayid Rivandi Patuti
ABSTRACT
Sashimi is a typical Japanese dish consisting of thin slices of raw fish or seafood, which are served raw and therefore have the potential to be contaminated with bacteria, particularly Gram-negative bacteria. Tuna (Thunnus spp.) is one of the main ingredients of sashimi that is widely consumed in Manado City, but information on the presence and identity of Gram-negative bacteria in this product is still limited. This study aims to identify Gram-negative bacterial species in tuna sashimi circulating in Manado City molecularly based on the 16S rRNA gene through an exploratory study by taking samples from three restaurants in real operational conditions in accordance with consumer purchasing practices. Bacterial isolation was performed using MacConkey agar selective medium, followed by isolate purification, DNA extraction, 16S rRNA gene amplification using Polymerase Chain Reaction (PCR), visualization of PCR products through agarose gel electrophoresis, and analysis of sequencing results. Species identification was performed through sequence comparison using BLAST in the GenBank database. The results showed that five Gram-negative bacterial isolates were successfully identified, including Klebsiella pneumoniae, Pluralibacter gergoviae, and Pantoea dispersa, each exhibiting 100% similarity in the 16S rRNA gene sequence. The presence of these bacteria indicates a potential health risk to consumers, thus providing a scientific basis for quality control and improved food safety in tuna sashimi products in Manado City.
Keywords: Gram-negative bacteria; 16S rRNA gene; molecular identification; tuna sashimi; PCR.
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