UJI AKTIVITAS ANTIMIKROBA BLIS (BACTERIOCIN-LIKE INHIBITORY SUBSTANCES) TERHADAP BAKTERI PEMBUSUK IKAN CAKALANG (ESCHERECHIA COLI, SALMONELLA, PSEUDUMONAS AERUGINOSA) MELALUI METODE MIC MBC

Skipjack tuna (Katsuwonus pelamis) is one of Indonesia's major fishery commodities, widely processed into fillet products for both export and domestic consumption. However, the high protein and moisture content of skipjack tuna makes it highly susceptible to microbiological spoilage, especially due to contamination by pathogenic bacteria such as Escherichia coli, Salmonella sp., and Pseudomonas aeruginosa. This spoilage process not only degrades the sensory quality and nutritional value of the fish but also reduces the competitiveness of Indonesian fishery products. One innovative approach to suppress the growth of spoilage-causing bacteria is the use of natural antimicrobial compounds such as BLIS (Bacteriocin-Like Inhibitory Substances). This study aims to examine the antimicrobial activity of BLIS, isolated from Enterococcus faecalis, against three major spoilage bacteria found in skipjack tuna, using the MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) methods. The results showed that BLIS was capable of significantly inhibiting the growth of all three bacteria. The lowest MIC values were obtained at 0.4% concentration for Salmonella and P. aeruginosa, and 0.5% for E. coli. MBC values demonstrated the bactericidal effectiveness of BLIS at concentrations ranging from 0.6% to 1.0%. OD600 measurements further supported the finding that BLIS treatment reduced bacterial growth compared to the control. Therefore, BLIS shows great potential as a natural antimicrobial agent to inhibit spoilage bacteria in skipjack tuna, playing an important role in extending shelf life and maintaining the quality of fishery products.