Bekasam is an Indonesian fermented fish product that tastes sour and mostly contains lactic acid bacteria(LAB). The aim of this study is to obtain and characterize LAB isolates from bekasam and to study theirpotency in inhibiting the growth of pathogenic bacteria, i.e. Escherichia coli, Salmonella typhimurium ATCC14028, Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes. LAB were isolated from bekasamusing media of MRSA supplemented with CaCO3 0.5%. Incubation was at 37°C for 48 hours. The pure cultureswere verified as LAB based on morphological and biochemical characteristics. Eight bekasam samples showedthat the total average of LAB were 1.4 x 108 to 9.0 x 108 CFU/mL. Seventy four isolates were successfullyisolated. It was found that 62 isolates (84%) belonged to LAB, and 23 isolates of them could inhibit the growthof the five pathogenic bacteria. The highest inhibition zone was accounted for S. aureus. However, neutralizedsupernatant of the LAB culture did not inhibit the growth of the pathogenic bacteria. These results indicate thatthe LAB inhibition to the pathogenic bacteria was due to the organic acid, and that perhaps the main factor inthe bekasam preservation by LAB.
Antimicrobial, Bekasam, Fermented fish, Inhibition index, Lactic acid bacteria