Antibacterial activity of lactic acid bacteria isolated from oncom, a traditional Indonesian fermented food

Lactic acid bacteria (LAB) are generally recognized as safe (GRAS) microorganisms and play an important role in food preservation due to antibacterial activity against potentially pathogenic bacteria. This study aimed to isolate lactic acid bacteria from oncom, a traditional Indonesian fermented food and to determine its antibacterial activity against foodborne pathogen. Isolation was done in MRS Agar with 1% CaCO3. Confirmation tests for lactic acid bacteria were carried out through Gram staining and catalase activity. The antibacterial properties of these isolates against food pathogen (Bacillus cereus, Salmonella typhimurium and Escherichia coli) were examined using agar diffusion method. Four isolates showed clear zone on modified MRS and CaCO3 agar, have characteristics as Gram positive and catalase negative were considered as LAB. Based on observations in inhibition zones, it is known that the range of inhibition against the three pathogenic bacteria is 7.60 mm to 12.00 mm. These results indicate that the isolated strains of lactic acid bacteria from oncom are able to synthesize inhibitory substances against pathogenic bacteria.