Strong Antimicrobial Acvitity of Lactic Acid Bacteria Isolated from Raw Goat Milk in Medan, North Sumatera, Against Staphylococcus aureus

Biopreservation is a method of foods preservation using natural ingredients by inhibiting the growth of spoilage food bacteria. Lactic acid bacteria is a bacteria that utilize as food preservation because it produce antimicrobial agent including bacteriocin and also act as probiotic. LAB could isolated from various natural source including raw milk. The aim of the study was to determined the antimicrobial activity of lactic acid bacteria (LAB) isolated from raw goat milk against food spoilage bacteria including Escherichia coli, Staphylococcus aureus, and Salmonella typhi. The result of the research indicated that the LAB isolated from raw goat milk(isolate EH1, EH2, EH3, EH4, EH5 and EH6) were Gram positive, homofermentative and negative in catalase test. The antimicrobial activity of LAB against indicator bacteria showed the strong antimicrobial activity against Staphylococcus aureus. The inhibition zone of EH1, EH2, EH3, EH4, EH5 and EH6 against S.aureus respectively were 19 mm ; 17,4 mm; 21,7 mm; 14,3 mm; 14,2 mm and 16 mm. The LAB isolates could not inhibit the growth of E.coli and S.typhi. It concluded that LAB isolated from raw goat milk has a potential as source of effective probiotic against Gram positive bacteria.