ISOLASI DAN SELEKSI BAKTERI ASAM LAKTAT DARI YOGHURT KEMASAN YANG BERSIFAT ANTIBAKTERI TERHADAP Escherichia coli DAN Salmonella typhi

Abstract

Yoghurt is a fermented product of a group of lactic acid bacteria (LAB) on milk that has
been pasteurized. LAB is a group of bacteria that are able to convert carbohydrates
(glucose) into lactic acid. LAB produces metabolites that inhibit the growth of
pathogenic bacteria. This study aimed to isolate LAB from yoghurt packaging with its
inhibitory against bacterial pathogens Escherichia coli and Salmonella typhi. LAB was
isolated from 9 samples with 3 brand products and 3 different flavors. Calculation of the
total population to the overall LAB samples was obtained between 6.4 × 10 6 cfu/ml to
2.1 × 10 7 cfu/ml. In this study, inhibition test of pathogenic bacteria E. coli and S. typhi
used samples yoghurt. The method used is the well-agar diffusion. The most effective
yoghurt in inhibiting E. coli was yogurt Ab with diameter of inhibiting zone 23.55 mm,
while the yogurt sample that had the highest inhibitory zone which is 19.93 mm for
S.typhi was yoghurt Ap.