Ketahanan terhadap Kondisi pH Asam dan Aktifitas Antagonis terhadap Bakteri Patogen Empat Jenis Bakteri Asam Laktat

Abstract

One of the most widely developed health foods was food products containing beneficial living microbial cells known as probiotics. The first probiotic product used Lactobacillus acidophilus and Lactobacillus casei bacteria as components in fermented milk. In its development, the number of microbial species involved in probiotic products was increasing rapidly. Type of lactic acid bacteria used was one factor that would determine the quality of probiotic products. The purpose of this study was to determine the properties of resistance to acid conditions and the antagonistic activity of pathogenic bacteria in four types of lactic acid bacteria (BAL). Lactic acid bacteria were L.acidophillus, L. bulgaricus, L.casei and S.thermophillus. Acid resistance properties  was done by growing the four types of lactic acid bacteria on MRS media whose pH was adjusted at pH 2.5 with the addition of acid (HCl). The antibacterial properties of pathogens were carried out by growing all four types of BAL on MRS media that had been inoculated with pathogenic bacteria ( B.cereus, E.coli and S.aureus). The results obtained were analyzed by Anova and if there was a significant difference (I± = 0.05%) followed by BNT Test. The results on acid resistance properties showed no significant difference to the difference in the number of lactic acid bacteria grown on the control medium with the acid medium (pH 2.5) between each type of lactic acid bacteria tested. The colony log difference between the amount of lactic acid control bacteria and the acid treatment ranged from 5.937 - 7.156 logs of colony / ml. Likewise on testing of antagonistic properties against pathogenic bacteria against B. cereus, E. coli and S. aureus, there was no significant difference in inhibition diameter between the four BAL types. Diameter of inhibition ranged from 1,142-1,373 mm. Based on the results of research that has been done, it can be concluded that from the aspect of acid resistence and antagonistic properties against pathogenic bacteria the four types of lactic acid bacteria potentially as probiotics. Keywords: antibacterial activity , lactic acid bacteria, acid resistance