Karakteristik Ketahanan Bakteri Asam Laktat Indigenous Kefir Sebagai Kandidat Bakteri Probiotik Pada Kondisi Saluran Pencernaan in vitro

Abstract

Functional food containing probiotic bacteria is potential for modification intestine microflora. The objective of this research was to assess the resistance characteristics of kefir indigenous Lactic Acid Bacteria (LAB) (LABs from kefir, Bifidobacterium longum Y-01 and Lactobacillus acidophilus Y-01) as probiotic bacteria through its ability to grow in gastrointestinal conditions such as pH conditions (pH 2, 2.5, 3.2 and 7.2), the presence of bile salts in the small intestine, its resistance to antibiotics (amoxycillin and chloramphenicol) and its microbial activity to inhibit the pathogenic bacteria growth (Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Salmonella Typhimurium ATCC 14028). The results of Gram staining and catalase assay showed that the three kefir indigenous LABs were not contaminated with other microorganisms. Three kefir indigenous LABs had good resistance in gastro intestinal conditions, as the population of all kefir indigenous LABs observed did not decrease when they were exposed to gastrointestinal condition. Kefir indigenous LABs were more resistant to chloramphenicol antibiotics than amoxycillin antibiotics. The antagonistic test of kefir indigenous LABs to pathogen bacteria showed that the three kefir indigenous LABs had a variety inhibition. The statistical analysis showed that different types of LABs had a significant influenced on the inhibition zone of S. aureus, E. coli and S. Typhimurium. Therefore, the three tested kefir indigenous LABs had potential characteristics as probiotic bacteria.