Simulated digestive juice tolerance and inhibitory effect on harmful intestinal bacteria of Lactobacillus gasseri NY0509 and Lactobacillus casei NY1301

Abstract

In the present study, we investigated the tolerance of Lactobacillus gasseri NY0509 and L. casei NY1301 against simulated digestive juice in vitro, and the inhibition of growth of harmful intestinal bacteria, Escherichia coli and Clostridium perfringens by these bacteria. In the tolerance test of the gastric juice (containing 0.04% pepsin), the viable cell counts of both L. gasseri NY0509 and L. casei NY1301 maintained these initial levels in pH 3.0 for up to 4 hrs. In the bile tolerance test, L. casei NY1301 could grow in 0.3% oxgall, and L. gasseri NY0509 also showed bile tolerance. When L. gasseri NY0509 and/or L. casei NY1301 were mixed-cultured with E. coli JCM 1649T or C. perfringens JCM 1290T, the viable cell counts of E. coli JCM 1649T and C. perfringens JCM 1290T were remarkably decreased, respectively. These results suggest that L. gasseri NY0509 and L. casei NY1301 reach the intestine alive after ingestion, and inhibit harmful intestinal bacteria.