Evaluation of probiotic properties of Lactobacillus strains isolated from traditional Chinese cheese

Twenty-seven Lactobacillus strains isolated from traditional Chinese cheese were evaluated for their probiotic potential by in vitro and in vivo tests. Seven strains were selected as they showed high resistance to low pH and simulated gastrointestinal juice. Further study indicated that five strains exhibited good adhesion to Caco-2 cells. Bile salt hydrolase (BSH) and high beta-galactosidase activities were shown by the five strains. They also showed various antimicrobial activity against pathogens. Among the five strains, an atypical resistance to chloramphenicol was detected in strain BJFU 10241. After a series of tests, the cat gene was observed in plasmids but not in genomic DNA. In vivo experiments showed that strains BJFU 10256, BJFU 10041, BJFU 10205, and BJFU 10025 could regulate intestinal flora. Significant increases in Lactobacillus spp. were observed. Moreover, the numbers of Enterobacter and Clostridium perfringens decreased significantly. The ability of the four strains to lower serum total and low density lipoprotein cholesterol in mice was observed, and this property was enhanced by ingestion of cell suspension compared to fermented milk. These four strains showed the best probiotic potential and could be used in fermented food in the future.