Safety assessment of two strains and anti-obese effects on mice fed a high-cholesterol diet.

Previous study documented that Lactobacillus paracasei S0940 and Streptococcus thermophilus ldbm1 have obvious cholesterol-lowering abilities in vitro. In this study, the safety of two strains were evaluated by nitroreductase test, hemolysis test and antibiotic sensitivity test and to evaluate the cholesterol-reducing abilities in vivo. The results indicated that two strains did not exhibit nitroreductase activities and were ɤ-hemolytic on blood agar plates. Further, both strains did not represent a health risk by antibiotic sensitivity test, and significantly reduced serum and liver cholesterol and triglyceride levels of high fat-fed mice. Compared with the high-fat model group, administration of the strains to mice fed a high-cholesterol diet increased fecal water content and fecal cholesterol and significantly improved the intestinal microbiota, which indicating that Lactobacillus paracasei S0940 and Streptococcus thermophilus ldbm1 have a positive effect on reducing cholesterol levels and may be used in functional food.