Water-soluble cholesterol was filter-sterilized and added at a
final concentration of 70 mL/100 mL to MRS broth containing 0.3 g/
100 mL oxgall (SigmaeAldrich, St. Louis, Mo, USA). The tube was
inoculated with each selected strains (at 1 mL/100 mL) and incubated
at 37 C for 2, 4, 9 and 24 h. After incubation, the cells were
centrifuged at 10,000 g for 10 min