The strains for each test were initially cultured for 24 h in MRS
broth at 37 C. After this period, the strains were centrifuged for
5 min and washed 3 times in Phosphate Buffered Saline (PBS) pH
7.0. Individual tubes containing each strain and test medium were
incubated for 3 h at 37 C in awater bath. Viability was evaluated in
duplicate at 0 and 3 h on MRS agar. Survival rates were calculated
according to the following equation: