The acid tolerance of the isolates was evaluated by the method with slight modifications.
Liquid cultures of the isolates were incubated in pepsinsupplemented
MRS broths that were adjusted to pH 2.0, 2.5, and
3.0 with 0.1 N HCl. After 3 h incubation at 37 C, viable cells that
survived at low pH were counted using MRS agar medium by the
plate count method. The type strain Lb. rhamnosus was used as the control
Survival rateð%Þ ¼ ½cell numberðlogCFU=mLÞsurvived in MRS
containing HCl=cell numberðlogCFU=mLÞof initial inoculated
cell 100