ACID AND BILE TOLERANCE OF PROBIOTIC BACTERIA USED FOR LACTIC ACID FERMENTATION OF VEGETABLE JUICES

The purpose of this study was to evaluate the probiotic Bifidobacterium animalis subsp. lactis BB-12 with regard to its resistance to simulated gastrointestinal stress. The tested strain was able to survive both in the presence of 0.3% bile salts for 5h and in the acidified MRS broth with pH 2.0 for 2h, the rate of viability being by 78% and 76% respectively. The presence of pepsin with a view to test the strain tolerance to gastric juice induced the decrease of the viable cells number with 1.4 log cycles after 6h. The behavior of Bifidobacterium lactis BB-12 was quite different when the exposure to gastric juice was combined with the exposure to bile salts, highest death rates being determined.