Effects of prebiotics on acid and bile resistance of Bifidobacterium lactis and Lactobacillus acidophilus probiotic bacteria

Rezumat

The effects of prebiotics on acid and bile resistance of probiotics were evaluated. Two commercial strains, Bifidobacterium lactis BB-12 and Lactobacillus acidophilus LA-5 had higher acid and bile resistance characteristics than the ATCC strains. B. lactis BB-12 was the most resistant to acid and bile and showed higher survival capacity. The counts of B. lactis BB-12 viable cells in pH 2 medium decreased by 2.7 log unit while the viability of other strains decreased by 4.5-7 log units. The counts of B. lactis BB-12 viable cells in the bile medium after 6 and 24 hours of incubation were determined as 6.1 and 2.8 log CFU/ml, respectively, while no viable bacteria could be determined for the other strains after 24 hours of incubation. The acid and bile resistance of probiotic bacteria remarkably varied with the type of prebiotics. Acid and bile resistance properties of L. acidophilus LA-5 and L. acidophilus ATCC 4356 were found higher when INU was present in the growth medium. Acid and bile resistance properties of B. bifidum ATCC 15969 was higher when the medium contained GOS whereas acid and bile resistance of B. lactis BB-12 was found to be higher when medium contained XOS.