First report on diversity of probiotics in dambalkhacho, traditional fermented milk product of Georgia

Abstract

Dambalkhacho is a traditional Georgian fermented milk product, protected under the patented brand name N 1585/071, manu-factured from cottage cheese, with unique starter cultures, in the mountainous regions of Georgia. This study was undertaken in order to gain insight into the microbiota, in particular probiotic strains that take part in the manufacture and ripening stages of Dambalkhacho. Tra- ditional cheeses are an important reservoir of microbial diversity that can have important biotechnological applications, starter cultures consisting of autochthonous bifidobacterial strains are of particular interest. To determine the strain identity and evaluate their probiotic potential, we made use of both culturing and the culture-independent methods of PCR. The main species isolated were B. bifidum, B. longum and B. longum subsp. Infantis. Culturing methods enabled the determination of a number of viable microorganisms from dif- ferent microbial groups and their isolation for potential future applications in specific starter cultures. Strains were tested for tolerance to low pH and high bile concentrations, simulating the human gastrointestinal conditions. The probiotic strain B (KB 1.4); C (TB 2); D (TB 6.2.1); B (TL 8.2); D (TL 2.4.1) met the suggested initial count of 106 CFU/ml with brand C recording the highest at 9.19 ± 0.14 log CFU/ml. The higher bile concentrations resulted in lower growth in all the strains. After pH 3.0 treatment, B (KB 1.4); D (TB 6.2.1); D (TL 2.4.1) have also met the requirement of survival at 2 % bile concentration. Based on the overall technological aptitude of the tested strains B (KB 1.4); D (TB 6.2.1); D (TL 2.4.1) met the initial count requirement, and exhibited good acid and bile tolerance therefore being a potentially good source of probiotic additives.