Abstract

PEREZ, Indira; FALCO, Aura; TAPIA, María Soledad  and  ALONSO, Guillermina. Isolation and identification of strains belonging to the Bifidobacterium genus found in fermented yoghurt type milk products. Rev. Soc. Ven. Microbiol. [online]. 2012, vol.32, n.1, pp.29-36. ISSN 1315-2556.

The identification of probiotic microorganisms belonging to the Bifidobacterium genus is very important due to their use as supplements favorable for consumer’s health. In Venezuela there have been few studies of the microbiological characterization of these bacteria and there are no official methods for their study in food. This investigation reports the standardization of microbiological and molecular techniques for the isolation and identification of bifidobacteria isolated from two yoghurt type products: I with probiotic and II without probiotic. Ten samples from each yoghurt type product were analyzed, one per week, and 3 colonies were isolated per sample. Results showed that of the 60 isolates analyzed, 27 colonies of Yoghurt I and 11 of Yoghurt II coincided with the characteristics of bifidobacteria. Bacterial growth was compared in two culture media (MRS-m, RCA), inoculating in-depth in plates and Miller-Pricket tubes; the best results were obtained with MRS-m medium and in-depth inoculations in tubes. By DNA extraction we obtained ERIC-PCR and REP-PCR patterns, determining that 34 isolates were indistinguishable clones, showing the same pattern of the B. lactis used as positive control. This methodology can be used by the industry and the institutions in charge of quality control of probiotic products

Keywords : Bifidobacterium; probiotic; yoghurt; microbiological characterization; ERIC-PCR; REP-PCR.

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