Background. The aim of this study was to evaluate selected probiotic preparations for determining the abundance and species affiliation of the strains contained in them. To meet the assumed objectives of this study, ten different preparations sold retail were used. The evaluation included a quantitative and qualitative analysis. The quantitative analysis was carried out using culture methods, which also allowed for the initial determination of the microbiota diversity of the preparations tested and the isolation of strains for further study.
Results and conclusion. A total of nine bacterial strains and two yeast strains were isolated. The qualitative analysis included biochemical tests using API® 50 CHL and API® ID 32 C tests, as well as a genetic analysis. Genetic identification was performed using the PCR technique with agarose gel electrophoretic separation of products. A pair of primers was used to identify yeast strains: ITS1 (5′-TCC GTA GGT GAA CCT GCG G-3′) and ITS4 (5′-TCC TCC GCT TAT TGA TAT GC-3′), which allowed to confirm their species affiliation to Saccharomyces cerevisiae. Genetic identification of bacteria of the genus Lactobacillus was carried out using primers 27F (5′-AGAGTTTGATCCTGGCTCAG-3′) and 1492R (5′-GGTTACCTTGTTACGACTT-3′). Only three of ten preparations met all declarations specified on the packaging, relating to the number of strains, their species affiliation and the number of CFUs in a single dose of the product. For one preparation, one bacterial strain not mentioned in the declaration was isolated, and one diet supplement showed <10⁴ cfu / dose of live microorganisms. For three preparations, one of the declared bacterial strains was not isolated.