Charakterizace vybraných kmenů Streptococcus salivarius subsp. thermophilus

This work dealt with characterization of Streptococcus thermophilus strains. In connection with technology and safety of foodstuff, acidification activity, production of exopolysaccharides, amino acids and biogenic amines or antibiotic resistance of Str. thermophilus strains were examined. Especially, it was focused on thermophilin production and inhibitory effects of Str. thermophilus strains. Further, molecular biology methods were used to both Str. thermophilus strains identification and to their typing, characterization and discrimination. It was established that studied strains are conducive to fermented milk production from technological and safety point of view. Gene for thermophilin formation (Streptococcus thermophilus thermophilin 13 operon) was demonstrated in 8 of total 12 streptococci strains. It was assigned by observation of inhibitory effects, that strains with gene for thermophilin 13 were more efficient than streptococcal strains without this gene. In addtition, it was confirmed that applied molecular biology methods are suitable tool for diagnostic of Str.thermophilus strains.