Phenotypic and genotypic characterization of lactic acid bacteria isolated from raw milk samples

Lactic acid bacteria used as starter cultures in the production of fermented food and produce some antimicrobial agents which is capable of inhibition on pathogenic bacteria. In this study; it is aimed to isolation of lactic acid bacteria from raw milk samples consumption in Amasya, investigation of antimicrobial activity on some pathogenic microorganisms, in addition this, the isolates have the potential to be bacteriocins showing the inhibitory effects are made identification to the species level with phenotypic and genotypic methods. 121 strains isolated from 77 raw milks and antimicrobial activity was investigated on pathogenic bacteria (S. aureus ATCC25923, E. coli ATCC 35218, B. cereus DSM4312, P. aeruginosa ATCC27853 and S. enteritidis ATCC 13076) using the well diffusion technique. 32% of these isolates have been antimicrobial effect on B. cereus, 31% on P. aeruginosa, 26% on S. enteritidis, 27% on E. coli, 21% on S. aureus. This isolates were identified phenotypically by general microbiological methods such as gram stain, catalase test, optimum growth temperature and pH, NaCl concentration can be developed. 17 isolates were identified at the species level by API 50 CHL and API 20 Strep tests. According to this definition, isolates were determined as 29.4% L. paracasei ssp. paracasei, 11.8% L. plantarum, 29.4% Leuconostoc spp., 11.8% E. faecalis, 11.8% A. viridans and 5.9% L. lactis ssp. cremoris. Basil form of lactic acid bacteria, L. paracasei and L. plantarum were typed using PCR for genotypic verification as 10.8% L. paracasei and 4.1% L. plantarum of 121 isolates.