Determination of some probiotic properties of bacteria isolated from fermented milk products

Current research findings on the effects of probiotic microorganisms in fermented foods on human intestinal microbiota have increased day by day. In this study, it was aimed to identify probiotic microorganisms in fermented foods such as terayağ and kaşar cheese and to clarify some basic properties which are important in terms of probiotics. Bacteria isolated by classical methods were identified by both biochemical and molecular methods. Acid and bile resistance in different concentrationn, exopolysaccharide production capacity, antimicrobial activity properties and resistance to some antibiotics of isolates were performed. As a result, one Streptococcus spp. and twelve Lactobacillus spp. strains were isolated. In the biochemical and molecular analysis, S.lutetiensis G1, L.fermentum G2, G3, G7, G10, G13, L. helveticus G4, G6, G8, G9, G12, L. delbrueckii G5 and G11 strains were identified. L. helveticus G9 was the best in terms of acid resistance (pH: 3,0), bile tolerance (0,3%) and EPS production capacity. There was a positive correlation between EPS production of strains and acid tolerance and bile salt tolerance. All of the strains were found to be resistant to ampicillin, oxacillin, chloramphenicol, vancomycin, and clindamycin antibiotics. Besides, antimicrobial activity against pathogenic microorganisms of isolates was not detected. It was detected the plasmids having quite small compared to genomic DNA sizes in all isolates. As a result, in our study, 13 strains were collected from butter and kashar cheese which we frequently use in our daily lives. It has been observed that L. delbrueckii G9 strain can be used as probiotic microorganisms in terms of that evaluated in the scope of study. However, to be able to use these strains as a full probiotic, it is necessary to investigate other useful properties for health. The selection and use of superior quality probiotics in fermented foods will be beneficial for health in this light. Keywords: Fermented food, probiotics, Streptococcus spp., Lactobacillus spp