Determination of propionic acid bacterial species in traditional Turkish cheeses and searching some of their probiotic properties

In this study, twenty-nine (29) strains of Propionibacteria were isolated from home-made traditional Turkish cheeses. Classical Biochemical tests, API 50 CHL, 20E and 20 kits were used in identification of propionibacteria strains. Identification results were assessed with numeric taxonomy program and showed that Propionibacterium freudenreichii subsp. freudenreichii was the predominant species (15 strains). When compared with acid production in YEL medium %0,08-0,21, acid production of strains in skim milk medium %0,07-%0,99 was determined to be high. Propionibacteria strains showed an inhibitory effect of %91 on Escherichia coli ATCC 11229, %56 on E. coli ATCC 35218, %56 on E. coli O157:H7, %50 on Staphylococcus aureus ATCC 25923, %29 on Listeria monocytogenes ATCC 7644, %59 on Salmonella enteritidis ATCC 13076, %53 on Bacillus cereus RSKK 863, %91 on Shigella sonnei Mu:57, %35 on Micrococcus luteus NRLL B-4375 and %76 on Pseudomonas aeruginosa ATCC 27853. Antibiotic susceptibility of strains were determined to be lowly resistant to streptomycin (29%), getamicin (24%), kanamycin (20%), rifampicin (26%), polymyxin (24%) and highest resistance to nalidixic acid (100%). Positive correlations have been obtained between production of exopolysaccharide and tolerance to bile salts (p<0.05) or resistance to low pH (p<0.05) or autoaggregation and coaggregation (p<0.05). P. freudenreichii subsp. freudenreichii DO7, P. jensenii BDP11 and P. thoenii AKP1 strains showed high autoaggregation (39-98%) and coaggregation (33-61 %) activities and also high acid production and antimicrobial activities. All strains showed hydrophobicity with ethyl acetate (25-61%). Because of having all of these properties, P. freudenreichii subsp. freudenreichii DO7, P. jensenii BDP11 and P. thoenii AKP1 strains can survive in the gastrointestinal system and also could show beneficial effects on the host. Hence, this study can suggest the use of P. freudenreichii subsp. freudenreichii DO7, P. jensenii BDP11 and P. thoenii AKP1 strains as probiotic bacteri.