Evaluation of probiotic potential of dairy propionibacteria

Abstract

According to propionibacteria natural habitats, nine species have been recognized to belong to the genus Propionibacterium and grouped to dairy propionibacteria. These strains were comprising Propionibacterium thoenii (3), Propionibacterium acidipropionici (2), Propionibacterium freudenreichii ssp. shermanii (1), Propionibacteriun freudenreichii (1), Propionibacterium freudenreichii ssp. freudenreichii (1) and Propionibacterium shermanii (1). All nine strains were subjected to in vitro analysis to assess their probiotic potential. Eight strains of Propionbacterium were fully tolerant to 0.3% and 0.5% bile salts and were able to survive at pH 3 for 3hrs while at pH 2 a few strains were able to survive. Moreover, good growth was observed in the presence of 0.3% phenol. Antimicrobial activity of Propionibacterium strains was found to be good against most of tested strains. In addition, all tested strains were sensitive to tertracyclin and trimethoprime/ sulfamethoxazole. Technological and productive characteristics tests showed that tested strains disaplayed various behaviours in their acidifying activity and four strains produced exopolysaccharide. In conclusion, eight strains P. thoenii P15, P. thoenii TL18, P. freudenreichii ssp. shermanii ATCC1907, P. freudenreichii 169TM, P. freudenreichii ssp. freudenreichii 111, P. shermanii B-123, P. acidipropinici TL2 and P. acidipropionici P124I were able to pass all the tests and  were considered as novel putative probiotic propionibacteria