IDENTIFICATION OF DAIRY PROPIONIBACTERIUM SPECIES BY RIBOSOMAL-RNA GENE RESTRICTION PATTERNS

A total of 78 strains of dairy propionibacteria, 4 reference strains o f Propionibacterium and 8 related bacteria were characterized by ribos omal ribonucleic acid (rRNA) gene restriction patterns (ribotyping). T he patterns were obtained after cleavage of total DNA with either BamH I or ClaI restriction endonucleases and hybridization of fragments wit h acetylaminofluorene-labelled 16+23S rRNA from Escherichia coli. The four different species of dairy propionibacteria, P. freudenreichii, P . jensenii, P. thoenii and P. acidipropionici, gave different restrict ion patterns with species-specific fragments. Moreover, ribotyping all owed the differentiation of P. freudenreichii subsp. freudenreichii fr om P. freudenreichii subsp. shermanii. The patterns of dairy propionib acteria were different from those of closely related bacteria and othe r bacteria used in the dairy industry.