PROPIONIBACTERIUM SPECIES-DIVERSITY IN LEERDAMMER CHEESE

Thirteen 'classical' Propionibacterium strains, isolated from Leerdamm er cheese samples, using three different media were characterized phen otypically. The phenotypic data of 74 tests, conducted on 27 propionib acteria, including four type, 10 reference strains and the 13 cheese i solates were analysed by numerical taxonomical techniques, using the s imple matching coefficient and single linkage cluster analysis. All th e strains were grouped in four major clusters, with a final linkage at the 81% S-level. The clusters were equated with the 'classical' P. ac idipropionici, P. freudenreichii, P. jensenii and P. thoenii species. The species were identified by relating them to specific type strains and by comparison of phenotypic characteristics. Differential characte ristics of each cluster were determined. Strains of P. acidipropionici , P. freudenreichii and P. jensenii, but no P. thoenii strains were is olated from the Leerdammer cheese samples. No 'cutaneous' propionibact eria were isolated. The largest cluster, representing 46% of the chees e isolates was equated with P. jensenii. Various red/brown pigmented s trains, which could be identified as the old 'P. rubrum' species were isolated from the cheese. These strains were, however, phenotypically identified as P. jensenii and also grouped in the P. jensenii cluster.