Identification of pediococci by ribotyping

Pediococci are among the most prevalent microbial contaminants in breweries and they can cause ropiness and the accumulation of high levels of diacety l in beer. The accurate identification of pediococci is important, because different species do not possess equal spoilage potential. In this study, 1 8 Pediococcus strains, mainly of brewery origin, were first identified usin g phenotypical characterization (API 50 CHL and SDS-PAGE profiling), and th en ribotyped using a RiboPrinter(R) System. Six Pediococcus type strains an d three other Pediococcus strains were used as references. Ribotyping showe d higher discriminative capacity than phenotypical identification methods. Strains could be identified to species level and in many cases, differentia ted even at strain level using this genetic fingerprinting method. The iden tifications performed by ribotyping were confirmed by 16S rDNA sequencing o f selected strains. Automated ribotyping was found to be a rapid and reliab le method for identifying pediococci, but requires the construction of a co mprehensive fingerprint library.