CHARACTERIZATION OF BACTERIOCINS PRODUCED BY STRAINS FROM TRADITIONALBULGARIAN DAIRY-PRODUCTS

As a result of extensive screening of over 300 strains from the Collec tion of ELBY Bulgaricum, PLC, thirty six strains were selected as prod ucers of bacteriocins, active against closely related lactic acid bact erial species and some food spoilage bacteria. The selected strains be long to L. helveticus, L. bulgaricus and S. thermophilus, which are ra re bacteriocin producers. Nineteen nonidentified producers were charac terized by molecular taxonomic approaches - M13 fingerprinting, repeti tive PCR, ribotyping and hybridization with species-specific probes, w hich allowed to affiliate them to the species L. delbrueckii. Several strains were found to harbour plasmids of different size. The estimate d activity against food borne pathogens makes the isolated substances perspective as safe food preservatives and the producing strains could be used as components of starters with improved quality.