DIFFERENTIATION OF LACTOBACILLI OCCURRING IN FERMENTED MILK-PRODUCTS BY USING OLIGONUCLEOTIDE PROBES AND ELECTROPHORETIC PROTEIN PROFILES

Rapid identification of Lactobacillus species that are used as starter organisms for fermented milk products was achieved by applying 23S rRNA-targeted oligonucleotide probes and numerical analysis of gel electrophoretic protein profiles. 23S rRNA genes of various lactobacilli were partially sequenced and complementary specific oligonucleotide probes were synthesised. Species specific probes for Lactobacillus delbrueckii, L. helveticus, and L. paracasei and group specific probes for L. caseil/L. rhamnosus and L. casei/L. paracasei/L. rhamnosus were designed. Moreover, the lactobacilli strains were examined by polyacrylamide gelelectrophoresis of sodium dodecylsulphate denatured whole-cell proteins. After numerical comparison of the resulting electrophoretic protein patterns, definite clusters could be determined, correlating well with the different species.