PHYSIOLOGICAL AND MOLECULAR TECHNIQUES FOR THE STUDY OF BACTERIAL COMMUNITY-DEVELOPMENT IN SAUSAGE FERMENTATION

The development of the microbial community involved in the production process of Italian dry sausage was investigated using physiological an alysis and molecular techniques for strain typing and taxonomical iden tification. A cycle of sausage production was followed collecting samp les during the 2 months of ripening process. Microbiological analysis allowed the identification of the main bacterial groups responsible fo r the fermentation process as lactobacilli and coagulase-negative stap hylococci. The use of a polymerase chain reaction-based technique of s train typing, RAPD fingerprinting, demonstrated that the environmental parameters interact to select a limited number of strains that domina te the fermentation process. The staphylococcal populations were chara cterized for their physiological properties and the two dominant strai ns were identified as Staphylococcus xylosus and Staph. sciuri. The us e of 16S rDNA sequencing allowed the definition of the taxonomical pos ition of the two dominant strains of lactic acid bacteria, as belongin g to Lactobacillus sake and Lact. plantarum.