Molecular characterization of dominant bacterial population in “Vastedda della Valle del Belìce” cheese: preliminary investigation

Abstract

The sensory characteristics of raw-milk cheeses are linked to the cheese-making process, to the environmental factors as animal feeding and to the biochemical and microbiological composition of the milk. In this report we temped to characterize the microflora in the typical Sicilian historical cheese as Vastedda della valle del Belice. Each cheese was previous subjected to microbial isolation on specific media (M17 and MRS). The colony obtained on the solid medium were subject to biochemical tests and DNA extraction. The microbial diversity occurring in the strains was evaluated by PCR, RFLP and sequencing targeted on 16S ribosomal DNA. A number of closest relatives species of lactic and contaminating bacteria were identified in a total of 18 cheeses. The more represented genus were: Enterococcus, Streptococcus, Lactobacillus, Lactococcus and Pediococcus. Moreover it was found only one strain Lactococcus lactis for producing bacteriocines. The different bacteria species probably could play a key role in the maturation of the cheese. The preliminary obtained data show the optimized method is usefully to detect and characterize the bacteria having implications in the fermentation process as well as preservation of traditional products.