Molecular characterization of the Lactobacillus community in traditional processing of Mozzarella cheese.

The natural Lactobacillus community involved in traditional Mozzarella cheese production has been investigated. The bacterial associations of whey, curd before stretching and Mozzarella were analyzed using randomly amplified polymorphic DNA (RAPD) to follow growth kinetics, and 16S rDNA sequencing to identify the taxonomical position of isolated strains. Analysis of RAPD fingerprints revealed that the Lactobacillus community was composed of 13 different biotypes and the sequence analysis of 16S rDNA demonstrated that the isolated strains belong to L. plantarum, L. fermentum, L. helveticus and L. casei subsp. casei. In addition, two strains of Weissella hellenica were isolated on selective media for lactobacilli. The four L. casei subsp. casei strains and W. hellenica contained sequences related to the prtP gene coding for proteinase, and the highest proteolytic activity in milk was found in one strain of L. casei subsp.casei.