Microbiome-based tracking of PDO Buffalo Mozzarella geographical origin
Date:
Abstract: Buffalo Mozzarella (BM) is a typical cheese from Southern Italy with unique flavour profile and texture. It is produced following a detailed Protected Designation of Origin (PDO) regulation, based on a traditional back-slopping fermentation. In this study, we sampled BM from 53 different dairies located in the area of Caserta (n=32) and Salerno (n=21), within the PDO area of production. We assessed Volatile Organic Compounds (VOCs) by gas chromatography-mass spectrometry (GC-MS) and the microbiome by high-throughput shotgun metagenome sequencing. Microbiome taxonomic profiles reveal Streptococcus thermophilus, Lactobacillus delbrueckii subsp. delbrueckii, and Lactobacillus helveticus as the dominating microbial species in all samples. However, the differential abundance of taxa resulted in an evident clustering of the samples based on their geographical origin, also showing that BM from Caserta has a greater microbial diversity. Furthermore, we reconstructed Metagenome Assembled Genomes (MAGs) from metagenomes. Different strains of Lb. delbrueckii were identified in the samples. In particular, cheeses from Caserta and Salerno area showed different strain profiles. Reconstruction of metabolic pathways related to flavour generation was screened, highlighting different abundance of several microbial pathways according to production area, such as superpathway of 2,3-butanediol biosynthesis and S-adenosyl-L-methionine salvage I. These results may explain the specific flavor profiles of BM from Caserta and Salerno. The microbiome may be regarded part of the terroir that links PDO BM with the specific area of production, also contributing to the peculiar sensorial traits. From this perspective, the metagenomic approach could be helpful in tracking the origin of PDO fermented foods.