Recovery and differentiation of long ripened cheese microflora through a new cheese-based cultural medium

A partial picture of the typical microflora of PDO Parmigiano Reggiano cheese was achieved by studying the cultivability of lactic acid bacteria associated with its manufacturing and ripening. A comprehensive sampling design allowed for the analysis of the cheese microflora during its production over 20 months of ripening. An innovative cheese agar medium (CAM) was prepared after testing 18 formulations all based on grated Parmigiano Reggiano ripened cheese. During cheese manufacturing and ripening, different samples were sampled and their microflora was recovered using CAM in comparison with other traditional media. Colonies which formed units from the different agar media tested were picked and isolated; the phylogenetic positions of 154 isolated strains were studied at level of species by 16S-rRNA gene sequencing. CAM seems to be able to recover the minority population coming from milk and whey starter, hardly estimable, during the first hours of production, on traditional media.