Impact of the use of an indigenous starter on microbial community structuring and aromatic profile of rocamadour protected designation of origin cheese

The use of indigenous strains as starters offers new opportunities that challenge the use of industrial starters, especially to strengthen the link between Protected Designation of Origin (PDO) cheeses and their terroir. This study investigated the effect of two starters, industrial and indigenous, on the microbial ecosystem and volatile organic compounds (VOCs) in Rocamadour PDO cheese. Metabarcoding analysis showed that regardless of the type of starter used, Lactococcus lactis and Geotrichum candidum largely dominated the microbial communities of Rocamadour (>96 %). The analysis of β-diversity based on the Bray-Curtis indices differentiated the starters according to their bacterial communities. VOC analysis showed that the starters were distinguished by three fatty acids characteristic of the goat cheese aroma ( p -value <0.05): decanoic, hexanoic, and octanoic acids. Hexanoic acid was not present in cheeses produced with the indigenous starter. This fatty acid was positively correlated with the presence of Paucilactobacillus nenjiangensis , Lactiplantibacillus sp. and Enterobacteriaceae , these microorganisms that were also characteristic of cheeses made with the industrial starter. Octanoic and decanoic acid, on the other hand, were suggested to be correlated with the presence of Leuconostoc mesenteroides . Cheeses produced with the indigenous starter differed in bacterial communities and aromatic signatures. • Regardless of the starter used, L. lactis and G. candidum were dominant. • Three free fatty acids were significantly different and discriminated the starters. • Indigenous starter provided distinct bacterial community and aromatic signature.