Linking Pelardon artisanal goat cheese microbial communities to aroma compounds during cheese-making and ripening

Pe?lardon is an artisanal French raw goat?s milk cheese, produced using natural whey as a backslop. The aim of this study was to identify key microbial players involved in the acidification and aroma production of this Protected Designation of Origin cheese. Microbial diversity of samples, collected from the raw milk to 3-month cheese ripening, was determined by culture-dependent (MALDI-TOF analysis of 2877 isolates) and-independent (ITS2 and 16S metabarcoding) approaches and linked to changes in biochemical profiles (volatile compounds and acids). In parallel, potential dominant autochthonous microorganism reservoirs were also investigated by sampling the cheese-factory environment. Complex and increasing microbial diversity was observed by both approaches during ripening although major discrepancies were observed regarding Lactococcus lactis and Lacti-caseibacillus paracasei fate. By correlating microbial shifts to biochemical changes, Lactococcus lactis was iden-tified as the main acidifying bacterium, while L. mesenteroides and Geotricium candidum were prevalent and associated with amino acids catabolism after the acidification step. The three species were dominant in the whey (backslop). In contrast, L. paracasei, Enterococcus faecalis, Penicillium commune and Scopulariopsis brevicaulis, which dominated during ripening, likely originated from the cheese-making environment. All these four species were positively correlated to major volatile compounds responsible for the goaty and earthy Pe?lardon cheese aroma. Overall, this work highlighted the power of MALDI-TOF and molecular techniques combined with vol-atilome analyses to dynamically follow and identify microbial communities during cheese-making and succes-sively identify the key-players involved in aroma production and contributing to the typicity of Pe?lardon cheese.

Automated summary

During the production of Pe?lardon cheese, microbial diversity increases, with Lactococcus lactis identified as the main acidifying bacterium and playing a key role in amino acid metabolism alongside L. mesenteroides and Geotricium candidum. These three species dominate in the whey. Meanwhile, other species like L. paracasei, Enterococcus faecalis, Penicillium commune, and Scopulariopsis brevicaulis, which likely come from the cheese-making environment, are positively correlated with the unique aroma of Pe?lardon cheese.