Céline DELBES is a Senior Scientist at the Institut National de la Recherche Agronomique (INRA), Cheese Research group of Aurillac (UMR 545 Fromage, Université Clermont-Auvergne, INRA, VetAgroSup), France. She received her Ph.D. in Microbial Ecology from the University of Lyon in 2000. Her research focuses around microbial ecology of the dairy food chain, in relation with cheese safety and sensory quality. Her research group has extensive expertise on raw milk and traditional cheese microbial diversity, cheese technology, metagenomic, transcriptomic approaches. The objective of her work is to better understand the drivers of milk and cheese microbial communities and the interactions that govern their dynamics and functions in the cheese ecosystem. Recent work, based on metagenomic approaches, highlighted the role of the teat skin microbiota and milk production practices, especially animal feed, in the assembly of microbial communities of milks and cheeses. To control undesirable microorganisms in cheeses, she pursues a dual approach, on one hand investigating the mechanisms involved in specific inhibitory microbial associations, on the other hand, relying on a more holistic approach of the farm considering all pathogens within microbiota.
The microbial ecology of raw milk cheese: an update of knowledge about the range of potential benefits.
Raw milk and raw milk cheese host a very diverse microbiota, including more than 400 microbial species. The most advanced DNA sequencing technologies today allow us to explore the diversity and functional potentialities of microbial communities with unprecedented accuracy (Almeida et al., 2014). Raw milk microbiota plays a major role in the development of the health and sensory qualities of ripened cheese (Montel et al., 2014). The ripening of raw milk cheese leads to more pronounced and richer flavors and odors (Frétin et al., 2017). Raw milk cheese microbiota may exert a barrier effect against undesirable microorganisms such as pathogens or spoilers, through the production of antibacterial agents, the competition for resources or the modification of the environment (acidification) depending on the characteristics of the matrix (Montel et al., 2014; Yoon et al., 2016). Microbial communities on the cheese surface show inhibition properties against Listeria monocytogenes (Callon et al., 2014). Raw milk cheese microbiota can be a source for anti-pathogenic strains or consortia (Callon et al., 2016 ; Delpech et al., 2017). The link between consumption of raw milk cheese and potential positive effects on human health (allergies…) is not yet fully explained, but promising studies pave the way to further work for better understanding of the mechanisms involved (Nicklaus et al., 2018).