Microbes Shape the Taste of France's PDO Cheeses

Around 46 regional cheeses in France are designated as having protected designation of origin (PDO) status. The terroirs, or diverse regional landscapes, of France influence the microbiological diversity of PDO cheeses, creating their distinct flavors.

After examining the bacteria, yeasts, and molds discovered in more than 2,000 samples of French PDO cheeses and in close to 400 milk sources, researchers from INRAE, CEA, CNAOL, and CNIEL made this astounding discovery. This experiment found a high correlation between microbial diversity and cheese production procedures, which was published in the journal ISME Communications.

An EU labeling program called Protected Designation of Origin (PDO) ensures that consumer food items have a true geographical identity. The PDO seal, which denotes artisanship and conformity to standards pertaining to production zones, production techniques, and livestock diets, among other variables, is present on 51 dairy products in France, including cheeses, butter, and creams.

The bacteria, yeasts, and molds introduced by milk sources and the fermentation process impact the flavor, texture, and development of cheese's rind. These microorganisms may then enhance the gut microbiota of cheese eaters.

For the first time, researchers from INRAE, CEA, the French National Council for Dairy Products of Designated Origins (CNAOL), and the French National Interprofessional Centre for the Dairy Industry (CNIEL) examined the microbial diversity of French PDO cheeses and their milk sources.

In collaboration with dedicated PDO stakeholders, the researchers collected samples from 386 farmers and cheese makers throughout France as part of the MetaPDOcheese project and acquired comprehensive data regarding cheese production techniques.

They examined 44 PDO variants of matured cheese. These cheeses served as examples of seven different cheese families consumed worldwide, such as pressed-cooked cheeses and blue cheeses.

Ultimately, Genoscope (CEA) researchers sequenced the microorganisms in approximately 400 milk sources and over 2,000 samples of French PDO cheeses.

The findings showed extraordinarily diverse microbial assemblages present in the cheeses (820 bacterial species and 333 mold/yeast species) and the milk sources (1,230 bacterial species and 1,367 mold/yeast species).

There was overlap for about 42% of the bacterial species and 64% of the mold/yeast species, indicating that a significant fraction of the microorganisms in the cheeses probably originates from the milk sources.

Following the integration of data on cheese production methods, the researchers discovered that elements for which PDO is an aggregate proxy included geography, regional topography, and anthropogenic drivers, all of which impact species assemblages. These results demonstrate that local artisanship contributes to the development of cheese's microbiota.

This work has provided important new information about the relationship between microbial diversity and PDO cheese production methods, particularly how climate change may impact these dynamics.