Strong effect of Penicillium roqueforti populations on volatile and metabolic compounds responsible for aromas, flavor and texture in blue cheeses

The study of food microorganism domestication can bring important insights on adaptation mechanisms and have industrial applications. The Penicillium roqueforti mold is divided into four main populations, with two populations domesticated for blue-cheese making and two populations thriving in other environments. While most blue cheeses worldwide are made with the same P. roqueforti clonal lineage, the emblematic Roquefort cheeses are inoculated with a specific population. To study the differences among P. roqueforti populations in the context of domestication for cheesemaking, we compared blue cheeses made with the four fungal populations following Roquefort-type production specifications. We found that the P. roqueforti populations had a minor impact on the cheese bacterial diversity and none on the main microorganism abundance. The cheese P. roqueforti populations produced cheeses with higher percentages of blue area and with different sets and higher quantities of desired volatile compounds. The Roquefort P. roqueforti population in particular produced higher quantities of positive aromatic compounds in cheeses, which was related due to its most efficient proteolysis and lipolysis, and also produced cheeses with lower water activity, thus restricting spoiler microorganisms. Our results show the strong influence of P. roqueforti populations on several important aspects of cheese safety, appearance and flavour. The typical appearance and flavours of blue cheeses are therefore the result of human selection on P. roqueforti , thus constituting domestication, and the two cheese populations have acquired specificities. This has important implications for our understanding of adaptation and domestication processes as well as for improving cheese production. Importance Several fungi have been domesticated for food fermentation, with selection for traits beneficial for food production. The mold used for making blue cheeses, Penicillium roqueforti , is subdivided into four genetically different populations, two being found in cheese, one being specific of the Roquefort protected designation of origin, and two in other environments. The cheese P. roqueforti populations produced bluer cheeses with higher quantities of desired volatile compounds. The Roquefort P. roqueforti population in particular produced higher quantities of positive aromatic compounds in cheeses, in relation to its most efficient proteolysis and lipolysis, and also produced cheeses with lower water activity, thus restricting spoiler microorganisms. Our results support that the blue cheese typical aspect and flavors are the result of a selection by humans and show the strong influence of P. roqueforti populations for several important aspects of cheese safety, aspect and flavor, paving the way for improving cheese production.