Importance of curd-neutralising yeasts on the aromatic potential of Brevibacterium linens during cheese ripening

Three cheese-ripening yeasts Kluyveromyces lactis, Geotrichum candidum and Debaryomyces hansenii were grown in a cheese slurry either individually or in association with the cheese-ripening bacterium Brevibacterium linens. Alcohols, aldehydes and esters were produced by the yeasts, and appeared in the early stages of ripening, whereas volatile sulphur compounds (VSCs) were produced late during the ripening process. The production of VSCs was greatly improved when the yeasts D. hansenii and K. lactis were associated with B. linens. In contrast to G. candidum, these yeasts efficiently neutralised the cheese slurry, which promoted the growth of B. linens. Our results gave evidence of metabolic synergies between the yeasts and B. linens. For instance, generation of S-methyl thioacetate was improved when a yeast that was able to produce esters and thus to accumulate acyl CoA was associated with a bacterium that was able to form large amounts of methanethiol.