Abstract
The microbial communities of kefir grains and kefir were evaluated over time using high-throughput amplicon sequencing. It was found that Lactobacillus kefiranofaciens and Lentilactobacillus kefiri consistently dominated kefir grains, whereas Lactococcus lactis dominated kefir. Many other bacteria and yeasts were detected that comprised the minor population of kefir grains and kefir. The community composition in the kefir was more variable than in the kefir grains with the relative abundance of both Lb. kefiranofaciens and Lc. lactis changing over time. The fungal communities of kefir grains were dominated by Kazachstania turicensis and Torulaspora delbruekii, although the ratio between the two varied significantly. These findings suggest that the microbial communities in kefir grains change over time, highlighting the need for further studies investigating the effect these changes have on the production of flavour and aroma compounds in kefir.