Advances in Microbial Diversity and Interactions in Kefir

Kefir is a fermented dairy beverage produced by using natural microbiota which mainly contains specific microbial communities such as lactic acid bacteria, yeast and acetic acid bacteria, and it has good flavor and health beneficial functions. However, the formation mechanism of kefir grains is not clear at present, and it is generally believed that the formation of kefir grains is based on bacterial biofilm as the precursor. This paper reviews the microbial diversity of kefir from different regions and the effects of microorganisms in kefir grains on the function and flavor of fermented milk, as well as the microbial interactions and succession during kefir fermentation. The role of biofilm formation in kefir grain formation is also described in order to provide some references for future research on the formation mechanism of kefir grains.