Question: what bacteria are in kefir grains?
Answer: Kefir grains contain yeast cells, lactic acid bacteria, and acetic acid bacteria (i.e., Leuconostoc, Lactobacillus, Kluyveromyces, and Saccharomyces). The microorganisms in kefir grains produce effective compounds such as organic acids, several types of bactericide which have a lethal effect on pathogenic bacteria.