Kefir. A beverage peculiar to the Russia and Nordic countries; originally made with mare's milk but now more commonly cow's milk soured with kefir grains. It results in a slightly alcoholic, sour drink similar to yoghurt but containing different types of beneficial bacteria. Kefir contains several major strains of friendly bacteria not commonly found in yoghurt, Lactobacillus Caucasus, Leuconostoc, Acetobacter species, and Streptococcus species. It also contains beneficial yeasts, such as Saccharomyces kefir and Torula kefir, which dominate, control and eliminate destructive pathogenic yeasts in the body. The curd size of kefir is smaller than yoghurt and it is a nutritious food for babies, invalids and the elderly, as well as a remedy for digestive disorders.