Matsoni (Georgian: მაწონი mats'oni, Russian: мацони, Armenian: մածուն maçun) is a fermented milk product found in Caucasian cuisine. It is made with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus lactic acid bacteria. It supposedly originated from ancient Georgia and later propagated to many neighbor countries, e.g. Armenia. Matsoni is made from cow's milk (mostly), goat's milk, sheep's milk, or a mix of them and a culture from previous productions. In Japan, Caspian Sea Yogurt カスピ海ヨーグルト is popular; soy milk is sometimes added to the milk