In the beginning of the 20th century a Russian microbiologist Ilya Mechnikov (1845-1916）, a Nobel Prize winner, wondered why there were more people over 100 years old in Bulgaria than in any other country. After investigation he attributed the secret of longevity to home-made yogurt, a staple food of Bulgaria, which later came in vogue in Europe and in the world.

The earliest yogurts were probably spontaneously fermented by wild bacteria living on goat skin bags carried by nomadic people more than 4,000 years ago. Different nomadic countries claim themselves as inventors of yogurt, though there is no clear evidence. Still Bulgaria is one of the most popular yogurt countries. Yogurt is believed to have been an important food item in Bulgaria as far back as ancient Thracian times. It is called “kiselo mlyako” - literally meaning sour milk. The English word yog(h)urt , however, is of Turkish origin.

Lactic acid bacteria in yogurt are known to regulate the function of the intestines and improve immunity, and have attracted attention in view of preventive medicine. Among these bacteria, the ones contained in the starter culture of so-called “Bulgarian Yogurt” are Streptococcus thermophilus, which develops its flavor, and Lactobacillus bulgaricus, which can grow only in Bulgaria and provides its acidity. Bulgarian Yogurt and its culture are exported to many countries including Japan.

The first yogurt sold in Japan was by Chichiyasu Company in Hatsukaichi city, Hiroshima in 1915, but it was not until after World War II that yogurt became popular. And “Bulgarian Yogurt” was put on the market in 1971 by Meiji Dairies Coropration, one of Japan’s largest dairy companies, and was allowed officially by Bulgaria to use the country name for their product.