Stamen Grigorov is a Bulgarian microbiologist and physician (Fig. A), who first described the bacterium Lactobacillus bulgaricus - one of the microorganisms that cause the formation and fermentation of yogurt. He was born in 1878 in the village of Studen Izvor, Transko (Fig. B). He graduated from high school in Sofia. He studied natural sciences in Montpellier and then did his doctorate in medicine in Geneva. His dissertation is on "Contribution to the pathogenesis of appendicitis"was awarded a special prize of the university. Stamen Grigorov works at the University of Geneva as an assistant to Prof. Leon Masol, Professor of Bacteriology. He appreciates the erudition of the young Bulgarian and guides him in his research activities, provides him with access to modern laboratories to test yogurt sent by his wife Darinka from Bulgaria. In 1905, Dr. Stamen Grigorov for the first time described the lactic acid microorganism that causes the fermentation needed to produce Bulgarian yogurt.
Initially, he described the lactic acid rod as "Bacillus A." Today the official name of this microorganism is "Lactobacillus delbureckii subsp. bulgaricus Grigoroff 1905 ". The publication in the prestigious Swiss medical journal" Revue Medicale de la Suisse Romande "deservedly arouses the interest of the entire world's scientific elite. Dr. Stamen Grigorov reports his results at the Pastoral Institute of Microbiology in Paris. The management of the institute instructs the future winner of the Nobel Prize in Medicine and Physiology Ilya Mechnikov to confirm the reported data. Ilya Mechnikov confirmed the results of Dr. Grigorov and based his theory on aging. Dr. Stamen Grigorov has been offered a number of prestigious positions - professor at the University of Geneva, director of the Pasteur Institute in Sao Paulo and others. He refused and at the end of 1915 returned to his homeland. He started working as a district doctor and manager of the hospital in the town of Trun – which today bears his name. Upon his return, he began research to develop a TB vaccine. His article on the subject was published on December 29, 1906 in the Parisian journal La presse medicale. During the Balkan War he went to the front, where he was a military doctor. At the end of the war he was demobilized and returned to his previous job in Trun. His brother, Hristo Grigorov, was wounded in the Battle of Kalimansko Field during the Inter-Allied War. Petrich fought the cholera epidemic. He was awarded the Order of Bravery and the Red Cross Gold Medal. From 1922 to 1924 he tested his tuberculosis vaccine at Prof. Parashkev Stoyanov's clinic at the Alexandrovska Hospital in Sofia. Veliko Tarnovo, Gorna Oryahovitsa, Provadia and Varna He continued his tuberculosis research in Italy after 1935. He returned to Bulgaria in 1944 and his work in Italy was continued by his son Dr. Alexander Grigorov. October 27, 1945 in Sofia. Today, near his native house in the village of Studen Izvor, there is the only Yogurt Museum in the country (Fig. 1).