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Google Doodle celebrates Dr. Stamen Grigorov, the biologist who discovered yogurt bacteria

On October 27, 1878, Dr. Stamen Grigorov, the microbiologist who discovered the bacteria responsible for creating yogurt, was born in Studen Izvor, Bulgaria. Google is celebrating Dr. Stamen Grigorov — as well as yogurt — with a homepage doodle for his 142nd birthday.

Yogurt is such a fantastic, fruity breakfast or snack, with surprising health benefits thanks to being high in vitamins. But have you ever given much consideration to what it is or how it’s made?

Traditionally, yogurt is simply fermented milk, but until the 1900s, no one was quite sure why the fermentation process was happening. What they did know was that over the centuries, those who ate yogurt were said to have incredible health, living longer than most. In French history, Francis I was even said to have been cured of a stomach ailment by simply eating yogurt sent by the Ottoman Empire.

In 1905, Dr. Stamen Grigorov was working at the Medical University of Geneva, Switzerland, the same university where he had received his doctorate the year before. While there, Grigorov’s wife sent him food from Bulgaria, to remind him of home, included in which was some yogurt.

Feeling inspired by this gift, and by yogurt’s long purported health benefits, Dr. Stamen Grigorov inspected the yogurt under a microscope and discovered a previously unknown bacteria, now traditionally called “Lactobacillus bulgaricus.” With some testing, it was proven that this bacteria is indeed responsible for the fermentation of yogurt, which involves fermenting the lactose — sugar — into lactic acid, which gives yogurt its pleasantly sour taste.

Dr. Stamen Grigorov’s continued career in biology proved many more uses for yogurt, including using the food in the treatment of tuberculosis. His work with penicillin also played a key role in the ultimate development of a tuberculosis vaccine.

Today’s Google Doodle depicts Dr. Stamen Grigorov — an early, alternate sketch shows a fox-like character instead — sitting down to eat a large bowl of the yogurt that he was best known for. All around him are examples of some of the delicious things you can mix into yogurt, from sweeter treats like berries to savory flavors like garlic.

Meanwhile, behind him, we see a simplified version of the process of making yogurt. First, the milk is heated close to boiling to ensure curds don’t form. Once it cools back down a bit, some of Dr. Stamen Grigorov’s discovery, Lactobacillus bulgaricus, is mixed in, kept warm, and allowed to ferment for a few hours. With that, you’ve got yogurt!

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Avatar for Kyle Bradshaw Kyle Bradshaw

Kyle is an author and researcher for 9to5Google, with special interests in Made by Google products, Fuchsia, and Stadia.

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