Live ants — and their microbes — make this yogurt tasty

In parts of Eurasia, the key to a tangy yogurt treat scurries along the forest floor. That secret ingredient? Ants!

A once-popular yogurt-making technique uses ants and their microbes. The bacteria are used to kick-start the fermentation process that makes yogurt so thick and tangy. The traditional recipe requires live ants — not frozen or dehydrated ones. Now, scientists have identified the exact microbes the ants have that make this creamy treat so tasty.

Yogurt-making dates to around 7,000 years ago. The process starts with warmed milk. Then people add safe, healthy bacteria to acidify and thicken the liquid. They keep the mixture warm for several hours, giving it time to ferment.

The bacteria used in making yogurt can come from many sources. Anthropologist Sevgi Mutlu Sirakova works at Ludwig-Maximilians-University Munich. That’s in Germany. Her ancestors came from a village in Bulgaria. Around there, it was once common to make yogurt with the help of red wood ants.

Sirakova traveled with a research team to her family village. There, they put the insect-based practice to the test. The team placed four live ants into a jar of warmed raw cow’s milk. They then buried the jar in an ant mound. The nest kept the mixture warm so it would ferment overnight. The next day, the now-acidic milk had begun the early stages of becoming yogurt. It even developed a tangy and herb-like taste.

Molecular tests showed that F. polyctena ants carry bacteria that produce lactic acid and acetic acid, which thicken milk. Enzymes supplied by both the ants and bacteria can digest the milk. This breaks it down to make that creamy yogurt.

Frozen or dehydrated ants carry microbes that don’t ferment milk as well as those from living ants, the team found. Sometimes, though, live ants can be infected with a hitchhiking parasite. In rare cases, that hitchhiker can harm people’s livers. That’s why, researchers say, you shouldn’t try this at home.