The origin of kefir cheese dates back to the Bronze Age

September 25 () –

For the first time, scientists have managed to extract and analyse DNA from samples of ancient cheese found alongside mummies in the Tarim Basin in China, dating back some 3,600 years.

The research, published in the journal Cellsuggests a new origin for kefir cheese and sheds light on the evolution of probiotic bacteria.

“This is the oldest known cheese sample ever discovered in the world,” says Qiaomei Fu, corresponding author of the paper at the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences. “Foods like cheese are extremely difficult to preserve for thousands of years, making this a rare and valuable opportunity. Studying ancient cheese in great detail can help us better understand the diet and culture of our ancestors.“.

About two decades ago, a team of archaeologists discovered mysterious white substances smeared on the heads and necks of several mummies found at the Xiaohe cemetery in the Tarim Basin in northwest China. These mummies date back between 3,300 and 3,600 years, to the Bronze Age. At the time, scientists thought these substances might be a type of fermented dairy product, but they could not identify exactly what type.

After more than a decade of advances in ancient DNA analysis, a team led by Fu has unraveled the mystery.

Researchers successfully extracted mitochondrial DNA from samples found in three different graves at the cemetery. They identified cow and goat DNA in the cheese samples. Interestingly, the ancient Xiaohe people used different types of animal milk in separate batches, a practice different from the mixing of milk types common in Middle Eastern and Greek cheesemaking.

Most importantly, Fu and his colleagues were able to recover microbial DNA from the dairy samples and confirmed that the white substances were, in fact, kefir cheese. They found that the samples contained bacterial and fungal species, including Lactobacillus kefiranofaciens and Pichia kudriavzevii, which are commonly found in modern-day kefir grains.

“This is the oldest known sample of cheese ever discovered in the world,” said Qiaomei Fu, corresponding author of the paper at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences. “Foods like cheese are extremely difficult to preserve for thousands of years, making this a rare and valuable opportunity to study ancient cheese in great detail.” “can help us better understand the diet and culture of our ancestors.”

Today, there are two main groups of Lactobacillus bacteria: one originating in Russia and the other from Tibet. The Russian type is the most widely used worldwide, including in the United States, Japan and European countries, for making yogurt and cheese.

The team found that the Lactobacillus kefiranofaciens in the samples was most closely related to the Tibetan group, challenging the long-held belief that Kefir originated solely in the mountainous North Caucasus region of present-day Russia.

“Our observation suggests that kefir cultivation has been maintained in the Xinjiang region of northwest China since the Bronze Age,” Fu said.

The study also revealed how Lactobacillus kefiranofaciens exchanged genetic material with related strains, improving its genetic stability and milk-fermenting capabilities over time.

Compared to the old Lactobacillus, Modern bacteria are less likely to trigger an immune response in the human gutThis suggests that genetic exchanges also helped Lactobacillus better adapt to human hosts over thousands of years of interaction.

“Furthermore, by examining dairy products, we have gained a clearer picture of ancient human life and its interactions with the world,” Fu said. “This is just the beginning, and with this technology, we hope to explore other previously unknown artifacts.”