Oldest cheese ever recorded found mummified in China

Bronze Age desert dwellers, unearthed from tombs in what is now northwest China, were buried with cheese spread over their heads and necks — perhaps as a packed lunch for the afterlife .

A decade after the discovery of dairy products in surprisingly intact remains mummified by the arid conditions of the Taklamakan Desert, Scientists have extracted and sequenced DNA from 3,600-year-old cheese the oldest recorded in archaeology.

The analysis revealed how the Xiaohe people made cheese, showing how humans used microbes to enhance their food and how these living things can be used to trace cultural influences through the ages.

The findings, published last Wednesday (25) in Cell magazineopen a “new frontier in ancient DNA studies,” with this “type of research unthinkable even a decade ago,” said Christina Warinner, associate professor of social sciences and anthropology at Harvard University. Warinner was not involved in the research.

“Today, fermented foods are predominantly produced using just a handful of commercial strains of bacteria and yeast, mostly grown in the lab,” she said.

“Little is known about the once diverse array of traditional microorganisms that people used in the past to produce today’s most iconic foods — ranging from bread to cheese, and beer to wine.”

A team led by Chinese paleogeneticist Qiaomei Fu identified goat and cattle DNA in samples of the cheese. The researchers were also able to sequence the DNA of microorganisms contained in the cheese, confirming that it was kefir, a type of cheese that is still widely produced and consumed today. Fu is the director of the ancient DNA laboratory at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing.

How an enigmatic desert people made kefir

Hundreds of mummified individuals were found in the 1990s in what is known as the Xiaohe Cemetery in the Tarim Basin, a harsh desert area in China’s Xinjiang region. Naturally preserved by the dry desert air, their facial features and hair color are clearly discernible, despite being up to 4,000 years old.

Buried in felted and woven clothing in unusual boat-shaped tombs, the so-called Tarim Basin mummies and their variety of cultural influences have long intrigued archaeologists. Despite belonging to a genetically isolated group, these individuals nevertheless embraced new ideas and technologies, according to a October 2021 study.

The new research suggested that the Xiaohe people did not mix different types of animal milk when making kefir, a common practice in traditional cheese production in the Middle East and Greece, although the reason for this remains unclear.

“The Xiaohe people would have made the food in the same way that traditional kefir farmers make kefir today, using previously made kefir grains (similar to the ‘mother’ of kombucha or a sourdough starter for bread) that were passed down through family, friends and other social contacts,” said Taylor Hermes, an assistant professor in the department of anthropology at the University of Arkansas who was not involved in the research.

“That’s what makes the study so important — we can see how these microbial resources were transmitted and spread throughout Asia,” Hermes added.

Evolution of probiotic bacteria

Fu’s team found that the three cheese samples from the tombs contained bacterial and fungal species, including Lactobacillus kefiranofaciens and Pichia kudriavzevii, respectively, both of which are commonly found in modern-day kefir grains. The grains are a mix of probiotic bacteria and yeast that ferment milk, turning it into kefir cheese.

Fu and his colleagues also sequenced the bacterial genes of ancient kefir cheese, revealing insights into how probiotic bacteria have evolved over the past 3,600 years.

There are currently two main groups of Lactobacillus bacteria — one that originated in Russia and the other in Tibet, an autonomous region of China, the study found. The Russian strain is widely used globally, including in the United States, Japan and European countries, in the production of yogurt and cheese.

When Fu and his colleagues compared the bacteria in ancient kefir cheese with modern species, they found that it was closely related to a less common group of Lactobacillus that originated in Tibet.

The origins of these microorganisms challenge the widely held belief that kefir began exclusively in the Caucasus Mountains region, Fu said.

“This is an unprecedented study, allowing us to observe how a bacterium has evolved over the past 3,000 years. Furthermore, by examining dairy products, we have gained a clearer insight into ancient human life and its interactions with the world,” Fu said in a statement. “This is just the beginning.”

Hermes highlighted how remarkable it was that not only had the cheese survived, but that it was possible to sequence the DNA of the food. “Analysis of ancient DNA, especially in microorganisms, is fraught with technical problems, mainly due to contamination by modern bacteria,” he added.

When did cheese production actually begin?

It was no surprise that the Xiaohe people fermented cheese, Warinner said. The process made the milk easier to digest, with the microbes producing lactic acid, which causes the milk to curdle and form the basis of cheese.

“In the absence of refrigeration, it is virtually impossible to store milk for more than a few hours without spontaneous fermentation occurring. Therefore, there has probably never been a time when milk and dairy products were consumed without fermentation,” she said.

“However, over time, people became better and better at controlling this process and selecting specific microbes that produced the most desirable effects in dairy production,” he added.

While the dairy product found with the mummies is the oldest intact cheese in the archaeological record, other evidence, such as animal proteins in human dental calculus and milk residue on pottery, suggests that production of the food originated much earlier, likely more than 9,000 years ago in Anatolia or the Levant, Warinner noted.

The team’s genomic analysis was truly groundbreaking, said William Taylor, an assistant professor of anthropology at the University of Colorado Boulder and curator of archaeology at the university’s Museum of Natural History.

“It’s amazing to see the complexity of the products these people were making, something that is not typically preserved in the archaeological record,” said Taylor, who was not involved in the research.

“These extraordinary discoveries show us that cheese and other dairy products were truly the foundation of an entire way of life that would remain important for millennia and is still a crucial part of life today.”

This content was originally published in Oldest cheese ever recorded is found mummified in China on the CNN Brasil website.

Source: CNN Brasil