By Stephen Beech via SWNS
The world’s oldest cheese, dating back 3,600 years, has revealed the origin of trendy kefir.
Kefir is a type of fermented milk that may help manage blood sugar and lower cholesterol, among other health benefits.
The name kefir comes from the Turkish word “keyif” – which refers to the “good feeling” a person gets after drinking it.
Kefir has long been thought to originate from Russia.
But a new study suggest it hails from China.
Scientists have successfully extracted and analyzed DNA from ancient cheese samples found alongside the Tarim Basin mummies in China, dating from the Bronze Age around 3,600 years ago, for the first time.
The research, published in the journal Cell, suggests a new origin for kefir cheese – and sheds light on the evolution of probiotic bacteria.
Corresponding author Dr. Qiaomei Fu, of the Chinese Academy of Sciences, said: “This is the oldest known cheese sample ever discovered in the world.
“Food items like cheese are extremely difficult to preserve over thousands of years, making this a rare and valuable opportunity.
Studying the ancient cheese in great detail can help us better understand our ancestors’ diet and culture.”
Archaeologists discovered mysterious white substances smeared on the heads and necks of several mummies found in the Xiaohe cemetery in China’s Tarim Basin around 20 years ago.
The mummies dated back to about 3,300 to 3,600 years ago.
At the time of the discovery, researchers thought the substances might be a type of fermented dairy product, but they couldn’t identify exactly what kind.
Now, after more than a decade of advancements in ancient DNA analysis, a team led by Dr. Fu has unraveled the mystery.
The Chinese research team successfully extracted mitochondrial DNA from samples found in three different tombs at the cemetery.
They identified cow and goat DNA in the cheese samples.
Dr. Fu said the ancient Xiaohe people used different types of animal milk in separated batches, a practice differing from the mixing of milk types common in Middle Eastern and Greek cheesemaking.
The researchers also managed to recover the DNA of microorganisms 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, both commonly found in present-day kefir grains.
Kefir grains contain multiple species of probiotic bacteria and yeast, which ferment milk into kefir cheese, much like a sourdough starter.
Being able to sequence the bacterial genes in the ancient kefir cheese gave the researchers the chance to track how probiotic bacteria evolved over the past 3,600 years.
They compared the ancient Lactobacillus kefiranofaciens from the ancient kefir cheese with the modern-day species.
Dr. Fu explained that, today, there are two major groups of the Lactobacillus bacteria – one originating in Russia and another from Tibet.
The Russian type is the most widely used globally, including in Europe, the United States and Japan, for making yogurt and cheese.
The researchers found that the Lactobacillus kefiranofaciens in the samples was more closely related to the Tibetan group, challenging a long-held belief that kefir originated solely in the North Caucasus mountain region of present-day Russia.
Dr. Fu said: “Our observation suggests kefir culture has been maintained in northwestern China’s Xinjiang region since the Bronze Age.”
The study also revealed how Lactobacillus kefiranofaciens exchanged genetic material with related strains, improving its genetic stability and milk fermentation capabilities over time.
Compared with ancient Lactobacillus, modern-day bacteria are less likely to trigger an immune response in the human intestine.
Scientists say that suggests that the genetic exchanges also helped Lactobacillus become more adapted to human hosts over thousands of years of interaction.
Dr. Fu said: “This is an unprecedented study, allowing us to observe how a bacterium evolved over the past 3,000 years.
“Moreover, by examining dairy products, we’ve gained a clearer picture of ancient human life and their interactions with the world.”
She added: “This is just the beginning, and with this technology, we hope to explore other previously unknown artifacts.”
