The world’s oldest cheese has been identified, over two decades since its discovery in a 3,600-year-old Chinese tomb.
The find was first made by researchers in 2003, when a mysterious yellow crumbly substance was revealed to be smeared around the necks of three Bronze Age mummies buried in Xiaohe Cemetery, in China’s northwest Tarim Basin. Studies since then have aimed to identify the curds and now a team at the Chinese Academy of Sciences has published a paper in Cell journal explaining how advances in DNA analysis have confirmed that the chunks are kefir cheese.
A living insight into diet and culture
“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,” study co-author Qiaomei Fu, a paleogeneticist at the Academy, said in a statement.
A living dairy product, kefir typically contains cow and goat milk as well as probiotic bacteria and yeast that promote fermentation. The ancient cheese was found to possess Lactobacillus kefiranofaciens and Pichia kudriavzevii, two types of bacteria still found in kefir today. Comparing ancient and modern bacterial samples and sequencing their genes, the research team were able to trace a relationship between the L. kefiranofaciens in the mummified cheese and cheese bacteria from Tibet.
How has kefir evolved?
Humans over time have made dairy products by combining different bacteria and experimenting with fermentation times. In this way, they have been able to improve how digestible various cheeses and yoghurts are.
Incredibly, much of that recipe evolution happened before anyone understood what bacteria really is, co-author Yichen Liu, also of the Chinese Academy of Sciences, highlights: “Fermentative microbes played such an important role in the daily life of these ancient humans, and they propagated these microbes for thousands of years without knowing the existence of them for most of the time.”
Evidence of China – Tibet exchanges
The link they found between the mummified cheese and Tibet suggests Nomadic groups of Chinese and Tibetan peoples interacted during the Bronze Age leading to “cross-regional exchanges”. Trading dairy products and transporting storage containers across Eurasia contributed to the “distinct spreading routes of two subspecies [of kefir microbe],” Fu told Popular Science.
The theory bucks commonly-held wisdom that kefir began solely in the Caucasus Mountains region, Fu said. The ”unprecedented” study has allowed 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.”
Just why the cheese was smeared around the mummies’ necks in the first place is another question.
