The cheese was dug up with mummified human remains in the Xinjiang region of China and offers insights into the origins of the dairy product known as kefir.
Around 3,600 years ago, a young woman died and was buried in the Tarim Basin, a desert in what’s now the Xinjiang region of northwestern China. The dry conditions and her sealed coffin preserved her body, so when archaeologists uncovered her grave in 2003, they found her naturally mummified remains, still dressed in a felt hat, tasseled wool coat and fur-lined leather boots.
They also found chunks of cheese, laid out like a necklace.
This dairy decoration is the “oldest cheese in the world,” said Qiaomei Fu, a paleogeneticist at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences. In a study published Wednesday in the journal Cell, Dr. Fu led a genetic analysis of the dairy products and microbes present in cheese from the Tarim Basin, shedding light on how it was made.
Humanity’s love affair with cheese goes back millenniums. Scientists have found fatty residues on 7,000-year-old pottery that were most likely from cheese, and 4,000-year-old Sumerian texts mention the dairy product. But the Tarim Basin samples are the oldest substances in the world that scientists can confidently call cheese.
Dr. Fu and her team took samples of cheese scattered about the necks of three mummies from the Tarim Basin. They chemically isolated the fragments of DNA that remained and compared them with the genomes of modern species involved in the cheese-making process. They found traces of cow and goat DNA, indicating that the milk of both animals was used in the ancient cheese. They were also able to track down the DNA of microbes responsible for fermenting the milk into cheese.
The researchers found species of bacteria and yeast that, together with milk, coagulate into clumps called kefir grains, which are used to produce fermented, yogurt-like kefir milk and soft, sour kefir cheese.