Archaeologists Find World’s Oldest Cheese Smeared on Mummies in China

The Guinness Book needs to update its records: the oldest cheese in the world has been found smeared on the heads and necks of 3,600-year-old mummies in China’s Tarim Basin, surpassing the age of a cheese identified in the tomb of an Ancient Egyptian mayor by several hundred years.

The cheese-covered mummies are in the Xiaohe Cemetery, part of the Xinjiang Uyghur Autonomous Region. The remains—confoundingly buried in boat coffins surrounded by miles of sand dunes—date from 2,000 BCE to around 200 CE.

The cheese on the mummies is kefir cheese, which is made by using yeast and probiotic bacteria to separate curd and whey. Researchers discovered the cheese on the mummies a couple decades ago, and suspected it was a fermented dairy product, but weren’t exactly sure. Now, they’re more confident, as the work describing the extraction of ancient cow and goat DNA from the cheese was published today in Cell.

“This is the oldest known cheese sample ever discovered in the world,” said Qiaomei Fu, a paleogeneticist at the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleoanthropology, in a Cell release.

The team also recovered the DNA of microorganisms in the dairy sample—bacterial and fungal species that persist in modern kefir grains. The team was able to take this information and track how ancient kefir cheeses differed in bacterial makeup from modern ones.

“The results offered new insights into our knowledge of the lifestyle, techno-cultural exchanges, human-microbial interaction of the past populations, and opened a new door for us to explore through microbial genomes how microbiomes interfaced with human biology and culture to influence human health, behavior, and quality of life,” Fu told Gizmodo in an email.

Today, there are two main groups of the Lactobacillus bacteria that come from Russia and Tibet respectively, according to the release. The team found that the DNA in the cemetery cheese is more similar to that of the Tibetan bacterial culture, indicating that kefir cheese did not only come from the North Caucasus mountains in Russia.

“Our observation suggests kefir culture has been maintained in Northwestern China’s Xinjiang region since the Bronze Age,” Fu said.

The cheesy research is the latest insight into the Xiaohe mummies, who continue to surprise scientists even after three millennia. The mummies don’t resemble modern locals to the area, which led various groups of researchers to posit the ancient individuals were from the Black Sea region, or the Iranian Plateau. A 2021 paper found that the Xiaohe mummies were direct descendants of the Ancient North Eurasians, a human population that was widespread during the Pleistocene and whose genetics now persist in some modern populations’ genomes.

Genetic studies of the mummies—and indeed, of the cheesy pastes smeared across them—are revealing a more complex portrait of the unique population.