The world’s oldest cheese is now revealing some of its secrets
A DNA analysis of the kefir cheese, first found about 20 years ago on 3,600-year-old mummies in China, confirms its age and pinpoints its origins.
Bacteria in cheese found on mummies is providing hints of how fermenting spread through Asia
A diffusion China’s Xiaohe mummies, like the one shown here, were mysteriously buried with bits of cheese near their necks.
Wenying Li
When scientists revealed the sector’s oldest preserved cheese smeared on the necks of ancient mummies in China, it raised a lot of questions.
Now DNA analysis is answering some of them. It solidified that two of the three curdled samples of kefir cheese are likely crafted from cow milk, while a 1/3 came from goat milk. And a more in-depth examine bacteria the total way throughout the cheese offers new insights into the origin story of Asian dairy fermentation, revealing how kefir culturing techniques spread across the continent, paleontologist Qiaomei Fu and colleagues report September 25 in Cell.
The samples were first found over 20 years ago in Xinjiang, China, on nearly three,600-year-old Xiaohe mummies. Scientists couldn’t fully change into responsive to the samples back then. In 2014, every other group reported evidence that the that the mystery curds were crafted from kefir. The yogurtlike drink is made by fermenting milk with kefir grains, which consist of reside bacteria and yeast cultures. When drained, kefir becomes a lumpy mass of cheese.
“That's the oldest preserved cheese sample the total way throughout the sector,” says Fu, of the Chinese Academy of Sciences in Beijing. It’s almost Four hundred years older than the previous record holder (SN: 8/17/18). However it didn’t feel like cheese, Fu says. When she squeezed the samples, they felt like “dense dust.”
Because kefir may be created most effective from existing kefir cultures, bacteria the total way throughout the grains may be a proxy to trace the spread of fermentation techniques. Fu’s team compared the bacteria’s DNA against 15 as much as date samples, building a bacterial family tree the total way throughout the strategy. Prior research proposed that kefir fermentation techniques largely spread from Russia to Europe, but the team mapped evidence showing an extra route running from as much as date-day Xinjiang, where the tombs were excavated, into Tibet and inland east Asia.
“From this contaminated, ancient sample, they managed to in finding one specific bacteria and in checking out the way it spread,” says Anna Shevchenko, a chemist on the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany. “To me, that’s what's most interesting.”
What the cheese changed into doing on the mum’s necks, on the alternative hand, remains a mystery.
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