The Chinese cheese dates back as early as 1615 BCE, and owes its conservation to the extraordinary conditions at Small River Cemetery Number 5, in northwestern China. First documented by a Swedish archaeologist in the 1930s, it lies in the fearsome Taklamakan Desert - one of the world's largest. A mysterious Bronze Age people buried dozens of their kin underneath what look like large wooden boats, atop a large sand dune near a now-dry river. The boats were wrapped so snugly with cowhide that it's as if they'd been "vacuum-packed," says study author Andrej Shevchenko, an analytical chemist at Germany's Max Planck Institute.
     The dry desert air and salty soil prevented decay to an extraordinary degree. The remains and grave goods were effectively freeze-dried, preserving the light-brown hair and strangely non-Asian facial features of the dead, along with their felt hats, wool capes and leather boots. Analysis of plant seeds and animal tissues showed the burials date to 1450 to 1650 BCE.
     Some of the bodies had oddly shaped crumbs on their necks and chests. By analyzing the proteins and fats in these clumps, Shevchenko and his colleagues determined that they're definitely cheese, not butter or milk, and was made by combining milk with a "starter" mix of bacteria and yeast. This technique is still used to make kefir - a sour, slightly fizzy dairy beverage - and kefir cheese, similar to cottage cheese.
     Most cheese today is made with rennet, a substance from the guts of a calf, lamb or kid that curdles milk. Making cheese with rennet requires the killing of a young animal. The kefir method does not. Shevchenko argues that would have helped drive the spread of herding throughout Asia, from its origins in the Middle East. Both kefir and kefir cheese are low in lactose, making them edible for the lactose-intolerant inhabitants of Asia.
     Bioarchaeologist Oliver Craig of the University of York in Britain says the study's suggestion that the cheese was made with kefir starter rather than rennet is hard to prove, because the proteins could have decayed too much. He thinks a study of animal bones or pottery is needed to confirm that the cheese at the cemetery was part of a technological spread across Asia.

Edited from USA Today (25 February 2014)