The tomb of Ptahmes, mayor of Memphis in Egypt over three millennia ago, was initially unearthed in 1885. After being lost under drifting sands, it was rediscovered in 2010, and archeologists found broken jars at the site a few years later.
One jar contained a solidified whitish mass, as well as canvas fabric that might have covered the jar or been used to preserve its contents. Dr Enrico Greco and colleagues wanted to analyze the whitish substance to determine its identity.
After dissolving the sample, the researchers purified its protein constituents and analyzed them with liquid chromatography and mass spectrometry.
The peptides detected by these techniques show the sample was a dairy product made from cow’s milk along with sheep or goat’s milk. The characteristics of the canvas fabric, which indicate it was suitable for containing a solid rather than a liquid, and the absence of other specific markers, support the conclusion that the dairy product was a solid cheese.
Other peptides in the sample suggest it was contaminated with Brucella melitensis, a bacterium that causes brucellosis. This potentially deadly disease spreads from animals to people, typically from eating unpasteurized dairy products. The sample represents the earliest reported biomolecular evidence of the disease.
“There are other samples of dairy products in the literature, but not solid cheeses in the strict sense,” Dr Greco, who is now at Peking University, told the media at the time. He claimed not to have sniffed the ripe lump, though it would have hardly mattered, having lost its odor somewhere along the millennia.
Not the oldest, but good to study
Cheese making predates the new find by thousands of years, however, but preserved cheese is hard to come by. Archaeologists have found older curds draped around the necks of Bronze Age mummies in China, which they reported in 2014 in the Journal of Archaeological Science.
Researchers had unearthed the Chinese cheese during excavations of the Xiaohe Cemetery, also known as Ordek's necropolis, between 2002 and 2004.
The mummies, which are each about 3,800 years old, were buried with the cheese hunks, presumably to provide the departed with a snack to enjoy in the afterlife. This particular cheese was also simple to make, nutritious and easily digestible, according to the study.
"Despite being extraordinary simple, it possessed the necessary qualities for supporting the economic expansion of ruminant animal herding into Eastern Eurasia," the authors wrote in the paper.
Researchers have found hints of cheese making from as far back as the sixth millennium BC, but samples of the ancient cheeses themselves have been elusive. Most evidence relied on residual fats found in pottery shards, but many of these traces had degraded over time or received only limited analysis. This made the evidence for ancient cheese circumstantial, the authors wrote.
The ancient necropolis was first discovered in a sand dune located by a dried-up riverbed in 1934. It harbors hundreds of mummies buried in large, wooden coffins that resembled upside-down boats, which were then covered with cowhide that sealed the coffins from the air. The dry air and salty soil had left many mummies and their accessories extraordinarily well preserved.
Elsewhere, ceramic vessels pocked with holes have pushed the earliest evidence for cheese making back to 7,400 years ago. Chemical signatures of milk fat in perforated pots used as strainers provide the telltale clues to early cheesemaking, according to a team led by biogeochemist Professor Richard Evershed, of the University of Bristol.
As with similar-looking cheese strainers today, these devices—previously found at ancient farming villages in Poland—separated fat-rich milk curds from lactose-containing whey, the scientists reported.
An earlier pottery analysis led by Prof. Evershed placed the origins of cattle milking at around 9,000 years ago in what’s now Turkey, although there was no evidence of specific milk products from that time.
With the latest discovery, however, scientists will have much more to go on, given the preserved nature of the cheese which has already revealed a number of its secrets. From it they will not just gain an insight into how cheese was made, it will also provide a glimpse of society’s tastes back in the 13th century BrieC.