Researchers said they found the earliest known chemical evidence of cheese-making, based on the analysis of milk-fat residues in pottery dating back about 7,500 years. The discovery suggests Europe's farmers added a cheese course to their diet almost as soon as they learned to domesticate cattle and started regularly milking cows. Scientists led by geochemist Richard Evershed at the U.K.'s University of Bristol tested ancient, perforated clay pots excavated at sites along the Vistula River in Poland, and found they had likely been used by prehistoric cheese mongers as strainers to separate curds and whey—a critical step in making cheese. The pots have long puzzled archeologists, but their new analysis, reported in Nature, revealed unique carbon isotopes of milk in the traces of fatty acids that had soaked into the ceramic sieves. "It is a no-brainer," said Dr. Evershed. "They have to be cheese strainers." No one knows exactly when or where cheese-making began, but experts said the traces of milk fat on these unglazed clay strainers are the clearest evidence yet of the origins of this basic biotechnology, which launched a dairy trade that today produces more than 11 billion pounds of cheese every year and as many as 5,000 different named varieties world-wide, from Appenzeller to Zamorano. Cheese historians suspect that the first cheese was most likely a soft, watery concoction, resembling a contemporary cottage cheese or a fromage frais, that was naturally curdled by the bacteria commonly found on a cow's teats. Shards of the distinctive urns, which resemble pottery cheese strainers still in use today, are found often at sites settled by the Neolithic-era tribes who first brought the innovations of agriculture and animal husbandry to central Europe. They almost always turn up in association with large numbers of cattle bones. In prehistoric times, when almost every adult was lactose-intolerant, the invention of cheese-making offered herders a way to turn fresh whole cow's milk into a food that they could consume without getting ill, experts said. Cheese contains far less lactose than milk. Moreover, cheese, which normally takes up a tenth of the volume of the milk from which it is made, is easier to store, transport and preserve. "Making cheese is a particularly efficient way to exploit the nutritional benefits of milk, without becoming ill because of the lactose," said archeologist Peter Bogucki, an associate dean at Princeton University, who was part of the international research team. In fact, evolutionary biologists at University College London have suggested that a genetic mutation to better tolerate lactose first originated in central Europe about the time this prehistoric cheese-making began. The inherited ability to digest cow's milk more easily is widespread today among people of European ancestry. For decades, archeologists have debated how the vessels pocked with holes were used. Some scholars theorized that the pots were used to brew beer. Others speculated that primeval chefs used them to separate meat from stock or honey from honeycomb. The containers also may have been fire pots to hold glowing embers safely. "Scholars have been duking it out for decades as to what these sieves were used for," said University of Vermont cheese chemist Paul Kindstedt, author of "Cheese and Culture: A History of Cheese and Its Place in Western Civilization." He wasn't involved in the research. "This new finding is really definitive —beyond a reasonable doubt—that this utensil was used for cheese making."

• published: 10 Dec 2014
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