Researchers on Wednesday said they found the earliest known chemical evidence of cheese-making, based on the analysis of milk-fat residues in pottery dating back about 7,200 years. The discovery suggests Europe's early 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...