Olive oil is the Swiss army knife of foodstuffs. It can dress salads, sauté vegetables, even grease squeaky hinges. And for archaeologists, its ubiquitous presence in excavated pottery offers a window into the economic, political and social organization of the ancient world.

But perhaps, in certain environments, that prevalence has been overstated.

An interdisciplinary team of Cornell researchers—ranging from classicists to food scientists to engineers—has determined that organic residues of plant oils are poorly preserved in calcareous soils from the Mediterranean. This means decades of archaeologists have likely misidentified olive oil in ceramics, failing to recognize other plant oils or perhaps mistaking them for animal fat.