Have you heard the story about the huge percentage of US olive oil that is not pure olive oil, but adulterated with other oils? Me too. Talking to Mary Zider about Colavita and olive oil got me curious, so I did a little digging. This widely disseminated bit of information comes from an erroneous interpretation of a report out of UC Davis in 2010 that looked at sensory standards for extra virgin olive oil, but did not perform any kind of testing on the purity of olive oil. And apparently even that report is suspect, as subsequent attempts to replicate it were unsuccessful, and the report itself is no longer up on the UC Davis website. You can read more at Snopes and at North American Olive Oil Association pages here and here.