Dr. Greger: “The ease of adulterating extra virgin olive oil, the difficulty of detection, the economic drivers, and the lack of control measures all contribute to extra virgin olive oil’s susceptibility to fraud.”

Of the five top-selling imported “extra virgin” olive oil brands in the United States, 73 percent of the samples failed the IOC sensory standards for extra virgin olive oils.

Report: Evaluation of Extra-Virgin Olive Oil Sold In California, UC Davis Olive Center at the Robert Mondavi Institute, April 2011

Our testing indicated that the samples failed extra virgin olive oil standards for reasons that include one or more of the following:

(a) oxidation by exposure to elevated temperatures, light, and/or aging
(b) adulteration with cheaper refined olive oil
(c) poor quality oil made from damaged and overripe olives, processing flaws, and/or improper oil storage

Conclusions: Our laboratory tests found that the top-selling imported brands of “extra virgin” olive oil sold in the United States and purchased at retail locations throughout California often failed the IOC’s sensory standards for extra virgin olive oil.