As much as 50 percent of the olive oil sold in the U.S. is not actually pure olive oil, as some brands claiming to be "extra-virgin" or "100 percent Italian," for instance, have actually been adulterated with toxic rapeseed oil, more popularly known as canola oil, soybean oil, and other low-grade oils. In his new book Extra Virginity: The Sublime and Scandalous World of Olive Oil, olive oil expert Tom Mueller explains that not all olive oil is the same, and offers advice on how to spot authentic olive oil amidst all the imposters.
During a recent interview with Terry Gross from NPR's Fresh Air, Mueller explains how olive oil adulteration is much more widespread than people think, if they are even aware of it at all. For olive oil to truly be considered "extra-virgin," it has to come from fresh, crushed olives, and not be refined in any way or contain any chemical solvents. It also has to pass certain tests of integrity in order to be considered legitimate, for which many of the brands popularly sold today would fail.
"The legal definition simply says it has to pass certain chemical tests, and in a sensory way it has to taste and smell vaguely of fresh olives, because it's a fruit, and have no faults," said Mueller. "But many of the extra-virgin olive oils on our shelves today in America don't clear [the legal definition]."
Beige olive oil in plastic bottles is most likely adulteratedReal extra-virgin olive oil should have a vibrant, almost peppery flavor, for instance, and not taste bland or watered down. It is also typically stored in dark, glass bottles so that its array of health-promoting antioxidants, its taste, and its forceful green color -- yes, olive oil should be green, not yellowish in color -- are not harmed by light or damaging UV rays from the sun. For this reason, avoiding olive oil in clear, plastic bottles is recommended.
"What [real olive oil] gets you from a health perspective is a cocktail of 200-plus highly beneficial ingredients that explain why olive oil has been the heart of the Mediterranean diet," added Mueller during his interview with NPR. "Bad olives have free radicals and impurities, and then you've lost that wonderful cocktail ... that you get from fresh fruit, from real extra-virgin olive oil."
Most imported extra-virgin olive oil appears questionable in authenticityThe University of California, Davis published a report on olive oil back in 2010 entitled Tests indicate that imported 'extra virgin' olive oil often fails international and USDA standards. In this report, researchers found that 69 percent of imported and ten percent of California-based oils labeled as olive oil did not pass International Olive Council (IOC) and US Department of Agriculture sensory standards for extra virgin olive oil.
