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For thousands of years, humans have been picking, prizing, and pressing the fatty drupes found among the oblong leaves of the gnarled, twisted olive tree into rich, green-gold extra virgin olive oil. And for almost as many thousands of years, humans have been coming up with ways to fake it, to pass off cheaper, less delicious, less nutritious oils as the real thing. The earliest known written mention of olive oil — from Syria, 24 BC — describes how court-appointed inspectors would tour olive oil processing facilities to ensure quality, purity, and the absence of fraud. In ancient Rome, the vessels containing olive oil bore detailed information about the contents, including varietal of fruit used, place of origin, name of producer, the weight and quality of the oil, the name of the importer, plus the name of the official who inspected it and confirmed the previously mentioned data. Let’s just say they really, really liked their olive oil, and that olive oil adulteration has always been an issue.
It continues today, of course, and studies are bearing out the fact that extra virgin olive oil is often adulterated with cheaper, more refined, deodorized olive oils, oils from olives deemed unfit for human consumption, and/or random nut, seed, and vegetable oils spiked with chlorophyll and beta-carotene to replicate the authentic color. An Australian study found that over half the supermarket EVOO was anything but, even the supposedly legit stuff from the Mediterranean countries; New Zealand researchers had similar results with Mediterranean imports into their country. Last year, a University of California at Davis study (PDF) found that 69% of imported extra virgin olive oils failed to meet international standards, while 90% of California EVOO tested passed (the study was partially financed by major California olive oil producers, and producers of some of the failed imports are crying foul). Similar adulteration is taking place in China, where imported olive oil is mixed with cheap seed oils. In 2007, the New Yorker published a harrowing account of widespread and longstanding fraud in the Italian olive oil industry (u201CProfits were comparable to cocaine trafficking, with none of the risks”), and more recently, a study found that four out of five Italian olive oils were “debased.”
I’ve spent the last few years recommending that you eat extra virgin olive oil, and now it appears as if the fraud is pervasive enough to throw everything you thought you knew into a state of confusion. So what are you supposed to do? How do you know if your olive oil is actually olive oil?
The Fridge Test
By now, you’ve probably all heard about it: to test the legitimacy of a supposed olive oil, stick it in the fridge for a day or two. If it begins to solidify, you’ve got yourself a bottle of true extra virgin olive oil. Does it hold true?
Pure monounsaturated fat, also known as oleic acid, solidifies at 39 degrees F. Since olive oil is primarily oleic acid (about 70-85 percent, generally), sticking a bottle of real olive oil in the fridge should elicit solidification. The original olive oil adulterants, sunflower oil and safflower oil, were mostly polyunsaturated, so adulterating olive oil used to be easy to spot. Now, with high-oleic sunflower oil, high-oleic safflower oil, and high-oleic canola oil on the scene, adulterated olive oil can still solidify in the fridge. Thus, the fridge test is still a necessary, but not sufficient, test for the legitimacy of your extra virgin olive oil. It’s really a test for the degree of monounsaturation in the oils. It’s important (toss any oils that fail the test), but it’s not the full story.
The Taste Test
Good olive oil is often bitter, pungent, spicy, and slightly abrasive. It’s not always smooth and easy going. In fact, the “off-notes,” the intense flavors that make the uninitiated screw up their face actually indicate the presence of high levels of polyphenols, those antioxidant plant compounds which make olive oil so good for you. If the olive oil you taste burns the back of your throat and tastes funny to you, chances are you’ve been using and are used to adulterated (or at least non-virgin) oil.
To my knowledge, olive oil adulteration hasn’t progressed to the point where scammers are able to simulate the flavor of true EVOO. If they were to do it, I’d imagine they’d have to add polyphenols or olive extracts to the vegetable oils, and that can’t be cheap. And even if they did add olive extracts and synthetic polyphenols, it’d be better than having none at all.
Does It Matter?
Aside from being cheated out of your money for a disgustingly disappointing mix of soybean and canola oils, can any real health issues arise from consuming adulterated olive oils?
There are allergy concerns, of course, if the adulterant contains an allergen, like peanut oil. Owing to the similarity of its fatty acids to olive oil’s, hazelnut oil is another popular adulterant as well as a fairly common allergen, and one study even showed that people with hazelnut allergies could identify olive oil spiked with hazelnut oil because they suffered symptoms after eating it.