Olive Oil Fridge Test? Don’t Count On It.

Dr. Oz

On a recent segment of his wildly successful daytime television program, Dr. Oz warned his viewers they are being duped into buying fake extra virgin olive oil (EVOO). He said some experts claim that nearly 70 percent of EVOO sold is counterfeit, and he urged everyone to check their olive oil with a test that he and his family use.

In the test, Dr. Oz puts a bottle of EVOO in the refrigerator. If it freezes at a normal refrigerator temperature, “then you’re pretty sure it’s pure,” said Oz.

Some experts, however, say that the so-called “Fridge Test” for olive oil authenticity is a long-standing myth.

Dr. Oz was investigating supermarket food fraud, including fake EVOO, in an episode that aired on February 11. He explained that people pay more for good olive oil for its health benefits, but if the oil they purchase is not EVOO, then they are not getting the desired health gains.

A 2010 study conducted by the University of California Davis Olive Center reported that 69 percent of imported oil labeled as extra virgin olive oil did not meet the standards for extra virgin.

Show guest Dan Flynn, director of the Olive Center, told the over 3 million viewers that EVOO is the top grade of olive oil because it is natural crushed olive juice; not altered by chemicals, solvents or heat. In the UC Davis study, falsely labeled samples pulled off grocery shelves were described by trained tasters as “musty, waste pond, baby diaper…the kind of things you don’t want to get near your salad,” Flynn said.

Shaun Kennedy, director of the National Center for Food Protection and Defense, also appeared on the Dr. Oz Show and explained that some producers pass off cheap oils, such as sunflower, hazelnut or industrial oil as extra virgin olive oil because they can make a big profit on it. “Some estimates say that the fake olive oil business is as profitable as the cocaine trade and it’s certainly a lot easier,” said Kennedy.

While Dr. Oz’s show brought needed awareness of olive oil quality issues to consumers, experts say the “fridge test” will not help consumers conclusively determine if their purchase is real olive oil. Dr. Oz informed viewers that the method is “not 100 percent foolproof.”

The North American Olive Oil Association called the home test “completely false and misleading.” Almost any oil will solidify at cold temperatures, depending on its chemical compounds, and even within the EVOO category, factors such as olive variety and time of harvest, will affect solidification.

Expert olive oil taster Richard Gawel said that the home test “is not a reliable indicator” of an oil’s EVOO authenticity. In his blog, Gawel explains why the myth may have come into being. EVOOs are largely made of monounsaturated fats that coagulate at refrigerator temperatures while other oils tend to be made of polyunsaturated fats that can only solidify at much lower temperatures — lower than regular refrigerators can reach.

The fridge test would work if EVOO were 100 percent monounsaturated and other oils were 100 percent polyunsaturated, said Gawel, but oils usually contain a combination of fats. He cites peanut oil as an example saying that it has high monounsaturated content and will pass the fridge test.

Even an EVOO that has been adulterated with a bit of canola oil will solidify in the refrigerator and pass the test, even though it is not pure EVOO, said Gawel.

Flynn told Olive Oil Times that the refrigerator method is not completely foolproof. “While it is true that refined oils will not coagulate in the cold, it is also true that some olive oil varieties will not coagulate either.” In addition, the test will not tell a consumer if the EVOO tastes good.

Eryn Balch, executive vice president of the North American Olive Oil Association said that the widely-circulated fridge test myth “illustrates the great need for reliable sources of olive oil education.”

Flynn advised viewers of the Dr. Oz show to check the harvest date on the olive oil bottle, and buy one indicating a harvest within the last 15 months to improve the chances of getting a good quality oil. He also recommended looking for quality seals on the bottles, such as the one from the California Olive Oil Council, that certify that the oil has passed chemistry and sensory criteria. Flynn noted that UC Davis is working on better methods of detecting olive oil fraud.

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This article was last updated December 17, 2014 - 9:15 PM (GMT-5)

  • Pete Maniza

    Really stupid comment comparing the Cocaine market to the olive oil market. Imported olive oils have been and will continue to be 100% authentic. Like any other industry you will always find 5% or so the try to cheat. Sounds to me like the Univ Calif. Davis guy is misinformed, he has been pushing California produced EVOO for years.

    • EVOO_Chick

      Really??? The UC Davis Olive Center coordinator is the one who is misinformed? I find the other option much more plausible…that being said, how do you know that the imported oils are 100% authentic? Why don’t they taste like the California-produced olive oils if they aren’t altered or rancid then? Maybe you should pick up a copy of Extra Virginity by Tom Mueller before you go putting down a well-respected and highly intelligent EVOO promoter/researcher.

      • DCDimon

        The UC Davis study is a taste test study, not a chemical analysis. And it was funded by major California olive oil producers so it’s questionable at best. The funder of the study has a vested interest in promoting CA oils, not in being objective. Taste is a subjective thing, what tastes good to one person may not to another. And taste does not prove whether an oil is adulterated or not. That can only be done with a lab test. So the study findings themselves mean nothing.

        The COOC does not perform one
        single test meant to detect adulteration. Rather, the group performs a taste
        test and 2 – 3 tests that indicate quality level of the oil.

        I do work for an olive oil bottler, just to fully disclose. We test the oil 7 times throughout the process (lab tests for content and taste). I have no vested interest in this issue one way or the other, only in making sure that facts are being presented.

        • OliveChirper

          Actually, the UC Davis study was only a taste test: it was, in fact, a very extensive study of all the major IOC-required chemical profiles, plus the PPP and DAG-ratio tests developed by the German Society for Fat Science (DGF) and adopted by the Australian voluntary standard for EVOO and as a standard method by the American Oil Chemists’ Society. The PPP study is very good at detecting one kind of adulteration (the use of oils treated by soft-column refining), and both are better than any other chemical test at detecting oils with off flavors. See the extensive chemistry in the report:


          Second, while some of the oils did fail on the sensory test, others failed because they were rancid or adulterated with canola oil.

          And while it’s true that (as you say) “Taste is a subjective thing, what tastes good to one person may not to another”, the taste test used by the IOC-approved laboratories and Modern Olives is not just to ask whether a random group of people like an oil or not, but is a highly-replicable and precise instrument, developed by training, certifying, and re-training testers to detect very subtle levels of specific taste defects. And contrary to what you seem to believe, the IOC has in reporting in Olive Oil Times strongly affirmed its ongoing support for the taste test. And, after all, one of the main points of even DOING chemical testing is to have a way to pick up on oils that were badly handled, to help make sure that the oils will taste good to the consumer; the palate remains a far more sensitive instrument than a gas chromatogram, and if the chemistry says an oil scrapes by under the very loose chemical standards advanced by the International Olive Council but tastes like it was made of fermented or frost-damaged olives, or rancid, it shouldn’t bear the label ‘Extra Virgin.

          • CatSmirk

            OliveChirper: Thank you for a well-written and knowledgeable post. I’ve learned a lot reading through all the comments and really appreciate your insight.

        • steven horton

          The depth of knowledge & level of understanding is going to be different in every place and between people. It is obvious from what information you are sharing that your plant & leaders are playing kindergarten tricks with you. Given your explanation of the value to you of those simple tests. The participants at UC and their co-workers are levels higher in technical & practical knowledge. Look to respect those that dedicate their lives to help make this year in this world a safer & healthier place. After all you or you family/ freind may need help when they are less fortunate. It takes one counterfeit oil to reduce the immunity of an innocent child to a diabetic, a blood disease or a cancer. Why allow a person who is less fortunate to die when you are not trained to know.

    • Ralph

      Pete, by any chance are YOU an importer of EVOO? (or cocaine??)

  • Melissa

    Thank you for setting the record straight. I’ve heard about this home test from a lot of people and I always had the feeling it wasn’t that simple.

  • Pete Manzia

    DC you could not have said it better, the gentleman has a self interst in Calif, Olive Oil. Calif Olive Oil companies are finding it difficult to displace imported brands on the grocery shelves. The NAOOA and the IOOC have been testing oilve oil for years, cheaters have beeen all along, I stand by my statement 95% of the imported brands of olive oil are legit…

    • steven horton

      Interesting Comment Pete but how many times have really tested an EVOO? Yesterday I went to the kitchen of a 2013 Michelin rated Spanish Chef.
      I was delighted when he accepted my challenge to take his chosen oil and a piece of fish and my Australian EVOO and heat his hot plate up to 200degrees C. The chefs oil tasted to me adulterated, at the side of the palate it tasted differently to the centre, because it was in a clear bottle and exposed to heat it did not fresh but OK. The Chef tasted the Aussie Enjoi oil, from a pressurised bottle that was filled 2 weeks ago and carried in my bag. The Chef found no separation in the palate, a sharper bite at the end (lower FFA). The oils where sprinkled onto the hot plate and the Spanish oil smoked across each splash on the plate. More oil was added and the oil slid away from the splashed area. The same was done with the Enjoi EVOO it did not raise any smoke stayed tightly in the area. The Chef added same thickness & weight fish to each area and sealed the fish in 2 mins with the Enjoi oil and 2:30 with the Spanish. The plates were then put onto the table so that neither of us new which oil made them. We both choose & highlighted superior aroma, look& taste of the Enjoi oil cooked fish. The Chef complimented the absence of any influence or oil exchange with the Enjoi oil on the fish – the texture of the fish was better. Whereas there was a slight taste & dryness to the other piece of fish made with the Spanish EVOO.
      My point is the counterfeit Spanish EVOO did not make the grade.

  • http://twitter.com/bathandbodysoap bathandbodysoap

    Fan of the Olive oil page old style cooking

  • Mia

    You should never ruin your Extra Virgin Olive oil by putting it in the fridge. You must buy from a reputable store and be able to taste what you are purchasing. Also you should look for these 3 points, 1) best before date 2) produced and bottled on the estate or co operative, 3) how the oil is stored in the store, never under light or by a window.

  • Claudia

    You need to do more than put your EVOO in the fridge to know if it is a true extra virgin olive oil. If your EVOO has gone rancid it will still solidify under 8 degrees because it remains a MUFA but then it is no longer an EVOO but a rancid olive.oil. A true EVOO should have nice fresh aromas, bitterness and pungency. Sorry Dr. Oz but you need to learn more about the product itself. However I congratulate you on knowing about its health benefits and cooking tips.

  • Tenuta Zimarino

    But when you accept the response of alkyl esters?

  • Olivenöl “MasseriaDonVincenzo”

    I suggest you to check alkyl esters!

  • http://www.facebook.com/profile.php?id=572744056 Justin Siemaszko

    just out of curiosity what ARE the margins of error? If there are olive oils that don’t coagulate, what percent of the market are they?

    If 5% of consumer olive oil might legitimately coagulate, but it also turns out that a 30% of the “olive oils” on the shelves coagulate it a test, then to me, it seems like this is still a pretty decent test.

  • Clara’s Mommy

    Thanks to the the Dr. Oz show I put my bottle labeled 100% olive oil in the fridge for two days and it didn’t solidify. I was horrified!!

  • workathome

    I just saw this on Dr. Oz, I called Bertolli (who is owned by Unilever, who is the largest user of palm oil) and was told that they don’t agree with Dr. Oz…. of course not, he isn’t the one making the profits! I can’t monitor everything and I am old, but I sure as heck do not have to pay a big business to stick it to me – Bertolli is no longer on my shopping list.



    • Nata, a nutritionist

      Well, living in the Middle East we rely on olive oil. We only use olive, coconut or sesame oils. Cold pressed, etc.
      We buy from small producers we know. The oil has a seal of the council for olive oil. Know what? It ALWAYS solidifies in the fridge. A couple of times we bought cheaper from just farmers selling at the roadside in rural areas, part of it did solidify, part never did. I do trust this test.