Olive oil regulation and adulteration

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International Olive Council building

Olive oil regulation and adulteration are complex issues overseen and studied by various governmental bodies, non-governmental organizations, and private researchers across the world.


The International Olive Council (IOC) is an intergovernmental organization based in Madrid, Spain, with 16 member states plus the European Union. It promotes olive oil around the world by tracking production, defining quality standards, and monitoring authenticity. More than 98 percent of the world's olives are grown in IOC member nations.[1] The United States is not a member of the IOC, and the US Department of Agriculture does not legally recognize its classifications (such as extra-virgin olive oil). On October 25, 2011, the United States adopted new olive oil standards, a revision of those that have been in place since 1948, which affect importers and domestic growers and producers by ensuring conformity with the benchmarks commonly accepted in the U.S. and abroad.[2]

The IOC officially governs 95 per cent of international production and holds great influence over the rest. IOC terminology is precise, but it can lead to confusion between the words that describe production and the words used on retail labels. Olive oil is classified by how it was produced, by its chemistry, and by its flavor. All production begins by transforming the olive fruit into olive paste. This paste is then malaxed to allow the microscopic oil droplets to concentrate. The oil is extracted by means of pressure (traditional method) or centrifugation (modern method). After extraction the remnant solid substance, called pomace, still contains a small quantity of oil.

The EU regulates the use of different protected designation of origin labels for olive oils.

US Customs regulations on "country of origin" state that if a non-origin nation is shown on the label, then the real origin must be shown on the same side of the label and in comparable size letters so as not to mislead the consumer.[3][4] Yet most major US brands continue to put "imported from Italy" on the front label in large letters and other origins on the back in very small print. These products are a mixture of olive oil from more than one nation and it is not clear what percentage of the olive oil is really of Italian origin. This practice makes it difficult for high quality, lower cost producers outside of Italy to enter the US market, and for genuine Italian producers to compete.

Investigations, incidents, and recalls[edit]

With Italian extra-virgin olive oil in high demand with concomitant high prices, adulterated olive oil has become the biggest source of agricultural fraud problems in the European Union.[5] While less than 10% of world olive oil production meets the criteria for labeling as extra-virgin, it has been estimated that up to 50% of retail oil is labeled "extra-virgin".[6] Some oil labeled "extra-virgin" is diluted with cheaper olive oils or other vegetable oils. In some cases, lampante, or "lamp oil," which is made from spoiled olives fallen from trees, is used, even though it can't legally be sold as food. One fraud ring is accused of coloring low-grade soy oil and canola oil with industrial chlorophyll, and flavoring it with beta-carotene.[5]

In the United States, the Food and Drug Administration (FDA) doesn't routinely test imported olive oil for adulteration, and some products are difficult to test.

An article by Tom Mueller in the August 13, 2007, issue of The New Yorker states that major Italian shippers routinely adulterate olive oil and that only about 40% of olive oil sold as "extra virgin" actually meets the specification.[7] In some cases, colza oil with added color and flavor has been labeled and sold as olive oil.[8] This extensive fraud prompted the Italian government to mandate a new labeling law in 2007 for companies selling olive oil, under which every bottle of Italian olive oil would have to declare the farm and press on which it was produced, as well as display a precise breakdown of the oils used, for blended oils.[9] In February 2008, however, EU officials took issue with the new law, stating that under EU rules such labeling should be voluntary rather than compulsory.[10] Under EU rules, olive oil may be sold as Italian even if it only contains a small amount of Italian oil.[9]

In 1993, the FDA ordered a recall of Rubino U.S.A. Inc., (Cincinnati, Ohio) olive oils which were nothing more than canola oil.[11]

In 1997, the Canadian Food Inspection Agency began conducting tests on 100 oils that claimed to be 100% olive oil and in 1999 the CFIA concluded that 20 per cent of the oils were fake.[12] In 2013, "Figures released at the [IOC's] Workshop on Olive Oil Authentication, held in Madrid June 10–11, show that one in four olive oils sampled in Spain, and nearly one in three in Canada, failed recent official fraud tests."[13]

In March 2008, 400 Italian police officers conducted "Operation Golden Oil", arresting 23 people and confiscating 85 farms after an investigation revealed a large-scale scheme to relabel oils from other Mediterranean nations as Italian.[14] In April 2008, another operation impounded seven olive oil plants and arrested 40 people in nine provinces of northern and southern Italy for adding chlorophyll to sunflower and soybean oil and selling it as extra virgin olive oil, both in Italy and abroad. 25,000 liters of the fake oil were seized and prevented from being exported.[15]

On December 22, 2008, the Guardia Civil in La Rioja (Spain) warned about the possible sale of adulterated olive oil in the area. This warning came after 550 litres of oil was found in a large container labelled "Astispumante 1510" in Rincón de Soto and after the theft of 1,750 litres of oil was reported in the area on December 18, 2008.[16]

In the first week of March 2010, researchers at the University of California at Davis' Olive Center purchased three bottles each of 14 imported olive oils and five California oils at retail stores in three different regions of California (Sacramento County, San Francisco Bay Area, and Los Angeles County). All of the oils were labeled "extra-virgin olive oil." Samples were shipped to the Australian Oils Research Laboratory in Wagga Wagga, New South Wales, and were analyzed by their laboratory (which is recognized by the IOC to provide chemical analysis of olive oil) and tested by their sensory panel (which is recognized by the IOC as qualified to perform olive oil sensory analysis). Duplicate testing was performed at the UC Davis olive oil research project laboratories. Sixty-nine percent of the imported olive oils and 10% of the California oils failed to meet the IOC/USDA taste standards for extra-virgin olive oil. Samples that failed had a median of up to 3.5 IOC-standardized sensory defects (such as rancid, fusty, and musty). The standard IOC/USDA chemical tests only identified 31% of the failed oils as defective, primarily by exceeding the IOC/USDA limit for ultraviolet absorbance of late oxidation products (K232 and K268); two more recently introduced German chemical tests (now incorporated into the Australian extra-virgin standard) were each more than twice as effective at detection of defective oils.[17] A subsequent round of testing in 2011 found similar results.[18] The UC Davis report was contested by the North American Olive Oil Association on the grounds that UC Davis has a conflict of interest due to the fact that they market their own olive oil and have an interest in promoting olive oil from California. The IOC stated that the study contained "[an] evident undercurrent of aggressive, inexplicable criticism of imported olive oil quality".[19]

On March 15, 2011, the Florence, Italy prosecutor’s office, working in conjunction with the forestry department, indicted two managers and an officer of Carapelli, one of the brands of the Spanish company Grupo SOS (which recently changed its name to Deoleo) and Pietro Coricelli. The charges involved falsified documents and food fraud. Carapelli lawyer Neri Pinucci said the company was not worried about the charges and that "the case is based on an irregularity in the documents".[20] However, in June 2017 the Italian Antitrust Authority (Autorità Garante della Concorrenza e del Mercato), found them guilty of unfair business practices regarding their olive oil brands and imposed fines on them and the discount supermarket chain Lidl, amounting to nearly €1 million. According to independent testing, oil from the brands Carapelli, Bertolli, Sasso, Primadonna and Coricelli labelled as "extra virgin" was in fact only "virgin." [21]

Standards Australia has adopted a code of practice for the testing of olive oils; however, while allowing oils to be certified as being genuine extra-virgin, the code regarding labeling is voluntary. The Australian Olive Association (AOA) is campaigning to have the Australian Competition and Consumer Commission force supermarkets to adhere to the code. After testing by AOA in 2012, every imported brand of extra-virgin olive oil fell below the standard that would be required for AOA certification.[6]

Adulterated oil is usually no more serious than passing off inferior, but safe, product as superior olive oil, but there are no guarantees. Almost 700 people died, it is believed, as a consequence of consuming rapeseed (canola) oil adulterated with aniline intended for use as an industrial lubricant, but sold in 1981 as olive oil in Spain (see toxic oil syndrome).[22]

Testing for purity[edit]

UV-Vis spectrscopy analysis of olive oil samples in an Italian laboratory

The detection of olive oil adulteration is often complicated with no single test that can accomplish the task. A battery of tests is employed to determine Olive oil authenticity and identity of the adulterant. Included in this testing regime is the determination of free acidity, peroxide value, UV extinction, fatty acid composition, sterol composition, triglyceride composition, wax content, steroidal hydrocarbons, and the Bellier test.[23] Methods employing chromatography/mass spectrometry and spectroscopy are often used to detect adulteration of olive oil [24][25][26] These methods can be very expensive, time consuming, and results are often incomplete, since components added/substituted can not always be identified.

Test results are measured against the International Olive Council trade standard to identify abnormalities. Each test provides key information which allows a decision to be made with respect to the grade of Olive oil and the identity of any adulterants. However, the International Olive Council does not test for deodorisation which makes up the bulk of fake extra-virgin oils. Soft column deodorisation is the process where steam is forced through a tank of inferior oil which removes all taste, colour and nutrients, colouring is then added before the tank is topped up with real extra-virgin oil to add flavour.[6]

A test published in 1887 described the detection of olive oil adulterated with mineral oil by a simple titration of the carboxylic acid moieties present in natural vegetable oils. The procedure involved boiling 10 milliliters of olive oil with 40 milliliters of approximately 1 molar potassium hydroxide in 95% ethanol, adding water to 100 grams to dissolve the saponified lipids, and titrating against a normal sulfuric acid solution using phenolphthalein as a pH indicator dye. The base stock solution was titrated to neutralize an equal quantity of the acid, so without the presence of vegetable oil it would require 40 milliliters of acid to cause a color change, but in the pure oils tested (almond, benne, cottonseed, cod liver oil, linseed oil, and olive oil, only 6 milliliters were required. In accordance with this, olive oil adulterated with 10% mineral oil required 8 milliliters, and with 20% 11 milliliters. The adulterated oil tested in 1887 required 14 to 17 milliliters to neutralize, so it might have been 30-40% mineral oil.[27]

Olive oil DNA analysis methods, based on the use of PCR (e.g. DNA fingerprinting), have been use for determining counterfeit. These techniques requires extensive sample preparation, which needs specific optimization to ensure extraction of sufficient DNA, and that PCR inhibitors are not affecting the analysis. To date, there is no DNA extraction method applicable to any sample.[28]

Another method against olive oil adulteration, making use of articial, sub-micrometer-sized DNA barcodes, has recently been developed. The barcodes consist of magnetically recoverable silica particles containing synthetic DNA sequences, which are added to the oil in very small amount (down to 1 ppb) and can be retrieved at any time for authenticity test by PCR/sequencing. The advantages of this method, compared to conventional techniques, are that it is low-cost, sample preparation is minimal and requires minute volumes, and the method is universal, since it can be applied to any oil type/sample without specific procedure optimization.[29][30][31]

Certifications of Quality[edit]

The North American Olive Oil Association offers a Quality Seal Program to guarantee authenticity of olive oil. Members of the association agree to have their oils tested twice a year to ensure the oil meets or exceeds the International Olive Council (IOC) standards. The testing includes both sensory (taste/smell) and chemical tests for purity. Samples are purchased from the retail marketplace to ensure that the products tested are the same as the ones purchased by consumers. The test samples are not selected and submitted by olive oil producers. Brands pay for the testing through a yearly licensing fee.[32]

The California Olive Oil Council tests samples of olive oil submitted by producers for extra virgin quality. The samples are provided by the producers. The testing is primarily sensory with some chemical tests.[33]

The Extra Virgin Alliance offers the EVA Mark of Quality and Authenticity. Auditors purchase oils from retail sources and test the oils against standards set by the EVA. The testing consists of sensory analysis and focuses on detection of defects.

Simple home tests[edit]


There is a persistent mistaken belief that when genuine olive oil (or, in some versions, extra virgin olive oil specifically) is refrigerated, it will solidify or become much more viscous. This mistaken belief is based on the fact that olive oil is composed mainly of the monounsaturated fat oleic acid, and pure oleic acid (triolein) has a melting point of 5˚C, which is slightly above the high end of proper refrigerator temperature. Thus, if olive oil were pure triolein, it would solidify in a properly set refrigerator. However, olive oil is a complex mixture with significant variability in its fatty acid structure, and can be anywhere from 55% to 83% oleic acid,[34][35] with the remainder a mixture of polyunsaturated fat and saturated fat, as well as containing waxes, phytosterols, and other compounds that affect its melting temperature. Thus, in practice, many olive oils have significantly lower melting temperatures.[36][37][38] In fact, one might expect a refined seed oil with very high oleic acid content (such as high oleic sunflower oil) to be more likely to solidify in the refrigerator, based on their fatty acid composition and lack of minor compounds.[36]

This was demonstrated by a test by scientists at the Olive Center at the University of California, Davis. Researchers put seven samples of different oils into a refrigerator at 4.7˚C, including a premium extra-virgin olive oil; low-quality extra-virgin olive oil; a blend of virgin and refined olive oil; refined canola oil; refined safflower oil; a 50-50 blend of premium extra virgin olive oil with refined canola oil; and a 50-50 blend of premium extra virgin olive oil with refined safflower oil. When tested at intervals up to 180 hours, not one of the oils fully solidified, and one of the oils that solidified the most was the olive oil-canola oil mixture. Thus, the "Fridge Test" is not reliable for determining oil purity or quality.[39]


Pure olive oil should burn in an oil lamp. The ignition test however, like the refrigerator test, is not conclusive.


  1. ^ International Olive Council International Olive Council
  2. ^ "New U.S. Olive Oil Standards in Effect Today" Olive Oil Times
  3. ^ Durant, John. US Customs Department, Director Commercial Rulings Division Country of origin marking of imported olive oil; 19 CFR 134.46; "imported by" language 2000-09-05.
  4. ^ United States International Trade Commission Rulings See reference to HQ 560944 ruling of the Customs and Border Protection (CBP) on April 27, 1998, "blending of Spanish olive oil with Italian olive oil in Italy does not result in a substantial transformation of the Spanish product" 2006-02-28.
  5. ^ a b Olive Oil Fraud Rampant as Demand Skyrockets, National Public Radio, August 7, 2007
  6. ^ a b c Deborah Bogle. Oils ain't oils in the olive grove. The Advertiser May 12, 2012, pp. 11-14.
  7. ^ Mueller, Tom. Slippery Business The New Yorker. 2007-08-13.
  8. ^ EUbusiness.com Archived 2008-03-09 at the Wayback Machine
  9. ^ a b "Telegraph article". Archived from the original on March 11, 2008. Retrieved 2010-05-20.CS1 maint: BOT: original-url status unknown (link)
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  12. ^ "CFIA Oil Authenticity". Archived from the original on April 18, 2009. Retrieved 2009-03-01.CS1 maint: BOT: original-url status unknown (link)
  13. ^ Butler, Julie (October 4, 2013). "Scientists Pool Expertise in Fight Against Fake Olive Oils". Olive Oil Times. Retrieved 22 October 2013.
  14. ^ Moore, Malcolm (2008-03-05). "Italian police crack down on olive oil fraud". The Daily Telegraph. London. Retrieved 20 May 2010.
  15. ^ "Forty arrested in new 'fake' olive oil scam - Scotsman.com News". Archived from the original on January 9, 2009. Retrieved 2009-03-01.CS1 maint: BOT: original-url status unknown (link)
  16. ^ "Spain: Adulterated olive oil warning in La Roija". 2008-12-22. Retrieved 19 March 2014.
  17. ^ Frankel, E.N.; Mailer, R. J.; Wang, S. C.; Shoemaker, C. F.; Guinard, J.-X.; Flynn, J. D.; Sturzenberger, N. D. (July 2010). "Tests indicate that imported "extra virgin" olive oil often fails international and USDA standards" (PDF). Robert Mondavi Institute for Wine and Food Science/Olive Center, University of California at Davis. Retrieved 22 October 2013.
  18. ^ Frankel, E. N.; Mailer, R. J.; Wang, S. C.; Shoemaker, C. F.; Guinard, J.-X.; Flynn, J. D.; Sturzenberger, N. D. (April 2011). "Evaluation of Extra-Virgin Olive Oil Sold in California" (PDF). University of California at DavisOlive Center at the Robert Mondavi Institute. Retrieved 22 October 2013.
  19. ^ "UC Davis Study of Imported Olive Oils Flawed By Across-the-Board Bias". North American Olive Oil Association. Retrieved 10 July 2015.
  20. ^ Investigations Into Deodorized Olive Oils Olive Oil Times. 2011-03-29.
  21. ^ [1] Olive Oil Times. 2017-06-23.
  22. ^ Riding, Alan (1989-05-21). "Trial in Spain on Toxic Cooking Oil Ends in Uproar". The New York Times. H. J. Raymond & Co. Retrieved 16 November 2008.
  23. ^ Amr, Ayed S.; Abu-Al-Rub, Ala'A I. (1993). "Olive Oil Composition Evaluation". Journal of the Science of Food and Agriculture. 61 (4): 435–437. doi:10.1002/jsfa.2740610409.
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  25. ^ Andrikopoulos, K. N.; Giannakis, G. I.; Tzamtis, V. (2011). "Analysis of olive oil and seed oil triglycerides by capillary gas chromatograsphy as a tool for the detection of the adulteration of olive oil". Journal of Chromatographic Science. 39 (4): 137–145. doi:10.1093/chromsci/39.4.137.
  26. ^ Tay, A.; Singh, R. K.; Krishnan, S. S.; Gore, J. P. (2002). "Authentication of Olive Oil Adulterated with Vegetable Oils Using Fourier Transform Infrared Spectroscopy". LWT - Food Science and Technology. 35: 99–103. doi:10.1006/fstl.2001.0864.
  27. ^ Pharm. Zeitsch. f. Russl., 1887, 65 translated in Meeting, American Pharmaceutical Association (1887). "olive+oil"+"adulterated+with+mineral+oil" Proceedings of the American Pharmaceutical Association.
  28. ^ Woolfe, M.; Primrose, S. (2004). "Food Forensics: Using DNA Technology To Combat Misdescription and Fraud". Trends in Biotechnology. 22 (5): 222–226. doi:10.1016/j.tibtech.2004.03.010. PMID 15109807.
  29. ^ Puddu, M.; Paunescu, D.; Stark, W. J.; Grass, R. N. (2014). "Magnetically Recoverable, Thermostable, Hydrophobic DNA/Silica Encapsulates and Their Application as Invisible Oil Tags". ACS Nano. 8 (3): 2677–2685. doi:10.1021/nn4063853. PMID 24568212.
  30. ^ Venema, Liesbeth (2014-03-27). "Invisible barcodes". The Guardian.
  31. ^ "Scientists Hope To Stamp Out Counterfeit Olive Oil With a Dash of DNA".
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  33. ^ "Olive Oil Quality Seals? Take Your Pick". Olive Oil Times. 2013-06-13. Retrieved 10 July 2015.
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  35. ^ Beltran; et al. (2004). "Influence of Harvest Date and Crop Yield on the Fatty Acid Composition of Virgin Olive Oils from Cv. Picual" (PDF).
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Further reading[edit]

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