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 most frequent type of adulteration is that oil of lower quality is mixed into olive oil.
Background of regulation The EU regulates the use of different protected designation of origin labels for olive oils. The International Olive Council (IOC) is an intergovernmental organization with 16 member states plus the European Union based in Madrid, Spain. 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. 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.
United States 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. In October 2011, the United States adopted new olive oil standards, revising those that had been in place since 1948, which affected importers and domestic growers and producers by ensuring conformity with the benchmarks commonly accepted in the U.S. and abroad. As of 1998, US Customs regulations on "country of origin" have stated 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. 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. In the United States, the Food & Drug Administration (FDA) does not routinely test imported olive oil for adulteration.
Testing for purity
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, Ultraviolet light extinction, fatty acid composition, sterol composition, triglyceride composition, wax content, steroidal hydrocarbons, and the Bellier test. Methods employing chromatography/mass spectrometry and spectroscopy are also used to detect adulteration of olive oil 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. 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. DNA analysis methods, based on the use of polymerase chain reaction (PCR) (e.g. DNA fingerprinting), have also been used. These techniques require 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. In 2014, an "invisible oil tag" using artificial, sub-micrometer-sized DNA barcodes was suggested by researchers from ETH Zurich. The barcodes consist of magnetically recoverable silica particles containing synthetic DNA sequences, which are added to the oil in a 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 its low-cost, minimal sample preparation and minute volumes, and its universalness, since it can be applied to any oil type/sample.
… excerpt ends here. Continue reading the full article.
