Detecting Adulteration in Olive Oil

There is no other food quite like olive oil. There is also, apparently, no better motivator throughout history than the chance to make a quick buck. In the case of extra virgin olive oil, it has been prized throughout the ages for possessing unique qualities that delight the senses based on its nutritional, medicinal, cosmetic, and even ceremonial value. As a result, it is one of the most expensive—and also one of the most adulterated—food products in recorded history.

The earliest written mention of olive oil, on cuneiform tablets at Ebla, Syria, in the 24th century B.C., for instance, describes royal inspectors visiting olive oil crush mills in search of fraudulent practices. The Romans also developed strict regulations concerning olive oil. According to one industry resource into the history of olive oil, the Roman amphorae, or jars where the olive oil was kept, were carefully inscribed to show where the olive oil was produced, who produced it, when it was produced, and the quantity and quality of the product. In more recent times, modern science has extolled the virtues of extra virgin olive oil for its nutritional value, high antioxidant (including vitamin E) content, and its low saturated fat when compared to other oils. That, in turn, has led to a fraudulent business estimated by one law enforcement agency to rival the profits of cocaine without the high risk of being caught. Indeed, olive oil adulteration continues to attract global attention in a variety of media, from major news exposes and magazines to research labs and courtrooms. Researchers at the University of California, Davis, for instance, released the findings of a now famous 2010 study showing that more than two-thirds of the extra-virgin olive oil sold in California is neither extra-virgin nor in some cases even olive oil, as the real oil is often adulterated with cheaper, more available oils.

In still another recent venue reported by the Olive Oil Times in November 2013—in this instance a Washington D.C. superior courtroom—olive oil played a starring role in a suit filed and won by a consumer against a local grocer “for violating the D.C. Consumer Protection Procedures Act (CPPA) by selling Pompeian brand olive oil mislabeled as ‘extra-virgin.’” According to the UC Davis study mentioned earlier, the Pompeian brand of olive oil was already known to be adulterated and the consumer simply purchased the product in order to file the suit for some quick cash. As outrageous as that lawsuit and its outcome appears, such reports continue to sound a clarion call for the oil industry and government regulatory agencies to take the necessary steps to guarantee the safety and purity of extra-virgin olive oil. Equally important is the need to restore the sense of trust consumers have lost in big olive oil brands and retailers who continue to sell adulterated products at a huge cost to consumers in terms of both money and, at times, their health. In 1981, more than 600 people died because of adulterated olive oil that contained rapeseed oil and aniline, causing a huge scandal.

Even now, however, some authorities continue to rely on little more than their senses to detect olive oil adulteration. Unfortunately, taste or smell may not be sensitive enough to detect more sophisticated adulteration or mislabeling techniques that fraudsters employ. Less expensive oils such as corn, safflower, sunflower, and sesame oils that are commonly used to “cut” olive oil share many of the same properties, only in different proportions, and are impossible to detect without the use of modern analytical equipment. Unfortunately adulteration remains a big issue. As the olive oil industry looks for new ways to detect and deter criminal activity, increasingly they are looking to science for answers.

Science Supplants the Senses to Uncover Fake Olive Oil

It was not until the 1950s that science started to replace the senses in detecting non-authentic botanical oil substitutes in olive oil. Even with the development of modern gas chromatography/mass spectrometry (GC/MS), and high performance liquid chromatography (HPLC/MS), developing a quick, reliable, and cost-effective analytical approach to identifying the adulteration of olive oil with cheaper oil substitutes has proven to be both a slow and expensive process.