The Rising Tide of Olive Oil Fraud
The olive oil industry is facing an unprecedented crisis of authenticity. The European Union’s data shows a dramatic jump from 15 suspected olive oil fraud cases in the first quarter of 2018 to 50 cases during the same period in 2024. This surge isn’t just a statistical blip – it represents billions in losses annually. Research shows adulteration costs approximately 8-12 billion euros per year.
What makes this particularly alarming is that these are only the incidents that have been raised by member states to the EU, with experts believing the true scale of fraud is considerably higher. The problem has reached such proportions that late last year, European authorities cracked down on counterfeit olive oil profiteers, charging 11 people with running a food fraud operation and seizing about 68,700 gallons of adulterated oil.
Understanding Why Quality Varies So Drastically
According to the Botanical Adulterants Prevention Program, adulteration of extra virgin olive oil is still listed among the most common food frauds worldwide. Olive oil’s distinctive sensory profile and its reputation as a healthy source of dietary fats has made it a premium product, and in turn a target for fraudsters. The variance in quality isn’t accidental – it’s often deliberate deception.
The most frequent type of adulteration is that oil of lower quality is mixed into olive oil. Sometimes the fraud goes much deeper. 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 was accused of coloring low-grade soy oil and canola oil with industrial chlorophyll, and flavoring it with beta-carotene.
The Truth Behind Storage and Transport Failures
Even legitimate olive oil can suffer quality degradation through improper handling. Light, oxygen, and heat are the main culprits that degrade the sensory qualities of extra virgin olive oil, and improper storage can quickly ruin its signature taste and smell. Research reveals startling facts about how quickly quality deteriorates under poor conditions.
Exposure of olive oil samples to light, high storage temperatures and large headspace volumes caused substantial deterioration in product quality parameters. The most pronounced effect was that of temperature and light while the smallest effect was that of headspace volume and packaging material permeability to oxygen. High temperatures can cut olive oil’s longevity by half, while light exposure can reduce antioxidant content by up to 30%.
How Modern Processing Methods Create Quality Differences
The way olive oil is extracted has evolved dramatically, yet many consumers remain confused about the terminology. The term first cold press originally referred to when, a half a century ago, hydraulic presses were used to make olive oil. After the first pressing of the olives, which yielded the best oil, the miller doused the “spent” olive paste with hot water and re-pressed it. That second pressing produced inferior oil. That description is outdated today, however.
Most commercial extra virgin olive oil around the globe is made through centrifugation – not pressing. For example: We crush our olives and process the resulting paste in a centrifuge to separate the oil from the water and sediment. Thanks to modern production systems, the current extraction process is superior in all aspects to the traditional one, which allows “cold extraction” extra virgin olive oils to have greater organoleptic properties than “first cold pressed” oils.
Temperature Control: The Make-or-Break Factor
Temperature during processing determines whether you get premium oil or degraded product. The temperature during processing can’t exceed 86 degrees Fahrenheit, note olive oil experts Paul Vossen and Alexandra Devarenne of the University of California Cooperative Extension. If the temperature range is too high during the crushing process, the quality of the oil will suffer.
Australian olive oil expert Richard Gawel notes 28 to 30 degrees Celsius (82.4 to 86 Fahrenheit) is “ideal, with 32 C (89.6 F) being the upper end of the temperature range used by most producers who are interested in quality.” Lower quality oils – those that aren’t classified as extra virgin – typically are crushed multiple times and at higher temperatures to extract more oil from the fruit. The resulting oil is much lower in quality.
Why Container Material Dramatically Affects Quality
The type of container you use for storing olive oil greatly impacts its flavor and aroma over time. The material choice isn’t just about aesthetics – it’s about preserving or destroying the oil’s integrity. Plastic allows oxidation, leaches chemicals, and speeds up oil degradation.
Results showed that the best packaging material for olive oil packaging was glass followed by PET. PP proved to be unsuitable for such an application. Even more revealing, dark glass extends shelf life to 12-18 months, while plastic reduces it to just 3-6 months. Although glass represents a good barrier against moisture and gases, transparent bottles can lead to photo-oxidation, not avoiding exposure to light.
Detection Methods That Expose Hidden Problems
Modern science has developed sophisticated ways to catch fraud and quality issues. Technology Networks attended RAFA 2024 to hear about one promising technique, direct analysis in real time–high-resolution mass spectrometry (DART-HRMS), from Sofia K. Drakopoulou, a postdoctoral researcher at the National and Kapodistrian University of Athens. These samples were then analyzed by the DART-HRMS technique, which managed to give an accurate snapshot of the oils’ contents.
The precision is remarkable. We have conducted an adulteration experiment using nine different adulteration levels in all categories starting from 50 down to 1% of adulteration level. And we managed to detect down to 1% of adulteration in the case of vegetable oils. 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. 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.
How Light Exposure Destroys Premium Oil
Light is one of olive oil’s most destructive enemies, yet many producers still use clear bottles. The results showed that the oils stored in the light had significantly lower tocopherol, carotenoid and chlorophyll contents than did the same oils kept in the dark. Moreover, the oils stored in the dark mainly contained primary oxidation products, while the oils kept in the light contained secondary oxidation products as confirmed by the K 270 values which exceeded the legal limits even after purification by means of alumina. Overall, the results obtained showed that the shelf life of the oils exposed to light is shorter than that of oils kept in the dark, and that after only 2 months of exposure to light the oils examined could no longer be considered as extra virgin.
The significant decreasing trend was observed in white light and oven treated samples, while UV and sunlight treatments were also effective and showed oxidation of different olive oils. Oxidation parameters like free acidity, peroxide and anisidine values represented similar trend in the deterioration of olive oils. Low temperature storage was found beneficial to olive oil; however, UV and sunlight are effective for depletion of carotenoids and consequent photo-oxidation.
The Reality Behind “Extra Virgin” Claims
The term “extra virgin” should guarantee quality, but enforcement varies wildly across regions. A 2020 study found that 69% of imported oils and 10% of California EVOO failed sensory standards. To ensure quality, the California Olive Oil Council (COOC) mandates evaluations by 8–12 certified tasters, requiring an 80% consensus on quality.
However, there’s controversy about these findings. The FDA tested 88 extra virgin olive oil samples directly off the shelves of Washington, D.C.-area retail outlets and found no confirmed adulteration in any of the samples tested. The discrepancy highlights how quality assessment methods can vary dramatically. The FDA’s findings mirror the results of the NAOOA’s own robust monitoring efforts, which sampled an average of nearly 200 olive oils annually directly from retail shelves for 20 years. The cumulative results of the NAOOA’s testing support the finding that 98 percent of olive oil sold in U.S. retail outlets is authentic.
Why Harvest Timing Creates Quality Gaps
Various studies have shown that the pool of phenolic compounds is greatly affected by the time of harvest. Specifically, the later the harvesting and extraction take place, the smaller the polyphenol pool. As a result, it doesn’t make much sense to ask for cold-extracted EVOO if it is not early harvest. Early harvest olive oil is typically extracted from late September to early November. After this point, the olive fruit is turning dark and polyphenols decrease in quantity.
The timing factor creates a natural hierarchy in quality that many consumers don’t understand. Timing is critical too – olives should be processed within 24 hours of harvest, with minimal exposure to oxygen and strict temperature control. Research shows that oils high in antioxidants are better at resisting oxidation, which helps them maintain their flavor for longer periods.
