Olive Oil: Why Prices Have Increased and What Research Can Do

We are in the time of year when the consumption of extra virgin olive oil (EVO) – an essential element of the Mediterranean Diet – should be at its peak. In the summer, people tend to consume more foods like salads and fresh vegetables, as well as a variety of cold dishes that are more appetizing when dressed with good extra virgin olive oil, also known as EVO. Yet, likely, even in these summer months, many consumers will use this condiment more sparingly, trying to make the bottles last as long as possible. The reason is well known: in recent years, there has been a significant increase in olive oil prices, especially EVO. According to Eurostat data, in January 2024, the price of oil in the EU was on average 50% higher than in January 2023 (Italian prices are slightly below this threshold). But what has caused this increase? And what could scientific research do to protect the quality of this very important food?

As Antonia Lai, a researcher at ENEA and head of the spectroscopy team for the METROFOOD-IT project, explains, “Olive Oil is produced not only in Italy but throughout the Mediterranean area, including Greece, Turkey, and North Africa. Spain is the largest producer, covering 63% of the entire European production, with a significant extent of olive oil cultivations especially in the vast Andalusian territory, the nerve center of Spanish olive production. However, it should be emphasized that the oil produced in Italy represents an excellence of Italian agri-food production and has particularly high-quality characteristics compared to the entire production of Mediterranean countries. The Italian olive sector benefits from exceptional biodiversity: in our country, there are more than 500 cultivars, distributed throughout the national territory.

This characteristic, along with the numerous cultivation areas distributed across the territory, allows for the production of a wide variety of EVO oil with different characteristics regarding aroma and the so-called 'intensity,' ensuring – precisely – a product of excellence. A significant problem related to EVO oil production, especially in recent years, is the climate change we are witnessing, which has led to a reduction in harvests with a consequent decrease in production volumes throughout the Mediterranean area, especially in Spain, whose economic weight is crucial in the market. Ultimately, this price increase is mainly due to climate change, for which, for example, we are witnessing episodes of extreme heat with periods of drought alternating with heavy rains, which can damage the blooms and fruits. Additionally, we have seen phenomena related to the spread of alien pathogens such as Xylella Fastidiosa, which have recently significantly affected olive groves in large areas of Italy due to rising temperatures, particularly in Puglia.”

In this context, it is almost impossible to combine quality with a low price level. “Extra virgin olive oil must meet various parameters within very narrow thresholds: it must have an acidity of less than 0.8% and must be obtained by mechanical means only from healthy, fresh olives with the right degree of ripeness. All this, of course, has a cost; to obtain 1 liter of EVO oil, about 5 to 7 kg of olives are needed. Therefore, it is practically impossible to buy quality oil for just a few euros per liter. Moreover, it has long been proven that extra virgin olive oil is cholesterol-free, low in saturated fats, and rich in antioxidants such as polyphenols and vitamin E, which help protect cells from damage caused by free radicals, which are responsible for cellular aging.” Consumers do not always immediately grasp these characteristics, so much so that the bitter taste of the oil (which is actually a sign of these positive components) is often interpreted negatively.

In the future, applied research could help increase awareness: “Consumers could have the opportunity to evaluate the quality of the olive oil before purchasing through portable sensors, for example, made with innovative technologies based on Infrared Spectroscopy, capable of detecting 'in real time' the presence of polyphenols, vitamin E, and various other antioxidant compounds, or even revealing any product alterations.” Agricultural producers in the sector, on the other hand, would need input from the research world, for example, to improve olive cultivation. But also to ensure greater product traceability and, consequently, to defend the quality of our product by adding further value to productions.”

ENEA researchers working within METROFOOD-IT have been working on these issues for several years. For example, three years ago, a methodology was developed to verify the authenticity of extra virgin oil through the traceability of the geographical origin of olives based on the elemental profile. The study (details here: https://www.media.enea.it/comunicati-e-news/archivio-anni/anno-2022/agricoltura-olio-extravergine-enea-studia-la-tracciabilita-delle-olive.html ) was conducted on thirty-seven samples of olives and leaves from eleven olive species, focusing on the analysis of the chemical elements present, and the results were published in the open-source journal 'Foods.' For this study, the ENEA team used highly sensitive analysis techniques that allow the quantification of even elements present in very low concentrations. “Our work was carried out on olive leaves and drupes (olives) and not on the finished product. The study was important because it also allowed us to demonstrate that, thanks to the use of non-destructive spectroscopic techniques – which complement those that allow quantitative but destructive analysis – it is possible to identify the geographical origin, distinguishing different cultivation areas. In other words, our rapid analysis based on Laser Photoacoustic Spectroscopy (LPAS), along with multivariate analysis, allowed us to screen multiple samples, confirming the same result obtained with more classical techniques,” concludes Antonia Lai. This result opens the door to the possibility of identifying the geographical origin of olive products more quickly and accurately and 'uncovering' any fraud, especially among PDO products, even in the finished product.

Another important research work is underway within the Agritech project and with the help of METROFOOD-IT's analytical facilities. In particular, the activities carried out on EVO oil concern the development of analytical methodologies for quality, safety, authenticity, and the determination of the geographical origin of olive oil samples from Italy, Slovenia, Croatia, and Greece. As researcher Emilia Pucci explains, “Specifically, for the evaluation of Safety & Geographical Origin, a method has been developed and validated for the direct analysis of the multielemental profile of extra virgin olive oils from different geographical origins using ICP-AES. Determining the multielemental profile in extra virgin olive oil is one of the most challenging analytical tasks due to the high viscosity of the matrix, the high organic load that increases the so-called 'matrix effect,' and the possibility of interferences. Moreover, the extremely low concentration of elements makes it highly susceptible to contamination during sample pretreatment. This new method developed allows direct analysis of extra virgin olive oil without the need for mineralization or extraction.” The extra virgin olive oils were only diluted in low-viscosity solvents before direct aspiration. This 'dilute and shoot' approach offers the following advantages: less sample preparation and handling, less use of pretreatment equipment such as high-pressure microwave mineralizers (completely skipping this step), lower risk of sample handling errors, less sample contamination, less sample dilution, and reduced acid use.

For the evaluation of Quality & Authenticity, methods have also been developed for evaluating the spectrophotometric constants K232, K270, and DeltaK using UV-Vis. UV-Vis is a technique used to study the properties of materials and evaluate aspects related to authenticity, quality, and preservation status of agri-food matrices, such as olive oil. The values of K232, K270, and DeltaK provide information on the oil's ultraviolet light absorption and thus its organoleptic characteristics. Specifically, the K232 value must be 2.5 to consider an oil extra virgin; higher values may indicate that the oil was produced with overripe or poorly preserved olives or that it has been adulterated, i.e., mixed with lower-quality oil. The K270 and deltaK values, on the other hand, indicate the oil's oxidation state during storage. UV-Vis also allows color analysis by examining the chromatic character directly on the sample. Through special software, it is possible to construct a model that describes the range of colors perceptible to the human eye, reconstructing them in space, describing brightness, red-green, and yellow-blue components. Therefore, colorimetric analysis allows for the significant and quick differentiation of various olive oil samples, assessing appearance and quality in relation to their chromatic character.