Informed Consumer
Information for consumers
Conservation and shelf life of Extra Virgin Olive Oil
Few people know that true extra virgin olive oil is a living product that changes over time. As soon as it is produced, it is not yet ready for consumption: its maturity will develop after one or more months, depending on the olive variety (for example, Coratina oil, which is the richest in polyphenols, requires several months to reach its optimal maturity). On the other hand, excessive storage period will lead to a gradual process of oxidation and loss of its organoleptic properties. For these reasons, in order to enjoy its proper taste on the palate and benefit from all its countless health advantages, extra virgin olive oil should be consumed after a few months and, in any case, within 18 months from its production.
For olive oil, we do not talk about an expiration date, but rather a minimum shelf life, which is the minimum period within which the product retains its properties. Beyond this time, it will gradually lose most of its characteristics (such as aroma, flavour, colour, etc.). It will still be completely safe to consume without harming our health, but its benefits will progressively decrease.
Unfortunately, the legislation stipulates that the minimum conservation time starts from the moment of bottling rather than from the moment of production: this allows bottlers and traders to buy oil at any time after production, even gaining several months (if it is even stated on the label), all to the detriment of the unaware consumers who do not know that they are buying oil that may have already lost part, or a good part, of its organoleptic characteristics. This is the classic case of oils sold by the large-scale retail trade, with decidedly low prices.
Few labels show the minimum shelf life, and even fewer include the production year. Only extra virgin olive oil made entirely from that year’s harvest can feature this information. If the production year is not listed, the oil may come from different harvests, including oil from the previous year or even older.
The optimal storage of extra virgin olive oils requires dry, cool and dark places (which is why bottles of true extra virgin olive oil are always dark): practically the opposite of the shelves of large retailers. Different conditions inevitably accelerate the degradation process of the oil which, let us remember, is a living product.
The processing steps and cold extraction
01
Milling, through a mechanical action, physically crushes the olive drupe into a mixture called olive paste, consisting of a solid part (skins, pulp and stones) and a liquid part (water and oil).
02
Malaxation, through a slow and continuous mechanical movement of the olive paste combined with gentle heating, allows small droplets of water and oil to coalesce into larger ones. This is a very delicate phase that significantly influences the yield, quality, and flavour of the final extra virgin olive oil—either positively or negatively.
A crucial factor in this stage is the temperature applied to the olive paste. Raising the temperature above 27°C can increase the oil yield; however, it significantly reduces the fruity notes and compromises certain chemical and organoleptic properties, including the content of polyphenols. Conversely, maintaining a lower temperature—typically between 25°C and 27°C—preserves the most important chemical and sensory characteristics, resulting in a higher quality oil, although with a reduced yield.
This second approach, involving lower temperatures, qualifies the process as cold extraction (or cold pressing).
03
Extraction divides the olive paste into two parts: one only solid (pomace) and another only liquid (water and oil). Extraction can be carried out mainly by two methods: with hydraulic presses or with decanters. With the first method, the paste is layered on several discs stacked on top of each other which, by means of a hydraulic press, are slowly compressed so that only the liquid part comes out.
04
In the second method, the olive paste is continuously fed into a decanter, which, through high-speed centrifugal force, separates the liquid phase from the solid phase. Extraction using a decanter is increasingly replacing traditional hydraulic press systems, as the latter involves prolonged exposure of the paste to air—sometimes for more than 45 minutes—which triggers the oxidation process of the oil. This oxidation causes the oil to deteriorate over time, resulting in a loss of its original flavour and the development of the typical rancid note.
This issue is avoided with the decanter method, as the paste never comes into contact with air (oxygen); the entire extraction process takes place in a completely enclosed system.
Finally—and equally important—in this phase too, the processing temperature can be increased beyond the well-known 27°C threshold, with effects identical to those described for the malaxation stage.
05
The decantation process, through centrifugation, divides the liquid obtained from the extraction into vegetation water and, ultimately, oil.
Raising the temperature during processing triggers a progressive deterioration of the oil’s chemical properties (such as polyphenol content, peroxide values, and free acidity) as well as its organoleptic characteristics (loss of flavour, fruity notes, and vegetal aromas).
In conclusion, hot extraction is more advantageous for the oil producer because it allows for a higher yield of oil, albeit at the expense of its quality. For the consumer, however, cold extraction is definitely the better option, as it enhances the true virtues of extra virgin olive oil, preserving its original flavour, organoleptic properties, and most importantly, its health benefits for the body.
Food Fraud, Adulteration, and Exploitation in Olive Oil
Unfortunately, it is becoming increasingly common to hear about fraud and adulteration in extra virgin olive oil (EVOO).
Too often, supermarket shelves are stocked with EVOO at remarkably low prices, leading the consumer, unaware of the actual content, to be dazzled by the economic appeal. However, they do not realize that they are purchasing (and unfortunately consuming) a product in which all the characteristics that typically make extra virgin olive oil healthy have been largely lost.
Among the most common forms of fraud and adulteration, particularly perpetrated by wholesalers and bottlers, is the mixing of seed oil with olive oil, passing it off as EVOO. At times, the Fraud Prevention Commission has found that seed oil was artificially coloured with chlorophyll and flavoured with beta-carotene to deceive consumers into thinking it was extra virgin olive oil.
Moreover, an increasing number of cases have been confirmed where oils are marketed as extra virgin olive oil when they actually contain lampante oil (which is not suitable for fresh consumption and is only intended for industrial use), with just small amounts of genuine EVOO, added solely to meet the required chemical parameters that characterize high-quality oils.
Another frequent occurrence is the blending of oils from multiple harvest years without properly informing the consumer. Long-term storage leads to a gradual oxidation process, resulting in the loss of both chemical and organoleptic characteristics of the oils.
Another issue that characterizes low-priced oils is exploitation. This often stems from the excessive power held by Large-Scale Distribution Chains (supermarkets), which impose on their suppliers the need to sell products at extremely low prices or force unreasonable promotions (such as “buy 2, get 3” offers), all aimed at reducing the final price. To meet these demands, the farmer is often forced to lower the quality of olive cultivation, the olive miller (or olive mill) is pressured to reduce quality at one or more (or sometimes all) stages of the oil production process, and the bottler is forced to compromise on quality, even resorting to adulteration. As a result, these products are of poor quality and pose a significant food safety risk.
It should also be noted that, at times, some of these actors voluntarily engage in these unethical practices without any direct pressure from supermarkets. What has been described so far addresses the qualitative and quantitative aspects of the issue, but there is also an ethical dimension: a low selling price means not adequately compensating the various stakeholders in the supply chain, not only those mentioned above. For instance (though not the only example), the farmer, in an attempt to cut production costs, exploits labour by paying workers below legal standards. The same applies to the miller and, to some extent, even the bottler.
Unfortunately, this is difficult for the consumer to detect, as they obviously cannot know what is inside the bottle of oil they are purchasing, nor the behind-the-scenes processes that led to the commercialization of a product with such an apparently “convenient” price. However, if properly informed, the consumer can make an informed choice between an economical product, which is absolutely not of quality (and is unethical), and a product that may cost only a few extra cents per day, but is truly beneficial for their health and their family’s, while respecting all the actors in the supply chain.
