The seizure, at the beginning of March, of around 10 thousand liters of cooking oil sold as olive oil once again exposed a problem that may go unnoticed by ordinary consumers: the difficulty in distinguishing a genuine product from an adulterated one simply by direct observation. According to ASAE, it was precisely for this reason that samples were collected for laboratory and sensory analysis, in order to confirm the composition of the product and assess possible risks to public health.
The operation was conducted by the Food and Economic Security Authority on the outskirts of Moimenta da Beira, in the district of Viseu, and resulted in the constitution of three defendants. According to the news, the product was being misleadingly marketed on social media as “virgin olive oil”.
According to the publication, in addition to around 10,000 liters of cooking oil, thousands of labels and packaging material marked “virgin olive oil”, 340 liters of liqueur wine without labels and without legal registration, four firearms and ammunition, and around R$200,000 in cash were also seized.
A problem that is not isolated
This type of fraud has been gaining expression, especially during periods when the price of olive oil increases. In its review of the sector’s inspection in 2024, ASAE itself says that, with the rise in prices, olive oil was the target of numerous fraud attempts, namely by mixing it with other vegetable oils, which led to a reinforcement of controls. 
In Portugal, the legal framework is also clear. According to the DGAV and Decree-Law No. 76/2010, the production of mixtures of olive oil and other vegetable oils for internal consumption is prohibited, and the labeling cannot mislead the consumer regarding the nature of the product. 
The aroma may raise suspicions, but it does not prove fraud
There are signals that may deserve attention, but none of them replace technical analysis. According to DECO PROteste and the International Olive Oil Council, extra virgin olive oil must be fruity and cannot present sensory defects. Therefore, an aroma that is not very fruity, too neutral or has unpleasant notes can raise doubts about the quality or category of the product. Still, this is not enough, in itself, to confirm adulteration. 
One of the most repeated pieces of advice on consumer items is the so-called freezer test. But this method is not reliable. DECO points out that olive oil can become cloudy and even solidify at low temperatures, and the UC Davis Olive Center concluded that this test is unreliable in detecting the purity or quality of the oil. In terms of authenticity, the rule remains different: only chemical and organoleptic analyzes allow the product to be correctly classified. 
Too low price should be a warning sign
Price remains one of the simplest signals to take into account. ASAE warned consumers about olive oil offers at lower than expected prices, precisely because this type of promotion can mask the sale of other oleic substances as if they were olive oil. The warning gains even more weight when the sale is made through informal channels or social media. 
Labels make a difference
The information on the label also helps. According to the General Directorate of Food and Veterinary (DGAV) and ASAE, the sales name must be clearly indicated and cannot be replaced by a fancy brand. In the case of extra virgin olive oil and virgin olive oil, the origin is mandatory. It must also include details such as the net quantity, the date of minimum durability, the nutritional declaration, the name and address of the responsible operator, the batch and the special conservation conditions.
If the product is a mixture of vegetable oils and olive oil, the labeling also has its own rules and must say so clearly. DGAV also reminds us that label mentions cannot give the product properties that it does not possess nor suggest special characteristics that are common to most olive oils. 
Neither color nor acidity solve the doubt
Looks can be deceiving. DECO emphasizes that the color does not reveal the quality of the oil, and that is why tasters use indigo blue glasses so that the sensory evaluation is not influenced by this factor. Also, acidity, often highlighted in marketing campaigns, should not be read in isolation: the European regulation itself says that its mention alone is misleading, as it suggests an absolute scale of quality that does not exist. 
More than a question of price
Olive oil fraud has been, from the beginning, an economic and consumer information problem. But it is not advisable to turn this idea into a false guarantee of safety: ASAE took samples in this case to confirm the composition and assess possible risks to public health, and the European Court of Auditors has already warned that adulteration in the olive oil sector may also entail health risks in certain cases. 
Pay attention when purchasing
ASAE’s operation reinforces a simple idea: consumers can recognize warning signs, but cannot confidently confirm on their own that an olive oil is genuine. Being wary of very low prices, reading the label carefully, favoring regular sales channels and realizing that neither the color, the acidity nor the freezer resolve the issue are more useful steps than the homemade tricks that circulate online. 
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