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Head of the Oils and Fats Department at the Food Industries and Nutrition Research Institute, National Research Centre.
When the Refrigerator Becomes a Judge and the Flashlight a Lab!
Every time a refrigerator door is opened or a phone's flashlight is aimed at a bottle of olive oil, a public debate arises, conflating physical phenomena with quality standards. Consumer awareness has morphed into a "home court," delivering definitive verdicts of innocence or guilt based on the "freezing test" or "light reflection."
Not everything that freezes is pure, not everything that remains liquid is adulterated, and not all that glitters is gold.
Between a common myth and scientific fact, this article reveals why the 'refrigerator test' and flashlight beam are unreliable indicators of olive oil quality, and how we can protect our food awareness from hasty, unscientific judgments.
As a specialist who has spent decades delving into the intricacies of oils, fats, and their derivatives, I state unequivocally: Today, these home tests have become a weapon in the hands of fraudsters, not consumers! The freezing of oil or the scattering of light through it are natural physical phenomena. However, in this age of 'reverse engineering fraud,' they are neither decisive nor definitive indicators. Science is not measured by fleeting visual impressions, but by precise analytical methods and the unmistakable sterol fingerprint.
To understand what truly happens below freezing, we must view olive oil as a complex chemical 'mosaic,' composed of both 'liquid' and 'solid' (saturated) fatty acids.
According to the standards of the Codex Alimentarius Commission, pure olive oil naturally contains:
These percentages act as the 'freezing dynamo'; when the temperature drops, these molecules begin to clump together, creating a solid appearance. However, the deception lies in the fact that fraudsters (as seen in international 'Agromafia' scandals) have begun to create blends of cheap oils that possess the same saturated fatty acid 'profile.'
The question that arises is: Why is freezing no longer sufficient to prove purity?
The answer lies in the evolution of 'reverse engineering fraud' methods. Fraudsters (as major international scandals like the 'Agromafia' in Italy have revealed) have capitalized on the public's trust in the refrigerator test, creating 'tailor-made' adulterated oil:
The result: A liquid that freezes in your fridge just like genuine olive oil! The adulterated "Trojan horse" has safely passed through your fridge's gate, acquiring a false certificate of authenticity while having no connection to the olive tree.
Many resort to using their phone's flashlight, searching for a "red halo" or a specific green reflection, believing this to be the definitive fingerprint. Unfortunately, this falls under the category of "Chemical Visual Deception".
What you see is the interaction of light with pigments (chlorophyll); today's fraudsters add synthetic chlorophyll pigments or natural ones extracted from cheap plant leaves to sunflower oils, to give the exact same light response.
This test is misleading because color intensity varies depending on the olive cultivar (Chemlali, Picual, Koroneiki) and the ripeness of the fruit, which might cause an excellent extra virgin olive oil to "fail" the flashlight test, while an adulterated oil designed to manipulate light wavelengths succeeds!
Holding up a frozen bottle or shining a light on it in a promotional video is a form of advertising deception. This logic is akin to saying:
"Since this animal swims, it must be a duck!"... ignoring that crocodiles also swim!
The fact that adulterated and genuine oils share "physical phenomena" does not mean they are equal in value, and research from UC Davis has confirmed that "frozen and visually dazzling" samples failed chemical purity tests.
The arbiter is "The Accredited Laboratory" which doesn't look for color or freezing, but for the "chemical identity" that cannot be faked:
Prof. Dr. Adel Gabr We put science at the service of your health.
