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Note: This article was AI-translated from Arabic and is currently under manual review. The author is not responsible for any translation errors. Please refer to the original Arabic text for the most accurate and authoritative information.
A test that shows a colour in some cases but may fail to detect other vegetable oils. So how do we avoid false reassurance?
You bought traditional ghee (samn baladi), ran a test you saw in a viral video, and the red ring did not appear. Does that mean the ghee is genuine? Not necessarily: it may be adulterated with an oil that does not respond to that test in the first place.
Simple food-adulteration tests circulate widely on social media, and some of them rest on sound chemical reactions. The problem begins when a test designed for one specific substance is turned into a blanket verdict on a product's purity. One of the most prominent examples is the sugar-and-hydrochloric-acid test circulated for detecting adulteration of traditional ghee.
The classic test known as the "Baudouin test" is based on a colour reaction with compounds characteristic of sesame oil, under specific chemical conditions. A modified version, known as the "Villavecchia test", uses furfural instead of sugar. Compounds such as sesamolin and sesamol contribute to this response.
Put simply: the test looks for a chemical marker linked to sesame oil, not for "the presence of any vegetable oil" at all.
Imagine three samples: pure ghee, ghee mixed with sesame oil, and ghee mixed with sunflower oil. The sesame sample may show the expected colour under the right test conditions, while neither the pure sample nor the sunflower-adulterated sample shows it.
Here lies the paradox: a genuine sample and an adulterated one can give the same negative result, because the test was never designed to detect sunflower oil. The same warning applies to other oils such as corn, soybean and palm oil: the absence of colour cannot be taken as proof that they were not added.
The Food Safety and Standards Authority of India (FSSAI), India's official food regulator, published a video explaining the sugar-and-hydrochloric-acid test for checking ghee, and it has since been widely shared. This test has a well-known context in India, where tests linked to sesame oil are used to indicate the presence of "Vanaspati", a manufactured vegetable fat to which Indian regulations require sesame to be added.
The experiment may therefore be useful for its specific purpose. But presenting it as a way to detect every form of ghee adulteration with vegetable oils is an unscientific generalisation. Criticising this generalisation does not cast doubt on the video or on the chemical reaction: the video comes from an official regulator and the reaction is sound. The objection is to stretching the conclusion beyond the limits of the test.
A qualitative test usually answers a narrow question: did a signal for the target compound appear or not? Quantitative analysis, by contrast, measures the amount of a specific substance using a calibrated method. Proving the authenticity of ghee requires a broader assessment that takes into account the type of milk fat, the substances that may have been added, and the limitations of the test method.
For this reason, the proportion of oil cannot be estimated from the intensity of the colour alone, nor can a negative result be turned into a "certificate of freedom from adulteration".
No single method works for all oils and all types of ghee. Qualified laboratories select tests according to the nature of the sample and the applicable standard. Among the most important tools are:
Important note: the ISO standard mentioned applies to a specific scope of milk fat, and its limits should not be applied automatically to buffalo ghee or blends without scientific verification of their suitability. Likewise, approved instruments and methods have detection limits and potential interferences, and there is no method that "never makes a mistake".
The red ring test may be useful when looking for markers of sesame oil under suitable conditions, but it does not necessarily detect adulteration with sunflower, corn, soybean or palm oil. Consequently, the absence of the red colour does not prove that traditional ghee is genuine.
Real science communication is not limited to showing an eye-catching experiment; it explains what the experiment proves and what it cannot prove. Do not let the result of a limited test become the basis for a purchase decision or a final verdict on a product's safety.