Why Ghee Adulteration is a Serious Problem
Ghee is one of the most widely consumed and most adulterated dairy products in India. Because of its premium price, long shelf life, and ubiquitous presence in Indian cooking and ritual, ghee is a frequent target for economically motivated adulteration — being mixed or substituted with cheaper fats and oils that closely mimic its colour, texture, and aroma. Reports from FSSAI surveillance, state food safety inspectors, and independent surveys repeatedly identify adulterated ghee as one of the most common food fraud categories in the country.
The most common adulterants used to dilute ghee include vanaspati (hydrogenated vegetable oil), palm oil, palm-kernel oil, refined cottonseed oil, animal body fat (tallow), and refined vegetable oil blends. Each of these has a different chemical and physical fingerprint — and one of the simplest, fastest, and most cost-effective methods of detecting these adulterations is the Butyro-Refractometer test, also known as the BR test or BR Reading.
This article explains what the BR test measures, how it works, what reading is acceptable for pure ghee, what readings indicate adulteration, the regulatory limits applicable in India, the step-by-step laboratory procedure, and the complementary tests we recommend for definitive ghee authentication.
What is a Butyro-Refractometer?
A Butyro-Refractometer is a specialised refractometer designed to measure the refractive index of fats and oils — particularly butter, ghee (clarified butter), and edible oils. It is named for “butyro,” referring to butterfat. Modern instruments typically display the refractive index value on a scale calibrated specifically for fats — known as the BR scale or BR Reading — rather than the generic refractive index scale used for other refractometers.
The Butyro-Refractometer is one of the oldest and simplest tools in food analysis. The test itself takes only a few minutes per sample, requires very little material, is non-destructive, and gives a defensible numeric result that can be compared against published standards. Despite the availability of more sophisticated chromatographic methods today, the BR test remains a standard component of dairy and edible-oil quality control in laboratories across India, including for FSSAI compliance and industry quality assurance.
How the BR Test Works — Refractive Index as a Purity Indicator
Every fat and oil bends light at a specific angle as it passes from one medium to another. This bending angle, the refractive index, is determined by the chemical composition of the fat — specifically the chain length of its fatty acids, the degree of unsaturation, and the presence of oxidised or modified fat fractions. Each pure fat (butterfat, palm oil, mustard oil, vanaspati, etc.) has a characteristic refractive index range, measured at a specific temperature.
When a sample is loaded onto the prism of a Butyro-Refractometer at the correct temperature, the instrument reads its refractive index and converts it to the BR scale value. Pure ghee, made entirely from cow or buffalo butterfat, falls within a known and narrow BR range. Any adulteration — whether with cheaper vegetable oil, vanaspati, or animal body fat — shifts the refractive index away from the pure butterfat range, producing a higher or lower BR reading than expected.
This is why the BR test is described as a screening test: it doesn’t tell you exactly what adulterant is present, but it gives a quick, reliable indication of whether the ghee deviates from pure butterfat composition.
BR Values for Pure Ghee
The Butyro-Refractometer reading for pure ghee is measured at 40 °C (the temperature at which ghee is fully melted and gives a stable, reproducible reading). Pure cow or buffalo ghee in India falls within the following well-established BR range:
| Sample | BR Reading at 40 °C | Source / Standard |
|---|---|---|
| Pure cow ghee | 40.0 – 43.0 | FSSAI / IS reference range |
| Pure buffalo ghee | 41.5 – 44.0 | FSSAI / IS reference range |
| Pure ghee (combined acceptable range) | 40.0 – 45.0 | Industry-accepted threshold for FSSAI screening |
| Vanaspati (hydrogenated vegetable oil) | ~46 and above | Adulterant indicator |
| Refined palm oil | ~46–48 | Adulterant indicator |
| Animal body fat (tallow) | Variable, often >45 | Adulterant indicator |
Regional variation: Pure ghee BR readings can vary slightly within the 40.0–45.0 range depending on the breed of cow or buffalo, the season, the diet (green fodder vs dry feed), and the geographic region of milk origin. This is why FSSAI and BIS reference ranges allow some breadth — a reading at 41.5 or 43.0 is well within the pure-ghee range and not by itself an indicator of adulteration.
Critical interpretation rule: A BR reading above approximately 45.0 is the classical indicator of adulteration with vegetable oil, vanaspati, or animal body fat. A reading below the pure-ghee range can indicate dilution with low-refractive-index materials or moisture/water contamination. In both cases, the deviating sample requires confirmatory chemical analysis.
What the BR Test Detects (and What It Doesn’t)
What the BR test reliably detects
- Vanaspati (hydrogenated vegetable oil) adulteration — vanaspati has a higher BR than pure ghee, so even moderate adulteration shifts the reading above 45.0.
- Refined palm oil and palm-kernel oil adulteration — both have higher BR readings than pure ghee.
- Animal body fat (tallow) adulteration — most animal body fats give readings above the pure-ghee range.
- Gross dilution with refined vegetable oil blends.
What the BR test does not detect on its own
- Specific identification of the adulterant — BR tells you something is wrong, but not exactly what. Chemical confirmation (chromatographic, colorimetric) is required.
- Adulteration with an oil that happens to have a similar BR to ghee — sophisticated adulterators sometimes blend oils to match the ghee BR range. This is why a panel of tests is always recommended for premium-grade certification.
- Presence of preservatives, colourants, or flavour enhancers — these are tested separately.
- Low-level adulteration below 5–10 percent in some cases — sensitivity depends on the specific oil/fat used.
For these reasons, the BR test is best used as a first-line screen. Samples that fail the BR test are confirmed by additional chemical and chromatographic tests; samples that pass the BR test but are intended for high-grade certification are typically subjected to a wider panel.
FSSAI and IS Regulatory Context
FSSAI has issued specific standards for ghee under the Food Safety and Standards (Food Products Standards and Food Additives) Regulations, 2011. These standards define ghee as the product obtained from cow or buffalo milk fat by clarification and specify acceptable limits for several physical and chemical parameters, including:
- BR Reading at 40 °C — within the pure ghee range
- Reichert Meissl (RM) value — minimum value that depends on cow or buffalo origin
- Polenske value — chemical fingerprint of butterfat
- Saponification value — within specified range
- Iodine value — upper limit
- Moisture content — maximum 0.3 %
- Free fatty acid (FFA) — within limit
- Antioxidant and additive limits — as permitted
A complete FSSAI-grade ghee analysis evaluates all these parameters together. The BR test alone cannot certify FSSAI compliance — it must be paired with at least the RM value and the saponification value for a defensible certificate.
The relevant Indian Standards include IS 3508 for ghee specifications and the BIS/AGMARK grade rules for ghee marketing — both of which incorporate the BR test alongside chemical assays.
How the BR Test is Performed in the Laboratory
A standard laboratory BR test for ghee follows this general procedure:
- Sample preparation — bring the ghee sample to a uniform liquid state by gentle warming. Mix thoroughly to homogenise. If the sample shows visible separation, layers of liquid and solid fat, or any moisture, note the observation.
- Calibration — calibrate the Butyro-Refractometer with a reference standard (typically distilled water or a certified reference oil) and confirm the instrument is reading correctly. The instrument should be at thermal equilibrium with its temperature-controlled water bath.
- Temperature stabilisation — set the instrument’s temperature bath to 40 °C and allow it to stabilise. This temperature is critical — readings taken at incorrect temperatures are not comparable to reference standards.
- Sample loading — using a clean dropper or pipette, place 2–3 drops of the molten ghee onto the prism. Ensure the prism surface is clean and dry before loading.
- Reading — close the prism cover, allow 30–60 seconds for thermal equilibrium, then read the BR scale value at the boundary line between light and dark fields. Record the value.
- Replication — perform the test at least in duplicate (preferably triplicate). Readings should agree within ±0.1 BR units.
- Interpretation — compare the average reading against the FSSAI / IS reference range for pure ghee. Flag any sample reading above 45.0 or below the pure-ghee range for confirmatory analysis.
- Cleaning — clean the prism with a soft tissue and laboratory-grade solvent (typically diethyl ether or hexane) between samples to avoid carryover.
The whole test, including replication, takes about 10–15 minutes per sample once the instrument is calibrated and the temperature is stable — making the BR test one of the fastest and most cost-effective screening methods available in food adulteration analysis.
Recommended Confirmatory Tests for Ghee Adulteration
When a ghee sample fails the BR test or when high-grade certification is required, we routinely combine the BR Reading with one or more of the following:
- Reichert Meissl (RM) value — measures the volatile water-soluble fatty acids that are characteristic of butterfat. A low RM value alongside a high BR reading is strong evidence of adulteration.
- Polenske value — measures volatile water-insoluble fatty acids. Together with RM, it establishes a butterfat fingerprint.
- Iodine value — quantifies unsaturation. Vegetable-oil adulteration tends to increase the iodine value of ghee.
- Saponification value — overall fatty acid composition indicator.
- Free fatty acid (FFA) — indicator of rancidity or processing quality.
- Sterol composition by GC-MS — identifies plant sterols (sitosterol, stigmasterol, campesterol) that should not be present in pure butterfat. Highly diagnostic for vegetable-oil adulteration.
- Triglyceride profile by GC-FID or HPLC — provides a detailed fatty-acid fingerprint and is highly specific for adulterant identification.
- DSC (differential scanning calorimetry) — thermal fingerprinting of fats; used in research-grade adulteration studies.
- Tests for vanaspati specifically — including the Bauduin test and FSSAI’s prescribed colour test for vanaspati in ghee.
A typical “ghee authentication panel” includes BR, RM, Polenske, iodine value, saponification value, FFA, and sterol composition. This combination definitively distinguishes pure ghee from any of the common adulterants.
Why This Matters for Manufacturers, Retailers, and Consumers
For ghee manufacturers and dairy brands, regular BR testing during incoming raw-material checks and outgoing finished-product release is essential. A single batch of contaminated ghee — whether from supplier fraud or process contamination — can trigger FSSAI improvement notices, retail delistings, social-media reputation damage, and consumer health complaints. Routine BR testing is one of the lowest-cost, highest-leverage quality controls a ghee plant can run.
For retailers and packaged-food brands that source ghee from third-party suppliers, lot-by-lot independent testing protects against adulteration risk in the supply chain. Many premium retail chains and export buyers now require third-party BR + RM + sterol certificates for every shipment.
For consumers and households purchasing ghee, the BR test is one of the standard parameters in any FSSAI-licensed laboratory’s “ghee panel”. Independent testing is inexpensive and provides peace of mind for ghee bought in bulk, from unbranded suppliers, or for ritual or religious use.
Conclusion — A Simple Test with Significant Power
The Butyro-Refractometer test is one of the clearest examples of how a simple, well-established analytical principle — the refractive index of fat — can be applied as a fast and powerful tool against food adulteration. Within minutes, and at a fraction of the cost of advanced chromatographic analysis, the BR test screens for the most common forms of ghee adulteration with high reliability.
It is not, on its own, a complete certification of ghee purity — that requires a wider panel of chemical and chromatographic tests. But for routine quality control, supplier verification, and FSSAI compliance screening, the BR test remains a foundational, indispensable method in any dairy or edible-oil quality programme.
Auriga Research operates NABL-accredited food testing laboratories across India offering Butyro-Refractometer testing as part of comprehensive ghee authentication panels — including RM value, Polenske value, iodine value, saponification value, FFA, sterol composition by GC-MS, and triglyceride profiling. Reports are issued under our NABL ISO/IEC 17025:2017 accreditation and accepted by FSSAI, BIS, and major retail buyers.
Need to verify the purity of your ghee or detect adulteration in dairy products? Request a free quote or explore our food testing services.
Dr. Saurabh Arora
Auriga Research is India's largest NABL-accredited testing network with laboratories in Delhi, Manesar, Bangalore, Baddi, and Bahadurgarh. Our team of scientists delivers accurate, regulatory-accepted results across pharmaceutical, food, water, environmental, and specialised testing.
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