How dairies detect adulteration
1. Sampling at the milk collection point
When a milk tanker or can arrives, the dairy takes a representative sample before unloading. This sample is used for quality testing.
2. Routine quality tests
Every batch is typically checked for:
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Fat percentage
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SNF (Solids-Not-Fat)
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Density (Lactometer reading)
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Acidity
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Temperature
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Organoleptic properties (appearance, smell)
These tests can indicate if something is unusual but may not identify a specific adulterant.
3. Rapid adulteration tests
Many dairies use rapid test kits to detect common adulterants such as:
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Added water
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Urea
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Starch
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Sugar
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Salt
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Detergent
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Neutralizers
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Hydrogen peroxide
These tests are designed to detect adulterants even at relatively low concentrations, depending on the sensitivity of the method.
4. Advanced laboratory testing
If adulteration is suspected, laboratories may use instruments such as:
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FTIR (Fourier Transform Infrared Spectroscopy)
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HPLC (High-Performance Liquid Chromatography)
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GC (Gas Chromatography)
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GC-MS (Gas Chromatography-Mass Spectrometry)
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LC-MS/MS (Liquid Chromatography-Mass Spectrometry)
These methods can detect and measure specific substances at very low concentrations—sometimes in parts per million (ppm) or even lower, depending on the analyte and method.
Can 20 ml in 200 liters be detected?
It depends on what was added.
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20 ml of water in 200 liters is only 0.01% of the total volume and is unlikely to be detectable with routine quality tests because it causes almost no measurable change.
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20 ml of a chemical adulterant (such as detergent, formalin, or another prohibited substance) may be detectable if the laboratory method used is sensitive enough for that specific chemical.
So the answer is not simply about the volume—it's about the type of adulterant and the detection limit of the test.
Example
| Adulterant | Typical Detection Method | Can 20 ml in 200 L Be Detected? |
|---|---|---|
| Water | Lactometer, cryoscope | Usually not at such a tiny addition |
| Urea | Chemical test kit, laboratory analysis | Possibly, depending on concentration and method |
| Detergent | Rapid detergent test kit | Often detectable if above the method's detection limit |
| Formalin | Specific chemical test | Often detectable with appropriate laboratory methods |
| Antibiotic residues | ELISA, LC-MS/MS | Detectable at very low concentrations |
How large dairies protect milk quality
Most organized dairies don't rely on a single test. They use multiple layers of quality assurance:
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Testing at milk collection centers
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Tanker sampling before unloading
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Laboratory verification
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Batch traceability
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Random surveillance testing
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Regulatory compliance testing