Mayalab Instrument

Lactometer is a simple laboratory instrument used to test the purity of milk by measuring its specific gravity (density). Since milk is a mixture of water, fat, proteins, and minerals, its density changes if it is adulterated
Working Principle

• The lactometer works on the principle of Archimedes’ principle (floatation method).

• Pure cow or buffalo milk usually has a specific gravity between 1.026 – 1.032 at 20°C.

• If water is added → density decreases → lactometer sinks more.

• If cream/fat is removed → density increases → lactometer floats higher.

• Procedure for Milk Purity Test

1. Collect milk sample in a tall, clean measuring cylinder.

2. Cool/maintain milk at 20°C for accurate reading.

3. Gently place the lactometer in the milk.

4. Note the reading at the milk surface level (the lactometer has a scale, usually 0–40 or 0–120).

   • Normal milk: 26–32 on lactometer scale.

   • Below 26 → possible water adulteration.

   • Above 32 → possible removal of cream/fat.

• Quick and simple to use.

• Low-cost method for preliminary milk purity testing.

• Only indicates density changes, cannot detect all adulterants (like sugar, starch, urea, detergents, etc.).

• For accurate composition, milk analyzers or chemical tests are needed.