Impurities in milk :

1. addition of water pure or impure.
2. addition of coloring matter.
3. addition of substance used for thickening after dilution ( soap is added) .
4. formalin (preservative of dead bodies) (liver and kidney damaged )used to increase storage period of milk.
5. table sugar.
6. starch.
7. Ammonium sulphate (increase lacto meter reading by maintaining density of milk).