How to Check Adulteration/Contamination

How to Check Adulteration/Contamination


Detecting presence of water
  • Put a drop of milk on polished slanting surface
  • Pure milk either stays or flows slowly, leaving a white trail behind
  • Milk adulterated with water will flow immediately without leaving a mark
Detecting presence of detergent
  • Take equal parts of milk and water. Shake thoroughly
  • If adulterated, dense lather will form
  • Pure milk will form a thin layer of foam


Detecting mashed potato, sweet potato and other starches
  • Take half teaspoon of ghee/butter, add 2-3 drops of tincture of iodine
  • Blue colour indicates starch adulteration
Detecting other oils in coconut oil
  • Place oil in refrigerator (not freezer) for 30 minutes
  • Coconut oil will solidify


Detecting malachite green in green vegetables
  • Rub the outer surface of a small part of the green vegetable with cotton soaked in water or oil
  • If the cotton turns green, then it is adulterated
Detecting green colour in green peas
  • Place a few green peas in a glass of water
  • Let them stand for half an hour
  • Clear separation of colour in water indicates adulteration


Detecting adulterants in chilli powder
  • Add a teaspoon of the powdered spice to a glass of water and examine the residue
  • A gritty residue indicates presence of brick powder or sand
  • If residue is smooth but soapy, soap stone is present
  • If sawdust is present, it will float
Detecting foreign resin in asafoetida (hing)
  • Burn a small quantity of asafoetida in a stainless steel spoon
  • The pure spice will burn with a bright flame like camphor
Papaya seeds in black pepper
  • Place a few corns of black pepper in water. Papaya seeds will float


Detecting presence of used leaves in fresh tea leaves
  • Spread few tea leaves on a filter paper
  • Sprinkle with water to wet the filter paper
  • Wash the filter paper under tap water and observe the stains against light
  • Pure tea leaves will not stain the filter paper
  • If coal tar is present, it will immediately stain the filter paper
Chicory in coffee
  • To a glass of water add a teaspoon of coffee powder
  • Coffee powder will float while chicory will sink

Wheat Flour

Detecting adulteration
  • When dough is prepared from pure flour, less water is needed
  • Chapatis will taste somewhat sweetish. Those prepared from adulterated flour are tasteless


Detecting presence of chalk
  • Stir a spoonful of salt in a glass of water
  • If chalk is present, the water will turn white. Other insoluble impurities will settle down
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