To be sure and use pure. Below are the methods through which you can detect food adulteration in food items:
Adulteration in Vegetable Oil
- Castor Oil: Take 1 ml. of oil in a clean dry test tube. Add 10 ml. of acidified petroleum ether. Shake vigorously for 2 minutes. Add 1 drop of Ammonium Molybdate reagent. The formation of turbidity indicates presence of Castor oil in the sample.
- Argemone Oil: Add 5 ml, concentrated Nitric acid (HNO3) to 5ml of sample. Shake carefully. Allow yellow and orange colour to separate. Crimson colour in the lower acid layer indicates adulteration.
Adulteration in Wheat flour
- Excessive sand and dirt: Shake a little quantity of sample with about 10 ml. of Carbon tetrachloride (CCL4) and allow to stand. Grift and sandy matter will collect at the bottom.
- Excessive bran: Sprinkle on water surface. Bran will float on the surface.
- Chalk powder: Shake sample with diluted Hydrochloric Acid (HCL) Effervescence indicates presence of chalk powder.
Adulteration in Food grains
- Hidden insect infestation: Take a filter paper impregnated with Ninhydrin reagent (1% in alcohol). Put some grains on it and fold the filter paper and crush the grains with hammer. Spots of blush purple indicate presence of hidden insect infestation.
Source: Ministry of Consumer Affairs, Food and Public Distribution