Simple Method for detection of Common Adulterants

i. Milk

i. The lactometer reading shall not ordinarily be less than 26.


ii. The presence of water can be detected by putting a drop of milk on a polished slanting surface. The drop of pure milk either stops or flows slowly leaving a white trail behind it, whereas milk adulterated with water will flow immediately without leaving a mark.

       Add a few drops of tincture of lodine or lodine solution. Formation of bvlue colour indicates the presence of starch.

   Add a few drops of tincture of lodine or lodine solution. Formation of blue colour indicates the presence of starch.

The lactometer reading will go above 26 while the milk apparently remains thick.

Boil a small quantity of sample with some water, cool and add a few drops of lodine solution. Formation of blue colour indicates the presence of starch.

Boil a small quantity of sample with some water, cool and add a few drops of lodine solution. Formation of blue colour indicates the presence of starch.

Mashed Potatoes, Sweet Potatoes and other starches.

Take about one tea spoon full of melted sample of Ghee with equal quantity of concentrated Hydrochloric acid in a stoppered test tube and add to it a pinch of sugar. Shake well for one minute and let it stand for five minutes. Appearance of crimson colour in lower (acid) layer shows presence of Vanaspati or Margarine.

The presence of mashed potatoes and sweet potatoes in a sample of Ghee can easily be detected by adding a few drops of lodine, when lodine, which is brownish in colour turns to blue then mashed potatoes/ sweet potatoes/other starches are present.

The test is specific for sesame oil which is compulsorily added to Vanaspati and Margarne. Some coal tar colours also give a positive test.

If the test is positive i.e. red colour develops only by adding strong Hydrochloric acid (without adding crystals of sugar) then the sample is adulterated with coal tar dye. If the crimson or red colour develops after adding and shaking with sugar, then alone Vanaspati or Margarine is present.

Take about one tea spoon full of melted sample of Ghee with equal quantity of concentrated Hydrochloric acid in a stoppered test tube and add to it a pinch of sugar. Shake wel for one minute and let it stand for five minutes. Appearance of crimson colour in lower (acid) layer shows presence of Vanaspati or Margarine.



The presence of mashed potatoes and sweet potatoes in a sample of Ghee can easily be detected by adding a few drops of lodine, when lodine, which is brownish in colour turns to blue then mashed potatoes/ sweet potatoes/other starches are present.

The test is specific for sesame oil which is compulsorily added to Vanaspati and Margarne. Some coal tar colours also give a positive test.

Take small quantity of oil in a test tube. Add equal quantity of concentrated Nitric acid and shake carefully. Red to reddish brown colour in lower (acid) layer would indicate the presence of Argemone oil.

Colourless (not yellowish) Nitric acid should  be used. Artificial colour if present will usually be a bright shade of colour, generally red or pink. The test may sometimes give misleading result. The test may not respond if the Argemone oil is present in small quantity.

Take 2 ml of the oil sample and add an equal quantity of N/2 Alcoholic potash. Heat in boiling water bath (dip in boiling water) for about 15 minutes and add 10 ml of water. Any turbidity shows presence of mineral oil.

If mineral oil is present in small quantity this test may not be positive.