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Why Are Milk And Dairy Products Bad For Me

There are many methods known for detection of adulteration in milk but the methods discussed below are simple but rapid and sensitive methods to detect adulteration.


I. Detection of Neutralizers in milk


1) Rosalic acid test (Soda Test)


In milk neutralizers like hydrated lime, sodium hydroxide, sodium carbonate or sodium bicarbonate are added which are generally prohibited.


How to detect?


Take 5 ml of milk in a test tube and add 5 ml alcohol followed by 4-5 drops of rosalic acid. If the colour of milk changes to pinkish red, then it is inferred that the milk is adulterated with sodium carbonate / sodium bicarbonate and hence unfit for human consumption.


This test will be effective only if the neutralizers are present in milk. If the added neutralizers are nullified by the developed acidity, then this test will be negative. In that case, the alkaline condition of the milk for the presence of soda ash has to be estimated.


How to proceed?


2) Take 20 ml of milk in a silica crucible and then the water is evaporated and the contents are burnt in a muffle furnace. The ash is dispersed in 10 ml distilled water and it is titrated against decinormal (N/10) hydrochloric acid using phenolphthalein as an indicator. If the titre value exceeds 1.2 ml, then it is construed that the milk is adulterated with neutralizers.


II. Test for detection of hydrogen peroxide


Take 5 ml milk in a test tube and then add 5 drops of paraphenylene diamine and shake it well. Change of the colour of milk to blue confirms that the milk is added with hydrogen peroxide.


III. Test for detection of formalin


Formalin (40%) is poisonous though it can preserve milk for a long time.


How to detect?


Take 10 ml of milk in test tube and 5 ml of conc. sulphuric acid is added on the sides of the test tube with out shaking. If a violet or blue ring appears at the intersection of the two layers, then it shows the presence of formalin.


IV. Test for detection of sugar in milk


Generally sugar is mixed in the milk to increase the solids not fat content of milk i.e. to increase the lactometer reading of milk, which was already diluted with water.


How to detect?


Take 10 ml of milk in a test tube and add 5 ml of hydrochloric acid along with 0.1 g of resorcinol. Then shake the test tube well and place the test tube in a boiling water bath for 5 min. Appearance of red colour indicates the presence of added sugar in milk.


V. Test for detection of starch


Addition of starch also increases the SNF content of milk. Apart from the starch, wheat flour, arrowroot, rice flour are also added.


How to detect?


Take 3 ml milk in a test tube and boil it thoroughly. Then milk is cooled to room temperature and added with 2 to 3 drops of 1% iodine solution. Change of colour to blue indicates that the milk is adulterated with starch.


You can find more tests to detect different adulterants in milk at MILK ADULTERATION TESTS


The author is a dairy expert, specializing in the technology and microbiology of dairy foods and holds a doctoral degree in Dairy Science; for more info on milk and dairy products please visit her site A Professional Dairy Site


Source: www.isnare.com