Milk adulteration normally involves dilution with water or whey and adding other nitrogen sources such as ammonium salts, urea, melamine or non-dairy proteins. The established method for detecting added water in milk is to determine its freezing point depression, however, this method would not be effective to detect most milk adulterations. Brazilian researchers have developed a rapid and simple method to screen milk for adulteration, which involves precipitation of the milk proteins with copper sulphate and measuring the intensity of remaining copper salt after complexing with EDTA with a smartphone and a colorimetric app. The method was tested by adulterating milk with ammonium chloride, urea and melamine, and was able to detect the addition of 1% added water to the milk.
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