Spectrophotometry and Melamine Detection in Milk

Got Milk? For most, drinking milk is something we do for our health. It’s high in calcium which strengthens bones, and a warm cup before bed helps us sleep. It’s something wholesome, safe, and part of many family recipes and our daily diet. But what if it wasn’t safe to drink? It is not uncommon to find Melamine in dairy products imported from China. Large quantities of tainted milk sat on the shelves of local food stores and were responsible for causing severe illness in thousands of people, particularly children.

Melamine is an industrial compound, high in nitrogen commonly found in plastics and fertilizers. In foods, this chemical is extremely toxic and can cause serious health issues and in certain cases can be fatal. After the initial problem with Melamine contamination, it became apparent that Melamine monitoring was an essential part of food safety testing. This was both a revelation and a problem because at the time testing for Melamine was very time-consuming and costly.

Recently, researchers have discovered a rapid and cost-effective way to test milk for Melamine using gold nanoparticles, visual inspection and spectrophotometry. After separating casein, which can mask the presence of Melamine, from the milk they added gold nanoparticles to the remaining solution. In milk with Melamine present, the gold particles reacted with the Melamine and the solution changed from a reddish color to blue. This can then be measured visually and then quantified with a spectrophotometer. Finally, to positively identify and specify that Melamine is causing this color change, cyanuric acid, which directly interacts with only Melamine, is gradually introduced. If Melamine is present, a precipitate will begin to form, the degree of this change is easily quantified by spectrophotometry. The supplies for this test are easy to manufacture which makes for easy widespread implementation and provides a quick and accurate process to determine if the milk is safe for human consumption.

Download our whitepaper to learn more about Spectrophotometry and Colorimetry in the food industry

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