Handheld melamine detector developed by IISc,Bangalore researchers

Researchers at the Indian Institute of Science (IISc), Bangalore have developed a handheld melamine detector. With this detecting melamine in milk is expected to become easy, quick and inexpensive.

How is it detected?

In this method, leaf extract of a commonly seen weed parthenium along with silver nitrate is used for detecting the presence of melamine in milk.

• Prior to melamine detection, the milk is processed to remove fat and proteins as they tend to interfere with detection.
• With this technique, the presence of melamine in milk can be detected at room temperature within a few seconds through a change in colour.
• The change in colour depends on the amount of melamine present and, therefore, the extent of its interference with the synthesis of silver nanoparticles. The colour change can be directly observed by the naked eye and also recorded by spectral change.
• The silver nanoparticles are reddish yellow in the absence of melamine, while it becomes nearly colourless when melamine is present. Light absorption at 414 nm wavelength is a signature of silver nanopartciles. But when melamine is present the absorption of light is reduced as nanoparticle formation decreases.

Why be concerned about Melamine in milk?

Melamine content of more than 1 ppm in infant formula and more than 2.5 ppm in other foods should be viewed with suspicion of adulteration.

What is melamine?

Melamine is an organic base chemical most commonly found in the form of white crystals rich in nitrogen.

What is melamine generally used for?

Melamine is widely used in plastics, adhesives, countertops, dishware, whiteboards.

Why is melamine added into milk?

The addition of melamine increases the nitrogen content of the milk and therefore its apparent protein content.

• However, addition of melamine into food is not approved by the FAO/WHO Codex Alimentarius (food standard commission), or by any national authorities.

What are the health effects of melamine consumptions in humans?

While there are no direct human studies on the effect of melamine data from animal studies can be used to predict adverse health effects. Melamine alone causes bladder stones in animal tests. When combined with cyanuric acid, which may also be present in melamine powder, melamine can form crystals that can give rise to kidney stones.

• These small crystals can also block the small tubes in the kidney potentially stopping the production of urine, causing kidney failure and, in some cases, death. Melamine has also been shown to have carcinogenic effects in animals in certain circumstances, but there is insufficient evidence to make a judgment on carcinogenic risk in humans.