New test to detect melamine in milk

MIAMI, April 9 (UPI) -- A 15-minute test using gold nanoparticles is a quick way to detect melamine, which was found in pet food and dairy products, U.S. researchers say.

Na Li, an assistant professor at the University of Miami, says melamine is an industrial substance used in plastics and fertilizers, which is high in nitrogen, and when added to foods can make products appear higher in protein in testing.

In 2007 and 2008, melamine tainted dairy products sickened thousands of people, especially children, and caused a recall of Chinese dairy products worldwide. It was also found in pet food that sickened pets and was fatal in some, Li says.

The researchers separated the casein-based milk component, which can interfere with melamine detection and added gold nanoparticles to the solution. The interaction between the gold nanoparticles and melamine causes the solution to change color from red to blue in seconds, Li says.

"Current methods of melamine detection in milk are costly and time consuming," Li says in a statement. "Our work represents a significant step towards the rapid detection of melamine, which addresses a critical global issue."

The findings are published in the journal Applied Physics Letters.