Innovation

The Chinese scientists have developed the labels changing colour depending on freshness of a product

Researchers in China have developed a tiny tag that changes color to indicate the freshness of a perishable product, like a carton milk, without opening the container.

The tag uses a simple color system to track the food's quality. The tag starts out as red, indicating that the food is fresh. The tag cycles through the colors of the rainbow, changing from orange to yellow to green as the food goes through different stages of freshness. Bright green means the product is spoiled.

The tags, which are roughly the size of a corn kernel, have a gummy-like consistency and stick right onto the product.They are made of tiny silver and gold nanorods and other chemicals, including chloride and vitamin C.

The technology has been patented in China, according to the media release, and the next step will be to contact manufacturers.