Color Code Smart Tags Help Determine Freshness of Food Product [VIDEO]

Using color coded smart tags, consumers can easily determine if the food product is fresh without opening it, a new study reveals.

Color coded tags are similar to the size of a kernel of corn. The tags made up of tiny metallic nanorods can even help determine if medications and other perishable products are active or fresh. These tags could also be customized for a variety of other foods and beverages.

"This tag, which has a gel-like consistency, is really inexpensive and safe, and can be widely programmed to mimic almost all ambient-temperature deterioration processes in foods," said Chao Zhang, Ph.D., the lead researcher of the study. "And a real advantage is that even when manufacturers, grocery-store owners and consumers do not know if the food has been unduly exposed to higher temperatures, which could cause unexpected spoilage, the tag still gives a reliable indication of the quality of the product."

Using these color coded tags, consumers can determine how fresh the packaged and perishable food items can stay over time. These tags can be of various colors. Researchers said that a red or reddish orange means that the product is fresh. Over time, the color of the tag changes from red to orange, yellow and finally green. The final color indicates that the product cannot be consumed. These colors indicate a range between 100 percent fresh to 100 percent spoiled.

The tags were developed and tested using E.coli, bacteria known for causing gastrointestinal problems, in milk.

 "We successfully synchronized, at multiple temperatures, the chemical evolution process in the smart tag with microbial growth processes in the milk," said Zhang.

The metallic nanorods used by the researchers are red, signifying the initial rag color. The tag also contains silver chloride and vitamin C that react slowly. Gradually the metallic silver settles on the gold nanorods making a silver shell coating. This is responsible for causing the change in the particle's chemical composition and shape. As the coating of silver thickens the tags slowly changes its color from red to orange, yellow, green and even blue and violet, researchers said.

The study was documented in the ACS Nano.