Chinese scientists have designed "smart tags" to effectively tell if the food is still safe to consume or not without opening or smelling it.
The tags, whose size resembles a corn kernel, are considered as an efficient and affordable means of monitoring if the food has gone bad. The gel-like smart tags could be attached to different food items including cans and bottles to detect spoilage even without opening the products.
These smart tags work by using nanorods, small compounds which were made out of silver and gold. These nanorods have acetic and lactic acids, agar, and vitamin C which all reacts with it in order to change its color. The scientists engineered the tags to show a reddish orange color if the food is fresh. The tags will gradually change their colors into orange, yellow, and green as the food quality deteriorates. A green tag indicates that the food is spoiled already.
Nanorods made up of gold has a natural red color when the silver compounds react with it, they change their composition and color. This process was made to emulate the decreasing quality of food as it nears its expiration date, as well as the adverse effects caused by different temperature levels.
The first application of the smart tags was done on milk. The milk was exposed to varying temperatures as well as bacteria culture to induce spoilage.
"We successfully synchronized, at multiple temperatures, the chemical evolution process in the smart tag with microbial growth processes in the milk," scientist at Peking University in Beijing and lead researcher Dr. Chao Zhang, expressed in a statement, as reported by CBS News.
The researchers also noted that the tags could also work on medication bottles and canned goods.
This research was presented at the American Chemical Society's National Meeting and was published on the March 17 issue of ACS Nano.
