KRICT’s ‘smart’ stickers let shoppers know if cold-chain food is spoiling

According tomedia New Atlas, can we tell with the naked eye whether any cold-chain food we receive has deteriorated? An experimental new sticker may help because it is designed to tell you if this has happened. South Korean scientists have developed a cold chain safety label that instructs cold-chain foods such as fish, meat, fruits and vegetables to deteriorate.

The one-off device, developed by scientists at the Korea Chemical Technology Institute (KRICT), can be attached to the packaging of temperature-sensitive foods such as meat, fish, fruits and vegetables. It can also be used in other products that need to be frozen or refrigerated, such as pharmaceuticals.

This thin, elastic sticker combines a surface film made of polymer nanofibers, which are neatly interlaced as long as the ambient temperature is low. This makes the film look opaque, so that the underlying image on the sticker is not visible.

However, if the temperature reaches at least 10 oC (50 oF) within a certain period of time, the fibers will “melt” and their structurewill will collapse, causing them to entangle themselves. As a result, the film becomes transparent and the image becomes clearly visible. The film remains transparent even if the sticker is then brought back to a cooler temperature.

Because some foods are sensitive to temperature, the film’s room temperature degradation time can be adjusted by using nanofibers of specific compositions and thicknesses. This means that at room temperature, the image of the sticker can be displayed within 30 minutes, or up to 24 hours later.

In addition, the technology claims to be inexpensive, with an estimated production cost of about 1 cent per sticker.

Scientists recently published a paper on the study in the journal Advanced Materials.