The German-based company said its OnVu ICE label is able to “memorise temperature” and provide a visual indication of the current state of chilled or deep-frozen foods. The label changes colour depending on temperature – with the darker its colour, the better the cold chain has been maintained. The system is more effective than relying on ‘best before’ dates, said BASF.
“Manufacturers, retailers and consumers will soon be able to tell at a glance whether ice cream, pizza, fish or any other products were kept constantly deep-frozen or should rather be discarded because the cold chain was interrupted significantly,” said Martin Angehrn, project manager at BASF Future Business. “OnVu labels, which sort of memorize temperature, help to keep chilled and frozen products fresh.”
Thermometer symbol
The temperature sensitive ink is printed as a thermometer symbol and can be added to a product label or stamped directly onto packaging in-line, said the firm.
The indicator at the centre of the thermometer is activated by means of ultraviolet (UV) light - which causes it to turn dark blue. The label provides a visual monitor of the cold chain.
“As long as the centre is darker than or the same as the reference colour, there has not been any significant interruption in the cold chain and the best before date shown on the packaging remains valid,” said BASF.
The colour of the labels become lighter with the passing of time as the “best by’ date approaches or if the cold chain is broken. The company confirmed that the speed of the colour change process and the temperatures that trigger it can be customized.
In frozen foods, the ink remains dark blue as long as the temperature is continually kept at -18C. The higher the temperature rises, the faster the colour changes.
“When the temperature rises to cause thawing, these foods should be consumed immediately,” Angehrn added. “Our OnVu indicator shows this reliably by changing colour.”