A temperature-sensitive ink is printed in the shape of a thermometer onto the product label or directly onto the package.

Animation: How OnVu™ works

The indicator is charged by exposing it to UV light on the packaging line, causing it to turn dark-blue. From that moment on, the indicator monitors the chill or frozen chain. As time passes and/or if the cold chain is interrupted, the color pales.

At higher temperatures, the discoloration happens faster. If the product is stored or transported at an excessive temperature for too long, the color in the middle of the thermometer gets lighter. As long as the color in the middle is the same color or darker than the surrounding thermometer outline, the cold chain is still intact.

The speed and temperatures at which the color changes can be customized according to the product or application needs.