Visible changes like these on small

Visible changes like these on small, inexpensive labels allow conclusions to be drawn about the conditions under which the packaged foodstuffs are stored and they can show whether the refrigeration chain has been properly maintained or not. If, in addition, the gradual change in label colour correlates with the product's loss of freshness, then the labels can also be used as an indirect indicator of freshness.
OnVu TTI (photochemical-TTI) activated by UV-light