Chemically and heat activated labels that sense and monitor temperature, visually display the freshness status of perishable products, and warn users if perishable products have spoiled or reached the end of their useful life

Device containing a chemically sensitive wick for measuring the freshness of perishable foods, namely a small device in the form of a plastic tag integrated with food packaging that chemically senses compounds produced by spoiling food, and visually displays the state of a food's freshness and warns when the shelf-life has expired