摘要 |
A device for monitoring the expiration of goods includes a substrate and an unreacted composition affixed thereto which is intrinsically reactive to one or both of its thermal environment and the length of time following activation. The reactivity results in a color formation of the composition with the color formation being a single color upon reaction to one of said thermal environment or length of time and multiple colors upon reaction to both. The device may be a label affixed to a container containing the goods to be monitored or may be printed directly on a container.
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