Time-temperature history indicators

Abstract

Compositions containing at least two conjugated acetylene groups (-C.tbd.C-C.tbd.C-) are suitable as integral time-temperature history indicators. These compositions exhibit sequences of irreversible color changes at combinations of times and temperatures specific to each composition. Thus, when supported on the surface of a product or on a substrate affixed to a product, they are useful for indicating whether a perishable (e.g., foodstuff, pharmaceutical, chemical, etc.) has been exposed to an undesirable time-temperature history that results in substantial degradation of the perishable or whether a product has been exposed to a desirable time-temperature history during processing (e.g., the sterilization of a foodstuff or biomedical material).

Dependencies are inferred from the claim text.