Abstract: An article of manufacture and a method or process adapted to indicate whether a product which has been kept at or below its freezing temperature has been permitted to thaw at some time subsequent to its initial freezing. The invention consists of two or more reagents being separated by an impermeable but removable or breakable barrier, said reagents being adapted to produce a chemical and/or physical change which is visually ascertainable once said barrier has either been removed or lost its integrity so that said reagents are thereafter permitted to intermix and/or interreact. Said reagents are situated within a translucent or transparent vessel in such a manner that after such reagents enter their solid states as the result of an appropriate reduction in temperature, said barrier loses its integrity as a reagent barrier only upon a subsequent and appropriate increase in the temperature about said article.