04382700 is referenced by 49 patents and cites 16 patents.

An indicator attached to perishable goods to show the remaining useful life are described. The preferred embodiment described includes a material, as for example a mineral jelly, which is in contact with a wick, such as a paper strip, such that the mineral jelly diffuses into the paper in accordance with changes in ambient temperature over a period of time. The amount of diffusion is indicated by an apparent change in color of the paper and is analogous to a change in the useful characteristic of the perishable goods.

Title
Shelf life indicator
Application Number
6/196751
Publication Number
4382700
Application Date
October 14, 1980
Publication Date
May 10, 1983
Inventor
Fred R Youngren
31 Highland Ave., Lexington, 02173
MA, US
Agent
Hamilton Brook Smith & Reynolds
IPC
G01K 3/06
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