05045283 is referenced by 81 patents and cites 32 patents.

A moving boundary device for monitoring the time-temperature storage history, i.e. shelf life, of perishable products. The device is constructed of an activator tape, containing an activator composition in an activator matrix, an indicating tape, containing an indicating composition in an indicator matrix in which the matrices are adhered together to form a wedge-shaped composite matrix, preferably by means of a pressure sensitive adhesive. The device operates by allowing the activating composiiton, e.g. an organic acid such as citric acid, to diffuse through the increasingly thicker composite matrix to continuously contact the indicating composition, e.g. an acid-base dye indicator such as 2,2',4,4',4",-pentamethoxy triphenylmethanol, to produce a visually observable color change at the temperature being monitored. The color change appears as a moving boundary at the color/non-color interface which moves transversely along the length of the device toward the thicker end of the composite matrix. The matrices are water-impermeable and the device preferably possesses activation energy and rate constant values for the color change which are substantially the same as those for product decay. This allows accurate and continuously observable monitoring of the available shelf-life of the perishable product to which the device is adhered.

Moving boundary device for monitoring shelf-life of a perishable product
Application Number
Publication Number
Application Date
August 2, 1988
Publication Date
September 3, 1991
Gordhanbhai N Patel
JP Labs
G01N 31/22
View Original Source