Indicator to reveal if frozen food has unsafe temp. rise - during distribution, has visible figure of distinctive shape which melts at critical temp.

摘要

A system for controlling the quality of frozen food by ensuring that any rise in temp. of the food between packaging and consumption is immediately apparent if such a rise exceeds a predetermined critical temp. - Each package contains an indicator which is visible through a transparent panel in the package. The indicator comprises a transparent sachet or similar container which contains a solid figure of distinctive shape at temps. below the critical level. Above the critical level of temp. the figure melts and loses its distinctive shape. The figure material can be prepared to have any required melting point. In partic., a mixt. of alcohol and water can be proportioned to have a wide range of suitable melting points.