Material temperature exposure timer apparatus and method

A temperature monitoring system for monitoring a cumulative time that a temperature of a raw material has is not within a predetermined temperature threshold over a given time period, said system comprising:

• a temperature sensor for continuously measuring a temperature of said material;
• a clock circuit for generating a clock signal;
• a switch responsive to said temperature sensor, said switch providing a first output when said temperature sensor is indicating that said temperature of said material is within said predetermined temperature threshold, and a second output when said temperature sensor is indicating when said temperature of said material is outside of said predetermined temperature threshold;
• and
• a counter responsive to said switch output and to said clock signal for maintaining a cumulative time that said temperature of said material is outside of said predetermined threshold;
• and
• a battery for powering said clock circuit and said temperature sensor.

A method for monitoring a cumulative time that a temperature of a material has exceeded a predetermined temperature threshold over a given time period, said method comprising:

• using a temperature sensor to continuously sense a temperature of said material;
• using a clock circuit to generate a clock signal;
• using a switch responsive to an output of said temperature sensor to generate an output indicating when a temperature of said material has crossed a predetermined temperature threshold;
• and
• using a counter responsive to said output of said switch to record a length of each time duration that said switch is indicating that said temperature of said material has crossed said predetermined temperature threshold, to thereby maintain a cumulative time total that said material has spent above said predetermined temperature threshold.