Can single-use temperature indicators be used to measure food temperatures?

Yes, but the reading must be validated by taking a second temperature using a numerically-scaled thermometer, such as a bi-metallic food thermometer or a thermocouple. Therefore, using these types of temperature indicators are not economically feasible for schools.

Currently there are two types of single-use temperature indicators –- (1) time-temperature indicator, to determine if a food has been exposed to unsafe temperatures during storage and transport and (2) disposable indicator, used with a specific food to determine if a safe endpoint cooking temperature has been reached. While both are very accurate, foodservice regulations require that all temperature measurements be taken with a thermometer that is numerically scaled, such as a metal-stem thermometer or a thermocouple.

Time-temperature Indicators. The longer food is exposed to extreme heat, the more likely it is to become unsafe to eat. Packaged food is often stored in a warehouse for months, so food could potentially be exposed to unsafe temperature conditions. Foods could also be temperature-abused during transportation to the delivery site. Time-temperature indicators, which are attached to food packages, allow one to determine if a food has been exposed to unsafe temperatures. Time temperature indicators usually have a clear bar that changes color as food is exposed to an unsafe temperature. Even if the food is returned to a safe temperature, the bar will still be colored in, showing that the food was temperature-abused.

Disposable Temperature Indicators. This type of single-use temperature indicator is used to determine if a safe endpoint cooking temperature of a specific food item has been reached. Currently disposable temperature indicators are available to measure the temperatures of beef, beef hamburgers, poultry, pork, and fish. To use, place approximately one-half inch deep (follow manufacturer's directions) and read within 5-10 seconds. The color band changes when the food has reached a specific temperature so only use with the food for which it was designed.

If you have questions, contact Dr. Angela Fraser, Associate Professor/Food Safety Education Specialist, Clemson University, Clemson, SC.

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