When choosing the right thermometer to check the temperature of your food, there are several different types to choose from, depending on how often you plan to use them, what temperature zone you are looking to check (hot or cold), whether you want internal temperature, air temperature, surface temperature, etc.
The basic type of thermometer, is the bimetallic stemmed thermometer. It has an indicator head, calibration nut, stem, and then a sensing area that would be just below a dimple in the stem. The standard scale for this type is from 0 degrees F (-18C) to 220 degrees F (104C). This allows for a wide range of temperature measures. To calibrate this thermometer, the easiest option is to place the thermometer in a glass of ice water. After at least 30 seconds, if the thermometer does not measure 32 degrees F (0C), then you just turn the calibration nut until it reads 32 degrees F.
Another type of thermometers are thermocouples and thermistors. These are generally described as digital thermometers that come in a wide range or styles and sizes. These thermometers can have interchangeable probes to check the temperatures through immersion, surface, penetration, and air. Because these thermometers are digital and have different probes that can be used, calibrations on this type usually needs to be done by a service company; however, some may have an internal reset button, and others may have a calibrate button that is pushed when you place the probe in ice water the same way you would calibrate a bimetallic stemmed thermometer.
Infrared (Laser) Thermometers are used to get accurate temperatures of food and equipment surfaces. Since the thermometer doesn’t need to come in contact with the food or equipment, it helps reduce the possibility of contamination. Calibration of this type of thermometer is completed by a service company.
Time-temperature indicators are single use items that help determine if a food item has entered the temperature danger zone and will register how long it has been in the danger zone. Food suppliers have attached these thermometers to food being shipped, in case there is an issue with delivery trucks. These time-temperature indicators change color and it provides an irreversible record of any incidents that may occur.
when it comes to taking the temperature of food, the following information should be taken into account:
1. Keep thermometers and their storage containers clean.
2. Calibrate thermometers regularly to ensure accuracy.
3. Never use a glass thermometer to monitor the temperature of food.
4. Measure internal temperatures of food by inserting the thermometer stem or prove into the thickest part of the product.
5. Wait for the thermometer reading to steady before recording the temperature of a food item.
If you have any questions about anything that I present in these lessons, or have a question about anything regarding food safety, please feel free to contact me.
Tomorrows lesson: Understanding H.A.C.C.P. for food safety.