Am I Hot Enough For You?
One of the top 5 foodborne illness risk factors in commercial kitchens is the improper cooking temperatures of potentially hazardous foods. The best way to ensure proper food temperatures is to use the correct calibrated thermometer for the job and there are several choices of thermometers available:
Bimetallic Stemmed Thermometer: The most commonly used and versatile thermometer should have – an adjustable calibration nut to keep it accurate, easy to read temperature markings, and a dimple to mark the end of the sensing area. This thermometer can measure food temperature in approximately 15 – 20 seconds. This type of thermometer should only be used at the end of cooking to check the internal temperature. The probe needs to be inserted the full length of the sensing area which is above the dimple area – about 2 -3 inches in order to get an accurate reading. If taking the temperature of a thin food, the probe should be inserted through the side of the food so that the entire sensing area is positioned in the food.
|Inexpensive||Not Tip Sensitive|
|Readily Available||Temperatures Averaged Over Sensing Area|
|Easy to Calibrate||Not as Effective for Thin Foods|
|Loses Calibration with Physical Shock|
|Dial may be Difficult to Read|
Thermocouple Thermometer: This thermometer measures temperatures using various types of probes with the results displayed on a digital readout. Of all thermometers, the thermocouple read and displays the final temperature within 2 – 5 seconds. Temperatures are measured at the junction of two fine wires located in the tip of the probes. A thermocouple thermometer can use the following types of probes:
Immersion – measures the temperature of liquids
Penetration – measures the internal temperature of solid or liquid foods
Surface – measures surface temperatures
|Digital Temperature Readout||May be Expensive to Calibrate|
|Tip Sensitive||Accuracy may Vary Due to Signal or Voltage Change|
|Variety of Probes Available||Accuracy may Vary Proportional to Cost|
|Provides Quick Readings|
Thermistors Thermometer: This type of thermometer uses a resistor (a ceramic semiconductor bonded in the tip with temperature sensitive epoxy) to measure food temperatures. The probe thickness is about 1/8 of an inch and it takes approximately 10 seconds to register the temperature on a digital readout. Since the semiconductor is in the tip, this thermometer works well for temperature measurement in thin as well as thick foods. It is still necessary to place the probe into the thickest part of the food since the center of the food is cooler than the outer surface.
|Provides Quick Readings||May be Expensive to Calibrate|
|Easy to Read||Accuracy may Vary Due to Signal or Voltage Change|
|Tip Sensitive||Accuracy may Vary Proportional to Cost|
Infrared Thermometer: This type of thermometer is used to measure surface temperatures only. It should not be used to check cooking temperatures but it can be a very useful tool in the receiving department as it can read temperatures up to 4 feet away in distance, provide a quick check of temperatures, and removes barriers because glass and shiny surfaces affect readings.
|Quick Readings||Cannot Measure Internal Temperatures|
|Accurate||Environmental Conditions, such as Humidity, Affect Accuracy|
|Nondestructive, Noncontact Measurements||Accuracy Affected by Surface Emissivity (the ability of a surface to emit heat by radiation)|
|Eliminate Cross Contamination||May be Expensive to Calibrate|
Single Use Temperature Indicators: This is a single use disposable temperature indicator which is very easy to use. These indicators are designed for specific temperature ranges and have sensors made from special temperature materials which have been approved by the FDA for food contact. The indicator is inserted into the food and when the food reaches the proper temperature, the sensor changes color. The indicator should not be used during the cooking process but should be used near the end of the cooking period.
|Easy to Use||Different Indicators are needed Depending on Temperature Ranges|
|Quick Readings Within 5 Seconds|
|Time Savings – no need for calibration or sanitizing|
|Available for a Variety of Temperatures|
|Eliminates Possibility of Cross Contamination|
|Indicator can be Saved on Temperature Documentation Forms as Evidence that Temperatures were Checked|