Food Thermometers: Essential for Food Safety and Quality

When it comes to food safety in the home, we can use many food handling and preparation practices to keep food safe and reduce the risk of illness. One such practice is to check the final cooked temperature of meats (hamburger, pork chops, roasts, etc.), poultry (wings, breasts, whole birds), seafood, eggs, and dishes containing these ingredients with a food thermometer. Using a food thermometer also prevents overcooking, ensuring moist, quality food.

The 2019 United States Department of Agriculture Economic Research Service (USDA-ERS) study, called "Consumer Food Safety Practices: Raw Milk Consumption and Food Thermometer Use," indicated that while 67% of adults have a food thermometer in the home, only 14% of home meal preparers use a food thermometer during a typical week. People often rely on the color of the meat, juices or texture to measure doneness, none of which are reliable indicators. The only sure way to know that these foods have reached the correct minimum internal temperature to destroy harmful microorganisms is to use a food thermometer. Additionally, using a thermometer takes the guesswork out of deciding if food is done, preventing overcooking that results in a dry, tough product and food waste.

Thermometers

There are two basic types of food thermometers readily available to consumers, digital and dial. The USDA Food Safety Inspection Service Kitchen Thermometer website describes the various types.

Digital Thermometers

• Displays temperature in a digital format.
• Types include thermocouple, thermistor, oven cord thermometer, thermometer fork combination.
• Gives a fast reading, between 2-10 seconds, depending on the type.
• Insert stem between ¼ to ½ inch or deeper into foods for an accurate reading.
• Use for both thick and thin foods.
• Requires a battery.
• Generally, they cannot be calibrated, but check manufacturer directions.

Dial Thermometers

• Displays temperature on a dial.
• Types include oven-safe and instant-read.
• Instant read thermometer gives a reading in 15 to 20 seconds; oven-safe in 1-2 minutes.
• Insert stem 2 to 2½ inches into foods—best for roasts, casseroles, and soups.
• If used with thin foods, insert the stem horizontally into the food.
• Many models can be calibrated; check manufacturer directions.

When using a food thermometer, be sure the temperature sensing area of the stem is correctly inserted in the food. This is especially important for the dial instant-read thermometer as the stem must be inserted in the food to the dimple for an accurate reading. Always insert a thermometer in the thickest part of the food and in two different locations. Check the instructions on the package for details.

The instant-read dial thermometers are generally able to be calibrated, and you should do this from time to time, especially if they are dropped or just get banged around in a drawer. While you may not be able to calibrate a digital thermometer, you can check for the accuracy of the reading.

Thermometer Calibration

To calibrate a thermometer, use the ice water method, as follow:

• Fill a glass with crushed ice.
• Add water to the top of the ice and stir.
• Immerse the stem of the thermometer at least two inches into the ice water. Be sure the stem does not touch the sides or bottom.
• For a dial thermometer, wait 30 seconds till the dial steadies.
• The temperature should read 32°F. If not, keeping the stem in the ice water, use a wrench to turn the adjustment nut under the dial head, so the pointer reads 32°F.
• For a digital thermometer, if the reading is not 32°F, replace the thermometer.

Thermometers should be hand-washed unless otherwise indicated. Wash the stem of the thermometer in hot soapy water, dry, and return to the protective sheath. Store thermometers in a sheath and in a way that they will not be bumped around in a drawer with other utensils, causing damage to the thermometer.

Minimum Cooking Temperatures

The FoodSafety.gov website provides a detailed list of safe minimum cooking temperatures for a variety of foods. In general, cook all poultry products and ground poultry to a final temperature of 165°F, all types of ground meat and meat mixtures to 160°F, fresh beef, veal, lamb, pork, ham steaks, roasts, and chops to 145°F with a 3-minute rest time; leftovers and casseroles to 165°F; and egg dishes (quiches, frittatas) to 160°F.

If you don't have a food thermometer, now you have the information you need to purchase one. Likewise, if you have one but don't use it, you can now feel confident pulling it out of the drawer to use.

References

Food Safety and Inspection Service. (2015, November 6). Kitchen Thermometer.  U.S. Department of Agriculture.

Rhodes, M., Kuchler, F., McClelland, K., & Hamrick, K. (2019). Consumer Food Safety Practices: Raw Milk Consumption and Food Thermometer Use. EIB-205. U.S. Department of Agriculture, Economic Research Service.

U.S. Department of Health & Human Services. (2019, April 12). Safe Minimum Cooking Temperatures Chart. FoodSafety.gov.