Coles County Health Department - Environmental Health - Safe Food Temperatures & Thermometers

Safe Food Temperatures and Thermometers

To keep food safe, you must make sure that temperatures are safe. Guessing the temperature of food is not accurate and can cause food borne illness. There are two questions that you probably don't think about very often that can be crucial to your family's health.

Why do I need to measure food temperatures?
What do I need to know about food thermometers?

Why is measuring the temperature of food important? Because microorganisms (germs, bacteria, and viruses) that can cause food borne illness grow best on foods in the temperature danger zone. The temperature danger zone includes the temperatures between 41 and 140 degrees Fahrenheit on a food thermometer. Food should be in this temperature range for no more than a total of four hours. This total includes the time food spends in the shopping cart, in the car, waiting to be put away, in preparation, cooking, waiting to be served, and cooling before storage. The rule of thumb is that after food has been prepared and served, it should never sit out for more than two hours before it is put away in the refrigerator or freezer.

Food thermometers take the guess work out of knowing the temperature of the food you will be preparing, serving, and eating. The most common food thermometer (and the least expensive) is called a bi-metallic stemmed thermometer. The stem of these thermometers is placed in the middle or thickest part of the food. The temperature is read from a dial at the other end of the thermometer. These thermometers are available at most grocery and hardware stores. Never leave a bi-metallic stemmed thermometer in food that is cooking in an oven, a microwave, or on a stove top. The bubble that covers the dial is plastic and will melt.

Digital thermometers are also available, although they are more expensive than the bi-metallic types. These measure temperature through a metal tip and show the temperature on a readout panel.

Single-food-use thermometers such as candy, meat, and deep-fry thermometers are used with only the type of food or use specified. The temperature range is designed for these foods and uses. Never use mercury filled or non-heat resistant glass thermometers (ones used for taking a person's temperature) with foods. These thermometers may break when used with food.

All thermometers must be measuring the temperature correctly or they won't help keep food safe. When you buy a thermometer in the store, check the degrees it is registering. Most stores are between 65 and 70 degrees F. inside, the thermometer should be reading about that temperature. If it is reading 120 degrees F. or 40 degrees F., it is a safe bet that something is wrong with the thermometer, so don't buy it. Once you buy a thermometer, you need to check to make sure it keeps reading the temperature correctly.

Here is a simple way to test a thermometer. Stick the sensing tip or stem in a clean, Styrofoam or glass cup that contains half ice and half water. Make sure the tip does not touch the side or bottom of the cup. Wait four or five minutes or until the needle is steady. The temperature should read 32 degrees F. If the thermometer has a calibration nut near the dial, and the dial does not read 32 degrees F, turn the nut until the needle is on 32. Less expensive thermometers do not have calibration nuts. If the dial is reading more than five degrees above or below 32 degrees, you should replace the thermometer. If the dial is reading between one and five degrees above or below 32 degrees, write the amount down and remember to add or subtract the amount when you are reading the thermometer. Or, if you think you may forget to do this, buy a new thermometer.

Now that you know how to check temperatures and how to test your thermometers, you need to learn what temperatures are necessary to make food safe.

Poultry, stuffed meats, and stuffed pastas should be brought to 165 degrees F., measured at the thickest part of the flesh if not stuffed or measured in the middle of the stuffing.

Ground beef, game, and pork should be cooked to 155 degrees F. or until no pink is visible in the meat or juice.

Pork, ham, sausage, and bacon should measure 155 degrees F. at the thickest part and away from any bones.

Beef roasts should be cooked to 145 degree F. at the thickest part and away from any bones.

If you are using a microwave, add at least 25 degrees F. to each of the above internal cooking temperatures.

It is just as crucial that you measure cold temperatures correctly. Hold cold food at 41 degrees F. or lower and never mix warm food in with cold food to cool it off. To cool large quantities of foods, like a thick stew or chili, pour into shallow pans. Try to keep the food no more than two inches deep. Place the pans on top shelves of the refrigerator and cover the pans when the food has cooled. Take the temperature of foods cooling in the refrigerator to make sure large quantities will cool to 41 degrees F. as rapidly as possible. Stir food to cool it more quickly and evenly.

Reheat foods to 165 degrees F. within two hours.

Do not mix reused food with fresh portions.

Keep food only two days before reheating, and reheat only once.

Measuring food temperatures using a thermometer is an important part of food safety. If you have additional questions about safe food handling, contact your nearest Environmental Health Officer with the Alaska Department of Environmental Conservation.

For more information about measuring food temperatures, go to the USDA site on Food Thermometers.