Food Thermometer Guide

• Using a food thermometer is essential to ensure food safety when cooking meat, poultry, and egg products.
• Food thermometers are the sole reliable method for ensuring these foods reach a safe minimum internal temperature, thereby eliminating potentially harmful microorganisms.
• "Doneness" is determined by sensory aspects of food, such as texture, appearance, and juiciness, which are subjective.

Color as an Indicator

• Visible indicators such as color changes are unreliable for determining if foods are adequately cooked.
• Ground beef may brown before reaching a temperature sufficient to destroy pathogens.
• A hamburger cooked to 160 °F, as measured by a food thermometer, is safe regardless of color.

Thermometer Use

• Consumers seeking "doneness" may overcook food, however using a food thermometer ensures both safety and quality without overcooking.

Recommended Temperatures

• Cook raw beef, pork, lamb, and veal steaks, chops, and roasts to a minimum internal temperature of 145°F.
• Let the meat rest for at least three minutes before consumption.
• Cook all poultry to a safe minimum internal temperature of 165°F.
• Use food thermometer to ensure cooked food is held at safe temperatures until served.
• Keep cold foods at 40 °F or below and keep hot foods at 140 °F or above.

Types of Thermometers

• Food thermometers vary in type, style, technology, and price.

Digital Food Thermometers (Thermocouple)

• Thermocouple thermometers rapidly display the final temperature within 2 to 5 seconds on a digital display.
• They measure temperature at the junction of two fine wires in the probe tip.
• Thin probes are suitable for thin foods, with varying thicknesses available.
• Thermocouples are designed for temporary insertion to check temperature and not for remaining in food during cooking.
• Accuracy can be calibrated.

Thermistors

• Thermistors use a resistor made of ceramic semiconductor, to measure temperature.
• The probe is approximately 1/8 inch thick, registering the temperature on a digital display in about 10 seconds.
• The tip placement allows them to measure temperatures in thin and thick foods.
• Thermistors are designed for temporary insertion to check temperature and not for remaining in food during cooking.
• Check the manufacturer's instructions to see if it can be calibrated.

Oven Cord Thermometers

• An oven cord thermometer allows the cook to check the temperature with the oven closed.
• It's equipped with a thermistor probe fixed into the food, connected via a metal cord to a base unit displaying temperature.
• The base unit is affixed to the stovetop/oven with a magnet and programmed to beep upon reaching the set temperature.
• Also suitable for stovetop use, but cannot be calibrated.

Thermometer Fork Combination

• This utensil integrates a cooking fork with a food thermometer, using either thermocouple or thermistor technology.
• Temperature is displayed digitally or via indicator lights on the handle within 2 to 10 seconds.
• Particularly useful for grilling, accurately measuring the internal temperature of thin foods.
• Designed for temporary insertion towards the end of cooking time.
• It cannot be calibrated.

Dial Food Thermometers (Bimetallic-coil)

• These thermometers contain a coil made of two bonded metals that expand differently when heated, moving the temperature indicator.
• They measure temperature from the tip and up the stem for 2 to 2 1/2 inches, so the resulting temperature is an average of the temperatures.
• Dial thermometers are “oven-safe” and "instant-read."

“Oven-safe” Bimetallic-coil Thermometers

• Designed to remain in food during cooking and common for large items such as roasts or turkey.
• If not left in the food while cooking, they can take 1 to 2 minutes to register temperature.
• It accurately measures relatively thick foods or deep foods (foods in a stockpot).
• Not appropriate to measure the temperature of any food less than 3 inches thick.
• There is concern that because heat conducts along the stem's metal surface faster than through the food, the area of the food in contact with the thermometer tip is hotter than the area a short distance to the side.
• To remedy this, the temperature should be taken in a second, and even third area, to verify the temperature of the food. Allow 1 minute to reach temperature from the last reading.
• Check the manufacturer's instructions to see if it can be calibrated.

"Instant Read" Bimetallic-coil Thermometers

• Measures food temperature quickly in about 15 to 20 seconds.
• It is not designed to remain in food while it is cooking in the oven.
• For accurate temperature measurement, insert the probe of the bimetallic-coil thermometer the full length of the sensing area (usually 2 to 3 inches).
• Some models can be calibrated.

Single-Use Temperature Indicators

• Disposable temperature indicators determine if a food has reached its final temperature.
• Designed for specific temperature ranges, the sensors must match the food being cooked.
• Made from temperature-sensitive materials, the sensor changes color when the safe temperature is reached.
• Reinsertion is possible until reaching the desired temperature, but cannot be left in food during cooking.
• Composed of FDA-approved materials.

Pop-Up Timers

• Commonly used in turkeys/ chickens since 1965, the "pop-up" style is a food grade nylon that contains a stainless steel spring.
• The organic firing material dissolves at predetermined temperatures, causing the stem to "pop up".
• Proper placement is important.
• Checking with a conventional food thermometer is always recommended.

Liquid-filled Thermometers

• Also called "spirit-filled", contains metal or glass stems, and requires at least 2 inches deep.
• The temperature is measured by the colored liquid stem as expands when heated.
• Can remain in the food while it is cooking.
• Some can be calibrated by carefully moving the glass stem within the holder.

Candy/Jelly/Deep Fry Thermometers

• These thermometers have measures ranging from 100 to 400 °F
• It measures the extra-high temperatures required of candy and jelly making, as well as frying with hot oil.

Appliance Thermometers

• It's important to verify the temperature of refrigerators and freezers.

Refrigerator/ Freezer Thermometers

• Refrigerators need to maintain a temperature of 40 °F or below.
• Frozen food needs to maintains 0 °F or below to have the longest possible time without expiring.
• These bimetallic-coil thermometers are specially designed to provide accuracy at cold temperatures.

Oven Thermometers

• Measures temperatures from 100 to 600 °F.
• These bimetallic-coil thermometers measures if the oven is heating at designed temperatures.

Food Thermometers Usage Considerations

• Thermocouples give a fast reading and is suitable for thick and thin foods but should not remain in food while it's cooking and can be calibrated.
• Thermistors gives a fast reading that's suitable for thin and thick foods, like Thermocouples, it and should not remain in food while cooking but some models can be calibrated.
• Oven Cord Thermometers can be used outside of the oven and it designed to remain in the food while it's being cooked, cannot be calibrated
• Thermometer Fork Combination can be used in most foods, like Thermocouples and Thermistors, it is not designed to remain in the food and they cannot be calibrated.

Bimetal Thermometer Usage

• Oven-Safe Bimetal thermometers can be used in roasts, casseroles, and soups and can remain in food while it's cooking but most models need to be calibrated.
• Instant-Read Bimetal thermometers can also be used in roasts, casseroles, and soups, the temperature is averaged along the probe and is not designed to remain in food.

Single-Use Temperature Indicators Usage

• Designed to be used only once for a specific temperature ranges and the temperature-sensitive material, which is what determines the food is done, will change color when the desired temperature has been reached.
• Liquid-Filled thermometers can be used in roasts, casseroles, and soups but should be checked if it can be calibrated and can remain in food while it is being cooked.

Safety and Doneness

• Pathogens are destroyed between 140 and 165 °F.
• Higher temperatures may be necessary to achieve sensory accpetability
• Food service professionals should consult their state or local food code.

Recommended Internal Temperatures

• Ground Meat and Meat Mixtures should measure at:
  • 160°F for Beef, Pork, Veal, Lamb
  • 165°F for Turkey, Chicken
• Fresh Beef, Pork, Lamb & Veal (steaks, roasts and chops) should measure at 145°F and leave to rest for at least three minutes.
• Ham
  • Fresh (raw) = 145°F and leave to rest for at least three minutes
  • Pre-cooked (to reheat) = 140°F
• Poultry
  • Chicken, Turkey, Duck & Goose (whole or pieces) = 165°F
  • Poultry breast, roast = 165°F
  • Stuffing (cooked alone or in bird) = 165°F
• Eggs and Egg Dishes
  • Eggs = Cook until the yolk and white are firm
  • Egg dishes = 160°F
• Leftover and Casseroles = 165°F

Using the Food Thermometer

• An accurate reading from the thermometer can only be given if it is in the proper location in the food.
• The food thermometer should be placed in the thickest part of the food, away from bone, fat, or gristle.
• Read the manufacturers instructions before using.

Thin Foods

• When measuring the temperature of a thin food use a thermistor or thermocouple food thermometer.
• If using a dial bimetallic-coil food thermometer, the probe must be inserted in the side of the food so the entire sensing area is positioned through the center of the food to not burn yourself.

Combination Dishes

• For casseroles and other combination dishes, place the food thermometer into the thickest portion of the food or the center of the dish.

Thermometer Care

• Food thermometers should be washed with hot soapy water and be careful not to immerse most thermometers in water.
• Thermometer probes are sharp and should be stored with the probe in the stem sheath.

Calibrating a Thermometer

• There are two ways to check the accuracy:
  • ice water
  • boiling water

Ice Water Calibration Method

• Fill a large glass with finely crushed ice.
• Add clean tap water, fully immerse the food thermometer for only a few minutes, touching neither the sides nor the bottom of the glass.
• Then hold the adjusting nut under and turn the head so the pointer reads 32 degrees.

Boiling Water Calibration Method

• Bring a pot of clean tap water to a full rolling boil.
• Immerse the stem of a food thermometer in boiling water for only a few minutes.
• Then hold the adjusting nut under and turn the head so the thermometer reads 212 degrees.