Ensuring foods are cooked and reheated to the correct temperature is a critical component of food safety. If food is not cooked correctly, dangerous pathogens could grow and result in a foodborne illness. Not only does this endanger your valued guests, but a foodborne illness could be costly to your business, resulting in loss of trust and reputation, negative media exposure, lawsuits and legal fees, decreased staff morale, increased insurance premiums and more. Thermometers play a vital role in this by providing precise measurements to prevent dangerous pathogens and potential foodborne illnesses.

Thermometer

To prevent this, it’s important to understand what the minimum internal cooking temperatures for each food type are and how to properly check temperatures.

This is part of our ongoing Food Safety 101 series. Check out our Crash Course in Food Safety here.

Minimum Internal Cooking Temperatures

Making sure food reaches its minimum internal cooking temperature and that they stay there for the proper amount of time is the best way to reduce pathogens to safe levels for consumption. What are the minimum internal cooking temperatures? This varies from product to product. The following temperatures and times have been developed for foods needing Time and Temperature Control for Safety (TCS foods), named because pathogens grow well in these types of foods. They include foods like dairy products; shell eggs; meat; poultry; fish and shellfish; baked potatoes; heat-treated plants like cooked rice, beans and vegetables; soy protein like tofu; sprouts; sliced melons, tomatoes and cut leafy greens; and untreated garlic-and-oil mixtures. TCS foods are not to be confused with ready-to-eat foods that can be eaten without further preparation or cooking – though they too need careful handling to prevent contamination.

165°F (74°C) for 15 Seconds

  • Poultry, such as whole or ground chicken, turkey or duck
  • Stuffing made with fish, meat or poultry

155°F (68°C) for 15 Seconds

  •  Ground meat like beef and pork
  • Injected meat like brined ham and flavor-injected roasts
  • Ground seafood
  • Shell eggs that will be hot held for service

145°F (63°C) for 15 Seconds

  • Seafood
  • Steaks/chops of pork, beef, veal, and lamb
  • Commercially raised game
  • Shell eggs that will be served immediately

145°F (63°C) for 4 Minutes

  • Roasts of pork, beef, veal, and lamb

135°F (57°C) for No Minimum Amount of Time

  • Fruit, vegetables, grains, and legumes (i.e. beans) that will be hot held for service

If a customer requests a lower temperature, you should inform them of the risk to foodborne illness. It’s important to also note that cooking to the correct temperatures reduces the risk of pathogens, but won’t destroy any toxins or spores that may have produced, so you must still handle the food correctly, following proper food safety techniques, prior to cooking.

It’s also important to always keep the temperature danger zone top of mind. Bacteria grows between 41ºF and 135ºF, and even more rapidly between 70ºF and 125ºF, so it’s critical food never falls into this range. To prevent, it’s not only important food is cooked to it’s minimal internal temperature, but also held at correct temperatures. Frequent monitoring needs to be an essential part of any commercial foodservice. Read more about food safe temperatures, the temperature danger zone and how to avoid time-temperature abuse here

Thermometer Types

In order to ensure your food reaches the proper internal temperature and held at food safety temperatures, it is important to know how to effectively check it. To do this, you must first select the right thermometer. There are three main types of thermometers you’re likely to come across, and four basic types of probes.

Bimetallic Stemmed Thermometers

A common type of thermometer, bimetallic stemmed thermometers can check temperatures from 0°F to 220°F, making it a great tool to check products throughout the flow of food process, from receiving to periodic monitoring while serving in a hot or cold holding unit. One of the main features of these types of thermometers is the metal stem with a dimple. The sensing area goes up the stem to the dimple, so when using to check temperatures, you must make sure it’s inserted far enough to reach. It’s great for checking temps of large or thicker foods, but not practical for thinner products. 

Thermocouples and Thermistors

These two types of thermometers are relatively similar, the only difference being the technology inside. Unlike bimetallic thermometers, the temperatures are displayed digitally and the sensing area is on the tip of the probe, making them great for checking both thick and thin foods because you don’t have to insert as far into the product.

A less common type of thermometer is infrared laser thermometer which are sometimes used to measure the temperatures of food and equipment surfaces. The main positives to this type are that they’re quick and easy to use, and do not need to touch the surface of a product to get their temperature, meaning there is less chance for cross-contamination to occur. However, they have their limitations. They can’t measure air temperature or the internal temperature of foods.

After determining which of the above types is right for you, the next step is to select the correct probe. There are four main thermometer probe types.

Immersion Probe

Deriving its name because of the need to immerse, predominately used to check the temperatures of liquids such as soups, sauces or frying oil.

Surface Probe

Used to check the temperatures of flat cooking equipment, like griddles.
Surface Probe Thermometers

Penetration Probe

This is the probe type you’re likely to use to check the internal temperature of food.
Shop Probe Thermometers

Air Probe

Used primarily to check the temperatures inside coolers and ovens.
Shop Air Probe

Checking Temperatures

To correctly check temperatures to make sure food has reached its minimum internal temperature, make sure to pick a thermometer with a probe that is the correct size for the food. For roasts or big cuts of meat, you may opt for a bimetallic thermometer with a penetration probe. For thin products, like hamburger patties, you’ll likely opt for a thermocouple thermometer.

Insert the probe into the thickest part of the food and wait for the reading to steady. Bimetallic thermometers traditionally take a little longer than digital thermometers. Allow at least 15 seconds, and then take a second reading in different locations to confirm it is safe to serve.

Thermometer Use and Care

A thermometer used to take the temperature of foods must be accurate within (+ or -) 2°F. Over time, thermometers lose their accuracy and must be calibrated to regain it. They should always be calibrated after they’ve been bumped or dropped, have been exposed to extreme temperature change, before new deliveries arrive, and before each shift. Some thermometers cannot be calibrated and must be replaced while others may need to be sent back to the manufacturer to have calibrated. It’s important to always follow the manufacturer’s directions regarding calibration, however, the most common method for calibrating a thermometer is known as the ice-point method.

To calibrate using the ice-point method:

1. Fill a large container with ice (crushed ice preferred if available). Add tap water until the container is full. 

2. Put the thermometer stem or probe into the water, ensuring the sensing area is submerged. Hold for 30 seconds, or until the indicator stops moving, careful not to let the stem touch the container.

3. Adjust the thermometer so it reads 32°F. For a bimetallic stemmed thermometer, you’ll adjust by holding the calibration nut with a wrench or similar tool.

Thermometer FAQ’s

The Internal Temperature of a Cooked Hamburger Patty is Best Measured with Which Thermometer?

A Penetration Probe thermometer would be best for checking the internal temperature of a cooked hamburger patty.

A Thermometer Used to Measure the Temperature of Food Must Be Accurate To What Temperature?

A thermometer used to measure the temperature of food must be accurate to: within plus or minus 2 degrees Fahrenheit (or plus or minus 1 degree Celsius) of the actual temperature.

What Temperature Should a Bi-metallic Stemmed or Digital Thermometer Be?

A bi-metallic stemmed or digital thermometer should be maintained to read 32 degrees Fahrenheit (0 degrees Celsius) in an ice bath or 212 degrees Fahrenheit (100 degrees Celsius) in boiling water, depending on the scale used, to ensure accuracy.

The Sensing Portion of a Bi-metallic Stem Thermometer Is?

The sensing portion of a bi-metallic stem thermometer detects and measures the temperature of the substance being tested. It is typically located at the tip or end of the metal stem. 

How Accurate Must Food Thermometers Be for Use in Food Service?

Food thermometers used in food service must be accurate to within plus or minus 2 degrees Fahrenheit (or plus or minus 1 degree Celsius) to ensure food safety and quality.

Food Probe Thermometers Must Have an Accuracy Of…

Food probe thermometers must have an accuracy of plus or minus 2 degrees Fahrenheit (or plus or minus 1 degree Celsius) to ensure precise temperature measurements in food.

When Should a Bi-metal Stemmed or Digital Thermometer Be Calibrated?

A bi-metal stemmed or digital thermometer should be calibrated regularly, typically before each use or at least once a day, to ensure accurate temperature readings.

Thermometers must be properly washed, rinsed and sanitized before using to prevent cross-contamination. Make sure you always have plenty of thermometers on hand. Read more about the importance of food safety here and check out our Resource Center for more educational materials, buying guides, tips and tricks, industry trends, and more.

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