Temperature Danger Zone
Chefs and kitchen staff know the temperatures that food should be at the kill bacteria. However, it is equally important to remember the temperatures where foods are susceptible to rapid bacterial growth. This is when they enter “the temperature danger zone,” which is anywhere between +41ºF to +135ºF. However, bacteria grows even more rapidly between 70ºF and 125ºF.
Foods reach the temperature danger zone when they are left too long within that temperature range. This is known as “time-temperature abuse.”
Time-temperature abuse quickly creates an environment for foodborne microorganisms to grow which can make guests sick. According to the Certified Food Safe Professional (CFSP) program, there are three ways time-temperature abuse can occur:
- Cooked or raw foods are not held or stored at required temperatures
- Food is not cooked or re-heated to a temperature to kill microorganisms
- Foods are not cooled properly
Bacterial Growth in Food
For bacteria to survive in food, all it needs is moisture, heat, and oxygen. The temperature danger zone is the most ideal environment to get all three. When the environment is right, bacteria will multiply very quickly.
Using an example from the CFSP program, bacteria can double their amounts at the following temperatures:
- +100ºF: Every 15 minutes
- +50ºF: Every 15 hours
- +36ºF: Every 15 days
- 0ºF: Most bacteria are dormant
How to Reduce Risk of Harmful Bacteria
Avoiding time-temperature abuse and keeping foods out of the temperature danger zone at a food service reduces the risk of customers contracting a foodborne illness.
Dave Crump, a CFSP product consultant at Central, advised managers to do routine walk-throughs to make sure employees are following proper procedures. This is how his management team ensured safety when he was in the restaurant industry.
“Managers had to do walk-throughs two-to-three times a day checking stations and products to see,” he explained. “That’s when we would find that something might not be held or stored properly. Without that, you fall into products falling into the danger zone.”
In addition to Dave’s advice, below are ways the CFSP program suggests for operators to limit growth:
- Defrost frozen foods choose one of the following methods: Under refrigeration at +41ºF or lower, submerged under running water at +70ºF, in a microwave or as a part of the cooking process
- Cook food until it reaches +165ºF for 15 seconds (this temperature kills bacteria)
- If holding food, keep hot foods at +135ºF and cold food under +41ºF
- Use two-stage cooling to chill leftover foods by taking them from +135ºF to +70ºF within two hours and then from +70ºF to +41ºF in four hours or less
- Keep food in wide shallow containers to allow food to obtain maximum cooling in a short period of time
- Use caution with high-protein foods as they are more susceptible to bacterial contamination–which especially includes foods that have been ground, chopped, etc. such as hamburger or eggs
- Properly cover all foods placed in a refrigerator so they are protected against contaminates above them
- If compatible with the food type or recipe, try to bring the pH level of food to an acidic state of 7.6 pH or higher by adding in ingredients such as apples, vinegar or tomatoes
- Do not let foods be out-of-refrigeration for any more than four hours of cumulative time from preparation to serving
In addition to securing food from the temperature danger zone when holding, it is also important to make sure food reaches its minimum internal temperature in order to reduce the risk of pathogen growth that can also result in foodborne illness. Minimum internal temperatures vary by food type, but they’re important to know. Learn about minimum cooking temperatures, how to properly check for temperatures, and the various types of thermometers here.
Tools to Help Combat Contamination
There are a wide variety of products to help food services stay out of the temperature danger zone and keep guests safe. For example, blast chillers quickly take hot food to cool food safe temperatures for storage. Meanwhile, food warmers keep foods at proper warm temperatures to avoid going below the 135 degree mark. Also, there are a wide variety of food service supplies with built-in antimicrobial protection with materials that kill or inhibit bacterial growth.
Check out our Crash Course on Food Safety for more information, including different types of contaminants and preventative measures. If you have any more questions about the danger zone or products to help keep food at safe temperatures, one of our expert product consultants are happy to assist! Give us a call at 800-215-9293 to learn more!
Hope has been a Content Specialist since November 2015, where she brings to the table years of experience in the food service industry in a variety of roles. Throughout her time with Central, Hope has focused on learning all things possible about everything from cooking equipment to concession and specialty products in order to empower operators with education on commercial equipment and supplies. Hope is a wife, new mom, avid crafter, and food lover (french fries please!).