Temperature - The Key to Food Safety
Temperature and time when storing and holding perishable food
play a huge role in whether it is safe to eat or needs to be discarded.
Many harmful bacteria such as salmonella and E. coli can
contaminate food without any physical signs, smells or tastes.
Bacteria can multiply rapidly in the DANGER ZONE of 41°F – 135°F.
The temperature of food must be monitored and controlled during
every stage of storage, preparation, and service.
What is "Perishable Food"?
Perishable food refers to types of food, such as meat, poultry,
seafood, dairy, and eggs, that will spoil (with potentially hazardous
results) if not properly refrigerated. Additionally, perishable food
has to go through a “kill stage” via cooking to an internal
temperature sufficient to kill off any harmful bacteria.
USDA-Recommended Safe Internal Temperatures
*When microwaving, a higher degree of caution is needed. 165°F is the threshold for all foods with rotation during the cooking process.
How Temperatures Affect Bacterial Growth
For every 10°F increase in storage temperature, the growth rate of bacteria doubles; for every 10°F decrease in storage temperature, the growth rate is cut in half. Storing foods below 41°F will slow the growth of most pathogens, extending the amount of time the food may be safely held for sale or consumption. Because pathogen growth is not stopped by refrigeration, potentially hazardous foods cannot be stored indefinitely. If potentially hazardous foods are mixed, prepared, handled, cut, wrapped, or packaged in a retail setting, they may be stored for a maximum of seven days at 41°F.
Bacteria are dormant when frozen (below 32°F) and do not reproduce. This affords a longer frozen shelf life, but will not save food that is already spoiled.
Food Needs to Have Its Temperature Taken
Without an accurate, working food thermometer, food safety efforts
are doomed to fail. Visual or tactile cues such as steam or “cool to the
touch” are not acceptable substitutes. A food thermometer should be
inserted in a few areas of the food or meat to ensure that proper
internal temperatures are uniformly achieved. When testing meat, be
sure thermometer is not in contact with a bone, which could result in
a false reading.
When holding foods, temperature must be checked a minimum of
every two hours, if not more frequently. Take at least two readings
from different areas.
Getting Food Temperatures Through the Danger Zone
During the process of chilling pre-cooked foods for storage or reheating, the temperature of foods must necessarily move through the Danger Zone (41°F – 135°F). Follow these guidelines:
Chilling Foods: Foods must be cooled from 140°F to 70°F in the first two hours, and from 70°F to 41°F within an additional four hours. Shallow pans and proper refrigerated air circulation will help achieve these required chill rates.
Reheating Foods: Foods must be reheated to an internal temperature of 165°F for at least fifteen seconds. Reheating must be done rapidly to reach this temperature in no more than two hours. Steam tables, warmers, or similar holding equipment do not heat food quickly enough and must not be used to reheat food.
Remember the Simple Rules
Keep hot food hot (at or above 140°F)
Keep cold food cold (at or below 40°F)
"Managing Food Safety", FDA (PDF link):
National Food Service Management Institute at The University of Mississippi: www.nfsmi.org
Taylor® Food Thermometer