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Keeping Foods out of the Danger Zone

An important weapon against pathogens is the observance of strict time and temperature controls. Generally, the disease-causing microorganisms found in foods need to be present in significant quantities in order to make someone ill, with the exception of E. coli 0157:H7. Once pathogens have established themselves in a food source, they will either thrive or be destroyed, depending upon how long foods are in the so-called danger zone.

There are pathogens that can live at all temperature ranges. For most of those capable of causing food-borne illness, the friendliest environment is one that provides temperatures within a range of 41° to 135°F/5° to 57°C—the danger zone. Most pathogens are either destroyed or will not reproduce at temperatures above 135°F/57°C. Storing food at temperatures below 41°F/5°C will slow or interrupt the cycle of reproduction. (It should also be noted that intoxicating pathogens may be destroyed during cooking, but any toxins they have produced are still there.)

When conditions are favorable, pathogens can reproduce at an astonishing rate. Therefore, controlling the time during which foods remain in the danger zone is critical to the prevention of food-borne illness. Foods left in the danger zone for a period longer than four hours are considered adulterated. Additionally, one should be fully aware that the four-hour period is cumulative, meaning that the meter starts running again every time the food enters the danger zone. Therefore, once the four-hour period has been exceeded, heating, cooling, or any other cooking method cannot recover foods.

Reprinted by permission from The Culinary Institute of America, The Professional Chef, 8th Edition (John Wiley & Sons, Inc. 2006).