Cooperative Extension, College of Agriculture & Life Sciences, the University of Arizona
Food Safety, Preparation and Storage Tips
Cooperative Extension, College of Agriculture & Life Sciences, the University of Arizona
Time and Temperature Make a DifferenceTime and temperature influence the growth of bacteria. Bacteria growth can cause food poisoning. Like other living things, bacteria need: (1) food to grow on, (2) warmth, (3) moisture and (4) time to grow and multiply. A standard rule, recommended by the U.S. Department of Agriculture, is to keep hot foods hot (above 140° F.) and cold foods cold (below 40° F.). The "dangerous temperature zone" is between the temperatures of 41 to 139° F. At danger zone temperatures, bacteria can double their numbers every 20 to 30 minutes. Food may not be safe to eat if you hold it for more than two to three hours at the danger zone temperature range where bacteria can rapidly multiply. Food can reach the two to three hour time limit cumulatively. For example, cooked meat left for one hour at room temperature, refrigerated, then left out for another hour (without proper reheating) is the same as leaving it out for two consecutive hours. Refrigerating or freezing cooked meat stops bacteria from increasing, but any bacteria already on the meat will remain alive. These bacteria will multiply when you put the meat back into the danger temperature zone. This means cooked foods should be rapidly cooled to refrigerator temperatures below 40° F. Reheat quickly to temperatures above 160° F. Check your refrigerator and freezer periodically. Keep your refrigerator at about 40° F. and your freezer at 0 ° F. Use a thermometer to be sure. Thaw meat and poultry in the refrigerator. Do not thaw food on the kitchen counter at room temperature. For faster thawing, place frozen packages in a watertight plastic bag under cold water and change the water often. Remember, keep foods out of the danger zone temperature. Keep cold foods cold at 40° F and hot foods hot above 140° F, and remember to figure time periods that food is held 2 hours at room temperature. After 2 hours at room temperature, throw the food out before it makes you or your family sick. Resources:
Material written by Mary Abgrall and Scottie Misner, April 1998. |