Avoiding the Temperature Danger Zone
Thawing frozen ingredients on the counter and putting hot food into the fridge are common time-savers, but they aren't safe.
Most bacteria thrive between 40 and 140 degrees Fahrenheit. Within this “danger zone,” bacteria double about every 20 minutes, quickly reaching harmful levels.
As a general rule, food shouldn’t stay in this zone for more than two hours (one hour if the room temperature is over 90 degrees).
Defrost in Fridge
Defrosting should always be done in the refrigerator, not on the counter at room temperature, where bacteria can multiply readily. Always place food on a plate or in a bowl while defrosting to prevent any liquid it releases from coming in contact with other foods. Most food will take 24 hours to thaw fully. (Larger items, like whole turkeys, can take far long-er. Count on about 5 hours per pound.)
When food is reheated, it should be brought through the danger zone as quickly as possible—don't let it come slowly to a simmer. Bring leftover sauces, soups, and gravies to a boil and make sure casseroles reach at least 165 degrees, using an instant-read thermometer to determine whether they're at the proper temperature.
Though it may go against your instincts, don’t put hot foods in the fridge immediately after cooking. This will cause the temperature of the refrigerator to rise, potentially making it hospitable to the spread of bacteria. The FDA recommends cooling foods to 70 degrees within the first two hours after cooking and 40 degrees within four hours after that. We stay within these guidelines by cooling food on the countertop for about an hour, until it reaches 80 to 90 degrees (food should be just warm to the touch), then transferring it to the fridge.