The answer to how many reheats food can take boils down to "it depends." Chilling and reheating foods safely requires strict attention to timing and temperatures. If you're scrupulous about that, you can reheat food several times. If you're not, even reheating leftovers once can be a gamble. A second consideration is the effect of repeated heating and cooling on the flavor and texture of your food. Some foods, such as chili, can stand successfully to repeated heating. Others deteriorate quickly, so you might not want to eat them even if they're food safe.

The first step in safe reheating is cooking your foods to the USDA-recommended food safe temperature. For most casseroles and other mixed dishes, that's 160 to 165 degrees Fahrenheit. Invest in an inexpensive instant-read thermometer, because measuring is the only way to know for sure. Once the food is cooked, cool it as quickly as possible to 90 F or 100 F. Shallow casseroles can be cooled in the pan, but food in large pots should be transferred to shallow, flat containers for faster cooling. It must reach the target temperature within two hours, then be refrigerated at 40 F or below.

When you reheat your meals, choose a method that's appropriate. Stews and soups can be heated in a saucepan or the microwave. Casseroles can be microwaved or reheated in the oven, and cold plates of meat and potatoes can be microwaved while the sauce or gravy boils in a separate saucepan. However you heat your food, it must come to at least 165 F, for at least 15 seconds, to be food safe. If you use a microwave, remember that they heat unevenly. Stir your food frequently as it heats, let it rest while the heat evens out, and test it in several places with your thermometer. Foods should heat completely in two hours or less.

Although time and temperature are the two most important factors in food safety, there are a few others to consider. Be sure your containers and serving utensils are scrupulously clean, and use separate utensils for each food. Be careful not to contaminate one dish with utensils from another, or to mix cooked and uncooked food. Whenever possible, refrigerate your leftovers in single-serving portions. That way, you can reheat each serving just once. This minimizes food safety risks by cutting down the number of opportunities to make a mistake, and also reduces the loss of quality caused by multiple reheatings.