How to Cook Leftovers and Make Them Taste Great

Here is a quick guide to storing, reheating, and eating leftovers safely and with maximum flavor.

Food becomes leftovers 2 hours after you cook it

Cooking kills most of the bacteria in food, but it almost never kills all of them. Cooked food is safe for 2 hours after cooking (1 hour if put on a serving table outdoors in hot weather), but at that point it must be refrigerated so that it does not go bad. The time starts just as soon as the food is taken off the stove or out of the oven, and continues while it is on the counter or on the table until it is put into the refrigerator. If you don't get your food back in refrigeration quickly, throw it out. Don't risk food poisoning to save on your food budget.

Wash your hands with soap and warm water before handling food you want to store for later

Bacteria transferred from dirty hands can incubate slowly and unnoticed on leftovers you store in the cooler, or even in the freezer. It is also essential to handle leftovers with clean utensils and to store them in clean containers. Don't put cooked food in the same containers or on cutting boards used when for preparing raw food.

Store food in shallow containers, no more than 3 inches (75 mm) tall

Mounds of food in a bowl provide a warm, cozy shelter for bacteria. Spreading food out in a shallow, closed container ensures that it chills evenly and quickly, stopping bacterial growth. It is also important not to stack food containers on top of each other. This also traps heat that can nurture microorganisms.

Salads with creamy dressings keep longer than chopped salads without dressings

Deli salads in general tend to be safe for leftovers if you don't leave them out too long. E. coli does not multiply in mayonnaise (although it's possible to buy a salad that has enough E. coli when you buy it to make you sick).

Adding vinegar to salads stops bacterial growth

Lowering the pH of a deli salad from 4.5 to 4.3 (roughly equivalent to adding a teaspoon of vinegar to half a pound/200 grams of salad) slows the growth of E. coli by 99%. Vinegar will not stop the growth of Listeria bacteria, but these bacteria do not grow to numbers that can cause food poisoning unless the salad is allowed to warm up to about 75° F/24° C.

Don't keep leftovers more than a week

Acidic foods may keep as long as a week in tightly closed containers. Most of the time, however, leftovers should be eaten in three days or less. Dating the container gives you a way to make sure you are not keeping a leftover too long and risking stomach upset or worse. If you are pickling a food, for instance, making sauerkraut or kimchi at home, room temperature storage while it is fermenting is OK.

If it smells bad, throw it out

No matter when you put leftover food into the refrigerator, don't eat it if it smells bad. Your nose knows when food is not fit to eat.

How to Heat Up Leftovers

Storing leftovers safely, however, is just part of the process. You also want to reheat them safely in ways that make them taste better.

Reheat most leftovers quickly rather than slowly

If you cook with care, you heat a dish until it's just right. The problem with reheating leftovers is that it is very easy to take them past the point of just-rightness. It's better to bring leftovers to a tasty temperature quickly rather than slowly so that they are not overcooked. It's also better to cook quickly so that bacteria don't have a chance to multiply. Don't reheat leftovers in a crock pot or slow cooker!

Use the microwave judiciously

Generally speaking, if a crispy food contains a lot of fat, it's not a suitable candidate for microwaving. Pizza, for instance, just turns into a soggy mess when cold pizza is reheated in a microwave oven. The oil in the crust and the oil in the cheese simply drip to the bottom of your plate.

For reheating just one or two slices of pizza, heat a skillet, preferably a cast-iron skillet, and add a tiny amount of oil (few drops), just enough barely to coat the heating surface. Heat the oil until it smokes and then take the pan off the heat, placing the slices of pizza in the pan for 3 to 5 minutes until the cheese remelts. This keeps the crust crispy and adds only a few more calories to this high-calorie dish.

For reheating an entire pizza, heat an oven to about 350° F/175° C. Put the pizza on a cookie sheet and allow to reheat until the cheese melts.

Other foods that taste better if they are not reheated in the microwave include:

• Chili. Chili meat absorbs liquid while it is refrigerated. Add a small amount of stock to the chili remaining in the pot and bring the mixture to a fast boil. Then take the chili off the burner and allow the meat to absorb the stock before serving.
• Pasta. Pasta also absorbs liquid from pasta sauce during refrigeration. Put a little stock or cream in a pan and bring to a boil. Then add the pasta with the original sauce to allow it to heat through.
• Burgers. Don't try to refrigerate a whole hamburger, patty, bun, and vegetables with mayonnaise, pickles, and mustard. Just store the burger itself, and serve on a fresh bun with fresh vegetables. Reheat the burger by placing on a baking sheet in a hot oven for 5 to 6 minutes, until the outside of the patty is hot to the touch.
• Pork chops, steaks, and roasted chicken. Leave the meat out on the counter for 20 to 30 minutes to bring back to room temperature. Place the meat in an oven-safe skillet and transfer the skillet into a preheated oven. Allow a crust to form on the bottom of each piece of meat (usually after 5 to 7 minutes) and then turn it over to cook on the other side. Take out of the oven and allow the meat to stand for 5 minutes before serving.