Health Library

Safe Microwave Cooking

PD V20 FD001677 Microwaves do not cook food like ovens do. In a regular oven, hot air makes the food and its container hot,. In a microwave, the air is cool. The waves it emits cause food molecules to vibrate. The friction it causes results in heat. This heat can be hot enough to kill the bacteria in foods. But there are some limits.

Microwaves mainly heat the molecules on the outside of the food. This can result in cold spots where bacteria can live. But there are steps you can take to prepare food safely.

Using a Microwave

Follow these tips when using a microwave to cook raw food or reheat a meal:

  • Cut food into pieces that are the same size to exposure more of the food to the microwaves.
  • Arrange thicker pieces on the outside of the dish where they will receive the most heat.
  • Cover the dish with a lid, paper towel, or microwave-safe plastic wrap. This will trap in moist heat that will help kill bacteria and keep the food temperature even.
  • Some microwaves have a rotating dish in the center. If yours does not, stop the microwave halfway through the cooking time to rotate the dish.
  • Stir the food halfway through its cooking time. This will help lower the chances of cold spots and bacteria.
  • Food keeps cooking after the microwave turns off. Let it sit before eating to let it fully heat and kill bacteria.

Food Safety

Here are some food safety tips you should follow when using a microwave:

  • Not all microwaves are the same. Some take more or less time to cook the same food. Use a food thermometer to make sure that the food has reached a safe cooking temperature:
    • Red meat: 160˚F (71°C)
    • Poultry: 165˚F (74°C)
    • Pork: 160˚F (71°C)
    • Leftovers: 165˚F (74°C)
  • Do not cook a stuffed poultry in the microwave. The stuffing may not reach the temperature needed to kill bacteria.
  • Large cuts of meat should be cut smaller or they should be cooked on 50% power (medium) to allow the heat to reach the center without overcooking the outer areas.
  • All defrosted foods should be cooked right away. Never partially cook food and store it for later use.

Take special care when heating baby formula in a microwave. It may result in a scald to the baby's mouth or throat. A bottle might not feel warm to the touch after it has been microwaved, but there may be hot spots in the liquid. Do not heat or thaw breastmilk in the microwave. The excess heat can destroy proteins and other nutrients.

Containers and Wraps

You will need to cook food in a container that will not melt. If the container melts, harmful chemicals can leak into the food.

Use cookware made of:

  • Glass
  • Ceramic
  • Other containers that are labeled as microwave safe

Never use:

  • Aluminum foil
  • Plates made of Styrofoam or plastic plates that do not say they are microwave safe
  • Storage containers, such as margarine tubs and take-out containers with metal handles

Plastic wraps are often used to cover food while cooking in a microwave. Wraps that are not microwave safe have chemicals that would be harmful if they leaked into the food. Steps should be taken to make sure that the plastic wrap does not touch the food at all. Never reuse plastic wrap. A paper towel or a lid for a microwave-safe container might be the safest choice.

Microwave Oven and Nutrition

Microwaves do not destroy nutrients. But heat can lower the nutrient level in foods. Water can also dissolve and wash away vitamins. This is true of any type of cooking.


Eat Right—Academy of Nutrition and Dietetics

Food Safety and Inspection Service—United States Department of Agriculture

Canadian Resources

Health Canada

Partnership for Food Safety Education


Cooking meat safely. Clemson University Cooperative Extension Service website. Available at: Accessed November 3, 2021.

Cooking safely in the microwave oven. United States Department of Agriculture website. Available at: Accessed November 3, 2021.

Dietary guidelines for Americans 2020-2025. US Department of Agriculture and US Department of Health and Human Services. Available at: Accessed November 3, 2021.

Microwave cooking and nutrition. Harvard Health Publishing—Harvard Medical School website. Available at: Accessed November 3, 2021.

Microwave ovens and food safety. United States Department of Agriculture website. Available at: Accessed November 3, 2021.

Proper storage and preparation of breast milk. Centers for Disease Control and Prevention website. Available at: Accessed November 3, 2021.