How to Choose Microwave Safe Containers

Co-authored by wikiHow Staff

Last Updated: September 18, 2022 References Tested

In recent years, there has been growing concern about potentially hazardous substances leeching into food from microwave containers.^{[1]
X
Trustworthy Source
Harvard Medical School
Harvard Medical School's Educational Site for the Public
Go to source} Most of the concern focuses on plastic containers, specifically those containing bisphenol-A (BPA) or phthalates.^{[2]
X
Research source} But you may use the microwave for the convenience of reheating and thawing foods. By informing yourself on different products available to heat food in the microwave, you can choose the best containers for your needs and protect your health.

Part 1

Part 1 of 2:

Finding Safe Dishes

1
Be aware of potential health hazards. Some microwavable containers, especially those made of plastic, can be potentially harmful to your health. Others, like glass or plastic dishes, are better for your health. Informing yourself about the potential dangers of certain types of microwave-safe containers may help you make a safer choice.^{[3]
X
Trustworthy Source
Go Ask Alice
Medical advice site with content written by health promotion specialists affiliated with Columbia University
Go to source} Some of the potential health hazards are:
- ”Endocrine disruption,” which mimics human hormones.^{[4]
  X
  Trustworthy Source
  Harvard Medical School
  Harvard Medical School's Educational Site for the Public
  Go to source} This may have effects such as modifying chemical signals that regulate metabolism and reproduction.
- Miscarriage and birth defects
- Lower sperm counts
- Early puberty
- Cancer
- Obesity and diabetes
- Neurobehavioral abnormalities.
2
Learn what substances to avoid. “Plastic” is a generic term for different materials, or plasticizers, that can form microwave containers. In particular, it's plastic containers with BPA, phthalates, polyvinyl chloride, and polycarbonate that may harm your health. Although the Food and Drug Administration (FDA) closely regulates plastic containers and materials that come in contact with foods, you may still want to learn and avoid potentially hazardous chemicals. The following containers may be harmful if microwaved with food:^{[5]
X
Research source}
- Plastic dishes
- Some Styrofoam containers
- Plastic storage or shopping bags
- Plastic wrap
- Takeout food containers, water bottles, and plastic tubs or jars that hold foods like margarine, yogurt, mayonnaise, or mustard.^{[6]
  X
  Trustworthy Source
  Harvard Medical School
  Harvard Medical School's Educational Site for the Public
  Go to source}
- Soft plastic containers
Advertisement
3
Look for safety designations. In many cases, containers are manufactured to be microwave-safe and may have labels on their packing and the products indicating this. In addition, you may want to make sure that the containers also bear other markers that can indicate they're safe for microwave use and your health. Check packaging and the product for the following symbols or statements:^{[7]
X
Trustworthy Source
US Food and Drug Administration
U.S. government agency responsible for promoting public health
Go to source}
- A label ”microwave-safe”
- A symbol of a dish with wave-like lines above it.
- A symbol of lines of waves.
- A symbol of a triangle, or Mobius loop, with a number in it. The number designates the type of plasticizer used in the product, which you may want to avoid.
4
Search your pantry. You may already have microwave- safe containers in your kitchen. Before purchasing new containers, look in your pantry to see what you have and can use.
- Read containers for labels including “microwave-safe.”^{[8]
  X
  Trustworthy Source
  Go Ask Alice
  Medical advice site with content written by health promotion specialists affiliated with Columbia University
  Go to source}
- Be aware that there is no consensus on plastic wrap and microwaves. If you use plastic wrap in the microwave, make sure the packaging says “microwave-safe.”^{[9]
  X
  Research source}
- Check for containers that are old, scratched, cracked, or have been used frequently. These may leech out more harmful materials. Consider throwing these away and investing in new containers.^{[10]
  X
  Trustworthy Source
  Harvard Medical School
  Harvard Medical School's Educational Site for the Public
  Go to source}
- Make sure glass or ceramic containers have the “microwave-safe” label and do not contain any materials, such as rims, made of gold or other materials not safe for the microwave.^{[11]
  X
  Research source}
- Be aware that, contrary to popular belief, you can microwave some Styrofoam or other polystyrene containers. Just make sure to check that they are labeled microwave-safe.^{[12]
  X
  Research source}
5
Purchase new containers. Even if you need microwave-safe containers and want to buy new ones, it's easy to find microwave-safe options at most retailers. Read package labeling and the product itself for descriptions and symbols that designate the product microwave-safe.^{[13]
X
Research source}
- Remember that glass and ceramic containers are the safest options for microwaving. Check to make sure that they also carry the “microwave-safe” designation.^{[14]
  X
  Research source} Just be aware that these products may be more expensive than plastic, though they may also last longer.
- Buy plastic containers and wrap marked microwave-safe.
- Consider checking the Good Housekeeping Institute's test results for the best and safest containers to use in the microwave.^{[15]
  X
  Research source}
6
Run a safety test. There is a method you can use to check a container's safety that you are unsure of or one that has a microwave-safe label. Running this safety test may help you decide if you want to use the container or opt for another one.^{[16]
X
Trustworthy Source
Michigan State University Extension
Extension program of Michigan State University focused on community outreach, education, and engagement
Go to source}
- Empty the container you want to test and place it inside the microwave.
- Put a second container containing one cup of tap water inside the microwave.
- Heat the microwave on high for one minute. If the empty container is cool, it's safe to use in the microwave. If it is warm, use it only to reheat food and if it is hot, don't use it in the microwave at all.

Part 2

Part 2 of 2:

Using Safe Microwaving Practices

1
Read microwave instructions. Microwaves make many things in our lives easier. But they don't come without potential hazards and it's important to read the instruction manual for your microwave to avoid harming yourself or others.^{[17]
X
Research source}
- Contact the microwave's manufacturer if you have any questions.
- Check online for product manuals if you lost your instruction packet.
- See if there are specific suggestions on the type of containers or wrap you can use. For example, some microwaves can use specific types of aluminum foil, while others can't.
- See if there are instructions or suggestions for specific foods. For example, most meats cannot be cooked at full power, but instead at half power for longer.
2
Follow prepared food instructions. If you want to cook prepared foods in your microwave, read the packaging instructions. In most cases, these containers can only be microwaved once and may also have specific heating requirements.^{[18]
X
Research source}
- Vent containers if required by puncturing them with a fork or peeling back a corner of the plastic wrap.^{[19]
  X
  Research source}
- Make sure you closely check the heating requirements. For example, some foods can only be cooked at 50% power and not following this could ruin your meal and your microwave.
3
Arrange food for reheating. If you're going to use a covered dish to reheat food, it's arrangement in the container can affect the heating process. Arranging your food evenly within the container can help ensure uniform cooking and may help destroy harmful bacteria.^{[20]
X
Research source}
4
Cover food safely. In many cases, you may need to cover food you've prepared yourself to heat it in the microwave. Making sure you use safe types of covers and vent the container can ensure that you don't cause unsafe chemicals to leech into your food.^{[21]
X
Research source}
- Choose plastic wrap that is labeled microwave-safe. However, never let it contact your food.
- Consider using waxed or kitchen parchment paper, white paper towels or plates, or a domed microwave container to cover your food.^{[22]
  X
  Trustworthy Source
  Harvard Medical School
  Harvard Medical School's Educational Site for the Public
  Go to source}
- Loosen or vent the lid or any wrap to allow steam to escape.
- Stay away from brown paper bags, newspaper, foam containers, and most aluminum foil as covers.
5
Check food during cooking. Midway through the microwaving process, check your food to make sure it is cooking properly. Consider rotating or stirring the food to eliminate cold spots.^{[23]
X
Research source}
- Be aware that cold spots in food can contain harmful bacteria.
- Use a food thermometer to check temperatures, especially of meat.

Community Q&A

Question

Are acrylic coffee mugs microwave safe?

Community Answer

It depends on the brand. You can usually tell by looking at the bottom or checking online on the brand's website.
Question

Are microwavable dinner foods safe in the microwave?

Community Answer

Yes. Any microwaveable food packages that say they are safe in the microwave, should be.
Question

Can I microwave plastic?

Community Answer

No, unless the plastic is marked as microwave safe.

Warnings

Use caution when removing items from the microwave oven. Remove the lid or cover with care to avoid being burned. Check the temperature of the container before lifting it with your hands.

⧼thumbs_response⧽
Helpful 0 Not Helpful 0
Never use the microwave to can vegetables or to sterilize the glass jars used for canning.^{[24]
X
Trustworthy Source
Penn State Extension
Educational organization dedicated to delivering science-based information to people, businesses, and communities
Go to source}

⧼thumbs_response⧽
Helpful 0 Not Helpful 0