Why you need to stop microwaving plastic
  /  
More +
This post may contain affiliate links, earning us a commission at no additional cost to you.
Learn more.
Kitchenware
Science
+ More

Why you need to stop microwaving plastic

Why you need to stop microwaving plastic

/

Microwaving food in plastic-based containers or packaging can shed up to billions of microplastic and nanoplastic particles into your next meal.

By
Tim Barrett
, the creator of No Plastic, No Problem and a writer focused on ways to reduce daily microplastic exposure.
Updated
Dec 29, 2024 9:28 PM
the tl;dr:
  • Microplastics interfere with human hormones, development, fertility, and more when consumed.
  • Single-use and reusable plasticware contaminates food on contact, and breaks down more rapidly under high heat applications.
  • ‘Microwave-safe’ plastic will still shed microplastics into food, even without being microwaved.
  • Switching to glass containers for storing and reheating food is an easy way to protect yourself from microplastic exposure.

Recommended in this article

Microwaving plastic containers can release billions of particles into your food.

Microplastics, which can be shed from plastic kitchenware, are already known to wreak havoc on human health and development. but under no circumstances should plastics of any kind be microwaved for purposes of reheating, cooking, or defrosting food.

According to a recent 2023 study by the American Chemical Society, every square centimeter of microwaved plastic could release millions, if not billions of microplastic and nanoplastic particles into your next meal.

microwave microplastic diagram

Billions of particles can leach every time you microwave plastic. Photo by American Chemical Society.

Microwave ovens operate by generating electromagnetic waves that excite water molecules in food, vibrating and creating heat through friction, cooking your food from the inside out. When these hot foods are in contact with plastic containers or materials, the breakdown of plastic accelerates substantially.

This applies to all plastic tupperwares, plastic baby bottles, plastic wrap, ziplock bags, and silicone kitchenware.

Microwavable plastic containers are never truly ‘microwave safe’.

‘Microwave safe’ has been a marketing label most commonly applied to polyethylene terephthalate (PET/PETE) plastics, such as microwave safe plastic plates and tupperware. Unfortunately, these claims have been proven false.

There is no definitive proof of any plastics that are 100% resistant to breaking down in any situation, and specifically under the high heat application of a microwave.

Can I use a ziplock bag in a microwave?

Since ziplock bags (and other generic brands) are made from low density polyethylene (LDPE) and linear low density polyethylene (LLDPE), a type of plastic that is even more susceptible to microplastic emission than PETE plastics, they should never be microwaved and ideally never used for food storage at all.

Can I microwave plastic glad wrap or saran wrap?

Similar to ziplock bags, Glad wrap or saran wrap is made from LDPE and sometimes polyvinyl chloride (PVC). PVC is particularly one of the worst offenders for microplastic leaching in your food, so it should not be microwaved.

Can I microwave plastic baby bottles?

Plastic or partially plastic (silicone nipple) baby bottles should also never be microwaved as well. Toddlers and young children are especially prone to the negative effect of microplastics such as disruptions to hormone balance and physical and cognitive development.

If you are going to warm baby formula in the microwave, use a glass-constructed bottle and be sure to remove the silicone or natural rubber nipple beforehand. 

You can learn more about the best plastic-free baby bottles in our product guide.

Can I microwave plastic to go containers?

Whether it’s Chinese takeout or leftovers from date night, you may be inclined to keep your General Tso’s chicken in its original container. These containers are made from polypropylene (PP, often referred to as #5 plastic).

This plastic, like many other types, is technically FDA approved yet modern studies still show that this material also releases microplastics

We recommend avoiding plastic to go containers when possible, or at least moving your food to a non-plastic container for storage. 

If you are in the restaurant business, or simply want safe non-plastic single-use food containers for home, see our article for more information and alternatives.

Avoid microplastics - microwave foods in glass instead.

If you want to safely reheat your food without microplastic contamination, opt an inert material such as glass.

Glass tupperwares do not release harmful chemicals into foods that are stored or reheated. 

Check out our product guide on plastic-free glass tupperwares to affordably replace your plastic food containers.