Can you microwave food in plastic containers?

Growing up in the 1970s and 1980s, Tupperware was always in my home. When we finished a meal, leftovers were stored in plastic Tupperware containers. They held everything from sandwiches for lunch, desserts for a party, to cheeses in the fridge.

When I moved out, I continued to use plastic containers to freeze the food I prepped. After a few minutes in the microwave, I had a healthy, hot, delicious meal. But since I was on a budget, I started using less expensive options like Gladware, Rubbermaid and Ziploc plastic storage containers.

I didn't think much about the safety of those containers. Unless you were a chemist or medical researcher, there wasn't a lot of information available. But I did start to question how stable they were. Anyone that's made a red sauce knows that if it's been frozen and later reheated, those red stains may never come out. I began to wonder if color can be absorbed INTO the plastic; can plastic leach OUT into my food?

Fast forward to 2008, and a lot of things happened. The United States National Toxicology Program released a statement based on their continuing research into Bisphenol A or BPA. That's one of the chemicals used to make plastics found in food and drink packaging, water and infant bottles, food can liners and children's toys.

They said, "The NTP has 'some concern' for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to BPA."

That same year, Health Canada declared BPA toxic "because of reproductive and developmental toxicity and environmental effects." That was the year Canada banned polycarbonate baby bottles that contained BPA.

Ultimately, researchers were able to conclude that BPA is an endocrine disrupter and linked it to developmental problems in fetuses, infants and children. Studies also showed BPA suppresses a hormone that protects people from heart attacks and type 2 diabetes.

Manufacturer's worked hard to remove BPA from products for infants and children and also things like water bottles and food storage containers. Gladware, Rubbermaid and Ziploc are all BPA-free.

Here's where things get a little confusing.

In 2018, according to the U.S. Food and Drug Administration, "...BPA is safe for the currently authorized uses in food containers and packaging."

As of July 2020, Health Canada states, "Exposure to BPA from food packaging does not pose a health risk to Canadians, including infants. There was a potential concern for infants, which led to added protective measures."

Even the European Food Safety Authority, as of 2022, believes there are "tolerable daily intake(s)" of BPA in things that make contact with food.

If BPA is safe, why has it been removed from so many products?

You have to read those statements very carefully. They set limits with "tolerable daily intakes" and clarify that it's OK in "currently authorized uses." Those authorized uses include the lining of food cans or in a container that's single-use.

The problems happen when you use BPA-laced containers repeatedly. Washing plastic in a high-temperature dishwasher breaks the chemicals down over time. When you reheat the containers in a microwave, they break down even more, potentially contaminating food. To avoid those problems, name-brand containers dumped BPA years ago and got certified "Microwave Safe."

But there's another problem.

Removing BPA is excellent for marketing, but it changes the properties of the plastic. So to keep the containers the same as before, BPA alternatives like bisphenol-S are used.

Now, you would think that if someone suggested replacing bisphenol-A with bisphenol-S, somebody would check to see if it was toxic. Companies should ensure bisphenol replacements don't have the same problems as what they're replacing. But if you thought that, you'd be wrong.

In a 2018 study, researchers found that; "'BPA-free' products produced using structurally similar bisphenols... are now detectable environmental and human contaminants." The alternatives may cause the same problems as the original.

Fortunately, there are a few simple things you can do. Here's what Consumer Reports suggests.

1. Never put plastic in the dishwasher or microwave. The heat can cause chemicals to leach out.
2. If possible, replace plastic with glass, ceramic or stainless steel containers.
3. When using glass or ceramic in the microwave, cover with a towel to prevent food splatter.
4. Hand wash the plastic lids that glass containers use. Lower heat in the sink helps prevent them from breaking down, they retain their form and rubber seals work longer.

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Reference Links:

Bisphenol A (BPA) from U.S. Food & Drug Administration

Food Packaging & Other Substances that Come in Contact with Food - Information for Consumers

Click Here for the Information: https://www.fda.gov/food/food-packaging-other-substances-come-contact-food-information-consumers/bisphenol-bpa

 

BPA Exposure and Health Effects: Educating Physicians and Patients

REBECCA ROBERTS, PhD, Ursinus College, Collegeville, Pennsylvania
American Family Physician, June 1, 2012; 85(11):1040-1044

Click Here for the Study: https://www.aafp.org/pubs/afp/issues/2012/0601/p1040.html

Bisphenol A (BPA)

Health Canada, Date modified: 2020-07-29

Click Here for the Information: https://www.canada.ca/en/health-canada/services/home-garden-safety/bisphenol-bpa.html

Bisphenol A

European Food Safety Authority, 2021

Click Here for the Information: https://www.efsa.europa.eu/en/topics/topic/bisphenol

Replacement Bisphenols Adversely Affect Mouse Gametogenesis with Consequences for Subsequent Generations

Tegan S. Horan, Hannah Pulcastro, Crystal Lawson, Roy Gerona, Spencer Martin, Mary C. Gieske, Caroline V. Sartain, Patricia A. Hunt
Current Biology, 24 September 2018, Pages 2948-s2954.e3

Click Here for the Study: https://www.cell.com/current-biology/pdfExtended/S0960-9822(18)30861-3

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9/12/2022
Updated 9/2/2025