The Information Age is upon us, but without the Internet and smartphones, it’s arguable for us to call the 21st Century the Plastic Age instead. Ever since the later 20th Century, plastic has become largely integrated into our everyday life. You can find plastic everywhere, from containers to our very appliances. You can even commonly find them in PET bottles (for bottled water), wraps, and bowls for food and drink storage, in fact.
With that said, is plastic microwaveable (or microwavable)? Can you microwave containers, bags, and bottles made of plastic? For the most part, the answer is no. Heating plastic at high temperatures can release toxic compounds that could contaminate your food. But there such things as microwaveable plastic.
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Can You Microwave Plastic?
People, mostly homeowners, are curious whether you can expose your food and yourself to microwaved plastic. Can you microwave plastic? The long and short of it is yes, but only the ones labeled as “microwave-safe” and are in good condition (it’s not old, it hasn’t been microwaved multiple times, and it doesn’t have any cracks or tears on it).
- According to Studies: According to studies, certain chemicals in the plastic can leak out of it and into food when they’re microwaved. Actually, microwaving them is only the start. This is also applicable to PET bottles that go past their expiration dates, thus making them unusable for water because they can contaminate the liquid. Damaged plastic, when microwaved or exposed to high temperatures, can produce toxicity and VOCs (volatile organic compounds) even if they are microwaveable. On that note, there’s a limit on the amount of times you can microwave microwaveable plastic.
- Toxic Chemicals in Plastic: Burnt or degraded plastic from microwaving or simple burning on the stove can release chemicals that have been linked to health issues such as reduced fertility and metabolic disorders like obesity. You do not want those chemicals leaching from the plastic to your food, leading to contamination. When plastic is exposed to heat, even when it’s not to the point of catching fire, the leaching can still occur. It’s worse when it’s melting and on fire though, since that definitely releases VOCs and carcinogens (cancer-causing compounds).
- The Earliest Missives: There’s a good reason why there are warnings against microwaving plastic. It releases carcinogens called dioxins that can latch unto your food, which can make you sick immediately or down the line. Dioxins are created not because the plastic has them from the start but instead when the plastic becomes hot enough to melt or burn, like in the case of a dumpster fire. You aren’t exposing yourself to dioxins as long as you don’t burn your food.
- Contaminated Food: The danger of microwaving food in single-use or damaged plastic containers that aren’t microwaveable is that you can get higher dosages of potentially harmful toxins, chemicals, and compounds from melting or compromised heated plastic. You don’t want your leftovers laced with carcinogens for obvious reasons. Even if the plastic is microwavable if it’s cracked or damaged it’s likelier to become toxic to the food you’re heating on it. It’s best to use a microwavable plastic container that has no cracks at all.
What are Plastics Anyway?
There’s no single thing or substance known as plastic. It’s more of an umbrella term. It covers many types of substances and materials made from a wide array of inorganic and organic compounds. Substances are often mixed or added to the plastic formula to make the material more stable or give it shape.
- Learn More About Plasticizers: A plasticizer is what the plastic formula used to stabilize and shape a plastic material is called. You can add something like BPA or bisphenol-A to create hard and clear plastic material. Meanwhile, you should use phthalates in order to make plastic more flexible and soft, like the plastic used for grocery bags. Phthalates and BPA could be called “endocrine disrupters” as well because they can mimic human hormones. In other words, you shouldn’t ingest them.
- Microwaving BPA and Phthalates: When you wrap food in plastic or place your leftovers in a non-microwavable plastic container, the heat can make the plastic leach out phthalates and BPA. Once these endocrine disrupters end up and contaminate your food through microwave-induced migration, you could end up with health problems down the line or sooner. Any migration of these substances is likelier to happen with fatty foods such as cheeses and meats compared to other food types like fish and vegetables.
- The FDA’s Take on Microwaved Plastic: Long, long ago, the Food and Drug Administration of the U.S. deemed that small amounts of plasticizers have the potential to migrate into food, especially when microwaved. Therefore, the FDA closely watches and regulates materials and containers made of plastic used for food packaging and leftovers for the sake of public safety. The government body requires plastic makers and manufacturers to rigorously give their containers a battery of tests that meet their stringent specifications and standards.
- The FDA Plastic Container Safety Test: The FDA requires plastic container makers to use FDA-standardized tests that the governing body then reviews before approving a container as microwave-safe or not. Some of these tests are capable of measuring chemical migration as temperatures in the wrap or container goes up during ordinary microwaving.
For a container to get approval, the agency has to make estimates like the following:
- The ratio of plastic surface area in relation to the food.
- How hot the food is predicted to get when microwaved.
- How long the container remains in the microwave oven.
- How often a person is likely to eat from such a container.
- 100 to 1,000 Times Less Per Pound: The scientists doing research on behalf of the FDA also measure chemicals that spill into your leftovers and how much of them they migrate in different food types. The maximum allowable amount according to FDA standards is 100 to 1,000 times less per pound of body weight than the amount shown that affects the health of lab animals over lifetime usage. Only plastic objects that pass the FDA test can be given the microwave-safe icon or have the label of such. Even then, if they’re broken or damaged in any way, you should stop using them.
- Not Necessarily Safe: Regarding microwave-safe containers, they’re technically or not necessarily unsafe. Rather, until further research is made unto them, the FDA has deemed them to not leach off or out chemical compounds like BPA and phthalates. In your case, you only need the check the label of the plastic to ensure yourself that it’s safe or not. Otherwise, you shouldn’t use it. You should only use FDA-approved, microwave-safe plastic containers for your own health to keep your leftover food from being contaminated.
What Should You Keep in Mind When Using a Microwave?
When using a microwave, keep in mind the following tips and issues.
- Err on the Side of Caution: If you’re worried about food contamination due to heating up plastic wrappers or containers in your microwave oven, err on the side of caution and transfer the food to a ceramic or microwave-safe glass container. Even if in the end you find out the container is microwave-safe, it’s okay.
- Plastic Wrap Alternatives: Don’t let plastic wrap touch your food while being heated in your microwave oven because of the melting risk. On that note, don’t let it touch the food after it was recently heated either. The better wrapper alternatives for handling food heating include a domed container, white paper towels, kitchen parchment paper, and wax paper.
- Plastics to Avoid: Other plastic containers that are more often than not microwave-unsafe include jars or plastic jars for mustard, mayonnaise, cream cheese, yogurt, whipped cream, and margarine as well as water bottles and single-use takeout containers.
- One-Time Use Microwaveable Trays: The takeout dinner trays that have the microwaveable label are made to be used for one time only or for single-use only. It will even declare as such on the package itself if you were to check.
- Don’t Use Old Containers or Recycle Them for Microwaving: Even the containers that are microwave-safe should be disposed of if they’re already old, have scratches and cracked portions on them, or have been microwaved multiple times. They’ve been compromised. At this point, they might soon leach out plasticizers themselves.
- Grocery Store Plastic Bags are a No-No: Absolutely don’t microwave food on plastic storage bags, garbage bags, or bags you’ve gotten from the grocery store. They aren’t food safe and they’re likely to melt and leave a smell inside your microwave oven if you insist on microwaving them.
In the end, it’s best to play it safe and just use ceramics or microwave-safe glassware for your reheating needs for leftovers you’ve taken straight from your refrigerator. Otherwise, always check of the “microwave-safe” label on the container.
There are several other things you need to keep in mind when using a microwave with a plastic container. Make sure the container is labeled as microwave-safe. Doubly so, make sure the container is new and without cracks. Furthermore, a container that’s been used for microwaving multiple times or is damaged in any way shouldn’t be microwaved any further. You should microwave a microwave-safe plastic container once or twice but not multiple times. Or you should avoid microwaving an old or decrepit container for fear of leaching of compounds.
- “Microwaving food in plastic: Dangerous or not?“, Harvard.edu, September 20, 2017
- Amy Reiter, “Is It Really That Bad to Use Plastic in the Microwave?“, Food Network, February 1, 2019