Packaged frozen dinners often come in plastic trays with a plastic film over the top. While most people cook these dinners in the microwave, the directions on some of them say you can place the plastic trays on a cooking sheet and bake them in a conventional oven. Does that mean it’s safe to put plastic containers in an oven?
Plastic containers should not be considered oven-safe at any temperature. Most plastic storage containers are made of polypropylene, which has a melting point of 240-260° F (115-125° C), whereas the average cooking temperature in an oven is 350° D (177° C). Even before the plastic melts, it becomes soft and could emit dangerous chemicals.
Special kinds of commercial-grade plastic, called crystallized polyethylene terephthalate (CPET) can withstand temperatures of 400° F (204° C). These are the kinds of plastic you may see in a frozen dinner. They should not be re-used.
The plastic containers you use to store leftovers are not made from CPET and are not oven safe. Most containers are made of polypropylene, but a few containers, such as Rubbermaid Brilliance, are made from Tritan plastic. Neither of these should be used in the oven.
If you have stored leftovers in a plastic container, do not reheat them in the oven. Instead, you can place the plastic container in the microwave, with the lid vented. Or, remove the food from the plastic container and put it in an oven-safe dish made of glass or metal.
Will Plastic Containers Melt In Oven?
If you follow instructions on the box of a frozen dinner that is safe to put in a conventional oven, then you will not have to worry about the plastic melting. However, exceeding the recommended temperature or using your own plastic container made of polypropylene can result in melting.
Even before polypropylene in a plastic container reaches its melting point of 240-260° F (115-125° C), the plastic will begin to warp, bend, and soften. If not removed, the plastic container will melt and could possibly stick to your cooking tray or your oven rack.
You may have witnessed the warping and bending if you’ve ever put plastic containers in the lower rack of your dishwasher. When the plastic is that close to the heating element, the high heat can ruin the container. Continuous heat, such as that produced in an oven, can result in melting.
If you put your plastic container in the oven and melting occurs, you will have a mess on your hands. You will have to cool the plastic and scrape it out piece by piece.
The CPET containers that are in packaged frozen meals will stay firm unless the temperature of your oven exceeds 400° F (204° C). Then, it will also start to melt.
Most plastic containers made from polypropylene do not contain BPAs, or Bisphenol A, a chemical that has been linked to cancer. However, inhaling the fumes from melting containers could irritate the respiratory system and cause coughing or asthma-like symptoms.
To be safe, do not put plastic containers in a conventional oven, ever.
Plastic containers are also not safe for toaster ovens, convection ovens, or air fryers. All of these appliances use heat that is higher than the melting point of plastic.
How Do You Know If A Container Is Oven Safe?
If a plastic container isn’t safe to put in an oven, should you be wary of other types of containers, also? How do you know if a container is oven-safe?
If your container is made of glass, metal, stoneware, or ceramic, it is safe to go in the oven. Most cooking sheets, casseroles, and baking pans are made of these types of materials. Silicone can also be used in the oven to temperatures up to 425° F (218° C).
Be very careful before putting any kind of storage container in the oven because these containers are often made of a combination of materials. For example, you will frequently find glass storage containers with plastic press-on or latching lids. You must remove the lid before placing the glass container in the oven because the lid will melt.
Also, use caution when heating food in disposable aluminum containers. These are often thin and flimsy; when you remove the hot container from the oven, the sides can bend, causing the contents to spill out and cause burns on your hands or arms.
Always place aluminum containers on a baking sheet before putting them in the oven. The solid surface of the baking sheet will provide needed support. It will also help the food cook faster.
Silicone containers should also be placed on a baking sheet or on a pan.
Is A Microwavable Container Safe For Oven?
It’s easy to get confused about what containers might be safe for the oven, the microwave, or both. For example, if you buy a Stouffers frozen lasagna, it will come packaged in a plastic tray, and the directions will say you can cook it in a conventional oven or a microwave. Without directions, how can you know?
The vast majority of microwavable plastic containers should not be used in a conventional oven because of the risk of melting. However, most types of glass, paper, and cardboard can be used in the microwave, as well plastic bags that have been opened or vented.
Microwaves and conventional ovens produce similar results, but they use very different processes when cooking. Conventional ovens, whether gas or electric, produce heat that raises the temperature of anything inside the oven—the food, the container, the oven racks, the door and window, and so on.
You learned this lesson the first time you opened the oven while it was cooking and accidentally touched a pan.
A microwave, however, does not raise the temperature inside the oven. Instead, the microwaves stimulate the molecules within the food, and that causes it to cook. That’s why you can put a paper plate in a microwave and pull it out with your bare hands.
However, cooking food in a microwave will cause some containers to heat up, if it’s cooked long enough. The heat from the food is transferred to the container. Glass and plastic can both get hot enough from the cooking food to burn your fingers.
So how can you tell if a plastic container is safe for a conventional oven? If the directions on the box don’t specifically say you can cook the food in the oven, don’t try it. For extra safety, there are some things to look for.
CPET containers, the kind that are oven safe, are almost always black. If your plastic container is white or clear, do not use it in the oven.
Some frozen foods are packaged in a type of thick paperboard. These are microwavable and may be oven-safe, if the directions on the package say it is.
For maximum safety, do not use any plastic container in the oven. Use the microwave instead.
What Containers Can Be Used In Oven?
Many people like to freeze leftovers or prepare meals in advance and heat them up a few weeks later in the oven. In those cases, you want to use a container that can easily go from freezer to oven.
The best freezer-to-oven containers are made of borosilicate glass. You can take these directly out of the freezer and put them into a preheated oven. However, many of these containers have plastic lids which must be removed before oven use.
These containers are also microwavable.
The most popular freezer-to-oven containers made of borosilicate glass include the following:
- Amazon Basics Meal Prep Glass Containers —These containers can withstand heat of up to 450° F (232° C). Lids are airtight with a silicone lining. They are vented for microwave use but must be removed before you put them in the oven. Just remove the plastic lid and cover with aluminum foil.
- Razab Glass Storage Food Containers — They can go into ovens as hot as 500°, according to the manufacturer. They also have airtight plastic lids that are not oven safe.
- OXO Good Grips — Remove the plastic lids before placing them in the oven.
Another good freezer-to-oven material is the type of ceramic used in Corningware. Corningware uses a mix of ceramic and glass to produce containers that can be used in the freezer, microwave, or oven.
- The Corningware French White bakeware set comes with two sets of lids—plastic lids for freezing and storing and glass lids for baking.