Does Microwave-Safe Mean Oven-Safe
The contents of this article are fact-based except otherwise stated within the article.
Author bio
Dr Anny March PhD is a food Engineer with expertise in Food Technology, Natural Polymers, Edible Films, Enzymes, and Nanotechnology.
Dr Anny Manrich’s Highlights:
- Research and Technology at the Brazilian Agricultural Research Corporation
In this brief article, we will be answering the question, “does microwave-safe mean oven-safe?”. This article will elaborate on the differences between microwave-safe and oven-safe dishes and will tell you which dishes you can safely use in each.
Does Microwave-Safe Mean Oven-Safe?
No, microwave-safe does not necessarily mean oven-safe. Microwave-safe and oven-safe are not interchangeable terms. If a container is labeled as microwave-safe, it does not always mean that it is safe to use in an oven as well.
While certain materials can be used safely in both appliances, many are not meant for both.
What Materials are both Microwave-Safe and Oven-Safe?
Materials that are both microwave-safe and oven-safe are pyrex, ceramic, corningware and some special plastic materials. They are described in the sequence.
Pyrex
This is a well-known and reputable glassware company that manufactures food containers and bowls that work safely in both the microwave and oven. The Pyrex glass contains borosilicate in its composition, which increases its resistance. These heavy-duty glass products are also safe for use in the dishwasher.
Ceramic
Ceramic dishes and bowls are commonly used in restaurants to serve desserts as well as individual dishes. They are safe to use in the microwave, and most are also durable enough for the oven.
However, it’s best to always check the manufacturer’s recommendations about the vessel. For instance, certain ceramic dishes are not glazed to handle the oven’s extreme heat and will crack on overheating.
Corningware
The Corningware company manufactures bowls and food containers made using a mix of glass and ceramic. Corningware cookware can be safely used in both the oven and microwave, as well as the dishwasher.
Special Plastics
According to the United States Department of Agriculture, there are some polymer materials that are safe to use in both conventional oven and microwave oven:
Polyester, thermoset: filled plastic which is heated to harden into a shape and does not soften when heated during normal cooking temperatures; example: plastic dishes in frozen dinner entrees; can be heated in the microwave or conventional oven.
PET (“polyethylene terephthalate”): a thermoplastic polyester used in beverage bottles and food trays designed for microwave and conventional ovens.
What Materials Are Microwave-Safe Only?
Materials that are microwave-safe only are materials that do not resist the temperature achieved in the oven, but are suitable for microwave heating. Examples are some microwave-safe plastics, such as microwave plastic wraps, wax paper, cooking bags, parchment paper, and white microwave-safe paper towels. These materials would melt or burn in the conventional heat oven.
For microwave irradiation to be able to achieve and penetrate the food, low microwave absorbing or microwave transparent materials such as borosilicate glass (Pyrex), quartz, or suitable polymers like PTFE (Teflon) should be used (5).
Food is often heated inside a plastic container in a microwave oven. When microwaves are used to heat substances relatively high temperatures can be reached in a short time, which facilitates migration. Food packages are often reused repeatedly after washing, which could cause unpredictable migration behavior due to polymer degradation. For an exemple, the effect of microwave heating on the migration from poly(vinylchloride) (PVC) is significantly higher compared to conventional heating. Some plastics are more susceptible to migration than others (1).
Microwave-safe plastics (labeled by the manufacturer) are generally more rigid and thicker than normal plastics. Usually, plastics made of polyamide and polypropylene are considered microwave-safe. These materials are durable enough to withstand microwave radiation and the heat produced when the food is warming up.
How To Check If A Bowl Is Microwave-safe?
To check if a bowl is microwave-safe, it is necessary to know its composition or to follow the manufacturer’s indications for the product, on the bottom or on the side of the bowl. If it doesn’t explicitly indicate that the bowl is microwave safe, it’s better not to place it in the microwave.
If your bowl is made of ceramic, plastic, corningware or porcelain, it’s most likely that it will be microwave-safe. Plastic food packaging should be designed to minimize the migration of additives and degradation products from the packaging material to food. Migrating substances can cause undesirable flavors in the food or even promote toxicity. Usually, crystalline plastics are microwave-safe (1).
What Materials Are Oven-Safe Only?
Materials that are oven-safe only are materials that resist heat but absorb too much irradiation emitted by the microwave oven or block them.
Examples are stainless steel cookware and cast iron bowls, which are extremely popular among chefs and are the best materials to use in an oven. These robust kitchen containers are perfectly suitable for reheating or baking and are also safe for use in the dishwasher.
Although pans and bowls made from stainless steel and cast iron heat food uniformly, they require a lot of effort to clean and also need regular maintenance.
Which materials are not microwave-safe and also not oven-safe?
Materials that are not safe for using either in microwave or in oven are:
- Plastic storage containers such as margarine tubs, take-out containers, whipped topping bowls, and other one-time use containers. These containers melt or burn.
- Thin plastic storage bags, brown paper or plastic grocery bags, newspapers.
What Will Happen If You Place A Metal Bowl In The Microwave?
If you place a metal bowl in the microwave, it can cause a fire and burn the appliance. A metal bowl should NEVER be put inside a microwave.
This is because metals are highly conductive and when microwave radiation is emitted on the metal, the metal electrons are excited to an extreme and unsafe state.This accelerated movement of electrons is too much for a microwave to handle, and the extensive amount of heat emitted from the metal ultimately results in it catching fire.
According to the United States Department of Agriculture Food Safety and Inspection Service, anything made with metal such as metal pans, china with metallic paint or trim, Chinese “take-out” containers with metal handles, or metal twist ties are not safe for microwaves.
What Will Happen If You Place a Plastic Bowl In An Oven?
When a conventional plastic bowl is heated in the oven, it softens and may melt. While plastics may be strong enough to handle warm and hot foods, they aren’t sturdy enough to handle the direct heat from an oven.
Putting plastic in an oven can melt it, ruining the container and the food inside it. However, plastics differ in their melting temperature and some of them can be used in the oven. An example is the polyester / PET bag, which is commonly used to roast chicken in an oven. Although considered safe, they can also release monomers to fatty food during cooking/ roasting at high temperatures (2).
Moreover, harmful fumes emitted from melted plastic are seriously injurious to health as well as the environment.
Conclusion
In this brief article, we answered the question, “does microwave-safe mean oven-safe?”. This article elaborated on the differences between microwave-safe and oven-safe dishes and discussed which dishes you can safely use in each.
If you have any questions or comments please let us know.
References
- Alin, Jonas, and Minna Hakkarainen. Type of polypropylene material significantly influences the migration of antioxidants from polymer packaging to food simulants during microwave heating. J App Polym Sci, 2010, 118, 1084-1093.
- López-Cervantes, J., et al. Migration of ethylene terephthalate oligomers from roasting bags into olive oil. Chromatograp, 2003, 58, 321-326.
- Cooking with microwave ovens, United States Department of Agriculture.
- Cooking safely in the microwave oven. United States Department of Agriculture.
- Gutmann, Bernhard, et al. Sintered Silicon Carbide: A New Ceramic Vessel Material for Microwave Chemistry in Single‐Mode Reactors. Chemistry–A Euro J, 2010, 16, 12182-12194.
