Could microwave oven heat up the plastic container?

[kenny1999]

A friend of mine told me something today that I never knew

He said that microwave oven does not heat up the plastic

container directly but only the food, and then the hot food

transfers the heat to the plastic container, he then concluded

that it is safer to use microwave with plastic than to heat the plastic with traditional

heat (I often put a plastic container on a stand and then heat

up the food inside with boiling steam because I don't have a microwave oven)

Is what he said true?

 

[WhateverYouWant]

It is true that microwaves create heat by friction of water molecules they excite, so yes, it will do little to heat plastic, glass, or ceramics.

Your method heats the plastic, which then conducts it to the food. I am not a fan of food cooked by plastic, which is a big reason I have not embraced sous-vide.

 

[GotGarlic]

Either method is still heating the plastic. I don't cook or heat anything in plastic - even food-grade. My mom heats foods in the microwave in plastic and I've seen too many warped, partially melted containers in her kitchen, I'm just not comfortable with it.

 

[pepperhead212]

Here's the thing you have to worry about when heating in plastic - oils heating up! Here's a photo of a piece of plastic that some idiot (who doesn't cook in my kitchen any longer!) heated something up in, and the damage it did:
Plastic damaged by microwave. by pepperhead212, on Flickr

I just use that container now for things that aren't heated at all, like storing pineapple cubes, and the like.

The problem with microwaving in plastic is that oils can heat up in outer spots enough to melt the plastic, while the inner part of the food can be cool still. Doing the entire cooking in the plastic could do even more damage.

I thaw frozen foods in plastic containers just enough to loosen them; then, I turn them out into a Corelle, or orther ceramic dish, if I'm going to heat it the rest of the way in the MW.

An afterthought - many of the containers we save, such as mushroom containers and those screwtop Talenti containers, will melt in a dishwasher, in just that heat. Imagine what a microwave would do to them!

 

[Chief Longwind Of The North]

Microwaves are electro-magnetic waves that heat, as was mentioned, by exciting molecules. Any metallic substances on, or in a container will heat rapidly, and even create super hot electric arcs. Water molecules are exited as well, and vibrate rapidly when exposed to microwave radiation. The friction between water molecules creates heat, which cooks the food. Plastic is generally free of both water and metal molecules, and so won't be directly heated by the microwave. I have had ceramic bowls heat up though, probably due to metal molecules in the ceramic. So you just have to test, and be aware. I don't like plastic in the microwave because all plastics are made from petroleum product. Many of them will leach dangerous contaminants into your food, when heated. Even cold, I have my suspicions. Foe example, when whipping egg whites into a meringue, it must be done in metal, ceramic or glass, as any oil will keep the meringue from forming. You can't make meringue in a plastic container for this reason. It just won't work. So does this mean that petroleum based oils, in trace amounts, are contaminating my food? I just don't like using plastics with food.

If I am going to use plastic, I prefedr hard, thermo-setting plastics. But you have to make your own decisions on the safety of plastics, especially soft plastics.

Seeeeya; Chief Longwind of the North

 

[Roll_Bones]

Good question. I have been meaning to ask our local Chinese restaurant if their take out plastic containers are microwavable?
Should there be any markings on the plastic vessels to indicate microwave heating is safe?
These containers are very sturdy and would be well suited for more uses. My wife always tells me to toss them even though it seems they would be great for other meals and leftovers. Even for storage.
Had I still been working, they would be perfect for hot lunches.

I do use them in the microwave, but have no idea if they are rated to this use?

 

[Real1shep]

I've not had that same experience. My microwave heats up plastic and anything else I put in there including dishes. Always best to check if it's 'microwave compatible' but with the inclusion of everything being made in China, I'm not so sure that them saying it's "safe" means anything.



I try to stay with glass in the microwave...Pyrex et al type containers. I think a lot of it with plastics is how long you cook with it in the microwave. It's one thing to warm up something in plastic with a microwave, but quite another to cook with it. Any plastic type container I put in my microwave that's subjected to three minutes or more gets HOT.


Kevin

 

[dragnlaw]

I will store and freeze in plastic.

As mentioned by 'pepper' if I can't get it out of the plastic, I will use the microwave just enough to get it out.

There are some new plastics out there that you can use in your regular oven but I still will not use them in my micro. I have plenty of other dishes that I can use that I don't even think or worry about it. Just don't have to!

 

[GotGarlic]

Good question. I have been meaning to ask our local Chinese restaurant if their take out plastic containers are microwavable?
Should there be any markings on the plastic vessels to indicate microwave heating is safe?
These containers are very sturdy and would be well suited for more uses. My wife always tells me to toss them even though it seems they would be great for other meals and leftovers. Even for storage.
Had I still been working, they would be perfect for hot lunches.

I do use them in the microwave, but have no idea if they are rated to this use?

I don't think there are any markings on them. Years ago, I bought packs of cup, pint and quart size deli containers (same as Chinese restaurants use) and use them for leftovers and for freezing purposes. I never cook in them. I defrost them in the microwave inside a Pyrex quart measuring cup or baking dish until it melts enough to slide out. Then I remove the container and finish defrosting.