Cooking Foods in Plastic Containers in the Microwave

[Shel_B]

I was over at Cook's Illustrated earlier, and read a review on Microwave Pasta Cookers.  These are plastic containers in which you put water and pasta, zap in the microwave, and cook the pasta.

 

I've always believed (and have read numerous articles and posts on the subject) that one should not cook food in the microwave oven in plastic containers because chemicals from the heated plastic can leach into the cooked food.  Whenever I cook or heat anything in the microwave, I use glass containers.

 

I have heard the term "microwave safe plastic" and always though that meant that the plastic was safe from melting, not necessarily safe for the food.

 

So, is cooking pasta in a plastic container a good idea?  Is cooking anything in a plastic container a good idea?  Do you cook in plastic containers, and if so, why do you think it's safe?

[BeeZee]

I will only warm things in microwave safe plastic, well below boiling. Right or wrong, it is my opinion that if it is labeled microwave safe, I won't be doing much harm if the temp stays moderate. I don't do it often, I prefer to use Corningware or Pyrex.

[IndyRob]

There are many types of plastic.  If Cook's Illustrated recommends it, it probably won't kill you.

 

In the case of a pasta container, the container isn't getting very hot.

[Tri2Cook]

You just have to make your own choices. There are about 1.3 things left in the world that aren't potentially bad for you... and those are still undergoing testing and should be certified dangerous sometime in the near future.

[Shel_B]

There are many types of plastic.  If Cook's Illustrated recommends it, it probably won't kill you.

 

In the case of a pasta container, the container isn't getting very hot.

 

CI has been wrong about many things in the past.  I wouldn't base any major decisions on their cooking recommendations.

[IndyRob]

CI has been wrong about many things in the past.  I wouldn't base any major decisions on their cooking recommendations.

 

So why would you be asking a question based on one of their recommendations?

Edited July 28, 2014 by IndyRob (log)

[weinoo]

So why would you be asking a question based on one of their recommendations?

Yeah, I don't get it either.  Why not just do the opposite of what they recommend?

[pbear]

I have heard the term "microwave safe plastic" and always though that meant that the plastic was safe from melting, not necessarily safe for the food.

 

A quick Google search on the phrase suggests this is mistaken.  Whether the "safe" side is right is disputed by some, but no one (AFAICT) says all that matters is whether the container survives.

 

[Norm Matthews]

While I agree that CI has been wrong so many times as to be considered unreliable, I don't nuke anything in soft plastic either.  However I wonder if cooking something in water is hot enough to affect the plastic as much as grease. I have seen the heat of grease melt plastic in the microwave but never noticed it with water.

[rotuts]

why even bother w any kind of plastic in the micro ?

 

there is glass, corningware,  pyrex:

 

http://www.amazon.com/Pyrex-Bakeware-2-Quart-Casserole-Dish/dp/B0000CF3UW/ref=sr_1_12/183-3143474-8326963?s=home-garden&ie=UTF8&qid=1406549482&sr=1-12&keywords=round+glass+bowl

 

I have two different sizes of the above, and lots of lidded corningware ....

 

this seems like a make-work question.

[dcarch]

While I agree that CI has been wrong so many times as to be considered unreliable, I don't nuke anything in soft plastic either.  However I wonder if cooking something in water is hot enough to affect the plastic as much as grease. I have seen the heat of grease melt plastic in the microwave but never noticed it with water.

 

Water cools itself down so it will not go above 212F.

 

Oil cools itself down, but not until it reaches to over 400F.

 

If you look carefully of the plastic containers you use to microwave food, you may notice a ring of pitting from oil melting the plastic.

 

dcarch 

[Mjx]

I'm fairly certain that you get also some interaction between plastics and lipids because both are composed of organic compunds.

[DianaB]

Being curious myself on this I did a quick search and found the following

http://www.health.harvard.edu/fhg/updates/update0706a.shtml

Personally I freeze portions of stuff like bolognese sauce in thick freezer bags (made by Lakeland in the UK, these are much thicker than other bags on the market here), I might then put the bagged sauce into the microwave on a very low setting to begin the defrost. As soon as the bag will come away from the sauce I decant the lump of sauce into a bowl to complete the process.

I checked the bags, neither pack nor bag makes any mention of microwave use.

I have some small plastic trays which I also use in both freezer and microwave. On the base are symbols that I believe mean I can use them in a dishwasher and a microwave. This site has examples of symbols that indicate 'microwave safe'.

http://virtualthoughts.org/2012/is-this-plastic-container-microwave-safe/

The lid for one of my trays has a microwave symbol and a freezer symbol, helpfully the words Freeze and Micro are included for those of us unfamiliar with the symbols

My giant roll of cling film says Freezer Fridge & Microwave safe. In smaller letters it says for use in a microwave as a lidding agent, do not wrap food for microwave use. It says do not use in a conventional oven.

The last warning brings me to another question. In recent months I have been attempting to perfect a chartreuse as an individual portion. I've seen this done on a cooking show, the chef used a circular ring to hold the thing together for cooking in a bain-marie. He wrapped cling film around the ring to form a base. They were placed in a bain-marie in a conventional oven, 80 c for 45 mins. Service was then simple, the film was removed, the chartreuse was put on the plate and the circle lifted away.

I can't find any cling film locally that says it is safe (even at low temps) in a conventional oven.

Any advice would be appreciated.

Diana

[Lindacakes]

I'm utterly paranoid where these things are concerned.  I don't nuke for a variety of reasons, none of which involve cancer, but I don't see any reason to cook in plastic.  I don't need a scientific research institute to tell me that it's safe.  It's just unnecessary.

[FauxPas]

Water cools itself down so it will not go above 212F.

 

But water can become superheated, especially in microwaves. it's easiest to do in glass or glazed containers. The water can rise to a temp above 100C or 212F. Here are some details from the Physics dept at UNSW in Austraila. 

 

http://www.animations.physics.unsw.edu.au/jw/superheating.htm

 

Plastic containers may be less prone to this? 

 

ETA - I'm not saying that it's completely risk-free to microwave in plastic containers, just that the superheating phenomenon (and its attendant risks) may be less likely in plastic. Also, there are various grades of plastic. Some are probably better choices than others, no?  

Edited July 28, 2014 by FauxPas (log)

[dcarch]

But water can become superheated, especially in microwaves. it's easiest to do in glass or glazed containers. The water can rise to a temp above 100C or 212F. Here are some details from the Physics dept at UNSW in Austraila. 

 

http://www.animations.physics.unsw.edu.au/jw/superheating.htm

 

Plastic containers may be less prone to this? 

 

ETA - I'm not saying that it's completely risk-free to microwave in plastic containers, just that the superheating phenomenon (and its attendant risks) may be less likely in plastic. Also, there are various grades of plastic. Some are probably better choices than others, no?  

 

It is a very interesting thing with water, it can actually be hotter than 100C without boiling (superheated) or colder than 0C without freezing (supercooled).

 

Superheated water can happen in any kind of container, including plastic. Mostly very pure water can be superheated, not soup, not broth. Coffee, tea, etc. homogenous liquids can superheat.

 

dcarch

Edited July 28, 2014 by dcarch (log)

[Norm Matthews]

why even bother w any kind of plastic in the micro ?

 

there is glass, corningware,  pyrex:

 

http://www.amazon.com/Pyrex-Bakeware-2-Quart-Casserole-Dish/dp/B0000CF3UW/ref=sr_1_12/183-3143474-8326963?s=home-garden&ie=UTF8&qid=1406549482&sr=1-12&keywords=round+glass+bowl

 

I have two different sizes of the above, and lots of lidded corningware ....

 

this seems like a make-work question.

I prefer to use clear glass (mostly pyrex) for food storage and microwave use.   I don't like putting food in containers that I can't see without taking off the lid. I think someone with a fridge full of tupperware has a fridge half full of spoiled food. 

[weedy]

Yeah, I don't get it either.  Why not just do the opposite of what they recommend?

that usually works for me

[dcarch]

I prefer to use clear glass (mostly pyrex) for food storage and microwave use.   I don't like putting food in containers that I can't see without taking off the lid. I think someone with a fridge full of tupperware has a fridge half full of spoiled food. 

 

Regular clear glass may easily crack if used in a microwave. Just like pouring hot water in a cold glass.

 

Many plastic containers are stackable, not glass.

 

dcarch

[Norm Matthews]

I use pyrex in the microwave.  Several of them do stack. There are more that are in use but I don't need a ton of them so stacking isn't all that critical.  

 

Edited July 29, 2014 by Norm Matthews (log)

[paulraphael]

Generalizing about plastic is like generalizing about metal. They are both such large families of materials that there is practically nothing you can say that's true for everything under those headings. We cook in stainless steel with impunity; we do not cook in lead. Tin, no problem. Mercury, big problem.

 

Plastic? Anyone who generalizes about it won't even be able to tell you what it is. 

 

The short version is that there are many specific plastics that we know leach potentially harmful chemicals into food. And there are many specific plastics that show no evidence of doing so. Just like with metals. There is nothing special about plastic as a category.

 

If you're scared of polypropylene (takeout containers, tupperware) HDPE (soda bottles) or LDPE (ziploc bags, plastic wrap), your fear is not based on anything known to science.

 

The only known issues with these plastics is they're not fantastically heat tolerant. I've never seen a ziploc bag melt from boiling water or steam, but I've seen them soften to the point that the seal can fail easily. I've seen steam generated in the microwave warp the lid of takeout containers. And plastic wrap is pretty wimpy when it comes to heat. 

 

Nevertheless, I heat polypropylene containers in the microwave all the time, and sous-vide in ziploc bags at temps up to 95°C. There's just no known reason to fear chemicals leaching from these materials at cooking temperatures.

 

A skeptic could say "you don't know for certain that they're safe." This is, of course, correct. But it's also correct for everything else in your kitchen. You don't know for sure that the stainless lining of your pans doesn't leach chromium; you don't know what's leaching from the particular borosilicate glass of your mixing bowl, or from the ceramic glaze of your dinnerware. It's probably nothing, but you don't know. The only difference here is the negative emotions attached to the world "plastic."

[annabelle]

I throw caution to the wind and warm leftovers in plastic containers in the microwave all of the time. 

 

I usually smoke a cigarette while it's warming up, too.

[Porthos]

I use a plastic steamer in the microwave for steaming veggies. I also thaw/re-heat brown rice in the Ziploc bag I stored it in. Most everything else is done in glass or ceramic just because it is already the right vessel to use - such a reheating coffee in a coffee mug. This is actually the number one use of our microwave. Just remembered that I defrost meats in the Ziploc bags they have been stored in. I just don't worry that I am exposing myself to high concentrations of bad chemicals. Breathing the air in southern California is a much worse thing to do but not breathing has rather immediate drastic results.