Microwave Safe Containers

I work for a company that is a plastics compounder - which means they getplastic directly from the nuclear power plants that cook it out of petroleum, mix it into different forms, and then ship it out to other companies that make products. The chemists that design the melts (plastic recipe runs) refuse to use 'microwave safe' or any other plastic containers in a food settling where the container gets hot.

The plastics that are labeled 'safe' for such conditions are the same plastics that would normally be unsafe, mixed with a strengthening additive. When, over the course of time and exposure to heat & other radiation, the plastic itself does not break down rapidly, but instead the additive 'takes the hit' and comes out of the container (with small quantities of plsatic).

The problem is that the strengthening additives are highly toxic - with various kinds having known connection with organ failures and nervous system problems. The safety tests done on the plastic compounds I've been able to research don't have any awareness of whether the small quantities of an additive that comes off from the plsatic container are stored in our body or pass through it. No sense of whether there is a internal system threshold for our body, even though it's known that people can reach thresholds through job exposure to some of them. ('Threshold' meaning once you're exposed to a certain amount of it you experience dramatic physiological reactions (vomiting, loss of consciousness, etc) when exposed further.

To wrap up the rest of this disclosure; I am highly sensititive to many chemicals - what is safe and/or unnoticable to other people can make me sick. For the month or two that I worked in the plastics plant (before I began telecommuting) there would be days that I would become nauseous, couldn't stay awake, sharp headaches, etc. My arguement is that the notion of a "food grade" plastic is probably best taken with a small footnote of caution (probably provided by me via this post ;)

-Zak

I thought nuclear power plants don't use petroleum - radioactive uranium or plutonium, steam, turbines, sure, but petroleum? Why did you even start witht hat "tidbit" of (mis?)information?

It makes me suspect your whole story...

Interesting article, this is exactly a topic I am interested in at the moment.


I have a large (25 kg) bag of whole wheat, that I mill at home. Any suggestions on how to store this? Food grade containers that I can find are way too expensive. Large ones do not even seem to exist in my country, and multiple small ones would cost hundreds of dollars. I now keep them in the original paper bag, and cover that with a plastic trash bag. So the grains do not actually touch the plastic. I wonder if the mill where I bought the grains stored them in food grade containers, by the way.

Any suggestions would be much appreciated. The solution I now have is not ideal because mice will still eat through the trash bag, of course.

Nuclear power plants have a "waste heat" cycle, where the system is producing heat that they can't use for turbines, etc. Rather than let that heat be wasted (dissipated into the atmosphere) they use it to heat giant vats of petroluem. The heat causes the petroleum to separate into layers of material; gasoline, ployethene, other plastics, sludge, etc.

I never said the nuclear reactors use petroluem for their fuel source. I shared it because it is a fun tidbit that reveals part of the way our system works. Thanks for being polite enough to make it a question, though...


Zak

lena, had you considered finding a wooden barrel? You could inquire into a local winery as to their source of barrels, as you can then be sure the barrel is not being treated with any dangerous chemicals (and barrel-makers are hard to find outside of the wine industry these days)

Otherwise look for a large food-safe plastic bag to use as a liner in and otherwise inappropriate container.



Zak

I think I remember that in Alton Brown's book: I'm Just Here For More Food (http://snipurl.com/exjv)
He uses a metal trash can (The fancy ones you put your foot on to open the top) to store flour. Of course this goes against the advice that you use food grade containers. :?

Lena,
The Baker's Catalogue has a 22 quart container. Here is the page:
http://shop.bakerscatalogue.com/items/item6069.html

What about using a galvanized steel can? I might be way off here, but it may be possible to store the grain in the bag inside of the steel can. Just a suggestion....good luck!

I stumbled on your fine forum searching for inexpensive containers for long term water storage (disaster preparedness). Since I like to cook I like the concept of Cooking for Engineers.

I have been using galvanized steel cans for storing bird seed and dog food on the back porch. I do use the food every day. Am I killing the wildlife and my dog?

Thanks for any feedback... :unsure:
Dianne

You can find used food grade barrel suppliers at www.pharmacal.com/recond.htm

One largish (20 qt) container that I use is a 5-gallon bucket. In particular, a 5 gallon bucket originally used to ship pickles to a fast food establishment, which they were happy to give me for free.

Considering the many plastic issues, even still I only use it for short-term cold temperature applications to reduce leaching. A wine barrel is an awesome idea. I have no idea how voluminous 25kg of wheat is.


Regarding your bird feed: I think your galvanized can is _probably_ fine, for several reasons:
1. Metals tend to be relatively nonporous and metals finishes (like galvanization) tend to be relatively robust and strong. I wouldn't necessarily sandpaper the finish and eat the dust, though.

2. You're not heating it, heating encourages everything (but especially plastics) to release all sorts of chemicals.

3. You're not soaking it. Filling something with a liquid vastly increases leeching from the container compared to storing solids, because it's easier to leech into the liquid and because the liquid will touch every last bit of the sides of the container. (A seed, for instance, will only touch a tiny piece of container but "block" a bunch more from being touched by other pieces; there are lots of tiny air pockets.)

First all plastics regardless of name brand or what have you give of chemical products that they were made from as like all chemical formulations they break down over time. What disturbs me is the lengths that the industry goes to silence any leak of facts that show microwaves are not healthy. just look at what happened to the two swiss researchers who were prosecuted for exposing the dangers of microwaved food. it was claimed they were interfering with commercial trade. fortunately the european court lifted the prosecution on appeal.
From my point of view after indepth research is never to eat anything out of a microwave oven. Im able to readily do this as im in control of my free will to decide what i eat and how its cooked, its that simple. Remember you are what you eat (what you do is what you get back, second natural law).

Let’s get a grip. Microwaving food is a good thing. Microwaves are non-ionizing, and do not leave any residual radiation of any sort. It’s good because it kills the micro organisms in the food that you are cooking or defrosting. You know the ones that can make you sick (like salmonella). Don’t use plastic, use Pyrex.

Larry

Is there any symbol used to understamp the container to show it is microwave safe?

Wine barrels are also often burned or smoked inside, to impart special flavours to wines or spirits, so barrel should be new and non-treated. And better to soak it with clean water, as barrels tend to be not airtight when newly done. Most woods also leach into the content if it's liquid. That's why oak barrels are so sought after in brandymaking.

About 25 kg -- just remember one simple estimate: 1 kilo ~ 2 pounds. So 25 kg of wheat is about 50 or 55 pounds, a size of rather largish paper bag.


If the container in question is steel, that I suspect, than it itself is rather safe, especially if laquered/enameled. But galvanization leaver the question of what coating is use. Often is is galvanized with some nonferrous metal that might be unhealthy itself, such as copper. Tin and zinc is usually best solution, but I still prefer enameled steel, as most enamels are in fact rather dense and nonporous glass compounds, are really durable an are generally food-grade from the start -- I never met non-food-grade enameled containers, in fact.

Larry, Microwaves can be used to kill microorganisms but the food would have to be kept at boiling temperature for at least ten minutes to do so. Any food that had been microwaved for ten minutes after it had reached 210 F would be pretty uneddible.

When you cook food, aside from making the flavors, textures and consistency more palatable, you kill microbes that would be found in normally healthy meat, poultry, fish and vegetables. We don't knowlingly eat contaminated or tainted food. The purpose of cooking is not to sterilize food. Sterilzed food (with the exception of soups that simmer a long time) would probably be overcooked, burned, dried out or just generally not very appetizing.

I often see this term "Microwave Safe" used on containers, plates, etc. How is this determined? Is there some sort of standard test that products must follow in order to be labeled as "Safe"? Or is there no real maning to this term?

Thanks,

Bryan Lagos
blagos@tycoint.com

In the U.S. that label can only be placed on containers that are constructed of materials that have been determined by the FDA to be safe for use in a microwave oven.

I have been unable to find any source which explains the use of petroleum as a coolant in nuclear power plants.

Could you cite one or two for me?

He didn't say that nuclear plants cool with petroleum -- most use evaporative (water) cooling, which is the purpose of the familiar concave tower. The extra heat is used to power the distillation of petroleum into components. This method of using the waste products of whatever generation technique is called "cogeneration".

Put another way, power plants (coal, natural gas, nuclear) produce electricity and heat. The heat is usually just exhausted into the atmosphere. But if there is some process that requires heat to work -- petroleum distillation for example -- it makes sense to take that "waste" heat and put it to use. This way you get more out of your fuel, you can usually increase your power plant efficiency (this is important since they typically have an efficiency of about 30% or less).

The FDA is bought and paid for by the producers of the products it is supposed to regulate, namely the pharmaceutical and plastics industries. The fact that FDA endorses food grade plastics as safe means absolutely nothing to me.

An acquantance uses ice cream containers for reheating large amounts of food - some times a gallon at a time. He is not convinced there is any harm in this. I can't believe there isn't. My ``gooleing' efforts brought me here - is there documentation someplace I can show this fellow?
Thank you

Seems pyrex manufacturers are missing opportunity to make spoons etc. that can be left in larger containers of materials while being microwaved.

Obviously, using plastic or metal stirrers is awkward and time consuming.

Stirring, using pyrex (that remains in the food) would be very simply done!

You can use a 44 qt cooler to store your wheat, I believe the cooler material must be FDA listed.

Another option is to find a local supplier of bulk goods such as your local cooperative food store. . They often receive products in 5 gallon, food grade buckets. It is what I use to store flour.

[color=violet:8a0b9f3b86]Pyrex doesnt make spoons? OUTRAGEOUS!!! thats so gooleing!
im going to throw metal bird seed at Pyrex for that![/color:8a0b9f3b86]

I have purchased Chinese made ceramic plates and bowls at Target that are listed as Microwave safe. However the cookware heats up too hot to touch while the food remains barely warmed. Is this really microwave safe or have they just put on the label. Who checks to see if it is really safe. The cookware changes to a new style every few months, so the old cookware can not be tested by the seller.

Another inexpensive source for food grade 5 gallon buckets is your local donut chain, such as Dunkin' Donuts. They often receive their fillings in the buckets which they discard when empty since it is not worth the labor expense to clean and reuse them. We used to get them for a couple dollars each. It's extra income for them and it reduces their waste stream. You have to wash them, of course. But you would also wash any new food container before use.

One caution about storing grains in plastic containers. If you have a rodent problem, put the plastic containers in a galvanized trash can. When we raised chickens we learned the hard way that even the heavy duty Rubbermaid Roughneck cans don't slow the rats down.

Katy, how do you explain the fact that flash-pasteurization -- which involves heating foodstuffs to 71ºC/160ºF for 6 seconds -- is often performed using continuous-flow microwave ovens?

My great grandpa has been microwaving his food in plastic containers since he was a wee lad and he's ok...

Based on all I ve read in this forum, does it mean plastic containers cannot be used for storing food at of any sort at all? Most portable food storage containers are made of these plastics and if these things are unsafe then wont it be wise for the FDA to halt the production of these unsafe ones? Millions of people around the world dont even know about the unsafe nature of these plastics and are using them. Please could anyone also tell me about the nature of the danger these plastics pose? what are the likely specific health problems do they cause? No one is saying.

Umar -

there are folks who get upset about a lot of things, don't worry to much about facts or real science, they hear something and immediately set about spreading the word that the sky is falling.

one can of course subscribe to the conspiracy theories that big [pick a name / business] has paid off the FDA, the USDA, along with every other world government agency, to 'suppress' the real dangers of "fill in the blank" - there's a lot of things touted as candidates for the blank.

one of my favorites is: canola oil will kill you - it's made from rapeseed - which in the mustard family - that's what they make mustard gas from! google mustard gas and see what it is really made from.

Bisphenol A has demonstrated health concerns in infants - hence the banned in baby bottle thing.

arsenic is toxic - no one debates that as "true"
one molecule of arsenic will not harm you.
ingesting many molecules will.

>>Please could anyone also tell me about the nature of the danger these plastics pose?
>>what are the likely specific health problems do they cause?

search engines will turn up all the information you every could need. just use your own brain and consider the source and science behind the claims.

>>No one is saying.
that should tell you something.

Question, do microwaves pass through pyrex glass unattenuated? Can a pyrex glass cover be used to prevent microwaved foods from splatering all over the microwave and still heat the food safely?

Bill -

short answer is "yes" - heat proof glass tops are fine.

glass may become hot - that's heat conducted from the food itself and/or steam generated - but glass all by itself does not "heat up" due to microwaves. passing through anything will cause some attenuation - but it's very minor compared to the degree water absorbs microwaves.

The Chinese plastic containers and plates from Target are likely melanine. I don't believe you're supposed to use that in the microwave. I've experienced them bubbling the cracking when heated too much.

Everyone ignors the fact that microwavable dinner plates over time get extremely hot without heating the food. Everytime this question is asked someone will say it is the food heating the plate...Wrong....I believe repeated heating in the microwave breaks the plates down or the combination of the dishwasher and microwave do it. We reheat leftovers fine on our dishes when new and over time (a few years) the plates and bowls are no longer usable for the microwave. I have bought dishes from different manufacturers and it doesn't matter. I'm looking for new dishes now. I cannot heat soups in my bowls because it will not heat the soup just the bowls. I have to use corning and then put into my dishware which makes the benefit of less work moot.

microwaves preferentially absorb by bi-polar molecules - water being the common example.

"glass" is a crystalline lattice, and (with a few exceptions) exhibits low bi-polar composition.

"plastics" - somewhat undefined - but yes they can contain bi-polar molecules which will heat up quite nicely via microwaves.

there is no "legal" definition to "microwave safe" - it is a marketing term that indicates the container will not "fail" when exposed to microwave energy. it does not mean the container will not get hot.

for example: "Pyrex" - which is a flavor of annealed boro-silicate glass - will heat up in a microwave. the boro-silicate composition makes for low expansion coefficients - which makes it microwave safe because when subjected to (relatively even) heating it does not break all too easily. the annealing process allows the molecules in the glass lattice to align - that makes 'stronger' but also it a bit on the bi-polar side, which is why it will get hot.

experiment: take a one cup pyrex measuring cup, fill it half (4 fluid ounces) with water, zap it in the microwave for 1 minute. use your finger to determine the temp difference between the "top" with no water) and the bottom (with water) - use care not to raise blisters on your fingers....

the top is warm, but noticeably less 'warm' than the bottom - some heat has indeed transferred from the water to the glass and up the sides. if you've got a more recent microwave oven that can running "empty" you can just put the empty measuring cup in and you'll notice it gets warm.

a microwave plate that gets hotter than the food simply means the Made-in-China of Who-Knows-What plastic is more readily absorbing the microwave energy faster than the water in the food.

"Corning Ware" is a bit problematic - from reading, the "Corning Ware" brand name was sold - not made by Corning Glass anymore, nor under their license or control. essentially a situation of "brand" made in China from who-knows-what to "no specifications applied" - if you've got 15 year old Corning Ware, you're golden. the new stuff may not live up to one's expectations.

Read some where and have passed it on by word of mouth several times that a number '5' or higher in the three wide mobius arrows found on the bottom of many (most) coffee cups and the like (The resin coding system introduced in 1988 by the Society of the Plastics Industry (SPI)), correlates to the container being 'microwave safe.' Research suggests this is true but I don't find it 'advertised.'

Comments/concerns?

here's the list of SPI id's and what they mean:

http://www.scn.org/~bk269/plastics.html

the number is - per that article - not a good guide to safety in the microwave.

Distilling petroleum is a complicated process. It requires more than just heat. Generally, it requires the facilities of a petroleum refining plant; there's a reason for distillation towers, cat crackers, and so on, plus the associated infrastructure. You can't just "heat up a vat" of petroleum and get anything except hot petroleum.

I have to assume that the OP mentioned nuclear power plants in order to make his story scarier to the average person. That "detail", however, which is not only contrary to logic but seems to exist nowhere else, throws the credibility of the whole post into question.

I do find it a little weird that it was posted on "Cooking for Engineers". But in any event, no, nuclear power plants aren't in the petroleum-refining business as a sideline.

I never mentioned nuclear power plants. Please don't judge Cooking For Engineers based on what random people on the internet choose to leave as comments.

So which plastics are safe for use in a microwave environment i.e. what are the technicals names for these... PTFE, PET, PEEK etc.

Thanks.

I have dishes that don't "pass" the test and do get quite hot when zapped along side 2 cups of water in a Pyrex cup for 2 minutes. The dishes say 'microwave safe'. My questions is whether they are safe for us to eat from, or whether there is a chance that they are leaching materials into the food. I have seen the coffee cups get hairline cracks in them (I heat a 1/4 cup of milk in my coffee cup for 45 seconds each morning for coffee.)

I don't care about them cracking - just about whether my family could be ingesting anything leaching out of the dishes. Michael, thanks for you website - I love it.

I personally don't use plastic containers. Over time you can litterally see the plastic breaking down which means you definately are ingesting it. I also personally think that that container imbues a plasticyyy taste into the food. It's not that much more difficult or expensive to just use pyrex food storage containers. Why take the risk? Why alter the taste of your food?

What is the chemical component that makes the containers microwave safe? Lexan? :/?

it's more of what additives may be in the plastics than the plastics themselves. and rarely is a container made 100% of a "pure plastic molecules only"

it's the additives that may breakdown or leach out with heat, and if they are harmful then the plastic container should not be labeled as microwave safe.

the kicker to all this is: what is considered harmful varies over time, and certainly by web authors, which come in all flavors from real science to whacko-spacey types.

in generalities, and with the caveat of not being modified by harmful adds:
polypropylene is commonly used.
LDPE is ok, but it softens at higher temps, making is less useful
PET and polycarbonate absorb heat.
Acrylic and polystyrene are not recommended.

polymethylpentene, polysulfone and flouropolymers are often used for labware.