The mystery of the ziplock omelet: Is it toxic?

So, a coworker related to me how his mother-in-law made an omelet by combining the raw ingredients in a plastic ziplock bag, sealing it, and boiling it in water for 14 minutes. I was a bit skeptical, but tried it last night, and it worked like a dream. It was so easy, didn't require any skill and there was absolutely no clean up required. I should add that it also tasted fantastic.

I posted on Facebook about it, and was surprised that many people hated on the idea. One of the main criticisms was that there are fears that toxic chemicals could leech out of the bag into the food.

I did some searching online, and saw some posts that the Boy/Girl Scouts used to use this method for camping, but no longer recommend it. And there are a lot of sites that reference a supposed University of Illinois release that says:

They [Ziploc] do not recommend using any ZIPLOC® brand Bag in boiling water, or to “boil” in the microwave. ZIPLOC® brand Bags are made from polyethylene plastic with a softening point of approximately 195 degrees Fahrenheit. By pouring near boiling water (water begins to boil at 212 degrees) into the bag, or putting the bag into the water, the plastic could begin to melt. Might I add that eggs and cheese have fat which gets much hotter than water thus the likelihood of melting the plastic increases.

This is where I get skeptical. Someone doesn't know basic physics if they think that the fat is somehow going to get hotter than the water in which it is boiling. Huh?! Not to mention that the writing style (and grammar) don't strike me as something to come out of an official University release.

So what are your thoughts on this? Does the convenience of this cooking method outweigh the potential risks? And is the risk even one that seems logical?

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Comment by Steven Qi on August 3, 2018 at 6:59pm

plastic = PET/PETE, HDPE and others, some kind of plastic can have a high temperature, they are PPS, LCP. 

Comment by Joe Agro on September 6, 2012 at 8:42am

There is a highly charged and biased movie out there called "Tapped" (available on Netflix) that goes into how PET/PETE, HDPE and some other plastics can contaminate the items held inside containers made of them.

I'm skeptical on a lot of it but I also won't drink from a water bottle that's been boiled, frozen or otherwise abused...  I presume the same logic could apply to the ziploc baggie thing.

Comment by Andrew Dreasler on April 23, 2012 at 2:06pm

The comment about the fat getting hotter is probably more aimed at 'microwave boiling.'  If you're 'nuking' the bag, the energy excites all the molecules that it hits.  Yes, the Magnetron is tuned to the resonant frequency of water, so that should absorb the energy more easily and heat up faster, but the fats could superheat as well, (how many 'pizza puffs' have a warning about the cheese being hot enough to cause burns after a mere 45-60 seconds in the microwave (I can barely make a cup of water boil in the microwave in 60 seconds).  Also, in the microwave, steam does not escape as readily as on the stovetop, and while it's in the 'nuking chamber' it's still getting energized, and it's still getting hotter and hotter.

The leaching chemicals part may be disputed, but the simple fact remains that unless the bag can withstand 250 degrees Fahrenheit or so without softening, it's best not to boil in it.  There ARE bags designed for boiling and steaming, but those are more durable than the typical Ziplock (R) bag of today, and a bit more expensive.

The older Ziplock (R) bags may have been tough enough to boil in, but that feature was lost in the pursuit of 'lightweighting' the products.

Comment by Paul J. Heney on December 21, 2011 at 1:31pm

Alex, I am waiting for the study that shows that drinking too much water causes cancer, lol. Of course, then a few years later, another one will be published showing that it's actually okay ...


Comment by Alyssa Sittig on December 21, 2011 at 12:41pm

I wouldn't be surprised to find out it causes cancer. But then, I am not a materials engineer, so I couldn't say for sure. It just seems too good to be true.

Comment by Paul J. Heney on December 21, 2011 at 11:15am

Tom, I though about those Eddies things, too! I imagine that it is a different plastic, given that they appear to be a hard plastic vs. the pliable clear plastic of a ziplock bag...but you are right, it would seem to have a similar safety concern. (If there is one at all!)

Comment by Tom Lazar on December 21, 2011 at 11:12am

Another point: there is a product on the consumer market called "Eggies" ( which also involves the use of a plastic-type device for cooking eggs in the microwave...should this product be one that the general public should be concerned with...?

Comment by Kathie Zipp on December 21, 2011 at 7:25am

Darn, this is disappointing if it is bad for you because I love omelets but unfortunately suck at making them...

Comment by Tom Lazar on December 20, 2011 at 8:44am

...well, firstly, having eaten one of these curiously-cooked omelets, I can tell you that they're amusingly very delicious...

But one has to wonder if, by engaging in the consumption of food products cooked in this manner, perhaps there is an inherent risk of using these baggies altogether...?  Furthermore, assuming that Ziploc bags are manufactured here in the US, it goes without saying that they're BPA-free...but what about "knock-off"/store brand versions?


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