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Keith Norris makes a great point about sous-vide I have been wondering about for some time:

In particular, check out the discussion associated with Episode 17, where I tossed-out the sous-vide/plastics leaching question that I initially brought up in this post. Paleolithic Solution reader/listener Mathieu Lalonde responded:

“I’m a chemist and I was waiting for someone to bring up this issue. I was personally horrified when I first read about “Sous Vide”, which means “under vacuum” in French. Take food, place it into a plastic bag, place the bag under vacuum, seal it, then heat it. I cannot imagine a better way to leach plasticizers into food. Especially with fatty foods. I would love to see someone study this. The phthalates would be trivial to detect by mass spec. Many plasticizers, including phthalates, are endocrine disrupters. I don’t care how good “sous vide” food tastes, I’m not touching it until the plasticizer issue has been studied and/or resolved.”

I have to agree with Mathieu, here. This just looks like too much of a plastics-leaching, perfect storm for me to feel comfortable with. For now, just roll with the ol’ fashion crock pot, and reserve the right to change my opinion on the subject later.

Bottom line: Is sous-vide safe?

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I have not bought one because of this issue and with people who have them the amount of lower sex steroids and vitamin D has been rather eye opening to me. Not sure why but matt and I are thinking alike on this – The Quilt Aug 22 2011 at 12:31

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For the last time, polyethylene and polypropylene (LDPE, HDPE, *PE, PP) never contain plasticizers. These are the cheapest commodity polymers and any additive besides the monomer significantly increases the price of the final product, so manufacturers minimize the amount of raw material to remain competitive.

I believe it is useful for people to be skeptical of the safety of polymers, given history, but that should go hand-in-hand with actual investigation. I linked the FDA's regulations not because the agency has any idea what is safe, but because it delimits the chemicals that are allowed in food-grade polyethylene. As in, those chemicals listed are the only things allowed. The only leachable small molecule in that list are silicone lubricants, which have been proven well are inert in the body.

For me, the tasty value sous-vide cooking provides outweighs the known risks and precaution of the unknown.

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Why "For the last time..."? I haven't seen this question on Paleo Hacks, yet? Also, citing a federal regulation for "generally recognized as safe in food and food packaging" may not pull a lot of weight with a bunch of people who do not think grain should be "generally recognized as safe" as food. The cited page lists a bunch of stuff with limits but that doesn't mean it doesn't leach into food. I think what we need is some research data and not a regulatory finding. Your link does allay some of my fear but I still have a problem with throwing away more plastic with every meal. – ScottMGS Mar 5 2010 at 18:03
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Well you can't prove a negative. I won't get into a lengthy debate on the merits of radical skepticism as a philosophy. I'm tired of paleo bloggers asserting with no evidence that vacuum-seal bags contain endocrine disrupters, etc. Polyethylene is a completely different class of polymer from polycarbonate (the one that contains BPA) -- polyethylene has a low glass transition temperature that means it does not need additives to flow, and the monomer is a low boiling gas that dissipates quickly. – Durandal Mar 5 2010 at 19:31
No assertion intended, simply posing a question. – Theory to Practice Mar 5 2010 at 19:37
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It would take very little effort for the people spreading FUD about vacuum-seal bags to send out a request to the manufacturers to ask what, if any, additives are used in LDPE bags. From what I know from my background in polymer engineering, food-grade polyethylene is safe beyond a reasonable doubt. – Durandal Mar 5 2010 at 19:38
Scott, it's possible to wash and re-use some of those bags. Not that that's a real solution, but it's better than nothing. Durandal, you're right that you can't prove a negative. Absence of evidence is not evidence of absence. Now there's evidence that suggests that #5 plastics (previously thought to be very safe) may leach certain chemicals (although we don't know for sure that this will cause health problems). I'm still not 100% convinced that using my SVS is perfectly safe, but your posts are reassuring me somewhat (for now). Thanks. – JJ Mar 5 2010 at 19:58
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And who's to say that plasticizers are the only possibly leached substance with which to be concerned? I remember back in the dark ages, when Teflon was "safe", too.

Keith

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The Eades have taken this one on numerous times. It's safe. They went so far as to have a lab analysis done though I can't find a link to this at the moment.

Edit: I can't find anything directly from the Eades at the moment but Richard at Free The Animal takes on the plastic issue in the comments of a couple of his posts:

He also brings up the great point that sous-vide allows foods to be cooked at low temperatures compared to grilling/searing techniques that are known to produce carcinogenic substances.

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Would definitely love to see the link. (I own a SVS and then I started reading more about plastics... sigh.) – JJ Mar 5 2010 at 19:49
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Good thread!

I've stopped storing my food in plastic, whenever possible. And definitely never heat anything in plastic. So I'd be hard pressed to buy something that actually cooks my food in plastic!

I'm with Keith on this one.

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good for you! The possible dangers are to risky to me. Plus the pollution making plastic causes.. and the terrible lack of recycling.. – Fonda Jan 11 2012 at 14:33
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Caveat: I lean very hard towards reconstructionism and have not read any of the studies about grilling creating carcinogens. That being said:

I'd think that cooking in plastic wrap is by definition not Paleo, and furthermore, all those stories of carcinogens in grilled meat just reek of Vegan propaganda. We've been cooking meat over open flames for easily thirty times longer than we've been eating grain; I'd think that we're well down the road towards adapation to it.

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The question is whether or not sous-vide is safe and the answer seems to be a definite maybe.

There are many things that have been (and still are) considered safe or healthful by the conventional wisdom that have since proved questionable or harmful (EMF radiation, fluoride, teflon, whole-grains, cigarettes, etc.)

What I do know is that skepticism is warranted given the nature of sous-vide (cooking foods vacuum sealed in a plastic bag). It is also pretty obvious that a paleolithic, late neolithic or even "traditional" (in the WAP sense) precedent for the method does not exist (as in the case of cooking foods over an open flame, boiling, etc.)

Sous-vide may be interesting, may be OK, and may offer some benefits (thorough cooking at controlled temperatures) but further inquiry is warranted.

On a somewhat related note, any opinions on other "new" cooking methods such as dry ice baths? The Quilt mentioned in another recent post that freezing food can oxidize PUFA content, and, if that is the case, submerging something in liquid nitrogen (ice cream, eggs, scallops, etc.) might be a poor nutritional choice. It might seem unlikely that the average person would do this, but it wasn't too long ago that sous-vide was limited to high-end restaurants.

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Recent 2 good new posts on possible issues with plastics, Sous Vide, and other issues.

It seems like even BPA-free plastics can have EA (estrogenic activity)!

http://chriskresser.com/how-plastic-food-containers-could-be-making-you-fat-infertile-and-sick

http://nomnompaleo.com/post/12463202060/cooking-sous-vide-plastic-safety

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Could you wrap food to be sous-vide processed in banana leaves, much like tamales? How paleo is that?

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Did studies on this for PhD and keeping short the results were conclusive that no issues were found with sous vide cooking in various manufactured for food plastics

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of course cigarettes don't cause cancer.. don't be silly.

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besides the question of plastic, sous vide appears to gelatinize [wikipedia.org] the food, which seems un-paleo and pro-inflammatory at the least.

would love for somebody to say otherwise, though.

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It has to be vacuum-sealable for sou vide cooking. A sheep's bladder might be worth a try, but I doubt that will hold up long enough in the water bath.

This could be a really fun experiment!

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I wish they'd made silicone bags instead. Those wouldn't have any leeching toxins.

The other way is to deep fry. Same kind of effect since at the right temperature, steam from the moisture in the meat you're cooking keeps the oil from seeping in. Sadly this way lies AGEs via browning, and carcinogens (at least from potato.)

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