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?
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.
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.
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.
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.
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.
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.
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)!