Sous Vide Cooking Method - nutrition and toxicity?

[AndieJ]

I am working with a new restaurant that is planning to use the sous vide cooking method and I was wondering if anyone can provide any research, thoughts, or experience to back up the safety or potential concerns with this cooking method. 
http://en.wikipedia.org/wiki/Sous-vide

In sous vide, food is placed in an airtight plastic bag, submerged in water, and cooked at a lower temperature (around 140 degrees F) for longer periods of time (up to 72 hrs).  The proponents of this method say that the lower temperatures preserve nutrients.  While that makes sense, there is concern regarding the toxicity of cooking in plastic (especially heated plastic).  The manufacturers of the plastic bags say that it is food grade plastic and completely safe. 

I would appreciate any research, experience, or opinions that you can share on this topic!

Many thanks,
Andie

[blujay]

hey Andie,

I've worked in a few places that used the sous vide method. Its becoming quite popluar in fancy restaurants as a way to cook foods to perfect doneness.

 From a culinary perspective its an amazing way to cook and produces consistent products, it adds another dimension to a chefs repertoire that can make for great food.

That said, from a health perspective, I would avoid it like the plague. Chefs tend to want to manipulate food in many different ways to coax as much flavor out of food. Which is why they cook things in so much oil, brown everything, loads of salt and sugar, msg, etc...So this is really just trading one method of unhealthy cooking for another. Heating liquid oils, at all, produces some nasty carcinogens and oxidised lipid with goes on to produce AGE's in our bodies. But then cooking sous vide leaches various petrochemicals into the food. And usually restaurants that would do sous vide will also do the frying/flavoring of the same food, so you are getting a double whammy...
    Also, they are likely planning on cooking foods sous vide that have alcohol, acid, or fat...all of which leach compounds out of plastics even faster than water (see study below).
    The cooking times will likely vary from 30 minutes to 2 days when cooking sous vide, and the longer the time and the higher the temperature, the more compounds will be leached from the plastic.
    Plus, this is another expensive piece of equipment that can be marketed to chefs and customers...so this is just another way to make a buck, without really having a concern for the customers best health. (restaurants weren't designed for that, your own kitchen is...)

This is some of the reasoning behind my recommendations that people really concerned about their health should avoid eating out at restaurants altogether (no matter the quality or promoted health benefits). Yes, extreme, but you would be surprised as to what other kind of contamination happens in the best of restaurants...trust me.

Here is some background on what I'm talking about...

Sous vide cooking products
http://www.sousvidesupreme.com/en-us/sousvide_cookingtips.htm

The plastic bags used in sous vide are likely made of PET (or HDPE) so here is a report on the leaching of a specific chemical at low temperatures. Even thought the EPA has set standards for contamination levels of such products, if these compounds are toxic at all, why would it be ok at ANY level, especially one with a carcinogenic level as low as 6ppb!
http://www.ncbi.nlm.nih.gov/pubmed/17707454

If you are the expert to put your stamp of approval on this restaurants practices, and they are concerned about sources of contamination, I could give you a litany of sources of even more disconcerting contamination vectors...

There is another way to cook sous vide which is much healthier, yet hasn't seen professional applications. There is a way to vacuum seal glass jars and cook sous vide.  Glass is a better conductor of heat and is less of a source of contamination and has zero leaching (plus they are 100% reusable/recyclable ). 

Hope this helps you...
j

[SousVide Supreme]

Hi Andie,

This is a perfectly valid concern.  However, just for your piece of mind, this method has been used for many years since the early 70's by renowned Chefs across the world.  As this technique is wonderful for the result of ultimate perfection, it is important to remember that you need to be mindful of what you use to cook your foods in.  I am the Culinary Director of SousVide Supreme and can tell you that we have produced an FDA approved vacuum pouch that is BPA free and sous vide ready/approved.  It has been through the proper testing and is completely safe for this method.  I would be very careful what you decide to cook in with this technique as I cannot recommend anything else, but we have never had issues or complaints with our product and we would not be FDA appproved if it weren't safe to cook in.  You may see more information on our website on www.sousvidesupreme.com  or contact cooking@sousvidesupreme.com if you have any questions as I would happy to answer them.

[blujay]

Whoa, that's quite a proactive marketing service you have...thanks for responding.

I completely agree with the method as a healthier way of cooking (slower, lower temp, low oxygen), just not the materials and ingredients that are used (PET bags). Yes, BpA is being phased out of many plastics, yet that is only one of many chemicals used in processing plastics that have potential negative health effects. (just as the above report states)

And just to give you more perspective, we aren't concerned only with the potential contamination of foods from this one source, but the accumulated effects of the many sources of such plastics and other toxins in our food production and environment...so we are trying to identify and avoid as many of these sources from peoples lives as possible.

If you would like to market this technique (and your products) to the health conscious Chef/nutritionist/consumer I would love to see you develop a reusable completely non-reactive container for the use in sous vide cooking. Then, I would definitely purchase and recommend that product. But until then, I'm not interested in cooking in plastics of any kind, especially one that has been "approved" by the FDA. (the FDA knew about BpA having human estrogenic properties since the 30's, yet made no regulations, only after consumer pressure was anything done)

still not convinced...
j

[Marlina E]

It IS pretty amazing how quickly this person found the discussion on the forum. 

[AndieJ]

Hi J, I really appreciate your reply and perspective on this!  I tend to share the same concerns re: plastics and wanted to be sure I wasn't missing anything. 

You said:
"If you are expert to put your stamp of approval on this restaurants practices, and they are concerned about sources of contamination, I could give you a litany of sources of even more disconcerting contamination vectors..."
--> I am the key person who is advising the restaurant on health and nutrition.  If you can briefly point me in the direction of any other sources, that would be helpful.

You said:
"There is another way to cook sous vide which is much healthier, yet hasn't seen professional applications. There is a way to vacuum seal glass jars and cook sous vide.  Glass is a better conductor of heat and is less of a source of contamination and has zero leaching (plus they are 100% reusable/recyclable )."
--> Yes!  I was wondering if glass was an option.  Is this a common practice?  Do you know of any manufacturers that supply glass for sous vide?

Many thanks!

[blujay]

Sorry for the delay...Chef Duties called...Here is what I could gather off the top of my head...

An effective HACCP plan (http://www.fda.gov/food/foodsafety/HazardAnalysisCriticalControlPointsHACCP/ucm114868.htm) can mitigate much of these vectors, yet they only control them to a point, not eliminate them, and the effects of these multiple contamination aren't considered in light of the consumers health (only to keep them from getting sick to stay in business)

Vectors of biological and Chemical contamination in Commercial Food service operations that can contribute to health complications:


Biological:
     -GMO's: the most insidious of all contaminations! (virtually in all processed/packaged foods including Nutritional yeasts, sugars
   Humans: (the more pretty your food on your plate, the more people touched it)
     -The handling of various foods during operations contributes to multiple cross
       contamination, no amount of washing and chemicals will prevent cross-comtamination. 
      Which makes Allergen free food services are very rare (for that sake, vegan/vegetarian
      /gluten/nut free food services if they serve those contaminants otherwise)
     -Human hair, skin, saliva (personal hygiene practices)
     -They are the main cross contamination vectors (trash to sink to food to toilet to food, etc...)
   Insect:
     -Foods naturally contain a certain level of insect parts (from fresh salad greens to grains),
      though they are rarely considered pathological for humans.
     -improperly stored foods can attract and contain insects
   Animal:
     -Foods naturally contain a certain levels of animal parts/fecal matter/hair, not normally
       considered pathological for humans, as long as its keep to USDA standards.
   Microbial:
      -Sources of comtamination: Water supply, air, humans, foods, pests,
       -Intrinsic properties of foods and processing (bacterial levels, Aflatoxin residues)
      -Humans
      -Equipment (cutting boards, ice-makers, water pipes, refridgerators, sinks, tables, small wares, storage ware, etc...)
Chemical:
       -Animal/plant products: conventionally raised livestock,wild/farmed fish and much of the 
          plant crops now contain certain levels of Hormones, pesticides, genetic modification,   
          environmental contaminations (organic or not)
       -City water supply (HALO's, Chlorines, bromines, florides, etc...)
       -Water pipes (copper, lead, plasticizers, iron, etc...)
       -coffee filters (material made with bleaching and other processing agents)
       -Dishwashers (highly toxic cleaners/sanitizers/rinse agents leave residues on flat ware and
       are sent into the air and water supply)
       -Cleaning agents: Tables, floors, equipment
       -Cook ware: aluminum, non-stick, plastic, (cookware, utensils, equipment) (can react with
           cleaning agents, foods and cooking methods to contaminate food)
       -storage ware: Cambros (#5, #7 containers), cellophane/plastic wrap, alluminum foil 
       -Service ware: (melamine, plastic, metal) plates, bowls, cups, utensils
       -Cooking methods: High heat cooking (searing/roasting/baking/frying/grilling/sauteing) 
         produce highly toxic compounds related to multiple health disorders for the people
         cooking them and the people eating them.
       -Disposable wares: (Plastic, wax, paper wares) my impression is that even
        bio-compostable wares are even more toxic, less stable bonds of materials and they still
         use petroleum/chemical plasticizers.   
       -Product packaging: Plastics, waxes, cardboards, biological control chemicals, fumigants,
            preserving agents.
       -Rubber/plastic/nitrile gloves: both the material and the Talcum/cornstarch/other
            powder/chemicals used in producing/packaging/ease of use.

So, its pretty much impossible to have a contamination free food service...you just have to choose your level of contamination that you are willing to accept...you control many of these factors when your produce your own food. So you see why I rarely eat out...
 
As I think of more I'll send them your way...

Contaminantly yours,
j
       

[AndieJ]

Thank you J for all this additional information!  There are certainly a lot of sources of contamination to consider - this is really helpful.

I appreciate your time and thoughtfulness!

-Andie

[davidm197]

Oil is the source of plastic. Oil leaks at the well. Oil leaks from the crankcase. It leaks at the refinery, and it leaks at the gas pump. All leaks end up in watersheds. The end product of oil, (plastics,) is thrown "away" in the landfills. There is no such thing as "away" anymore. (Just like there is no such thing as safe nuclear waste disposal.)  Its time that humanity gives up its dependence on oil in any way we can. The age of "The Graduate" is over. Plastics is not the answer!  What can we do to sustain life on the planet and the life of the planet?
Please, lets not forsake the future for profits and gadgetry.
Sincerely, David Mallin

[blujay]

Oh yeah, sorry...here is my recommendation for cooking sous vide in clean reusable containers....

I use ball canning jars, and ensure that there is some kind of liquid surrounding the food to ensure a good contact with the glass, and at least 2 inches of head space (the vacuum process will raise the level of contents) Then vacuum out the remaining air to produce a strong vacuum, then proceed with cooking. Times may need to be adjusted due to the energy transfer of the jar, and the thickness of the food in the jar.

-Ball canning jars (half pint or pint jars work best, but any size will work as long as you can fill the jar and fit it in your bath)
http://www.freshpreserving.com/pages/home/258.php?pid=291&product=298

Pump and seal vacuum
http://www.pump-n-seal.com/

Joy in a Jar,
j

[dhuang72]

Hi -- I stumbled on this thread after purchasing a Sous Vide Supreme.  I was so excited and happy with my initial results --then, thought about how often I was using it and decided I better look for some alternatives to the plastic bag method if I was going to adopt it as a fairly frequent method of preparing foods.

My question is, when you say you surround the item to be cooked with liquid, are you doing this inside the canning jars (so immersing the item)?  I performed one test run where I only made sure the water level on the outside of the jar was higher than the item to be cooked and it didn't really turn out the same as the plastic bag method.  If you are immersing the item completely, does that complete change the outside texture because it is just sitting ina liquid pool?  so, any seasonings that would normally be dry are no longer possible?

Just trying to test out this glass jar method -- any comments would be greatly appreciated.  Thanks!

-Dan

[blujay]

Great question. I don't have the luxury of having a sous vide device at my home and I no longer work where I have access to one, so I couldn't test your theory out.

Since the concern with cooking in plastic came from the contact of fats and acids (both liquids), I see less of a concern if you want to cook dry ingredients in a plastic bag (what dry items are you cooking?) So maybe a way to do the dry cooking would be to coat your items in lots of dry ingredients (spices, nuts, flours, salt etc...) then just scrape off that extra portion of dried ingredients that came in contact with the plastic.

But since most sous vide foods have some kind of liquid (even if its their own) then I would stick with cooking with glass. Just be sure that the liquid has some kind of flavor (stock, wine, brine, butter, etc...) otherwise it will suck out the flavor of your foods and leave them bland. The good thing about this is that you are infusing flavors AND more nutrients into your foods (ie, sous vide broccoli in herbal green tea). Plus you can use this liquid multiple times getting more flavor and nutrients in each batch (this works well with fat).

There are a few more concerns when cooking this way.
-Since you are using a denser material (than plastic) cooking times will likely need to be raised and be different than other recommended cooking times (if you develop some good formulas, please share!)
-The jar/container acts like a heat sink and can cool the food. So if possible, completely submerge the jar (weigh it down). At minimum keep the level of the food at or below the level of the water.

Test this out...Try using the thinner sealable glass containers with plastic lid (not letting food touch the lid) then fully submerging them to cook.
http://www.amazon.com/Kinetic-Premium-Storage-Container-Containers/dp/B002PDOC68/ref=sr_1_4?ie=UTF8&qid=1313478758&sr=8-4

Pura Sous Vida!