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Plastic in Ziplock Safe? (Been eating Sous Vide for 10 years)


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Hi everyone,

 

I have been eating Sous Vide meats (mostly chicken) almost every day for about 10 years. 

 

Now that I'm getting older, I've been thinking about the safety of the Ziplock freezer bags.

 

Is the plastic in the Ziplock freezer bags safe for Sous Vide? 

 

I usually portion out 6 pounds of meat, Sous Vide them in Ziplock bags, and then freeze them.   I usually Sous Vide chicken 165F for 1-2 hours.  I also Sous Vide pork shoulder and pork ribs for 24 hours.

 

I understand once in a while it may not be a big deal, but I eat Sous Vide meats almost every day!

 

Perhaps to be safe I should just Sous Vide in water?

 

What are your thoughts?

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From Bonappetit:

 

"The reason they're not necessarily “good” plastics is because a 2011 study found that when some were heated, these plastics —in fact, most plastics on the market, including those advertised as BPA free—release non-BPA chemicals that disrupt hormone activity. The amount of chemicals released, however, is unknown.

 

There currently aren’t any published studies specifically focused on the migration of chemicals in sous vide conditions, so you should sous vide only if you’re comfortable with the gray area surrounding the effect of chemicals in non-BPA plastics."

 

 

 
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32 minutes ago, torolover said:

From Bonappetit:

 

"The reason they're not necessarily “good” plastics is because a 2011 study found that when some were heated, these plastics —in fact, most plastics on the market, including those advertised as BPA free—release non-BPA chemicals that disrupt hormone activity. The amount of chemicals released, however, is unknown.

 

There currently aren’t any published studies specifically focused on the migration of chemicals in sous vide conditions, so you should sous vide only if you’re comfortable with the gray area surrounding the effect of chemicals in non-BPA plastics."

 

 

 

Yes, but...

If you click through and look at the actual study, they did three kinds of tests. One simply exposed the plastics to UV, intending to simulate exposure to sunlight or (in the case of baby products) a UV sterilizer. Another test heated the samples to 134C for 8 minutes in an autoclave (ie, a pressure cooker), to simulate a dishwasher (??). The third microwaved them for 2 minutes on High in a 1000 watt microwave. I can't find anywhere in the paper where it mentions how much saline they placed inside the test articles, but I can tell you for certain that mine will bring a cup of water to a full boil well before 2 minutes have passed.

In either case, the temperatures will be much higher than you'd use in sous vide cookery. Does this necessarily mean they're 100 percent safe to use at sous vide temperatures? (shrug) I don't know, and I have too much work on my plate at the moment to dig into it. But the data from the study are probably (largely) invalidated by the differences in temperature.

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“Who loves a garden, loves a greenhouse too.” - William Cowper, The Task, Book Three

 

"Not knowing the scope of your own ignorance is part of the human condition...The first rule of the Dunning-Kruger club is you don’t know you’re a member of the Dunning-Kruger club.” - psychologist David Dunning

 

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Could you explain your proposed alternative?  "Just sous vide in water" sounds like you intend to ditch the bag and just poach stuff at low temps?  THAT is a recipe for foodborne illness... you're culturing everything in the air in your kitchen that happens to land in the pot full of growth medium at the right temp for bacterial growth.

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Christopher D. Holst aka "cdh"

Learn to brew beer with my eGCI course

Chris Holst, Attorney-at-Lunch

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I will not comment anything more on the subject itself. As others have pointed out, material-wise vac-sealer bags and zip-locks should not differ in terms of safety. If endocrine disruptive effects would be present, a decade of daily exposure would have led to a manifestation. 
 

Concerning the cited study: please look through the author list and their affiliations. If you are looking for „harmless“ plastics, two of the authors work for a company that certifies these (for a fee). 

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Posted (edited)
23 hours ago, cdh said:

Could you explain your proposed alternative?  "Just sous vide in water" sounds like you intend to ditch the bag and just poach stuff at low temps?  THAT is a recipe for foodborne illness... you're culturing everything in the air in your kitchen that happens to land in the pot full of growth medium at the right temp for bacterial growth.

I have a Sous Vide Supreme.  I was thinking of "Sous Vide" the meats without bags in the Sous Vide Supreme with just water.  The Sous Vide Supreme has a cover, though it's not perfectly air tight.

 

I would do Chicken Breasts at 141F for 2 hours, Chicken thighs at 165F for 2 hours, and Pork Shoulder at 156F for 24 hours.  Then I would freeze them for future use.

 

Do you think this is dangerous?

 

Thanks for all the helpful thoughts everyone!

Edited by torolover (log)
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Yes.  Low temp poaching then cooling and freezing stuff that is not isolated from the environment is going to be MUCH more dangerous due to microbiologicals than any potential emissions from the plastics.  Are you planning on removing plastic from the equation entirely and wrapping in wax paper for the freezing?  

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Christopher D. Holst aka "cdh"

Learn to brew beer with my eGCI course

Chris Holst, Attorney-at-Lunch

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i think calling it dangerous with such decisiveness is, at best, incorrect. certainly once something is cooked through at a constant temperature the only risk of microbial contamination is going to be on the surface. if you properly cool, store, and reheat the products, they're perfectly safe. a bigger issue, imo, is that you're essentially poaching the food in a big tank of water and it's got to dilute the flavour in some respects.

 

anyway i can't speak to other bags and films, but i'd argue ziploc bags specifically are pretty safe, as far as plastics go. they're made from polyethylene and ziploc swears (for whatever this is worth) that they don't use bpa (i don't know about other compounds in the bisphenol suite) or other plasticizers in their bags. the biggest reason they don't recommend using ziploc bags in heated temperatures is because they become extremely soft and pliable when they're warm, which can cause spills and burns if a customer isn't careful - which is something the corporation is going to be more concerned about than we likely are. i don't know the extent to which the vacuum bags i use make any of these same claims.

 

i suppose one in-between solution might be to find a 100% silicone pouch that has some sort of closure or seal that would allow one to evacuate the air.

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Do please tell me what calling low temp poaching and cooling and reheating open to the environment "much more dangerous" than sealing the stuff is at worst, if at best it is wrong?  You'd advocate doing it, and do it yourself?  Are you calling me a crazy alarmist or something?

 

Let's see your risk assessment of sealed in plastic sous vide vs low temp poaching.  What's your HACCP for the latter procedure?

 

While you're at it, what's your risk assessment for ziploc plastic leaching unidentified bad stuff into the food?  How's that compare to the microbiological risk to health you just did the math for in the previous question?

Edited by cdh (log)
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Christopher D. Holst aka "cdh"

Learn to brew beer with my eGCI course

Chris Holst, Attorney-at-Lunch

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Nobody has addressed whether endocrine disruption is actually a thing in people or just in the lab.

4 hours ago, torolover said:

I have a Sous Vide Supreme.  I was thinking of "Sous Vide" the meats without bags in the Sous Vide Supreme with just water.  The Sous Vide Supreme has a cover, though it's not perfectly air tight.

 

I would do Chicken Breasts at 141F for 2 hours, Chicken thighs at 165F for 2 hours, and Pork Shoulder at 156F for 24 hours.  Then I would freeze them for future use.

 

Do you think this is dangerous?

 

Thanks for all the helpful thoughts everyone!

 

I'd say that t here are two issues with using a SV to poach meat...the leaching away of flavor by the big volume of water and the inability to get a SV magic in particular clean enough to cook in as you would a pan. Lots of nooks and stuff in the SVM (if its anything like my SV Supreme).  I suppose you could heat it up to 200F between cooks....

 

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there is no need to respond so aggressively. op is talking about, functionally, braising in a pot at 60C. that’s what the svs is. as long as the food remains submerged most of the time, the fact that it isn’t in a plastic bag is irrelevant to the question of microbial growth while cooking since the temperature precludes it.

 

once the item is finished cooking, you could then wrap it up and store it in the fridge as you would any leftovers. it wouldn’t stay as fresh as if it were vac packed, but that’s not the issue here. it’s no more dangerous than any other kind of cooking in that it has the same risks - you’d want to quickly cool it and then bring it back up to proper temps on the other side. 

 

i don’t think it’s a great idea but it’s because i don’t think the product will taste as good not because it’s inherently unsafe. 

Edited by jimb0 (log)
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