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Does boiling sous vide chicken stock kill everything including Botulism Spores?


torolover
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I often sous vide 5 pounds of chicken thighs for 8 hours at 156F.  There is a lot of chicken juice and fat left over in the bag.

 

I plan to save all the juices and fat every time I sous vide until I get about 4 cups of chicken juice.  Then I can make chicken soup and use the fat for frying veggies.  This may take me a month of saving juices however.  Is storing the juices and fat for a month or longer safe?

 

If I empty all the juices and fat from the bags, and boil them, will this be safe to store for long periods in fridge or freezer?  I am also concerned about Botulism Spores which I understand is heat resistant.

 

Thanks!

 

 

 

 

Edited by Smithy
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If the chicken is safe to eat, why wouldn't the juices be?  Maybe I'm missing something but I don't see any problem with saving the liquid in the freezer.   Wouldn't keep it in the fridge for long, there are other things besides botulism that would make it go bad. 

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The issue is storage. Neither SV nor boiling kill botulism spores.  If you use immediately, or after a short period of refrigeration, the spores won't have time to grow.  Long storage, even in the fridge, opens the possibility of spoilage.

 

So freeze what you can't use immediately.

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If I could manage to save it, I'd just freeze it. I have a ton of vac bagged stocks in my freezer, and they're safe for basically forever (provided that you chilled them properly). But SV jus is something I always intend to save, but just end up using immediately. The best thing to do is move it directly from the bag to a pot and bring to a simmer or light boil for several minutes. This will cause many of the proteins to coagulate together and form a raftlike scum you can try to fish out and strain (cheesecloth works best). Chill and defat it. If this all works out correctly, you'll end up with clarified (or semi-clarified) jus that's incredibly flavorful and ripe for saucework or glazing.

 

For sauces:

Steep some herbs in the warm jus for 10 minutes and strain again. 

Mount it with a fat of your choice (tallow or butter for beef jus, butter or bacon fat for pork, butter or duck or schmaltz for chicken).

Salt to taste

Finish with an acid of your choice. Or maybe some sherry, white, or cognac. 

 

For glazes: Use clarified, salted, jus to glaze panroasted vegetables or potatoes. Feel free to mix it with other things you've got around the place -- soy sauce, fish sauce, chili sauce, whatever -- and throw on whatever you want to.

 

If, for some reason, you cannot find an immediate application for your clarified SV bag jus, chill and transfer it to a freezer bag (vacuum or otherwise), and freeze it until you need it. But I find I rarely have a storage problem.

Edited by btbyrd (log)
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btbyrd,

 Many thanks for this.   I have printed it out for future reference.

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Anna Nielsen aka "Anna N"

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"Cooking is about doing the best with what you have . . . and succeeding." John Thorne

Our 2012 (Kerry Beal and me) Blog

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I sous vide turkey thighs for 24 hr @ 165°F, then chill and hold in the refrigerator. There isn't much juice when a single thigh is de-bagged so it winds up in soup or sauce within a day or two.  But if you are doing a lot of chickenthighs perhaps the best approach is to understand what botulism spores demand and what it takes to denature the toxin:

C. botulinum spores can be killed by heating to extreme temperature (120 degrees Celsius) under pressure using an autoclave or a pressure cooker at for at least 30 minutes. The toxin itself can be killed by boiling for 10 minutes.

So eat the thighs quickly, and freeze the juice until you have enough to make soup. Then pressure cook the juice for 30 min if you are concerned, or simmer it for 10 min even if you are not, before you make your soup.  I find that the long cooking time facilitates the liquid in the bag dissolving a large fraction of the connective tissue, though not all.  However, after a few careful dissections you become quite familiar with the anatomy of the bird and can disassemble the pieces into bone, fat, residual connective tissue, and mouth watering tender flesh. If you have enough residual fat you can shred it and make confit. Or torch it and top a salad or soup or put it in a taco or burrito or make an omelet or a souffle, or just put it into the soup.

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You don't need to sterilize for botulinum spores for safe storage, which are the treatments that are being suggested here. A heat treatment of 90ºC/10 min is considered enough for fridge storage of food under vacuum below 8ºC(http://acmsf.food.gov.uk/sites/default/files/mnt/drupal_data/sources/files/multimedia/pdfs/acm777annex.pdf). And the juices will not be under vacuum after the initial SV cooking, so it would be even safer. So just boil the juices for 10 minutes, make them cold fast and keep in the fridge as cold as possible. But take into account that with that treatment spoilage will arrive earlier than any botulism hazard, so in any case I suggest you freeze the juices after boiling them.

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