[Modernist Cuisine] Sous Vide Cooking Safety: Times, Temperatures, Storage, and Reheating

[KennethT]

The smell test will not tell you if pathogenic bacteria are present. These are the bacteria which make you sick, and there is no smell, taste or sight cues which will alert you to their presence.

The bacteria which "smell" are spoilage bacteria, which while yucky, will not give you food poisoning.

[paulraphael]

The smell test will not tell you if pathogenic bacteria are present. These are the bacteria which make you sick, and there is no smell, taste or sight cues which will alert you to their presence.

The bacteria which "smell" are spoilage bacteria, which while yucky, will not give you food poisoning.

 

Possibly the biggest danger when storing sv'd food a long time is spores from anaerobic bacteria like c. botulinum. The spores aren't killed by normal cooking temperatures, and the oxygen-free environment inside the bag is exactly what triggers the spores to activate. The two things that keep this from happening are high-acid environments (which you don't have with meat) and temperatures below 38°F (for c. botulinum type-e). 

 

So yeah, it would be a good idea to get a conservative read on your fridge temp at the location where the meat was stored. One way to do this is to put a container of water in there for 24 hours, and measure its temperature after a time of day when the door gets opened a lot.

[rotuts]

did you 'rapid-chill' in ice to get them to the low '30's before you put them in the refrig?

 

doing that is supposed to be key, rather than a much slower cooling off by just putting them warm in the refrigerator.

[kayb]

did you 'rapid-chill' in ice to get them to the low '30's before you put them in the refrig?

 

doing that is supposed to be key, rather than a much slower cooling off by just putting them warm in the refrigerator.

No, I didn't. I cooled them on the counter until they were cool enough to handle easily, then stuck them in the fridge. They were probably on the counter for 30 minutes.

 

A thermometer in the fridge for an extended period of time revealed readings between 34 and 36F.

[Anna N]

No, I didn't. I cooled them on the counter until they were cool enough to handle easily, then stuck them in the fridge. They were probably on the counter for 30 minutes.

 

A thermometer in the fridge for an extended period of time revealed readings between 34 and 36F.

Good health care coverage? Affairs in order? Willing to gamble it all on 4 pork chops? Ditch 'em. I would.

[rotuts]

ice- bath cooling for SV I think is worth noting  

 

I don't have one of those Auto-Icemakers.  in the past for large SV , my forte, I made ice in various odd containers.

 

I realized there is a Liquor store very very near me.  I just go there now and buy a bag of ice.

 

its classified as 'Food"   no tax.   !.49

 

for SV use MA would have to charge me tax.

 

Edited September 3, 2015 by rotuts (log)

[paulraphael]

If you have cold packs in the freezer, these work too. Not nearly as efficient as ice in my experience, but it's easy to run out of ice around here.

 

One thing you can do to conserve ice, if you're chilling something that cooked at a high temperature, is not throw the food in straight out of the ice bath. You only have to chill it rapidly after it gets below 130°F or so. Pre-cooling it in plain water works great. Then an ice bath, and then into the fridge after it's down near 40°.

[EnriqueB]

Using the generally accepted rules, if you chilled to 3ºC in less than 2 hours and you are absolutely sure that your food has been under 3ºC all the time, then the food should be safe to eat.

 

If your food has rather been between 3 and 5ºC, the maximum conservation time goes down to TEN DAYS, given the measured germination and toxin production of the most dangerous C.Botulinum spores. Even if this is a low-likelihood scenario, in this case your food is NOT necessarilly safe.

 

Fast chilling does not seem clear from what you post. Fridge temperature seems ok from your measurements, but you should be absolutelly sure, i.e. are you sure the fridge door was not being opened frequently during conservation, which would likely take temperature above 3ºC? Honestly, I would throw the food away and not run the risk.

[kayb]

OK. I'm going to side with safety. Out the chops go. Thanks, everyone, for your contributions to my future well-being.

[paulraphael]

I face decisions like this a lot (while I talk a good game on the internet, my fridge organization skills struggle against entropy).

 

It often comes down to who I'm feeding. If it's just for myself I usually go for it. If my girlfriend's joining, then I'm a little more cautious. If there's someone pregnant, or people I don't know, or my 80+ year old parents, I do it by the book.

[pbear]

Kenneth, do yourself a favor.  Take the time (and it will be considerable) to learn the food science behind this.  Good starting points would be the FDA Bad Bug Book and the 1999 CDC study on foodborne illness.  The statistics will be almost entirely about the U.S., of course, but the science applies everywhere.  Also handy, by the way, is this concise chart by food scientist Peter Snyder summarizing salient characteristics of the most common bugs.

[paulraphael]

Your meat was pasteurized when the heat went off, so the danger is from anaerobic bacteria, like c. perfringes and c. botulinum. These love warm temperatures in a low-acid environment in a bag where there's no air. They produce toxins that are not destroyed by normal cooking temperatures.

 

It's impossible to say how likely this was in your situation. I don't think there's any way to predict the presence of these organisms on raw meat, or any way to test for the toxins (without a chemistry or biology lab). My guess is that the probabliity is low. But the stakes are high. Like daveb, I'd be inclined to eat it but not to play Russian Roulette with guests.

[Martin Fisher]

Data schmata!!!

The only way to know if something in question is safe is to analyze IT!!!

Realistically, who's going to do that? Not many folks!

When in doubt, toss it out! It's not worth the risk!

Edited October 22, 2015 by DiggingDogFarm (log)

[paulraphael]

Data schmata!!!

The only way to know if something in question is safe is to analyze IT!!!

 

What do you mean? When we cook food to pasteurization—to make it safe—we base our times and temperatures on data. At least that's what I do. I don't have a lab to analyze my food.