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

[EnriqueB]

72 hours at 54C (130F) is absolutely incredible. Currently doing that now. A bag might have leaked, but I'm letting them go and see how it turns out.

 

Check this out - http://www.chefsteps.com/activities/short-ribs-time-and-temp

 

Shocked at that profile. 54,5ºC is considered the minimum temperature for long cooking periods, and then to get it you usually apply a water temperature at least 0,5ºC higher. At 54ºC Clostridium perfringens is not guaranteed to die (see Douglas Baldwin's guide). I also see in the comments for that page that they are using nitrites, which may justify using that temperature as it provides extra safety (I don't know whether it takes care of perfringens but given that it takes care of other Clostridium like botulinum, it may do), but most people following that profile will not, and that is not a good idea.

Edited October 10, 2014 by EnriqueB (log)

[Robenco15]

Shocked at that profile. 54,5ºC is considered the minimum temperature for long cooking periods, and then to get it you usually apply a water temperature at least 0,5ºC higher. At 54ºC Clostridium perfringens is not guaranteed to die (see Douglas Baldwin's guide). I also see in the comments for that page that they are using nitrites, which may justify using that temperature as it provides extra safety (I don't know whether it takes care of perfringens but given that it takes care of other Clostridium like botulinum, it may do), but most people following that profile will not, and that is not a good idea.

 

 

I'm not going to get into this too much as this is not the thread for it and I don't have the time. ChefSteps is made up of some of the most knowledgeable chef's in the world and at the forefront of sous vide cooking, etc. They are the guys who wrote and researched the Modernist Cuisine volumes. I would trust the guys at ChefSteps with anything food related. Their community, which I am an active member of, is also probably one of the best and easily the most exciting food community around right now. If they say 54C for 72hrs., then I'm doing 54C for 72hrs and not giving it a second thought. My only issues I ever have is that since I use Ziplock bags I worry about bag leaks, but so far I'm 2 for 2 and probably 3 for 3 by dinner tonight. I don't know much about nitrites, but from what I know they use it specifically keep the red color of the ribs nice and bright.

 

By the way, Douglas Baldwin now WORKS for ChefSteps.

[EnriqueB]

I'm not going to get into this too much as this is not the thread for it and I don't have the time. ChefSteps is made up of some of the most knowledgeable chef's in the world and at the forefront of sous vide cooking, etc. They are the guys who wrote and researched the Modernist Cuisine volumes. I would trust the guys at ChefSteps with anything food related. Their community, which I am an active member of, is also probably one of the best and easily the most exciting food community around right now. If they say 54C for 72hrs., then I'm doing 54C for 72hrs and not giving it a second thought. My only issues I ever have is that since I use Ziplock bags I worry about bag leaks, but so far I'm 2 for 2 and probably 3 for 3 by dinner tonight. I don't know much about nitrites, but from what I know they use it specifically keep the red color of the ribs nice and bright.

 

By the way, Douglas Baldwin now WORKS for ChefSteps.

 

I'm talking about science here, not about anybody's merits. You wanna risk your health at the popularity of some cooks, go ahead. But I don't want to see such a profile here in a public forum where people can follow it without any further justification for what clearly is a food safety risk. I know perfectly well who ChefSteps are, I follow them since they started. I was likely the first person to receive and read the MC volumes in Spain. I teach sous-vide classes, and food safety is a key issue for me. 54ºC for 72 hours without any additional safety measures is not guaranteed to be safe for what we know from Baldwin and MC, so it deserves furher justification. Period.

 

And I am also surprised that ChefSteps put that profile without any additional comment about safety in that page. I will later ask directly in their page.

Edited October 13, 2014 by EnriqueB (log)

[c oliver]

I'm talking about science here, not about anybody's merits. You wanna risk your health at the popularity of some cooks, go ahead. But I don't want to see such a profile here in a public forum where people can follow it without any further justification for what clearly is a food safety risk. I know perfectly well who ChefSteps are, I follow them since they started. I was likely the first person to receive and read the MC volumes in Spain. I teach sous-vide classes, and food safety is a key issue for me. 54ºC for 72 hours without any additional safety measures is not guaranteed to be safe for what we know from Baldwin and MC, so it deserves furher justification. Period.

 

And I am also surprised that ChefSteps put that profile without any additional comment about safety in that page. I will later ask directly in their page.

I'm pretty new to SV but cook at that temp and lower for that long.  You're talking science.  I guess I must be talking medicine or microbiology.  If there's no pathogen there to begin with, it's not going to materialize.

[Robenco15]

I'm talking about science here, not about anybody's merits. You wanna risk your health at the popularity of some cooks, go ahead. But I don't want to see such a profile here in a public forum where people can follow it without any further justification for what clearly is a food safety risk. I know perfectly well who ChefSteps are, I follow them since they started. I was likely the first person to receive and read the MC volumes in Spain. I teach sous-vide classes, and food safety is a key issue for me. 54ºC for 72 hours without any additional safety measures is not guaranteed to be safe for what we know from Baldwin and MC, so it deserves furher justification. Period.

And I am also surprised that ChefSteps put that profile without any additional comment about safety in that page. I will later ask directly in their page.

Whatever man. You have your opinions and I have mine. Chefsteps and Douglas Baldwin are more than enough for me to cook for 72hrs at 54C.

I have no idea if this is useful information or not for you, but I pre-sear my ribs before cooking to eliminate all surface bacteria. I also am not putting anybody elses health in danger by reposting from a reputable source with scientific backing. Since you read Modernist Cuisine, I would hope you'd understand that saying they are just some popular "cooks" is innacurate and a bit rude.

Please contact ChefSteps though. I's be interested in hearing what those cooks have to say, either way. Truly.

Edited October 13, 2014 by Robenco15 (log)

[EnriqueB]

I'm pretty new to SV but cook at that temp and lower for that long.  You're talking science.  I guess I must be talking medicine or microbiology.  If there's no pathogen there to begin with, it's not going to materialize.

 

At your own risk. What you say is true, but how do you guarantee the total absence of pathogens to start with?

 

I suggest reading UK Food Standards Agengy Safety of sous vide foods report. An excellent analysis without the nonsense of many official agencies recommendations (where times are not mentioned, etc.)

[nickrey]

My main concern when you're skirting close to the safety margin is the accuracy of sous vide machines.

 

I'm sure that Chefs Steps have properly calibrated sous vide equipment but when I've used a properly calibrated reference thermometer to check temperatures (and yes this is different from my thermapen), I've found variations in target temperature of 1C or higher. This means that a reading of 54C on the sous vide machine could reflect a cooking temperature of 53C or less. In a domestic environment I'd be putting a safety margin on there, which is why I tend to use a minimum temperature for long cooks of around 57C. 

[c oliver]

 

At your own risk. What you say is true, but how do you guarantee the total absence of pathogens to start with?

 

I suggest reading UK Food Standards Agengy Safety of sous vide foods report. An excellent analysis without the nonsense of many official agencies recommendations (where times are not mentioned, etc.)

I honestly have no interest in guaranteeing no pathogens.  I eat RAW meat and eggs pretty regularly in fact.  I drink tap water almost all over the planet.  The ONLY time I've been sick from food was from US produced peanut butter that was tainted with salmonella and hadn't been pulled from the shelf. I was in Brazil at the time and self-medicated with Cipro and all was well.   I think there is the rare person that has issues with food but tons of people who are convinced or or afraid it will happen to them.  As my late friend and food scientist, Dr. Sam Fujisaka said, we live in a "magic house" and our friends get the protection also  

[weedy]

At your own risk. What you say is true, but how do you guarantee the total absence of pathogens to start with?

 

I suggest reading UK Food Standards Agengy Safety of sous vide foods report. An excellent analysis without the nonsense of many official agencies recommendations (where times are not mentioned, etc.)

 

with all due respect,

how do you "guarantee the total absence of pathogens" in a raw oyster?

and yet, many of us eat them like that

 

I'm not expecting a guarantee of "the total absence of pathogens"

[btbyrd]

Like some have mentioned already, the interior of intact cuts of meat can be presumed to be sterile. A quick blanch in boiling water will kill any pathogens on the surface of meat destined for long SV cook times. I usually don't even bother. The FDA pasteurization tables list a 112 minute pasteurization time @ 54.4C for beef and pork. A short rib and cheek (and most other tough cuts) are thin enough that they'll reach that core temperature in well under an hour and a half. There's no worry cooking at 130F for extended time unless you're using a large cut like a chuck roast that's been boned out and might have contamination deep inside the cut. Even still, it'd have to be a big hunk of meat to not reach pasteurization temps within 4 hours.

[nickrey]

It's not just a matter of reaching core temperature. The long cooking tenderises the meat.

[EnriqueB]

c oliver and weedy, of course I also consume raw meat and fish. But we are not talking about that here. We are talking about a long cooking process that has the potential of making any existing pathogens in the food grow, or at least not be destroyed to a low-enough number such the food is safe to eat.

[EnriqueB]

Ok, please let me restate the issue that gave origin to the discussion in this thread:

 

On this page, the ChefSteps team is proposing very long sous-vide cooking times (48-72 hours) for short ribs at 54ºC, without any explicit mention of additional safety measures. On the comments they suggest preblancing or presearing (preciselly because some user tried one profiles and his bag showed symptons of bacterial growth) and that they are using nitrites (which prevent growth of several pathogenic bacteria), but nothing is mentioned about these in the main text.

 

I argued that proposing those profiles without any further safety measure goes below the well established temperature threshold of 54.4ºC which has been long known as the mininum temperature for pasteurization because it is the minimum temperature that has shown to destroy the highest temperature-resistant food bacteria, Clostridium perfringens. This minimum temperature for long cooking times of meat has been thoroughly discussed in this same forum in many posts, such as:

 

http://forums.egullet.org/topic/144706-cooking-with-modernist-cuisine-at-home-part-2/?view=findpost&p=1911109
http://forums.egullet.org/topic/144301-sous-vide-recipes-techniques-equipment-2012/?view=findpost&p=1887437
http://forums.egullet.org/topic/144300-sous-vide-recipes-techniques-equipment-2011/?view=findpost&p=1843578
http://forums.egullet.org/topic/136275-sous-vide-recipes-techniques-equipment-part-8/?view=findpost&p=1769246

 

So I claim that going below the 54.4ºC limit deserves a detailed explanation of the food safety issues involved and the science behind, which is something that has always been done in this forum.

 

It is my understanding that they are playing with the growth/no-growth/destruction limits of C. Perfringens. 54.4ºC is suppossedly the temperature at which it starts to be destroyed, but at around 52ºC it stops growing. Thus, if we do not have a high enough initial population of C. Perfringens in the meat to start with, the profiles could be safe. In order to guarantee a low initial population, intensive presearing or preblanching would be a must in those recipes, as well as ensuring the meat is intact, i.e. the potential bacteria has not entered the interior of the meat (which, as btbyrd says, is generally assumed to be sterile). Beware that unknown jaccarding, marination, or a careless knife incision could have contaminated the interior, which is the reason why it is usually required that the core of the meat reaches pasteurization temperatures in less that 4 or 6 hours (depending on the source).

 

In any case, these profiles are really pushing the limits of food safety, and in those cases the very precise calibration of the sous-vide equipment becomes critical, as nickrey has said. Even a -0.5ºC error in the temperature, easily found in home equipment, could well move us into the growth zone, and 72 hours in that zone are likely to take any C. Perfringens in the surface of the meat to dangerous levels. C. Perfringens is not to be taken lightly: it is the third pathogen contributing to domestically acquired foodborne illnesses in the US, according to CDC estimates for 2011, and also the third in strong-evidence outbreaks in the EU according to EFSA report for 2012.

 

And an extra caution: in my conversations with food safety experts, they argue that the no-growh/growth limits (such as 52/54.4ºC) are not something that should be taken as set in stone from just one or two studies. Those numbers may well vary with factors some as type of food, pH, or the presence of given plasmids. Also, the growh and destruction dynamics around the threshold temperatures is far from clear, and may well differ form the well-established dynamics at higher or lower temperatures, respectively. All this is well analysed in the report I mentioned above, from UK Food Standards Agency: Safety of sous vide foods. What this report hightlights is that, despite the excellent work made by people such as Douglas Baldwin or the Modernist Cuisine team, several of which are now in ChefSteps, some of their values are just extrapollations based on limited research. New research comes from time to time that may challenge some of those limits, see for example Extreme Heat Resistance of Food Borne Pathogens Campylobacter jejuni, Escherichia coli, and Salmonella typhimurium on Chicken Breast Fillet during Cooking.

[EnriqueB]

Since you read Modernist Cuisine, I would hope you'd understand that saying they are just some popular "cooks" is innacurate and a bit rude.

 

 

That was just irony, given that on your first answer you seemed to disregard any discussion about the basis and safety of the profiles, claiming that they come from reputable sources. It looked like "hey, this comes from this well known people, who are you to question what they are saying?".

 

Precisely the strength of this forum is that it is one of those places were these things ARE discussed, irrespective of the source.

 

Of course the MC team and ChefSteps are reputable sources that have made unvaluable contributions to sous-vide cooking and other subjects, but thas does not imply that we do not analyze what they propose.

[Leigh Jones]

Shocked at that profile. 54,5ºC is considered the minimum temperature for long cooking periods, and then to get it you usually apply a water temperature at least 0,5ºC higher. At 54ºC Clostridium perfringens is not guaranteed to die (see Douglas Baldwin's guide). I also see in the comments for that page that they are using nitrites, which may justify using that temperature as it provides extra safety (I don't know whether it takes care of perfringens but given that it takes care of other Clostridium like botulinum, it may do), but most people following that profile will not, and that is not a good idea.

If you are a restauranteur, you're going to follow your approved health plan. Otherwise, you have some personal influence. Clostridium perfringens Is not guaranteed to die at these temperatures, but neither are they when grilled or broiled to medium rare temperature traditionally. Their numbers are significantly reduced. Sous vide has the capability of making a given level of doneness more healthy than traditional cooking methods and with greater reliability. Now, sure, 72 hours at 55 degrees would probably be great, too, but remember that Clostridium perfringens stops reproducing and beggining to diminish in numbers at well below these temperatures.

[weedy]

If you are a restauranteur, you're going to follow your approved health plan. Otherwise, you have some personal influence. Clostridium perfringens Is not guaranteed to die at these temperatures, but neither are they when grilled or broiled to medium rare temperature traditionally. Their numbers are significantly reduced. Sous vide has the capability of making a given level of doneness more healthy than traditional cooking methods and with greater reliability. Now, sure, 72 hours at 55 degrees would probably be great, too, but remember that Clostridium perfringens stops reproducing and beggining to diminish in numbers at well below these temperatures.

 

I think that's an important observation

 

it's easy to get all 'booga-booga' scared about sous vide cooking,

but the truth is that cooking that hamburger to med-rare on a 500F grill often results in an interior tat only reaches 130F or so for a minute (nd then it comes off the grill) as opposed to holding it for an hour there sous vide.

(just for example)

[paulraphael]

According to Modernist Cuisine, the upper limit for c. perfringens growth is 52°C, so it should be a non-issue.

 

I would be concerned about cooking at 54C only if there was reason to think the interior of the meat was contaminated. Especially if it were a thick piece, which would lead to the interior spending a long time at dangerous temperatures.

 

In other words, I would want meat from a trusted source, and it must be whole (not ground, not rolled, not cut and reassembled). 

 

I only worry about pasteurizing to the core if I'm doing cook/chill or if I'm serving immune-compromised guests. Lots of food served routinely at home and restaurants is unpasteurized ... any conventionally cooked medium rare meat, any fish that's still moist, etc...

 

The only common pathogen that I can find that seems able to reproduce at 54C is bacillus cereus (its upper limit is 55C). I don't see this organism being considered in any of the SV pasteurization models, so I don't pay attention to it. Maybe someone else can say why cooking community is less worried about this one.

[PedroG]

According to Modernist Cuisine, the upper limit for c. perfringens growth is 52°C, so it should be a non-issue.

 

I would be concerned about cooking at 54C only if there was reason to think the interior of the meat was contaminated. Especially if it were a thick piece, which would lead to the interior spending a long time at dangerous temperatures.

 

In other words, I would want meat from a trusted source, and it must be whole (not ground, not rolled, not cut and reassembled). 

 

I only worry about pasteurizing to the core if I'm doing cook/chill or if I'm serving immune-compromised guests. Lots of food served routinely at home and restaurants is unpasteurized ... any conventionally cooked medium rare meat, any fish that's still moist, etc...

 

The only common pathogen that I can find that seems able to reproduce at 54C is bacillus cereus (its upper limit is 55C). I don't see this organism being considered in any of the SV pasteurization models, so I don't pay attention to it. Maybe someone else can say why cooking community is less worried about this one.

Where did you find Bacillus cereus growing up to 55°C?

FOOD PATHOGEN CONTROL DATA SUMMARY  (page 2)  says:

 

4.  Bacillus cereus

Temperature range for growth = 39.2°- 122°F (4°- 50°C)

    (van Netten, et al., 1990;  Kramer and Gilbert., 1989)

 

and

 

9.  Clostridium perfringens

Temperature range for growth = 59° - 125°F (15° - 51.7°C)

    (Labbe, 1989; Shoemaker and Pierson, 1976)

 

The recommendation to cook above 130°F/54.4°C takes into account some thermometer inaccuracy; with a NIST or ISO calibrated thermometer 54°C should be safe.

 

Edited November 6, 2014 by PedroG (log)

[paulraphael]

Where did you find Bacillus cereus growing up to 55°C?

FOOD PATHOGEN CONTROL DATA SUMMARY  (page 2)  says:

 

4.  Bacillus cereus

Temperature range for growth = 39.2°- 122°F (4°- 50°C)

    (van Netten, et al., 1990;  Kramer and Gilbert., 1989)

 

and

 

9.  Clostridium perfringens

Temperature range for growth = 59° - 125°F (15° - 51.7°C)

    (Labbe, 1989; Shoemaker and Pierson, 1976)

 

The recommendation to cook above 130°F/54.4°C takes into account some thermometer inaccuracy; with a NIST or ISO calibrated thermometer 54°C should be safe.

 

Modernist Cuisine Vol. 1 and the following book say it reproduces up to 55°C:

 

International Commission on Microbiological Specifications for Foods. 1996.bacillus

cereus. 20-35. In Micro-Organisms in Foods. 5. Characteristics of Microbial Pathogens.

Roberts, T.A., Baird Parker, A.C. and Tompkin, R.B. eds. Published by Blackie

Academic & Professional, London.

 

I don't know the source being used by MC, and have absolutely no idea how to evaluate these sources when they come to different conclusions. I'm happy to have the file you linked as another data point. It's possible that they're using different criteria or methods. Possibly even different strains of the bug.

 

I'd love to hear from a biologist on this issue. Up til now I never payed attention to bacillus cereus, since no one seems to use it in their pasteurization calculations for s.v.

Edited November 6, 2014 by paulraphael (log)

[kayb]

I have what is probably a really stupid question, but it's one to which I really don't know the answer.

 

A couple of weeks ago, I was expecting guests for dinner on Sunday, so on Saturday, I sous vided two frozen packages of pork loin chops (two chops each) for about three hours at 145F. These had been cut from a frozen pork loin I defrosted in the refrigerator earlier in the summer, broke down into a roast and several packages of chops, and re-froze. (The whole loin came from the butcher shop, frozen.)

 

I took the chops out of the sous vide on Saturday evening, and put them in the refrigerator to go on the grill the following day. Guests couldn't come, I didn't grill, and the chops got shoved to the back of the refrigerator -- where I found them today. They are still in their vacuum packaging, seal unbroken. They've been under refrigeration since they cooled from the sous vide cook, at least two (but possibly three -- memory fails!) weeks ago.

 

My question -- are they safe to open and cook? Their only potential exposure to any pathogen came when I was cutting them up and repackaging them, and I keep a pretty clean kitchen -- not surgical suite clean, but I've never given anyone food poisoning, either, and I'm pretty meticulous about washing down cutting boards, etc.

 

Appreciate any input. Hate to ditch the chops, but would rather do that than have food poisoning.

 

 

[gfweb]

My bet is that they are fine. Baldwin's pasteurization time for a 2 inch thick piece of meat is 1.75 hours at 140F. You were higher and longer. Since they stayed in the sv bag in the fridge there was no way to contaminate them.

[Dave W]

What temperature is your fridge. There's a big difference here between 34F and 40F

[kayb]

What temperature is your fridge. There's a big difference here between 34F and 40F

Good question. I don't know. I'll check.

[JoNorvelleWalker]

If they were mine I'd cook them.

[kayb]

If they were mine I'd cook them.

I'm inclined that I will. Particularly after gfweb's point about pastuerization. As long as they pass the "smell" test.