Sous Vide: Recipes, Techniques & Equipment, 2011

jmolinari · May 12, 2011

Do you have any info on the food safety of MAP/Pro gas vs. propane?
Jason,
This doesn't specifically address safety, but in MC, page 2-274, "MAPP gas or oxyacetylene torches work better than propane or butane for producing high temperatures and no gas flavor"
HTH,
Larry

Right, but they don't discuss MAP/Pro which is the MAPP replacement which is discontinued, and i find it kind of curious that they don't even in passing mention that it's food safe blah blah blah. I'm just wondering if anyone has any reference to feel that it's safe or not.

KennethT · May 12, 2011

Robert, I don't think doing the reverse (131 first, then 120 second) will work, because holding at 120 increases tenderness due to enzymatic action. Cooking to 131 first will effectively denature all the enzymes so holding at 120 won't really do anything. Besides, once meat is cooked to a certain temp, you can't undo it by holding it at a lower temp. So once it's cooked though to 131, it'll never get more rare than that by holding at a lower temp. I've used the MC approach before, and it works great - sear the surface to kill any surface bacteria first (I do a quick once over with the torch - not for color, just to kill bacteria) then hold at 120 or 122 for a couple of hours. Then increase the temp of the bath to 131, and hold to pasteurize. Finally, a torched sear (this time for color and flavor). I find the best crust comes when I first spread some oil over the meat, and then use the torch - the oil layer seems to conduct the heat better than just the torch alone.
Kenneth, you may very well be right. However, it certainly isn't obvious to me, at least, that 131F will kill off all enzymatic activity, such that subsequent holding at 120F would then essentially do nothing. Do you believe that it is enzymes that converts collagen to gelatin? I though that was mostly just due to heat? I suppose enzymes must play a role, somehow, but I don't know at what point they would be come deactivated. But I doubt it is as low as 131F.
I do understand that lowering the temperature after cooking meat for a relatively short while doesn't somehow "undo" the previous higher temperature, and make the meat go into reverse!. But on the other hand, it is not obvious that cooking something for say two hours at 131 followed by 48 hours at 120 is going to produce an identical result to holding the meat at 131 for the entire time.
Certainly we know that as meat cooks, particularly at higher temperates (like in a braise), the muscle fibers contract and squeeze out the juice, and that is what causes an overdone piece of meat to become dry and tough. But it isn't obvious that this takes place instantaneously, such that once it's been subjected to 131F, that's it, and nothing more is ever going to happen.
I therefore think that an experiment is in order. I happen to have a couple of pieces of chuck in the freezer, and sufficient SV apparatus to cook both simultaneously at two different temperatures, beginning later this afternoon for dinner tomorrow night. These are 30mm thick, so they will take 1:23 to come up to temperature, after which I will hold them for 90 minutes to pasteurize them throughout. I will then lower the temperature on one to 120F/50C, and keep the other at 131/55C, and taste the difference after 24 hours.
Fair?

Robert - I am not a food scientist, so I can't say that I know the answers to your questions. But, I am an engineer, and scientifically minded, and like knowing how things work. I don't have the book in front of me, but my memory of reading MC was that most of the enzymes deactivate somewhere above 123-124 degrees. I don't know if that's all, or just some, or most... but I do know that once deactivated, they do not reactivate. From what I've read, it seems that meat undergoes tenderization via several mechanisms - enzymatic happening around and just above body temperature, which is a completely separate mechanism from collagen denaturing. One has nothing to do with the other - while they may go on simultaneously. I remember Nathan saying in the old sous vide thread that collagen does denature into gelatin at low temperatures such as 122 degrees, but very very slowly. Collagen denaturing isn't like flipping a switch in that it's on or off, it's a gradual, logarithmic increase where it accelerates as temperature increases.

If I had to guess, I would assume that meat cooked to 131 for 2 hours, then held for 22 hours at 120 would be less tender than meat held at 131 for 24 hours because the collagen denaturing will happen more quickly at 131 than 120. At 120, it's barely creeping along. But, I'm very eager to see the results of your experiment!

Another thing to do is to do a search in the sous vide thread (not sure if it's in the old one or new one) for PedgroG's post regarding "turbo-aging" as I think he called it. I think he held meat at various temperatures (increasing) to take advantage of the various enzymes that deactivate at various temperatures. If I have a minute, I'll look for that post and put a link to it...

ETA: also - from a safety perspective, I don't know how safe it is to hold meat at 120 for 22 hours, even if it's been pasteurized. In MC, they describe that if you are to enzymatically tenderize, you are to get rid of surface bacteria by dunking in boiling water for 15 seconds (or torching/searing) and then hold at 122 for no more than 4 hours, then put immediately into a pasteurizing cooking bath.

2 hours at 131 may cause a 6.5D reduction in bacteria (or something around there, I haven't done the math to see what the actual reduction would be after 2 hours), but the spores are still alive, and I'd imagine would be very active at 120F!! Just something to think about!

ETA (again): here's the link that I mentioned. PedroG, as usual, gives a very thorough treatment in this post, and in the posts linked from it.

Edited May 12, 2011 by KennethT (log)

Robert Jueneman · May 12, 2011

Do you have any info on the food safety of MAP/Pro gas vs. propane?
Jason,
This doesn't specifically address safety, but in MC, page 2-274, "MAPP gas or oxyacetylene torches work better than propane or butane for producing high temperatures and no gas flavor"
HTH,
Larry
Right, but they don't discuss MAP/Pro which is the MAPP replacement which is discontinued, and i find it kind of curious that they don't even in passing mention that it's food safe blah blah blah. I'm just wondering if anyone has any reference to feel that it's safe or not.

See http://en.wikipedia.org/wiki/MAPP_gas, and the Material Data Safety Sheet at http://www.bernzomatic.com/Portals/8/Resources/msdsSheets/eng-Mapp_Gas_MSDS_2008.pdf.

The gas is stated as having an unpleasant garlic/fishy odor at 100ppm (1/10 strength), and may be an asphyxiant, in addition to the liquid gas causing skin freezing. Oh, and the usual State of California cancer and birth defect warnings that apply to damn near everything, although the MDDS does not indicate any carcinogenicity.

Personally, I have never smelled anything from my MAP/Pro torch, and the fact that it burns so hot means that I'm probably reducing the carcinogenicity of torching the meat. You could equally well worry about using canola oil, eating red meat in general, burning the house down, etc., all of which might be a higher risk.

Now, if I were 50 years longer, and working in a restaurant and using it for 12 hours a day, day in and day out, I might worry a bit more, or change professions.

jmolinari · May 13, 2011

didn't even thinkabout looking at teh MSDS...thanks~!

e_monster · May 13, 2011

Certainly we know that as meat cooks, particularly at higher temperates (like in a braise), the muscle fibers contract and squeeze out the juice, and that is what causes an overdone piece of meat to become dry and tough. But it isn't obvious that this takes place instantaneously, such that once it's been subjected to 131F, that's it, and nothing more is ever going to happen.
I therefore think that an experiment is in order. I happen to have a couple of pieces of chuck in the freezer, and sufficient SV apparatus to cook both simultaneously at two different temperatures, beginning later this afternoon for dinner tomorrow night. These are 30mm thick, so they will take 1:23 to come up to temperature, after which I will hold them for 90 minutes to pasteurize them throughout. I will then lower the temperature on one to 120F/50C, and keep the other at 131/55C, and taste the difference after 24 hours.
Fair?

Bob,

Pasteurization only kills the living bacteria, it does not kill spores. So, pasteurizing the meat and then holding the meat at 120F sounds iffy to me. I think you would need to sterilize (rather than pasteurize) the outer surface. Killing the spores requires high temperature--so you would need to do that with a torch and be confident that you don't have spores in the bag, etc.

If you search the old thread (it is probably in the index), you will find an extensive discussion in which Nathan and Douglas discuss the various methods by which meat becomes tender. As mentioned above, the enyzmatic process by which meat becomes tender is a completely different process than the breakdown of the collagen. They discuss the various temperatures at which these things happen and how temperature comes into play. My understanding is that the length of time needed to pasteurize the meat is probably long enough to denature the enzymes. The time that it takes collagen to break down at 120F may be many times what it takes at 131F.

That's my take anyway.

Best,

Edward

Robert Jueneman · May 13, 2011

Certainly we know that as meat cooks, particularly at higher temperates (like in a braise), the muscle fibers contract and squeeze out the juice, and that is what causes an overdone piece of meat to become dry and tough. But it isn't obvious that this takes place instantaneously, such that once it's been subjected to 131F, that's it, and nothing more is ever going to happen.
I therefore think that an experiment is in order. I happen to have a couple of pieces of chuck in the freezer, and sufficient SV apparatus to cook both simultaneously at two different temperatures, beginning later this afternoon for dinner tomorrow night. These are 30mm thick, so they will take 1:23 to come up to temperature, after which I will hold them for 90 minutes to pasteurize them throughout. I will then lower the temperature on one to 120F/50C, and keep the other at 131/55C, and taste the difference after 24 hours.
Fair?
Bob,
Pasteurization only kills the living bacteria, it does not kill spores. So, pasteurizing the meat and then holding the meat at 120F sounds iffy to me. I think you would need to sterilize (rather than pasteurize) the outer surface. Killing the spores requires high temperature--so you would need to do that with a torch and be confident that you don't have spores in the bag, etc.
If you search the old thread (it is probably in the index), you will find an extensive discussion in which Nathan and Douglas discuss the various methods by which meat becomes tender. As mentioned above, the enyzmatic process by which meat becomes tender is a completely different process than the breakdown of the collagen. They discuss the various temperatures at which these things happen and how temperature comes into play. My understanding is that the length of time needed to pasteurize the meat is probably long enough to denature the enzymes. The time that it takes collagen to break down at 120F may be many times what it takes at 131F.
That's my take anyway.
Best,
Edward

Edward, thanks for the comments.

I do indeed understand the difference between pasteurization and sterilization with respect to killing spores, and not just bacteria, but to the best of my understanding, this is not likely to be a problem for meat that is being cooked and not stored for long times, e.g, under anaerobic conditions and not frozen.

I guess I will have to go back and review the old threads with respect to meat tenderization, specifically with regard to the denaturation of enzymes, or read/reread that section of MC. But by tomorrow night I should have a practical answer as well, and hopefully it won't kill me!

Bob

e_monster · May 13, 2011

Edward, thanks for the comments.
I do indeed understand the difference between pasteurization and sterilization with respect to killing spores, and not just bacteria, but to the best of my understanding, this is not likely to be a problem for meat that is being cooked and not stored for long times, e.g, under anaerobic conditions and not frozen.

Hi Bob,

I believe that you are mistaken in thinking that the issue of spores is only relevant to long-term storage under anaerobic conditions. There are both aerobic and anaerobic pathogens that you need to worry about. And you are talking about holding the spores in a growing medium for an extended period of time in the danger zone.

To me, that sounds like an opportunity to incubate the spores and have them start growing. Keeping the meat in the high end of the danger zone is more likely to result in growing the spores and having the resulting bacteria multiply than storing unsterile but pasteurized meat for long times in the refrigerator where the multiplication rate is retarded by the temperature.

Perhaps, I am mistaken. But I wouldn't risk it without hearing from someone with real expertise because if you are wrong, you could end up being very sorry.

Best,

Edward

Robert Jueneman · May 13, 2011

Edward, thanks for the comments.
I do indeed understand the difference between pasteurization and sterilization with respect to killing spores, and not just bacteria, but to the best of my understanding, this is not likely to be a problem for meat that is being cooked and not stored for long times, e.g, under anaerobic conditions and not frozen.
Hi Bob,
I believe that you are mistaken in thinking that the issue of spores is only relevant to long-term storage under anaerobic conditions. There are both aerobic and anaerobic pathogens that you need to worry about. And you are talking about holding the spores in a growing medium for an extended period of time in the danger zone.
To me, that sounds like an opportunity to incubate the spores and have them start growing. Keeping the meat in the high end of the danger zone is more likely to result in growing the spores and having the resulting bacteria multiply than storing unsterile but pasteurized meat for long times in the refrigerator where the multiplication rate is retarded by the temperature.
Perhaps, I am mistaken. But I wouldn't risk it without hearing from someone with real expertise because if you are wrong, you could end up being very sorry.
Best,
Edward

Edward, the more I think about it, the more I'm afraid you may have an excellent point, and may have saved me from an unpleasant experience.

Basically, and without really thinking it through carefully, I was proposing to violate the cook-chill recommendations, whereby food should either be cooked and promptly eaten (still hot), or rapidly chilled (no more than 6 hours total, from cold to cooked to cold again) to below the germination point of the spores, or around 4C.

As I understand it, spore production during the cooking cycle is not much of a concern, assuming the meat is being held within the pasteurization zone -- if a spore does germinate, the result would quickly be killed. (I'm not entirely clear on what happens to any neurotoxins in that case, but my understanding is that spore germination is a process that takes days, and not hours.)

But in my experiment, although the meat would have been pasteurized initially, the spores would not have been destroyed, and they might then germinate and recontaminate the meat. Even thoroughly searing the meat (or reheating it back to 131F) prior to service wouldn't necessarily make it safe again, especially if any neurotoxins have already formed, since pasteurization does nothing to such toxins. (Whether searing would destroy such toxins I don't know (I suspect it would), but it would be difficult to sear the entire steak, including the edges, sufficiently well to be sure everything was safe. And I've got enough problems right now recovering from pneumonia without adding botulism to the list!

So the conclusion is, DON'T EVER DO WHAT I SUGGESTED, PEOPLE!

I'm going to toss out the meat that's been incubating overnight at 120F, and enjoy the 131F chuck for dinner.

Thanks again for your concern.

Robert Jueneman · May 13, 2011

[
If I had to guess, I would assume that meat cooked to 131 for 2 hours, then held for 22 hours at 120 would be less tender than meat held at 131 for 24 hours because the collagen denaturing will happen more quickly at 131 than 120. At 120, it's barely creeping along. But, I'm very eager to see the results of your experiment!
Another thing to do is to do a search in the sous vide thread (not sure if it's in the old one or new one) for PedgroG's post regarding "turbo-aging" as I think he called it. I think he held meat at various temperatures (increasing) to take advantage of the various enzymes that deactivate at various temperatures. If I have a minute, I'll look for that post and put a link to it...
ETA: also - from a safety perspective, I don't know how safe it is to hold meat at 120 for 22 hours, even if it's been pasteurized. In MC, they describe that if you are to enzymatically tenderize, you are to get rid of surface bacteria by dunking in boiling water for 15 seconds (or torching/searing) and then hold at 122 for no more than 4 hours, then put immediately into a pasteurizing cooking bath.
2 hours at 131 may cause a 6.5D reduction in bacteria (or something around there, I haven't done the math to see what the actual reduction would be after 2 hours), but the spores are still alive, and I'd imagine would be very active at 120F!! Just something to think about!

Kenneth, just to make absolutely sure that I don't kill someone, please read my response to e-monster, above, and DON'T DO WHAT I WAS SUGGESTING IN MY EXPERIMENT!

Bob

KennethT · May 13, 2011

[
If I had to guess, I would assume that meat cooked to 131 for 2 hours, then held for 22 hours at 120 would be less tender than meat held at 131 for 24 hours because the collagen denaturing will happen more quickly at 131 than 120. At 120, it's barely creeping along. But, I'm very eager to see the results of your experiment!
Another thing to do is to do a search in the sous vide thread (not sure if it's in the old one or new one) for PedgroG's post regarding "turbo-aging" as I think he called it. I think he held meat at various temperatures (increasing) to take advantage of the various enzymes that deactivate at various temperatures. If I have a minute, I'll look for that post and put a link to it...
ETA: also - from a safety perspective, I don't know how safe it is to hold meat at 120 for 22 hours, even if it's been pasteurized. In MC, they describe that if you are to enzymatically tenderize, you are to get rid of surface bacteria by dunking in boiling water for 15 seconds (or torching/searing) and then hold at 122 for no more than 4 hours, then put immediately into a pasteurizing cooking bath.
2 hours at 131 may cause a 6.5D reduction in bacteria (or something around there, I haven't done the math to see what the actual reduction would be after 2 hours), but the spores are still alive, and I'd imagine would be very active at 120F!! Just something to think about!
Kenneth, just to make absolutely sure that I don't kill someone, please read my response to e-monster, above, and DON'T DO WHAT I WAS SUGGESTING IN MY EXPERIMENT!
Bob

Bob - exactly... it occurred to me after I had written the last post, which is why I edited it to bring up the safety issue... I'm glad you didn't try eating your experiment!

jmolinari · May 13, 2011

Basically, and without really thinking it through carefully, I was proposing to violate the cook-chill recommendations, whereby food should either be cooked and promptly eaten (still hot), or rapidly chilled (no more than 6 hours total, from cold to cooked to cold again) to below the germination point of the spores, or around 4C.

You mean you violated the cook-chill recommendation for meat that isn't pasteurized correct? Because you were going to keep it at 120?

If you brought it up to 131 for pasteurization time the 6 hour total no longer applies, right? Just want to make sure i'm understanding.

Robert Jueneman · May 13, 2011

Basically, and without really thinking it through carefully, I was proposing to violate the cook-chill recommendations, whereby food should either be cooked and promptly eaten (still hot), or rapidly chilled (no more than 6 hours total, from cold to cooked to cold again) to below the germination point of the spores, or around 4C.
You mean you violated the cook-chill recommendation for meat that isn't pasteurized correct? Because you were going to keep it at 120?
If you brought it up to 131 for pasteurization time the 6 hour total no longer applies, right? Just want to make sure i'm understanding.

Well, let's think about that.

Because I was proposing that the meat be pasteurized initially, it's true that the 6 hour rule no longer applies, and I could hold it at the same pasteurization temperature until it completely falls apart.

But I neglected to adequately consider the fact that pasteurization doesn't kill spores, which could then still germinate in that nice 120F Petri dish, and that that temperature is presumably NOT high enough to assure on-going pasteurization. How long it would take for a dangerous level of neurotoxins to develop, and how dangerous it might be, I'll leave up to someone who is a far better microbiologist than I'll ever be.

I don't need Botox, either on the inside or the outside of me!

Bob

jmolinari · May 13, 2011

Basically, and without really thinking it through carefully, I was proposing to violate the cook-chill recommendations, whereby food should either be cooked and promptly eaten (still hot), or rapidly chilled (no more than 6 hours total, from cold to cooked to cold again) to below the germination point of the spores, or around 4C.
You mean you violated the cook-chill recommendation for meat that isn't pasteurized correct? Because you were going to keep it at 120?
If you brought it up to 131 for pasteurization time the 6 hour total no longer applies, right? Just want to make sure i'm understanding.
Well, let's think about that.
Because I was proposing that the meat be pasteurized initially, it's true that the 6 hour rule no longer applies, and I could hold it at the same pasteurization temperature until it completely falls apart.
But I neglected to adequately consider the fact that pasteurization doesn't kill spores, which could then still germinate in that nice 120F Petri dish, and that that temperature is presumably NOT high enough to assure on-going pasteurization. How long it would take for a dangerous level of neurotoxins to develop, and how dangerous it might be, I'll leave up to someone who is a far better microbiologist than I'll ever be.
I don't need Botox, either on the inside or the outside of me!
Bob

Right, sorry. What i should of said is that you intended to hold it for 6+ hours below pasteurization temperatures but well above fridge temps. Even if you had previously pasteurized it, it would still be a problem b/c of the spores. Ok...i understand and agree.

KennethT · May 13, 2011

On a related note to Bob's issue, I made a major mistake last night.

I was making the MC beef cheek pastrami for a party for Saturday, which involves brining (with nitrates) for 3-4 days, then cooking SV at 144F for 3 days - so it's a big time investment and impossible to recreate for tomorrow to say the least...

So, late last night, I took the bag out of the waterbath and put it in a bowl of ice water in the sink to cool. Unfortunately, my wife discovered it still in the sink about 20 minutes ago!!!!

I'm going to assume that the ice water bath had gotten to room temp or so probably about 8 hours ago or so. Granted, this is not nearly as bad as the 120F incubator, but I think it's bad enough to consider all the issues.

I was considering putting it back into a 140F bath for 6 hours or so to re-pasteurize... any thoughts about this? I'm not worried about botulism, since it was done in a zip lock bag which had plenty of residual oxygen to inhibit that.

Thanks in advance for everyone's thoughts - I'd really like to not have to throw these away, but I don't want to get a bunch of people sick either.

Robert Jueneman · May 13, 2011

On a related note to Bob's issue, I made a major mistake last night.
I was making the MC beef cheek pastrami for a party for Saturday, which involves brining (with nitrates) for 3-4 days, then cooking SV at 144F for 3 days - so it's a big time investment and impossible to recreate for tomorrow to say the least...
So, late last night, I took the bag out of the waterbath and put it in a bowl of ice water in the sink to cool. Unfortunately, my wife discovered it still in the sink about 20 minutes ago!!!!
I'm going to assume that the ice water bath had gotten to room temp or so probably about 8 hours ago or so. Granted, this is not nearly as bad as the 120F incubator, but I think it's bad enough to consider all the issues.
I was considering putting it back into a 140F bath for 6 hours or so to re-pasteurize... any thoughts about this? I'm not worried about botulism, since it was done in a zip lock bag which had plenty of residual oxygen to inhibit that.
Thanks in advance for everyone's thoughts - I'd really like to not have to throw these away, but I don't want to get a bunch of people sick either.

I did the same thing with six nice rib-eye's -- bagged them up with the chamber vacuum, then left them sitting on the counter!

Repasteurization MIGHT be safe, but I would first open the package and smell it. You might have lactic acid build up, which although relatively benign, won't taste or smell very good.

I'd say it was time to head for the local deli.

Bob

KennethT · May 13, 2011

On a related note to Bob's issue, I made a major mistake last night.
I was making the MC beef cheek pastrami for a party for Saturday, which involves brining (with nitrates) for 3-4 days, then cooking SV at 144F for 3 days - so it's a big time investment and impossible to recreate for tomorrow to say the least...
So, late last night, I took the bag out of the waterbath and put it in a bowl of ice water in the sink to cool. Unfortunately, my wife discovered it still in the sink about 20 minutes ago!!!!
I'm going to assume that the ice water bath had gotten to room temp or so probably about 8 hours ago or so. Granted, this is not nearly as bad as the 120F incubator, but I think it's bad enough to consider all the issues.
I was considering putting it back into a 140F bath for 6 hours or so to re-pasteurize... any thoughts about this? I'm not worried about botulism, since it was done in a zip lock bag which had plenty of residual oxygen to inhibit that.
Thanks in advance for everyone's thoughts - I'd really like to not have to throw these away, but I don't want to get a bunch of people sick either.
I did the same thing with six nice rib-eye's -- bagged them up with the chamber vacuum, then left them sitting on the counter!
Repasteurization MIGHT be safe, but I would first open the package and smell it. You might have lactic acid build up, which although relatively benign, won't taste or smell very good.
I'd say it was time to head for the local deli.
Bob

For sure, if after re-pasteurizing I open the bag and it stinks I'll go in the garbage... but it doesn't have to stink to not be safe...

From what I gather, heading to the corner deli would not be a good substitute for this pastrami (that stuff shoudln't even be called pastrami as it's usually a disgrace) - in fact, Katz's is not far from me, and I gather they've got nothin' on this pastrami either! I was hoping to use this as an additional proof to the claim...

jmolinari · May 13, 2011

The nitrites should keep it safe from botulism, and the increased salt level should make it less likely for other stuff to grow as well, but it's still a risk to have left something out at room temp for 8+ hrs....

really sucks, but i wouldn't eat it.

DouglasBaldwin · May 13, 2011

Hi Kenneth,

You didn't happen to measure the water temperature when you found it?

The very long cooking will have inactivated all the vegetative (living) pathogens, so you'll only need to worry about the spores of Bacillus cereus and Clostridium spp. According to the FDA's Fish and Fishery Products Hazards and Controls Guidance (Table A-2), the maximum cumulative exposure times for these spore forming bacteria are:

Growth and toxin formation by Bacillus cereus
5 days at 39.2--43°F (4--6°C)
1 day at 44--59°F (7--15°C)
6 hours at 60--70°F (16--21°C)
3 hours above 70°F (21°C)
Germination, growth, and toxin formation by Clostridium botulinum type A, and proteolytic types B and F
11 hours at 50--70°F (10--21°C)
2 hours at above 70°F (21°C)
Growth of Clostridium perfringens
21 days at 50--54°F (10--12°C)
1 day at 55--57°F (13--14°C)
6 hours at 58--70°F (15--21°C)
2 hours above 70°F (21°C)

Salting would increase these times, but I can't tell you by how much since I don't have MC at the office to see what the salt and nitrite levels are.

I hope this information will help you make a more informed decision. It sounds like you could be on either side of the maximum cumulative exposure time (especially when factoring in safety margins and the salt and nitrite levels).

KennethT · May 13, 2011

Douglas, thanks so much for weighing in on this. Unfortunately, I didn't check the temp. because I didn't discover it - my wife did... I can pretty safely say that it wasn't higher than 65F since we keep the apartment pretty cool, and I know I left the a/c on last night - so the room temp definitely was not higher than that.

I'd say I'm about at the borderline for B. Cereus and Perfrigens, based on your info, however I think I will be safe because of the salt and nitrite levels. Unfortunately I don't have the book with me either, but I'll check it once I get home, but the beef cheeks were completely cured (4 days in the equilibrium brine, with cheek thickness about 1") before cooking, not just a surface cure.

I'm going to take the beef out of the re-pasteurizing bath tonight. And I think I'm going to eat a small-ish sample - since these are going to be used for 1 bit apps, I'll eat a few slices which will be double the amount that any guest would ever eat, but still not enough to seriously get me sick (I don't think). If I get even the slightest bit uncomfortable by the next day, I won't serve it. Otherwise, I think it'll be good to go - I'll just make sure to keep the portion size small!!!

Robert Jueneman · May 14, 2011

The very long cooking will have inactivated all the vegetative (living) pathogens, so you'll only need to worry about the spores of Bacillus cereus and Clostridium spp. According to the FDA's Fish and Fishery Products Hazards and Controls Guidance (Table A-2), the maximum cumulative exposure times for these spore forming bacteria are:
Growth and toxin formation by Bacillus cereus
5 days at 39.2--43°F (4--6°C)
1 day at 44--59°F (7--15°C)
6 hours at 60--70°F (16--21°C)
3 hours above 70°F (21°C)
Germination, growth, and toxin formation by Clostridium botulinum type A, and proteolytic types B and F
11 hours at 50--70°F (10--21°C)
2 hours at above 70°F (21°C)
Growth of Clostridium perfringens
21 days at 50--54°F (10--12°C)
1 day at 55--57°F (13--14°C)
6 hours at 58--70°F (15--21°C)
2 hours above 70°F (21°C)

I'm increasingly glad I threw out my experiment!

But Douglas, maybe you can enlighten me.

How can the spores of these bacteria be destroyed, BEFORE cooking/pasteurizing? In particular, considering pre-searing vs. blanching, would one method be better than another? (Seems to me a thorough pre-sear with a torch or a hot oil filled pan would be best -- it will get a lot hotter than blanching.)

Likewise, suppose that some spores HAVE germinated -- the primary threat is the neurotoxins, right? How can they be neutralized/destroyed?

I am assuming that the meat has not been Jaccarded or otherwise punctured, so (presumably) the interior of the meat is still sterile, and all we need to worry about is what might be on the surface. True?

Bob

KennethT · May 14, 2011

Hi Kenneth,
You didn't happen to measure the water temperature when you found it?
The very long cooking will have inactivated all the vegetative (living) pathogens, so you'll only need to worry about the spores of Bacillus cereus and Clostridium spp. According to the FDA's Fish and Fishery Products Hazards and Controls Guidance (Table A-2), the maximum cumulative exposure times for these spore forming bacteria are:
Growth and toxin formation by Bacillus cereus
5 days at 39.2--43°F (4--6°C)
1 day at 44--59°F (7--15°C)
6 hours at 60--70°F (16--21°C)
3 hours above 70°F (21°C)
Germination, growth, and toxin formation by Clostridium botulinum type A, and proteolytic types B and F
11 hours at 50--70°F (10--21°C)
2 hours at above 70°F (21°C)
Growth of Clostridium perfringens
21 days at 50--54°F (10--12°C)
1 day at 55--57°F (13--14°C)
6 hours at 58--70°F (15--21°C)
2 hours above 70°F (21°C)
Salting would increase these times, but I can't tell you by how much since I don't have MC at the office to see what the salt and nitrite levels are.
I hope this information will help you make a more informed decision. It sounds like you could be on either side of the maximum cumulative exposure time (especially when factoring in safety margins and the salt and nitrite levels).

OK, here's the total info.... the ratio is:

100% beef cheek

225% water

7.5% salt

1.5% Insta Cure #1

This sat in the fridge for 4 days for about 1.25" thick cheeks

The cheeks were then removed from the brine, rubbed, and smoked for about 30 minutes on my stovetop smoker.

The brine was boiled, with foam skimmed, then strained and cooled.

The smoked cheeks were then bagged with 100% of the boiled brine and cooked at 144 for 72 hours, then taken out and put in an ice bath and forgotten about until the next day in a 65F room.

As an aside, I tasted the pastrami and it is excellent as everyone says... although it may be a little drier than I remember Katz's pastrami being... Most of the raves are making this with short rib, so I'll have to try it again, minus the possible bacteria... If people don't hear from me after the next 18-36 hours, you can assume I'm in the hospital!!! haha....

dougal · May 15, 2011

C. bot toxin (which is the danger) is broken down by fairly gentle heat. (The spores produce the toxin, which is why spores need to be considered, but its the toxin that is the actual danger.)

Expect something like a 100x reduction in toxicity with every 30 minutes at 56C (133F) ...

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=4700984

so 10,000x (10^4) after 1 hour, 1,000,000x (10^6) after 1 hour 30, 100,000,000x (10^8) after 2 hours and so on.

Re-pasteurising should be effective against C. bot toxin. (If there was any there with your nitrite and salt.)

But you do need pressure-cooker temperatures 120C+ (250F+) to hurt the spores themselves ...

Is C. perf very different?

Edited May 15, 2011 by dougal (log)

rotuts · May 15, 2011

SV ground meats?

several years ago America's Test Kitchen had a show on 'Meaty Lasagna' I a big fan of this show with a few reservations:

they never have removed the tendon on the chicken/turkey breast on the smaller muscle: the petoralis minor: how hard is that? it makes the whole deal a bazillion time better

...

anyway I made this L with no-boil noodles and loved it and actually made it for friends visiting from Italy and they loved it. ...

my goal is to SV the beef/pork/italian sausage (fennel) with some cream cheese ( it works well if you do not keep heavy cream around you only need 1 -2 tbs which you mash up with a little water = heavy cream)

to 130 in bags that I can then freeze and pull out for a single width noodle Lasagna

so the question is: what would this meat prep be like?

for me SV does so many things for me: but one fine one is I can make a lot of "meats" in one batch

(i use a coleman beer cooler 32 qts -- it allows easily 15 lbs of smaller packed 'meats')

please let me know if you have SV'd ground meats for a prep such as this

thanks

:biggrin:

I forgot to mention I 'cuisinart' my own beef/pork/fennel to get a sl more corse grind .. SV would make it tender 130 for that!

Edited May 15, 2011 by rotuts (log)

MartinH · May 16, 2011

SV ground meats?

My experiments with SV ground beef were disappointing. The meat emerged with a pronounced "liverish" taste. I tried adding plenty of seasoning, but that did not do the trick.

rotuts · May 16, 2011

Ive had this 'liver-ish" taste myself a few times. it was with 'tender' meat that I think I left too long in the bath

it was young leg of lamb that I carefully removed all the fat and sinew the books do mention that although sv is forgiving, you can leave meat too long in the bath

auto digests?

I think the next time I fire up the bath ill have to try a sample

my idea was to get chuck, separate the muscle groups, get rid of extra tendons etc and then cut into cubes ( 1 " ? ) by hand, chill, cuisinart briefly, chill, etc to the desired size.

not too small then SV

maybe even check each 6 hours and re seal.

sv makes a great appeal for doing somethiikng like this in bulk well ahead and freezing

im wondering if others have had thed 'liver-ing' issue com up

id like to hear others thoughts on these issues.

many thanks !

(on further thinking: wasnt one of the 'signature' pictures from MC that complex hamburger ... wasnt it SV'd ? .... if dont have the book Yet!)

Edited May 16, 2011 by rotuts (log)

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