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Is sous-vide chicken technically undercooked?

v
violet42 Aug 27, 2012 09:45 AM

so I recently got the Sous Vide Supreme, and had my first venture into at-home sous vide last night with two chicken breasts. I did everything the directions told me to do - sealed the chicken in the pouches with a little bit of butter, then cooked at 2 hours at 146F. When I took the meat out, its temp was around 143F and it was white all the way through - not pink at all. The meat was very juicy and extremely tasty.

However, a couple hours later, the two of us who ate the chicken started to have the dreaded rumbly tummy, and are experiencing somewhat unpleasant gastrointestinal symptoms even this morning. Nothing crazy, but definitely the feeling of "I ate something not so good." I can't imagine that any of the other things we ate with the chicken would have caused this, but then again, you never know.

So tell me this - is there any way we could have gotten sick from using the above method? Though I grew up always thinking you had to cook chicken to 160F in an oven, my understanding is that keeping anything above 140F during the sous vide process is enough to kill bacteria.

Thanks in advance for any thoughts or wisdom you may have!

  1. pikawicca Mar 8, 2013 08:11 AM

    I've been cooking chicken breasts in this manner ever since I got my SVS three years ago; no one's ever gotten sick.

    1. p
      Puffin3 Feb 19, 2013 05:49 AM

      Just a note about the importance of having the water circulating. If you have gone the DIY route and made your own SV bath using a big pot and Zip locks held in place with the weight of the lid...as I have done, it's an easy matter to get a vertical circulation going in the water. Just move the pot off the burner a couple of inches. One side of the pot stays slightly cooler than the side on the burner. This an old trick used in commercial kitchens when making large amounts of stock. The slight vertical circulation keeps the scum accumulating on the cooler side on the pot making for easier removal.

      1. h
        hightechcooking Feb 18, 2013 09:16 PM

        I'm glad you didn't have anything worse then "rumbly tummy". Food poisoning is nasty and it could have been worse. I been sous vide cooking for the past 3 years. I own 2 "Sous Vide Supreme"s and a Poly Science Immersion Circulator. You can say that I'm serious about this style of cooking.

        The first thing I'd do is check the water temperature with a thermometer that I calibrated myself. I found that my Sous Vide Supremes were off by 2 and 4 degrees Fahrenheit. This is to say that neither one of them were correct.

        Then I'd look at water circulation. Were the racks that came with the Sous Vide Supreme used? Since this appliance doesn't use forced water circulation, you need to use the racks to ensure passive water circulation. Piling the bags on top of each other and allowing them to touch is a no-no.

        Lastly, I'd check the thickness of the food in the bags. I'm assuming that the bags have no air bubbles in them and they were completely submerged in water for the entire cooking time. I'd made chicken breasts that were 2 inches thick and that would require 2 1/2 hours at 146F. Since your health is at stake, I'd measure them with a ruler and not just eye-ball them.

        It is odd that your final chicken temperature was 143F -- It should have been the same temperature as the water bath. Perhaps it cooled, but then again maybe it didn't and the temp of the water bath was off.

        The only thing I remember about the pamphlet that came with the Sous Vide Supreme was that I was unimpressed. I immediately threw it out. I felt they were over simplifying and leaving out many details. Of course, there is such a thing as too many details. But still, I'd recommend browsing http://www.douglasbaldwin.com/sous-vi... and then compare that to the single FDA rule of cooking to 160F for 15 seconds. Life was much simpler in the old days. Good luck and be careful.

        2 Replies
        1. re: hightechcooking
          c
          calumin Feb 19, 2013 06:24 AM

          I'd second the suggestion to calibrate thermometers.

          If you're off by 4 degrees, the time required to pasteurize is almost 2.5 times longer (143 degrees = 17.1 min, 139 degrees = 39.6 min).

          Also in my experience there is usually a temperature delta of a couple degrees between the water bath and the food inside the bag. The Modernist Cuisine cookbook references a similar delta in temperatures in all of its recipes.

          To answer the question in the title, sous vide chicken is not technically undercooked. The food safety guidelines published by the USDA are provided as easy-to-remember temperatures for the general public, but the USDA relies on the same science as that used by sous vide cooks -- which is represented by graphs that show pasteurization times as a result of temperature.

          Like the USDA, it makes sense to apply a safety range above the minimum to account for the variability in ensuring temperature is reached everywhere in the meat. Even if you add 100% time buffer to the minimum pasteurization times you won't sacrifice quality. But it is important that your equipment is measuring temperature correctly.

          1. re: calumin
            h
            hightechcooking Mar 7, 2013 07:05 PM

            I wanted to make a correction to my earlier reply. Earlier, I had stated that at 160F it takes 15 seconds to make chicken safe. This is incorrect. The correct values are as follows: At 160F, it takes 5.19 seconds. At 165F, it takes 1.64 seconds.

        2. k
          kramark Nov 30, 2012 07:59 PM

          http://www.edinformatics.com/math_sci...

          Enough said.

          1. dave_c Aug 29, 2012 09:29 AM

            A couple more things that come to mind...

            You got sick within a couple hours. That's pretty fast for something you just ate. Could it been something else you ate that day or before?

            Also, chicken is the main "suspect" since that's the expectation. Could it been something else? Cantaloupes, for example?

            8 Replies
            1. re: dave_c
              v
              violet42 Aug 29, 2012 09:35 AM

              Ha, no cantaloupes. It was definitely the sous vide meal as the other person and I hadn't eaten any other of the same things, but we had the exact same symptoms maybe 4 or so hours later.

              1. re: violet42
                b
                blue_skiesMN Aug 29, 2012 09:59 AM

                What else was on the menu? 4 hours seems more likely for something like Bacillus cereus or Staph aureus intoxication. It's a little short for Clostridium perfringens, but that's a possibility as well.

                1. re: violet42
                  cowboyardee Aug 29, 2012 10:58 AM

                  I have laid out some of the common safety mis-steps of sous vide above. But here is a question for you: how exactly did you seal the chicken in the bag? And then how did you submerge the bags in the bath?

                  I ask because this is another plausible avenue for contamination - if your food wasn't fully submerged, that can be a problem. That's obvious. Less obvious (and something I'm sometimes guilty of myself) - it the food was fully submerged but the bag itself had a corner sticking out of the bath, that also allows for the possibility of the meat to be contaminated as you're pulling it out of the bag after cooking. Ideally, you want the entire interior of the bag to be rendered safe before eating. This is another reason I am a fan of a fully submerged but brief dip in a hotter bath at the beginning of cooking.

                  1. re: violet42
                    m
                    mpjmph Aug 29, 2012 11:06 AM

                    It may well have been a stomach bug that was not food borne. Two people with shared contact can get norovirus without ever eating a common food. It also might have been the chicken, but not because of bacteria or virus. Just plain indigestion. The timeline you presented just doesn't support the chicken (or anything else at that meal) as the cause of your symptoms.

                    1. re: mpjmph
                      cowboyardee Aug 29, 2012 11:13 AM

                      In the interest of accuracy, there are some forms of food poisoning whose onset is in the 1-4 hour range. Staph comes to mind. Though notably, campylobacter - the most common form of chicken-related mild GI illness - is NOT among them.

                      I agree with you otherwise.

                      1. re: cowboyardee
                        v
                        violet42 Aug 29, 2012 11:20 AM

                        There are numerous times where I've eaten something and a mere few hours later it "blows right through me", or so they say. With this incident, I definitely was feeling rumbly 3-4 hours after eating, and the unpleasant GI symptoms lasted for less than 24 hours.

                        Like many have said, it's kind of pointless to try to diagnose it as it really could be a number of things. However, I do believe it came from this particular meal, as me and my dining companion both had identical symptoms and had eaten completely different things up to that point.

                        1. re: violet42
                          dave_c Aug 30, 2012 11:41 AM

                          3 to 4 hours... Yes, it makes sense that the sous vide chicken may be the primary culprit.

                          Now the hard part is trying to figure out what went awry, excluding the consumption of cantaloupes, mangoes, Skippy Peanut butter, bagged spinach, alfalfa sprouts... etc. lol

                          1. re: dave_c
                            drongo Aug 30, 2012 03:52 PM

                            I believe we're arguing needlessly here because I think nobody disagrees that it's safe to eat a reasonably-sized chicken breast that's cooked sous vide at 146F for 2 hours with entire bag completely submerged, with no visible air (or other visible reasons for poor heat transfer), and at accurate water-bath temperature. So we're making speculations or assumptions about what else might have happened, and we really can't know.

                2. g
                  GH1618 Aug 29, 2012 09:07 AM

                  It seems to me that the sous vide apologists are in denial when they claim it most likely wasn't from the chicken. If two people ate the chicken and got sick, and everyone else did not eat chicken and did not get sick, then the chicken was the source almost certainly.

                  As for incubation times, the sous vide process will put the food into the optimal temperature range for incubating bacteria for a long time. If you don't reach the killing temperature (including a safety margin) everywhere in the food, and stay there a sufficient time, you could have a big problem. In this case, the OP did have a problem, and the solution is higher temperature and longer cooking time.

                  4 Replies
                  1. re: GH1618
                    cowboyardee Aug 29, 2012 09:43 AM

                    Sorry, GH, but you're just wrong. This is a fairly widely used technique, the OP used common time and temperature guidelines for chicken breast made with this technique (taking the OP's word that the chicken breasts were sufficiently thin), and it relies on the principles of pasteurization which are time-tested. It's a common misunderstanding about food poisoning that a layman can easily point exactly to what made someone sick and how just by noting that X and Y just ate Z and now they both feel sick. It's more complicated than that. See my third paragraph above.

                    Frankly, you've made several claims in this thread that are plain incorrect and continue to do so. 165 is not the 'killing' temperature - it is the temperature at which pasteurization happens in a matter of seconds, and thus the recommended temperature when cooking in such a way that food is not held at a given temperature for prolonged periods. A sous vide bath does not hold food in the optimal temperature range for incubating bacteria for a prolonged time any more so than traditional cooking does. In fact, I'd wager that when roasting a bird, the cavity stays in that sub-120 range longer than any meat does when cooking a breast sous vide.

                    I admittedly can't rule out absolutely any possibility that the chicken made the OP sick. Perhaps the OP had a problem with his/her technique (and hence my suggestions in the second half of my post above). Perhaps the chicken was tainted with staph toxin, in which case traditional cooking to 165 wouldn't have helped either. Perhaps the chicken was recontaminated upon coming out of the bag - none of us are immune to cross contamination - though it would have had to have been a heck of contamination, or else the chicken would have had to sit for a good while after cooking and before eating. Or perhaps the culprit was something else - including things that they ate days before the onset of symptoms. You're clinging to a very simplistic understanding of food safety and a layman's misunderstandings about the ease of finding the source of food poisoning while ignoring mountains of evidence that pasteurization can reliably be achieved at 145 and even lower.

                    There is really no need to call people who've researched sous vide and pasteurization 'apologists' or claim that they are 'in denial.' Look more deeply into sous vide yourself and its food safety implications. Put aside the federal chicken cooking guidelines which were never intended to apply to sous vide and read into low temperature pasteurization. It is a safe process if it is done correctly.

                    1. re: cowboyardee
                      g
                      GH1618 Aug 29, 2012 09:55 AM

                      Now you are misrepresenting my position. I did not say that 165°F was necessary for a "killing temperature." I also pointed out that pasteurization can occur at 145°F if that temperature is reached everywhere and for a sufficient time. It seems pretty obvious that in the particular instance the process was not sufficient to kill all the pathogens. As for why it was not, I don't believe you are in any better position than I to diagnose it.

                      1. re: GH1618
                        cowboyardee Aug 29, 2012 10:07 AM

                        "As for why it was not, I don't believe you are in any better position than I to diagnose it."
                        ____________
                        Except for extensive practice with and research into the technique. Sorry to be blunt.

                        "I did not say that 165°F was necessary for a "killing temperature." I also pointed out that pasteurization can occur at 145°F if that temperature is reached everywhere and for a sufficient time."
                        ________
                        I misread you a bit. Apologies. But here's the thing: you can usually pasteurize a chicken breast at 137 at the times given by the OP (assuming the chicken breast wasn't ridiculously thick or starting off frozen). Even if the OP did not reach 145 with absolute consistency through the whole breast, s/he was already working with a pretty decent margin of error. (though if parts of the breast were frozen before cooking, that could potentially make for some bigger discrepancies). I'm saying you're barking up the wrong tree because I know that the OP already had a decent margin of error.

                        "It seems pretty obvious that in the particular instance the process was not sufficient to kill all the pathogens."
                        _________
                        No. Regardless of appearances, the likely explanation is that the culprit was something else. If you know any bacteriologists, run this situation by them. As I've said several times, pinpointing the cause of food poisoning (or even confirming that the illness is indeed food poisoning - the OP and guest could have both come down with a norovirus for all we know -actually a very plausible explanation) is far trickier than most people believe it to be.

                      2. re: cowboyardee
                        porker Aug 29, 2012 10:38 AM

                        cowboy, I tried to capture the essence of your post in a much shorter message above. I enjoy your attention to detail.
                        I don't think it can be stressed enough that as members of an internet forum, we are unable to properly diagnose almost any problem. I don't mean this from a legal perspective (America, the land of lawsuits), but from a pure practical perspective.

                        How many times is there a post: "I left my cheerios on the counter with 2% milk for 72 minutes. Is it safe to eat?"
                        How can we possibly know 100%?
                        In this sous-vide case, even the OP is making assumptions.

                        I think that many people get irked when discovering scientific method and facts go against popular belief (the world is flat comes to mind).

                        "But the government says 165..."
                        Well, the government is trying its best for the lowest common denominator

                        I have never sous-vid in my life simply because I had no wish to persue it. However, I appreciate the science behind it. I think its the popular belief apologists who are in denial.

                    2. m
                      mpjmph Aug 29, 2012 04:36 AM

                      In general, it takes at least 8 hours (or up to 72 hours) from exposure before salmonella symptoms appear. The other big names for food borne illness from chicken take days or weeks to cause symptoms. It's very likely your symptoms came from a pathogen ingested prior to the chicken, or that they weren't pathogenic at all.

                      13 Replies
                      1. re: mpjmph
                        b
                        Bryan Pepperseed Aug 30, 2012 05:36 AM

                        +1
                        Back in my Navy days I was told by a hospital corpsman that it takes at least 24 hrs before getting any "it must have been something I ate" thoughts. Inspired by this post, a quick read of google links like this one -

                        http://www.cdc.gov/salmonella/general...

                        seem to indicate that I should probably adjust my thought process from "What did I eat yesterday?" to something closer to maybe 12 hrs but the point is that 2 hrs is probably a little too soon.

                        1. re: Bryan Pepperseed
                          g
                          GH1618 Aug 30, 2012 09:08 AM

                          It's pretty obvious that just a few hours is sufficient for symptoms such as the OP described here.

                          1. re: GH1618
                            twyst Aug 30, 2012 11:01 AM

                            "It's pretty obvious that just a few hours is sufficient for symptoms such as the OP described here."

                            No, it's not. For it to be "pretty obvious" we would have to know for sure that the chicken is in fact what made them sick. It's far more likely something else made them sick.

                            1. re: twyst
                              g
                              GH1618 Aug 30, 2012 11:38 AM

                              The OP believes it was the chicken, and there is sufficient evidence to support that conclusion. The only posters who seem to have a problem accepting this are the sous vide apologists, who seem awfully defensive about their craft, in my opinion.

                              The only thing in doubt is exactly what pathogens were present, and that will never be known.

                              1. re: GH1618
                                cowboyardee Aug 30, 2012 12:18 PM

                                Here are three things we KNOW with near certainty (in absence of a new heat resistant strain of ... whatever) did NOT cause the illness:

                                - The basic mechanics behind sous vide.

                                - The temperature at which the chicken was cooked (assuming good sous vide technique and non frozen chicken of sufficient thinness).

                                - The time for which the chicken was cooked (assuming the same).

                                I cannot absolutely rule out a flaw in the OP's sous vide technique or a miscalibrated bath. Nor can I rule out the possibility of something like staph toxin in the chicken, which is heat stable and would have made the OP sick regardless of how the chicken was cooked. I also cannot rule out many other explanations for why the OP and guest got sick (norovirus, something else in the meal, something else in a much-previous meal, plain coincidence), and neither can you despite claims to the contrary.

                                We may disagree on the likelihood that the chicken was the culprit. And that's okay. But if you disagree with the three points I made at the beginning of this post, you're just plain, undoubtedly, 100% incorrect. There's really no other way around it. That you continue to blame the technique is kind of mindblowing to me. Read up on it. It wasn't invented yesterday.

                                1. re: cowboyardee
                                  porker Aug 30, 2012 01:05 PM

                                  you, sir, are flogging an expired equine.

                                  1. re: porker
                                    twyst Aug 30, 2012 01:12 PM

                                    "you, sir, are flogging an expired equine."

                                    I feel his pain though. Combating anecdotal evidence with actual science to no avail can be frustrating to say the least.

                                    1. re: twyst
                                      g
                                      GH1618 Aug 30, 2012 01:26 PM

                                      Science in the abstract can not answer the question for the particular case which is most important: What was the temperature profile in every part of the chicken throughout its preparation?

                                      Scientists and engineers (I am an engineer) do not analyze a failure from speculative data — actual data are required. It requires a leap of faith to believe that the chicken was cooked everywhere at the proper temperature for a sufficient time.

                                      Nonscientists quoting (and misapplying) "actual science" does not amount to good science.

                                      1. re: GH1618
                                        twyst Aug 30, 2012 01:33 PM

                                        "Scientists and engineers (I am an engineer) do not analyze a failure from speculative data — actual data are required."

                                        Exactly. You have nothing but anecdotal evidence that the chicken was in fact the culprit. They probably also touched the same doorknob, breathed the same air etc etc etc.

                                        "Nonscientists quoting (and misapplying) "actual science" does not amount to good science."

                                        Hahahahahahahaahahah.
                                        You know nothing of my background and what I did before I changed careers and went to CIA. The fact that you think the OP has presented strong evidence that the chicken made him sick and also have a degree in a science related field makes me a little sad to be honest.

                                        1. re: twyst
                                          g
                                          GH1618 Aug 30, 2012 01:42 PM

                                          It's a hypothesis that the chicken was the culprit, which is strongly supported by the evidence. One generally starts with the most likely hypothesis, not the least likely one. The detailed analysis of why the chicken was undercooked is open, and cannot be determined at this point, in my opinion.

                                          There is an elementary principle of engineering operating here: safety margins. The smaller the margin of safety, the greater the probability of failure. Sous vide cooking operates with small safety margins, so it is not at all surprising that in a home environment there should be an occasional failure. This is an example.

                                          1. re: GH1618
                                            twyst Aug 30, 2012 02:00 PM

                                            "There is an elementary principle of engineering operating here: safety margins. The smaller the margin of safety, the greater the probability of failure."

                                            I definitely understand this, I was a working architect for 12 years before I went to culinary school and took a crapload of classes on food science and safety as well. Im not arguing that things can not go wrong with sous vide cooking, its actually a HUGE ordeal to get the board of health to certify your HACCP plan in a restaurant if you are using sous vide. The problem lies in the fact that there are SOOOOOOOO many unknown variables here and all we know is that the OP got slight tummy ache 2 hours after eating a meal according to the original post.

                                            1. re: twyst
                                              carolinadawg Aug 30, 2012 05:26 PM

                                              Mine's bigger! No, mine's bigger!! No, mine's bigger!!! lol

                                        2. re: GH1618
                                          cowboyardee Aug 30, 2012 04:29 PM

                                          "Science in the abstract can not answer the question for the particular case which is most important: What was the temperature profile in every part of the chicken throughout its preparation?"
                                          ____________
                                          You might be surprised.
                                          If you know the temperature of the surrounding bath, the starting temperature of the chicken, the thickness of the chicken, and the conductivity of chicken meat, you can indeed deduce with a reasonably high degree of accuracy the temperature of every part of the chicken breast as a function of cooking time*. That, along with known bacterial reduction criteria established through experimentation, is what pasteurization tables are based off of. These tables already account for minor real world discrepancies in some of the above variables, and are designed to err on the side of safety.

                                          As I've said above, significant departures from the expected temperature are indeed possible, but they're the result of missteps in one's technique, failures of equipment, etc. If you get it right, it's reliable and repeatable.

                                          *Just so we don't wind up discussing the size of the bath or conductive properties of the bag, I'll admit that there are other variables at play even when sous vide is done correctly. But they're minor ones, and they're accounted for by the margin of error in sous vide pasteurization tables and by the design of sous vide equipment.

                        2. g
                          GH1618 Aug 28, 2012 03:13 PM

                          You need to cook chicken to an internal temperature of 165° F. To be sure you have killed all harmful bacteria.

                          http://www.cdc.gov/nczved/divisions/dfbmd/diseases/campylobacter/

                          http://www.fda.gov/food/foodsafety/fo...

                          Campylobacter jejeuni is nothing to take lightly. Not only is it a common cause of food poisoning, but in some people infected by it, it will lead to Guillain-Barré Syndrome, a devastating illness.

                          9 Replies
                          1. re: GH1618
                            v
                            violet42 Aug 28, 2012 03:19 PM

                            okay, here's the thing I don't get. people's reactions to sous vide seem to be on one side or another: those who say cooking to the suggested sous vide temperature for the correct period of time is fine, and those who have the knee-jerk reaction of "OMG the meat isn't cooked to 165". who is correct?

                            1. re: violet42
                              g
                              GH1618 Aug 28, 2012 03:48 PM

                              It is correct that cooking chicken to an internal temperature of 165 °F throughout will kill all the bacteria. It is also correct that most people who cook chicken sous vide to 145 °F will not get sick. Lower temperatures will work if the times are extended. For example, pasteurization can be done at 145 °F, but that temperature must be reached by every particle and held for 30 minutes to be considered properly pasteurized. If you start your sous vide process at 145 °F and cook for two hours, that does not mean two hours at 145 °F for each particle of the food.

                              You can pay your money and have your choice, as they say. I happen to choose to be conservative with chicken because I have an autoimmune disease myself. It's not something you ever want to get. I also happen to be recovering this very day from a bout of food processing most likely caused by a raw oyster. As much as I like them, I should give them up entirely.

                              If you must cook chicken sous vide, you can improve your chances by including an acid. I don't know how much you would need, however, or whether it would be effective for a thick chicken breast.

                            2. re: GH1618
                              drongo Aug 28, 2012 03:32 PM

                              Listeria, which I mentioned in a post previously today, is more hardy than Campylobacter or Salmonella or E. coli. So using conditions that keep you safe from Listeria also suffice for those other bacteria.

                              The government has a very simple guideline for the general public (i.e. heat poultry to 165F) but more complicated guidelines for businesses (e.g. see the FSIS/USDA PDF file I linked to in an earlier post today). For "sous vide" you need to be willing to follow (or at least accept) the more complicated approach to food safety.

                              1. re: GH1618
                                porker Aug 28, 2012 03:43 PM

                                Actually, Campylobacter jejeuni will be killed between .74 and 1.0 minutes @ 55C (131F). Even at a paltry 48C (119F), these puppies will die between 7 and 13 minutes

                                http://naldc.nal.usda.gov/download/40...

                                Most claims of safe cooking temps (to X degrees) are blanket terms to try to protect a general public. Destroying foodborne pathogens is a function of both time *and* temperature.

                                1. re: porker
                                  g
                                  GH1618 Aug 28, 2012 04:06 PM

                                  That's a thorough discussion of C. jejuni. Thank you.

                                  It is true that recommended cooking procedures, like all good safety protocols, have a generous margin of safety. The smaller the margin in the procedure, the greater the liklihood of a bad outcome. It does appear from the OP's description that food poisoning was contracted from chicken cooked sous vide. So it does not seem helpful to argue that, theoretically, it shouldn't have happened. What the OP needs to know is how to adjust the process to avoid a recurrence.

                                  Of course the culprit may have been something other than C. jejuni. That is merely an example of the nasty things that can be found in chicken.

                                  1. re: GH1618
                                    porker Aug 28, 2012 04:55 PM

                                    Well like many, I'm an armchair expert (tongue-in-cheek).
                                    I liked the OP's question, as cooking to 143F seems to fly in the face of "accepted" food handling (cooking) guidelines.

                                    I will respectfully disagree that its not helpful to argue that theoretically it shouldn't have happened; this seems to be the crux of the original question. I would say that properly sous-vide cooking chicken to 143F is theoretically not undercooked.
                                    I do agree that it should be investigated as to why there was a problem.
                                    But...
                                    As pointed out throughout the thread, its difficult to determine the true culprit, if there actually was one...cross contamination, faulty equpiment, incorrect temps, non-food related, something else, (even the OP says "I can't imagine that any of the other things we ate with the chicken would have caused this, but then again, you never know.") etc etc.

                                    1. re: porker
                                      v
                                      violet42 Aug 28, 2012 05:10 PM

                                      Maybe I'll just chalk it up to the fact that the chicken was refrigerated and that, since it was only at 143F when removed (checked with two thermometers, BTW) that it perhaps wasn't maintained at a high-enough temp for a long-enough time. I just wanted to know if there was something blatant that I had missed. No doubt that I'll be trying it again sometime, so maybe this time I'll raise the temp and the time a bit for safety's sake. Or just cook dark meat so it has to be at 165F to begin with ;)

                                    2. re: GH1618
                                      cowboyardee Aug 28, 2012 05:38 PM

                                      "It does appear from the OP's description that food poisoning was contracted from chicken cooked sous vide. So it does not seem helpful to argue that, theoretically, it shouldn't have happened."
                                      __________
                                      It's not really a matter of arguing that food poisoning theoretically shouldn't have happened. Rather, from the OP's description, the most reasonable conclusion is that something other than the chicken (at least the chicken that came out of the bag) caused the problem.

                                      The OP's symptoms sound plausibly similar to campylobacter. And campylobacter is common in chicken. But the incubation time for campylobacter is typically 2-5 days (though shorter periods aren't unheard of). And at any rate, by the OP's account, the chicken was fully pasteurized.

                                      In truth, there are just so many opportunities for cross contamination, for eating other things earlier that were contaminated and experiencing symptoms only after eating the chicken, for bacterial or fungal toxins to have developed prior to cooking that would be impossible to 'kill' even if the chicken were cooked to 165 (staph toxin is the most obvious example), or even just for stomach discomfort not caused by food poisoning that it is very hard to say with certainty exactly what caused the illness. All I can say is that the sous vide method of low-temp cooking was an unlikely culprit compared to the many other things that can make you sick.

                                      I should note a few things about sous vide safety though -
                                      A lot of the most-quoted pasteurization times (such as the tables cited by Doug Baldwin) assume that the water bath is circulated. Food comes to temperature quicker in a circulated bath than it does in an uncirculated one, especially if the bath is crowded or if the food starts off frozen. Meanwhile, many of the most popular home methods of sous vide cooking are uncirculated - the sous vide supreme, for example. So for complete safety, it can be a good idea to allow for a longer cooking time in these kinds of devices. How much longer? I can't say for certain, though doubling the pasteurization time is almost undoubtedly safe.

                                      Likewise, home methods of creating a vacuum seldom work as well as a professional chamber vacuum. And small amounts of air in the bag can effectively provide some degree of insulation for the food. So the same thing goes - a little extra cooking time beyond the standard recommendations might be smart.

                                      Another option, and one that I use often - at the start of the cooking process, dip that bag briefly in a hotter bath. A couple minutes at 160-170 will generally only effect the doneness of the meat right at the surface, and since most pathogens are at the surface of the meat, this provides some extra insurance. Note that it doesn't help when parasites and trichinella are a concern or possibly when the meat has been pierced before cooking.

                                      Finally, with any sous vide set up, it is very important to periodically check the bath temperature with a well-calibrated thermometer. If your sous vide bath is miscalibrated, then that can of course lead to food safety problems.

                                      All of this is a long way of saying that cooking sous vide requires a more nuanced understanding of food safety than simply being familiar with the most often quoted federal guidelines. But it sounds like the OP erred on the side of safety, so chances are that the cooked chicken wasn't the problem.

                                      1. re: cowboyardee
                                        drongo Aug 29, 2012 04:07 AM

                                        Good point about small amounts of air... not only can they insulate but can cause the bags to float on surface of the bath (if not held under in some way - I don't know design of Sous Vide Supreme) and if they float then heat transfer is slower.

                                2. j
                                  jilkat25 Aug 28, 2012 12:12 PM

                                  Believe it or not, I use my XL Butterball Indoor Electric Turkey Fryer (model 20011210) for sous vide since at the moment I can't afford the Sous Vide Supreme. I have the rack for the SVS and a Foodsaver with long rolls of Italian-made bag material which I cut long and fold the collar over several inches while I put the food in the bag so the seal isn't compromised when I take the air out. The fryer holds the water at whatever temp I set it for for a long as I need and it works great even without circulating the water. I recently made boneless lamb shoulder which I had brined/marinated in yogurt and spices, (divided into 5 or 6 packages with olive oil, Greek herbs, lemon, and salt) for, I kid you not, three days at 134-135 (as per thermometer reading-NOT the machine's setting which was123-124! I rotated the bags occasionally. The meat never overcooked. It stayed pink and was silky-tender and yummy. We ate one package the first day (after about 6 hours) but the others stayed in the machine. I added hot water a time or two but very little ever really evaporated off. Next time I plan to give the meat a quick, hot sear before I put it in the bags so it looks somewhat brown when I take it out but without the risk of cooking it more after sous viding it.
                                  Having said that, I have several different thermometers and every one shows a different temp when I use it. Specifically, for sous vide I use as my default thermometer (Polder foldable instant type, less than $20 from QVC) the one that registers the lowest temperature compared to my other ones. If it says my meat's internal temp is 145, my other thermometers probably say the temp is above that. Your 143 reading is so close to the margin of safety it makes me suspect that the thermometer could be off, and even a degree or two in this range could make a difference in food safety. I would 1. start my (rinsed) chicken while very, very cold and simply let it cook longer, 2. sous vide chicken breasts at 147-150, and 3. check the temp of your finished product with more than one thermometer and consider the one with the lowest reading as the most accurate. Glad you didn't get real sick! It may not have been the chicken at all. In my experience, it usually takes at least 10-12 hours for food poisoning to set in. We had a quickie dinner using an unfamiliar jarred spaghetti sauce (Mrs. something) the other night, and we were all, let's just say, rumbly in the tumbly all the next day!
                                  One last thought on sous vide cooking: salt tends to dissipate for some reason and many of my early experiments came out needing salt. I have learned to add a bit more than I would ordinarily use when I sous vide. There's a book called Cooking For Geeks which has a long chapter on sous vide cooking that explains the science behind how sous vide works to break down connective tissue, leaving really tender meat without "drying" it out or causing stringiness as pressure cooking, crock-pot cooking, or even braising can do.
                                  Hope that helps! Have fun with your SVS!

                                  1 Reply
                                  1. re: jilkat25
                                    s
                                    slrpro02 Mar 23, 2013 01:12 PM

                                    I use the same XL turkey fryer for sous-vide cooking. It does the job. I also use a Turkey Fryer Remote Thermometer made by Maverick Industries. It is off by 5* so I adjust for that. Helps allot. http://www.amazon.com/gp/product/B000... It has a alarm to warn you if the Temps. go to high-or low, it also tells you the average temp. Your the only other person I know of that uses this turkey fryer for Sous-Vide It is really good to be able to use it because of the versatility. Sous-Vide, Boil, Steam, or Deep Fryer. The Temp. swing is 6*(+or-3*).

                                  2. ipsedixit Aug 27, 2012 09:10 PM

                                    Is sous-vide chicken technically undercooked?
                                    _________________________________________

                                    No.

                                    1. todao Aug 27, 2012 10:51 AM

                                      I recall a routine that Bill Cosby performed where he said "Awww, I ate a dead frog once and I didn't get sick". Well, some people have eaten undercooked poultry without getting sick. But that doesn't mean it's a good idea. Even when groups of people share a meal of contaminated foods not everyone always becomes ill.
                                      The bacteria danger zone is generally held to be between 40 degrees and 140 degrees. FSIS/USDA insist that poultry cooked below an internal temperature of 165 degrees is risky and temperature dwell times for any food requires careful measurement of temperature throughout the food's mass, not just the cooking temperature of the medium used. Saying that a chicken breast cooked at a given temperature for a given period of time is "safe" misses the point that chicken breasts differ in mass. The time allowed for a 5 ounce chicken breast will be quite different form one weighing 8 ounces (yeah, I know, big chicken) and whether the meat is "bone-in" or boneless is also a factor to consider.
                                      You survived the sous-vide chicken, whatever the bacteriological contamination might have been. Hope you do as well if some future exposure involves E Coli.

                                      6 Replies
                                      1. re: todao
                                        twyst Aug 27, 2012 11:34 AM

                                        " Saying that a chicken breast cooked at a given temperature for a given period of time is "safe" misses the point that chicken breasts differ in mass"

                                        Thats the whole point of sous vide cooking. Its the ability to hold the entire mass as a precise temperature for a given time period. When someone says that a chicken breast needs 12 minutes at 145 degrees, that doesnt mean throw a chicken breast in a water bath for 12 minutes, it means that once the whole breast is at that temperature you need to hold it at that temp for that long to insure safety.

                                        1. re: twyst
                                          todao Aug 28, 2012 08:40 AM

                                          Thanks, twyst. That's an excellent explanation of sous vide cooking. Using the time you drop the package into the machine as a cooking start time is where problems develop with controlling food borne bacteria.
                                          Another point that we haven't discussed here is cross contamination. The OPs chicken may have been fully "cooked", in terms of safe consumption guidelines, we can't know that for certain. But when the chicken was handled during preparation there is a possibility that cross contamination with knives, counter tops, momentarily touching items with unwashed hands when handling the chicken, handles on cooking vessels, cutting boards, etc. could have easily caused contamination of other foods prepared for the meal.
                                          I often read these forums and wonder how many of those offering advice on food safety have experienced a food handler's training course. Some of the information included in those programs will make your hair stand on end and it can truly change your perspective on how to handle food.

                                        2. re: todao
                                          drongo Aug 28, 2012 09:38 AM

                                          I think 2 hours with a setpoint of 146F is longer than is typical for chicken breasts, and should certainly have been OK unless these were truly humungous breasts.

                                          For some FSIS data, see http://www.fsis.usda.gov/OPPDE/rdad/FSISNotices/RTE_Poultry_Tables.pdf . See Attachment 2 for the times to reach the recommended 7 log reduction at various temperatures. Of course, we've got to account for the lowest internal temperature rather than the surface or bath temperature. There are data available that let you estimate how long it takes for the internal temperature of chicken with various thickness to get within, say, 1 degree of the bath temperature -- I'll have too look for that when I get home.

                                          Also see the nice graph entitled "Bacteria and Safety" about 2/3 of the through the following PDF: http://www.cookingissues.com/uploads/...

                                          1. re: drongo
                                            v
                                            violet42 Aug 28, 2012 09:42 AM

                                            OP here. The chicken breasts were not humongous, and I am always very careful with food safety and cross-contamination. The one thing I can think of is that when we took the breasts out, after 2 hours at 146, the internal temp was only 143. They were just refrigerated, not frozen. Maybe they internally spent too long below 140? Or maybe I should have rinsed them before sealing, as a precaution?

                                            1. re: violet42
                                              drongo Aug 28, 2012 02:58 PM

                                              Did you measure the temperature of the bath with the same thermometer you used for the internal temperature? My sous vide setup has a significant offset in the measured temperature vs setpoint, so I have to make an adjustment.

                                              I looked in Douglas Baldwin's "Sous Vide for the Home Cook" and he has a table of pasteurization times for poultry in a 140F water bath. For a thickness of 3/4", the required time is 60 minutes; for a thickness of 1 1/4" it's 105 minutes; for 1 1/2" it's 135 minutes. Baldwin uses very conservative estimates -- e.g. he calculates based on Listeria rather than Salmonella, because Listeria is more heat resistant than Salmonella. He also uses worst-case scenario for heating up -- assuming "slab" of uniform thickness into which heat is transferred into the poultry only through top and bottom (with no heating through sides). So for "not humungous" breasts you should have been fine (even if the water bath temperature were to have been only 140F rather than 146F).

                                              1. re: violet42
                                                g
                                                GH1618 Aug 28, 2012 04:09 PM

                                                Rinsing doesn't make any difference — it just spreads the stuff around. That is why the USDA-FSIS recommends against it.

                                          2. dave_c Aug 27, 2012 09:51 AM

                                            Killing Salmonella has to do with temperature and time.

                                            From what I remember, sorry I can't find the source, Salmonella can only survive a few seconds at 160F while at 140F it takes more time to knock those buggers down. I don't remember what that time is, but 2 hours sound sufficient. I'm sure someone else here knows those values by heart.

                                            Also, in terms of cooked, I guess there are different definitions. The way I see it as long as the proteins have "cooked", it's cooked.

                                            1 Reply
                                            1. re: dave_c
                                              twyst Aug 27, 2012 10:04 AM

                                              10 minutes at 142 degrees is sufficient to kill salmonella.

                                            2. twyst Aug 27, 2012 09:50 AM

                                              Breasts are fine at 145, its the thighs that need to go to 165.

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