Sous Vide, Smokers, and Food Safety - We're Safer Than We Thought

Discussion in 'General Discussion' started by johnmeyer, Dec 13, 2015.

  1. johnmeyer

    johnmeyer Smoking Fanatic

    I sometimes cook using a sous vide method of cooking. Like smoking, it is a low-temperature, slow-cook method. With sous vide, you place the thing to be cooked into a vacuum bag, and then put it into water that is held precisely at the temperature you want the food to be when it is fully cooked. So, if you want rare steak, which is 130 degrees F, you put the bagged food into 130 degree water, and let it sit there for several hours. It sounds awful, but it actually works really well. (You sear the steak at the end, to create the needed surface flavor).

    But here's the thing: how can it be safe to eat meat that has never had any part go above 130 degrees? The same thing with chicken. I cooked a chicken breast by putting the vacuum bag into 143 degree water. The breast never got above that temperature. The USDA figures tell me that I will die if I don't get my chicken to 165 degrees.

    Why am I not dead?

    My reason for posting is that I found out that the simple USDA guidelines do not tell the whole story about food safety, and it isn't until you delve way down into the USDA site that you find out that you can achieve the same level of food safety at lower temperatures, but only if you keep the food at those temperatures for a long time.

    If you want the hard-core science behind it, here's a link to the USDA's food safety paper on the subject:

    This one is just for poultry, but there are similar papers for other food, with slightly different temperatures and times.

    Here's the bottom line: the usual food safety temperatures with which we are familiar are designed to kill the bacteria almost instantly. However, those same pathogens, if exposed to lower temperatures, but for a longer time, will eventually succumb. Here is a chart from which is derived from the USDA paper I linked to above:

    As a result, my 143 degree chicken breast which was cooked in a 143 degree water bath was perfectly safe, but only because it was held at that temperature for more than 27.5 minutes. It was also the most amazingly moist, wonderful chicken I have ever tasted, with a wonderful texture I've never before experienced when eating chicken, without a hint of that pink, under-done poultry taste you may have experienced on Thanksgiving or Christmas with a turkey or other fowl that never quite got done.

    So for most smoking that involves heat (i.e., NOT "cold smoking"), you will be OK if you use low temperatures, as long as the internal temperature of the food is at or above 135 degrees for the times shown above.

    One note: you still need to make sure to get the food up to that 135-140 degree range relatively quickly in order to avoid any possible toxins created by bacteria that are allowed to breed out of control by spending too much time in the "danger zone." So, my point here is not meant to encourage anyone to let food linger for more than a couple of hours in that really low temperature zone. Instead, my reason for posting is to make sure that people don't feel they have to "nuke" their wonderful, flavorful 140 degree meat in order to get it to the much higher temperatures found on the first page of the USDA site. Also, you need to use a good thermometer, inserted into the center of the food, in order to make sure the inside of the food really is at or above 135 degrees.

    So, long and slow, at any temperature above 135, will be safe, according to the USDA.
    geezer likes this.
  2. Thanks for that post. 
  3. Outstanding Information !!

    Thank -You,

  4. frankly

    frankly Fire Starter

    Sorry - posted under wrong thread...  Not sure if I can delete this...

    But great info in this thread and I ended up with two open!
    Last edited: Mar 11, 2017
  5. dirtsailor2003

    dirtsailor2003 Smoking Guru OTBS Member

    @DaveOmak has posted the guidelines on this here in multiple threads.
  6. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    These charts are from the FSIS / USDA

    Poultry Time and Temp



    ...................... Time

    °F (°C).............. 12% fat

    136 (57.8)......... 81.4 min

    137 (58.3)........ 65.5 min

    138 (58.9)........ 52.9 min

    139 (59.4)........ 43 min

    140 (60.0)........ 35 min

    141 (60.6)........ 28.7 min

    142 (61.1)........ 23.7 min

    143 (61.7)........ 19.8 min

    144 (62.2)........ 16.6 min

    145 (62.8)........ 13.8 min

    146 (63.3)........ 11.5 min

    148 (64.4)........ 7.7 min

    150 (65.6)........ 4.9 min

    152 (66.7)........ 2.8 min

    154 (67.8)........ 1.6 min

    156 (68.9)........ 1 min

    158 (70.0)........ 40.9 sec

    160 (71.1)........ 26.9 sec

    162 (72.2)........ 17.7 sec

    164 (73.3)........ 11.7 sec

    166 (74.4)........ 0 sec

    Table C.2: Pasteurization times for a 7D reduction in Salmonella for chicken and turkey (FSIS, 2005).





    °F (°C)


    °F (°C)


    130 (54.4)

    112 min

    146 (63.3)

    169 sec

    131 (55.0)

    89 min

    147 (63.9)

    134 sec

    132 (55.6)

    71 min

    148 (64.4)

    107 sec

    133 (56.1)

    56 min

    149 (65.0)

    85 sec

    134 (56.7)

    45 min

    150 (65.6)

    67 sec

    135 (57.2)

    36 min

    151 (66.1)

    54 sec

    136 (57.8)

    28 min

    152 (66.7)

    43 sec

    137 (58.4)

    23 min

    153 (67.2)

    34 sec

    138 (58.9)

    18 min

    154 (67.8)

    27 sec

    139 (59.5)

    15 min

    155 (68.3)

    22 sec

    140 (60.0)

    12 min

    156 (68.9)

    17 sec

    141 (60.6)

    9 min

    157 (69.4)

    14 sec

    142 (61.1)

    8 min

    158 (70.0)

    0 sec

    143 (61.7)

    6 min

    144 (62.2)

    5 min

    145 (62.8)

    4 min

    Table C.1: Pasteurization times for beef, corned beef, lamb, pork and cured pork (FDA, 2009, 3-401.11.B.2).

    Last edited: Mar 12, 2017
  7. johnmeyer

    johnmeyer Smoking Fanatic

    Wow, that's a lot of information -- even more when you cut/paste it twice!!

    I still don't buy into the recommendation to not rinse. I understand the concept, but given how much stuff splashes around as you handle, cut, move the chicken, unless you are using a high pressure sprayer, I don't think the particles from the rinsing are going to put any more gunk around the kitchen than when you accidentally flick some of the packaging and the juice goes all over the place. I personally feel it is far more important to get the remaining slaughterhouse juices out of my food. Back in business school we got to see how mass-produced chicken is prepared for market, and when you see the tanks of water that are used to clean the chicken, you too would want to make sure you get rid of the stuff left over from the entrails, etc.

    While much of what you posted duplicates my original post that started this thread, I was hoping perhaps you would get into one other topic that is at the heart of so many of the food safety posts in this forum: the danger zone.

    It has never been clear to me whether I should worry about this. If I eventually get my food into the 130+ range, and keep it there for long enough time to kill the bacteria, then do I need to care about the bacteria? I am well aware that the king of food pathogens, botulism, is actually a toxin created by the bacteria, and that the toxin will survive heating. However, botulism is anaerobic, so not an issue for most smoking recipes.

    So my question is: if I eventually heat my food to one of the FDA-approved time/what is the actual danger created by leaving meat and poultry in the danger zone for too long?
  8. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    John, morning... You are correct....  that piece sucked...   BAD...  anyway, there are charts displayed that are from the gummint...  

    You should probably re think the statement you made, that I copied and pasted below....

     However, botulism is anaerobic, so not an issue for most smoking recipes.

    Below is an interesting article that may shed some light on the "danger zone"...

    HACCP AND SLOW-ROASTING TURKEYS by O. Peter Snyder, Jr., Ph.D Hospitality Institute of Technology and Management November 2008 edition

    Slow roasting turkey overnight seems to be a very common practice dating from the 1930s. There has been a persistent question, however, about the microbiological safety of slow-roast poultry, especially in terms of the production of Staphylococcus aureus toxin. In 1988, a well-done study was run at the University of Minnesota, Department of Food Science, by Eckner, Zottola, and Gravani, which provided the answer to the question of safety.
    The study
    Four frozen turkeys were used in the study. The turkeys were thawed in a refrigerator. The weight of the turkeys ranged from 11.7 to 25.5 pounds. Hence, they would take different times to cook. The carcasses were thoroughly washed, dried with a paper towel, and were stuffed with stuffing prepared using a standard recipe formulation. Cultures of Staphylococcus aureus, Salmonella typhimurium, and Clostridium perfringens were added to the stuffing of two turkeys. The population of each organism ranged from 100,000 per gram to 10,000,000 per gram of stuffing.
    The stuffed turkeys were placed in a preheated, 350°F oven and baked for 1 hour. A cooking curve for a 29-lb. turkey is shown at Figure 1 (Eckner, et al., 1988).

    Figure 1. Rate of heat penetration at the slowest heating points in 29-lb. turkey
    OPS-papers-for-publication:turkey-papers-on-web-OPS / web:Documents: Turkey rev 11/5/08 print 12:48 PM 11/24/08

    The temperature of the oven was then reduced to 225°F, and the turkeys were roasted an additional 12 hours. If the juice of the turkeys was pink. The turkeys were roasted an additional 1 to 2 hours at 300°F, or 1 hour at 350°F. A critical fact was that the final temperature of the stuffing was 165°F. The longest time between start of cook and getting to above the safe temperature of 130°F for the slowest cooking / largest turkey was about 8 hours.
    As expected, no salmonellae or staphylococci was recovered. They were killed above 130°F as the turkey was cooking. Actually, if the stuffing had been sampled at 140 to 150°F, they would have found that these organisms would be dead, considering that 140°F for 12.7 minutes gives a 7D reduction of Salmonella in beef.
    At the end of cooking, the stuffing and turkey were still positive for C. perfringens, as expected. Temperatures above 130°F are lethal for salmonellae and staphylococci, as these are vegetative pathogens. However, the spores of C. perfringens survive 165°F. Some of the C. perfringens spores may germinate to vegetative cells during a slow cook, but vegetative C. perfringens is very easy to inactivate. Therefore, when the turkey reaches 140°F, the vegetative C. perfringens, if produced, is destroyed. Once cooked, the turkeys cooked in this manner would be safe as long as they are above 130°F. Of course, uneaten portions of the stuffing (and turkey) must be handled properly to prevent C. perfringens "toxinfection" from the outgrowth of the spores during inadequate hot holding below 130°F or cooling too slowly to refrigeration temperatures.
    How long does one have in cooking to get above the safe temperature of 130°F? Willardsen et al. (1978) reported on the multiplication of the C. perfringens vegetative cells in precooked hamburger during slow come-up in cooking. If the time to go from 50 to 130°F was about 7.6 hours, the vegetative cells might multiply 10,000 to 1. If the time was 5.8 hours, the multiplication would be about 1,000 to 1. If the time was 3.5 hours, the multiplication would be about 10 to 1. So, slow cooking might permit C. perfringens vegetative cell multiplication. By the time the hamburger reached 140°F, all of the C. perfringens vegetative cells that had multiplied will be destroyed. They used C. perfringens strains that multiplied about one every 7.5 minutes at 113°F. Common illness strains multiply more like once every 15 minutes at 113°F. Hence, this experiment was looking for extremes of safety. The times would probably be twice that reported for more "normal" C. perfringens.
    From a HACCP perspective, what would be our concern? It would be toxin production from S. aureus growth during cooking. However, in raw turkey / food, S. aureus does not multiply, because there are competitive spoilage microorganisms. Therefore, with raw turkey, it would not multiply during cooking. Even if it did, as on cooked turkey with 100 S. aureus per gram, which was slowly reheated, the fastest I have found S. aureus to multiply is about once every 20 minutes in milk--3 times slower than the C. perfringens experiment by Willardsen et al. Staphylococcus aureus would have to multiply at least 1,000 to 1, or 10 generations, to make enough toxin to make anyone ill. The danger time to go from 50 to 130°F in cooked food starting with 100 S. aureus per gram would be expected to be approximately 3 times that of C. perfringens, or 15 hours. Note, this shows that the FDA-required food reheating to 165°F and holding for 15 seconds in less than 2 hours has absolutely no scientific validity. There is a small reason to set a minimum time for raw food cook come-up, but no justification for reheating as a safety control.
    OPS-papers-for-publication:turkey-papers-on-web-OPS / web:Documents: Turkey rev 11/6/08 print 12:48 PM 11/24/08 2

    It is true that there is a phenomenon whereby Salmonella can double or triple in resistance to inactivation if it spends some time at about 110F, which it will during slow cooking. However, it makes no difference; 12.7 minutes at 140°F gives a 10,000,000-to-1 kill (7D reduction). Assume that the time becomes 45 minutes. During slow cooking, the food still spends plenty of time at lethal temperatures above 130°F to kill all vegetative pathogens.
    As a final point, remember, the code says that raw, potentially hazardous food must be held at 41F. There is no science for any temperature by itself. There must be time factored in, because Listeria monocytogenes, Yersinia enterocolitica , and Aeromonas hydrophila all begin to grow at 29.3°F. If we choose 7 days at 41°F as a control, which actually allows for about 10 multiplications of L. monocytogenes in 7 days, or if 45°F, 4 days, or if 50°F, 2.4 days, and if 110°F, 4.5 hours, all of these times and temperatures allow for the same amount of growth (Snyder, 1998). When we use HACCP in retail food operations, no one needs to measure the refrigerators again in terms of raw food hazard control. The vegetative pathogens will be killed in cooking.
    There is getting to be an extensive body of science indicating that below about 55 to 60°F, food "spoils safe." The FDA has provided no justification for imposing a raw food 41°F cold-holding temperature. Epidemiological experience of the last 100 years suggests that food held at 55 to 60°F has limited pathogen growth and spoils safe. There are many quality reasons for keeping raw food at 28 to 32°F. However, this is shelf life and quality, and not safety.

    Eckner, K.F., Zottola, E.A., and Gravani, R.A. 1988. The microbiology of slow-roasted, stuffed turkeys. Dairy Food Sanit. 8(7):344-347.
    FDA Food Code. 1999. U.S. Public Health Service, U.S. Dept. of Health and Human Services. Pub No. PB99-115925. Washington, DC.
    Snyder, O.P. 1998. Updated guidelines for use of time and temperature specifications for holding and storing food in retail food operations. Dairy Food Environ. Sanit. 18(9):574-579.
    Willardsen, R.R., Busta, F.F., Allen, C.E., and Smith, L.B. 1978. Growth and survival of Clostridium perfringens during constantly rising temperatures. J. Food Sci. 43:470-475.
    OPS-papers-for-publication:turkey-papers-on-web-OPS / web:Documents: Turkey rev 11/6/08 print 12:48 PM 11/24/08
  9. frootboi

    frootboi Newbie

    Never knew this, but it makes sense! Thanks for the official data.
  10. johnmeyer

    johnmeyer Smoking Fanatic

    I found that article extremely confusing (not very well written either). After reading it twice and trying hard to understand the implications of what was written, my interpretation of the story is that the turkey would not have toxins, even if left in the danger zone for eight hours because there are other pathogens that keep in check the one that might create toxins. Therefore, if the turkey is eventually brought into the higher temperatures and kept there for sufficient time, all will be OK.

    It would have been much more helpful if the author had drawn some conclusions.

    However, I certainly am not going to start ignoring the "safe zone" advice, based on reading this one article, but I'm not going to obsess about it either (and never have). Almost every safe zone food poisoning news story I've read over the past half century usually seems to concern picnics where things like egg salad were left out in the open, sometimes in the sun, for most of the afternoon, without any refrigeration. It also seems that most of the stories I read about these days, where people actually got sick (as opposed to the much more frequent stories about a precautionary food recall without any actual reports of illness) seem to stem from contaminated produce, not meat or poultry; or from a food worker who did not properly wash their hands.
  11. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    You are on the same page as I am....   Food safety "seems" to be a fluid subject..  the only hard and fast rules, for us laymen, are 4 hrs. - 40-140 rule...  which is fine with me.... it circumvents all the "grey" areas...

Share This Page