Cure uptake with immersion brining

Discussion in 'Curing' started by wade, Jan 19, 2015.

  1. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    Let us not turn this thread into a confrontation from any side. On the surface the calculation contains "sound" logic however it does appear to rely on the big assumption that the Nitrite uptake is directly proportional to the weight increase. This has not been clarified yet - however if we can find a government reference (or other reputable scientific paper) that confirms that this is the way to calculate the Nitrite uptake, then we would need to take that as said. If not, then I think the jury still needs to be out on this one.
     
  2. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    Now that would probably make the assumption more likely to hold true I think. Not all of the cells may be ruptured though so may even add to the uncertainty. 
     
  3. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Pops has mentioned, in an old thread where....   The USDA or FDA did testing on their curing solutions and uptakes and certified them as either SAFE or GRAS....  I can't remember....  but the analysis of the meat met their "nitrite uptake criteria"....
     
    Last edited: Jan 19, 2015
  4. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    So now comes the task of finding which one of his 5.5K posts that it is in - LOL
     
  5. There are any number of published papers or books on the subject of nitrite/nitriate and meat curing, but again, one must understand the concept of calculable ingoing nitrite for regulatory purposes..
    It's not a measure of the actual nitrite in the meat, the only way to determine that is through laboratory analysis.
     
    Last edited: Jan 19, 2015
  6. wade likes this.
  7. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    Lots of good information there. I have checked out the site before however I have now taken a closer look at his references. Unfortunately his one about nitrite is inconsistent with what he is saying in the text... In the text he is quoting that in CFR Title 9 318.7 

    "Parts per million (ppm) of restricted curing ingredients permitted in curing solutions... Sodium or Potassium Nitrite 220/120 ppm in bacon"

    What the CFR actually says is...

    "The use of nitrites, nitrates, or combination shall not result in more than 200 parts per million of nitrite, calculated as sodium nitrite, in finished product"

    Which unfortunately is not necessarily the same thing.
    Now an interesting thing that is included in the same regulation is that the stronger brine using a figure of 10% is mentioned. However ONLY in the context of brine pumped bacon

    "2 lb to 100 gal pickle at 10 percent pump level". This, like dry curing, would effectively deliver a known amount of the cure to a known amount of meat with no risk of exceeding the desired Nitrite levels. There is no mention of immersing in a 10 x concentrated brine until there is a 10% increase in weight though.

    Martin, is it possible that you are mixing up the 2 methods and applying the concentrated pump brine calculations with the immersion cure, on the assumption that a 10% increase in water take up with immersion is equivalent to a 10% increase due to pumped brine?

    Thanks for your other reference too. If you know that your method is described in there could you point me to the relevant pages? As you say there are over 500 pages and I started reading in bed last night but kept falling asleep
     
  8. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    I had another crack at the first part of it this morning and the part that discusses "Methods of adding Nitrite to meat products" does not seem to discuss weight increase using the immersion technique. https://archive.org/stream/healtheffectsofn004248mbp#page/n59/mode/2up

    I will continue reading though as it contains lots of great general information.

    [​IMG]Points for sharing such an interesting reference
     
    Last edited: Jan 20, 2015
  9. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    Until we get positive credible confirmation that the assumptions used in this technique are valid I think we should be very careful in suggesting on this forum that it is used. The basic questions that I have at the moment are:

    The assumption that the only uptake of Nitrite will be that which is directly proportional with the weight increase of the meat. This does not seem to take into account:
    • Simple diffusion of the highly concentrated brine throughout the existing interstitial meat fluids - thus not necessarily leading to an increase in weight. 
    • Any selective uptake or blocking of nitrite by intact cells
    • The effect of large scale cell rupture if meat had previously been frozen - this is likely to increase the effects of simple diffusion
    The accuracy of the weighing of the meat when measuring any weight increase that does take place - consistency between weighing
    • If you do assume that the only uptake of Nitrite is directly proportional to the increased meat weight (??) then a 5% inaccuracy in the weighing would result in a 50% difference in the resulting cure concentration.
    No apparent supporting documentation that shows this method reliably produces the expected residual levels of Nitrite in the end product.

    I am happy to revise my opinion though if the evidence is forthcoming.
     
  10. [QUOTE name="Wade"]
    Now an interesting thing that is included in the same regulation is that the stronger brine using a figure of 10% is mentioned. However ONLY in the context of brine pumped bacon
    "2 lb to 100 gal pickle at 10 percent pump level". This, like dry curing, would effectively deliver a known amount of the cure to a known amount of meat with no risk of exceeding the desired Nitrite levels. There is no mention of immersing in a 10 x concentrated brine until there is a 10% increase in weight though.

    Martin, is it possible that you are mixing up the 2 methods and applying the concentrated pump brine calculations with the immersion cure, on the assumption that a 10% increase in water take up with immersion is equivalent to a 10% increase due to pumped brine?[/quote]

    "Nitrite in Immersed Products
    Method One
    The first method assumes that the meat or poultry absorbs not more than the level of
    nitrite in the cover pickle. Hence, the calculation for nitrite is based on the green weight
    of the meat or poultry (as is the case with pumped products), but uses percent pick-up as
    the percent pump.
    The percent pick-up is the total amount of cover pickle absorbed by
    the meat or poultry. It is used in the calculation for immersion cured products in the same
    way percent pump is used in the (previous) calculation for pumped products."


    PICH, Page 22


    [QUOTE name="Wade"]
    Thanks for your other reference too. If you know that your method is described in there could you point me to the relevant pages?[/quote]

    My method? What do you mean?
     
    Last edited: Jan 20, 2015
  11. I said that the book contains SOME relevant information, not all the information.
    I think you'll need to contact the FDA and the FSIS directly and ask them to back-up their rules and regulations.
     
    Last edited: Jan 20, 2015
  12. Last edited: Jan 20, 2015
  13. On what credible basis do you assume that all this wasn't taken into account when nitrite/nitrate limits were set?
     
  14. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    Thanks Martin, this does address one of the questions. It does not confirm the main assumption regarding weight increase being proportionate to Nitrite intake though. All that this is confirming is that the meat will not accumulate Nitrite to greater concentrations than is in the brine. That is good - however that just limits the total uptake by the meat to the concentration of the brine - which is much higher than the desired end residual Nitrite levels.
    Unfortunately the link you provided above does not seem to support the assumption that the increased weight caused by immersion is proportional to the Nitrite uptake. The only references to weight increase being used in the calculations are for injected brine - which would make sense.

    You have mentioned a couple of times that I should contact various agencies regarding the questions I have about the cure calculation that you posted. I think I am doing my best to ascertain that the calculation you posted is valid - however it is you who are posting it, and therefore I would assume that you already have the published evidence to hand to back it up. All I am doing is asking to be pointed to it.

    Cheers

    Wade
     
  15. Wade,

    It's the policy of this forum that in cases of food safety FDA and USDA rules and the like be followed...or at least recommended.
    Nitrate/nitrite limits have been posted here countless times. They are the regulators' numbers, not my numbers, and only the regulators can back those numbers up.
    If you're not comfortable with that then maybe you should do your own research and set your own limits.
     
    Last edited: Jan 20, 2015
  16. wade

    wade Master of the Pit OTBS Member SMF Premier Member

    That is absolutely correct. I have no question about the published limits. It is the method and calculation that you posted that I am questioning - and the more I have looked into it the more concerned I am becoming. It is making a big assumption regarding the weight increase of the meat while it is in the brine being directly proportional to the amount of Nitrite that is in the meat - and therefore the residual nitrite in the end product. When using such high concentrations of brine, logic suggests that simple diffusion would play a significant role in final Nitrite levels and this is not necessarily related to any increase in weight of the meat. Without any evidence to the contrary it would appear likely that this method/calculation could result in significantly higher concentrations of residual Nitrite than the published limits permit.

    As your calculation for residual Nitrite appears to be based in part on the increase in meat weight while it is in the brine, I am simply asking for credible evidence that this is actually the care. All the evidence I have seen so far relates only to injected brine techniques and not for immersion.
     
    Last edited: Jan 20, 2015
  17. There's a lot to this Wade, and yes, it's certainly possible that more than 200ppm of nitrite will be absorbed into the meat (or that more nitrite will be in the meat due to reduction of nitrate....700ppm ingoing nitrate in permitted in immersion cured products), but let's not forget that immersion curing takes time and that the nitrite begins reducing with the curing action.
    Permitted residual nitrite is 200ppm. The only way to confirm residual nitrite is through laboratory analysis.
     
    Last edited: Jan 20, 2015
  18. atomicsmoke

    atomicsmoke Master of the Pit OTBS Member

    How long does it usually take for the meat to pick up 10% in weight?
     
  19. That depends on lot of different factors....concentration of the brine, temperature, composition of the piece of meat and how it's cut, etc.
     
    Last edited: Jan 20, 2015
  20. atomicsmoke

    atomicsmoke Master of the Pit OTBS Member

    For a belly, full strength brine (4oz/gallon)...roughly 2 days, 1 week, 2 weeks?

    Once is at 10% what's next? Smoke? Or does it have to wait for the curing process to be completed?
     
    Last edited: Jan 20, 2015

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