Cure uptake with immersion brining

[wade]

Following on from a recent thread on here…

I smoke quite a bit of bacon however I do almost all of it using dry cure. I have wet brined some bacon with mixed success however for this I have been blindly following the recipes of others. 

When dry curing it is straightforward to calculate the maximum possible amount of Nitrite that can be in your bacon as it cannot exceed the total amount added with the cure. If not all of it penetrates then at least you will end up with less than the desired cure and not more.

After my recent wakeup call – where I found that a common commercial brand of cure over here, when used as directed actually exceeded the EU maximum levels for both Nitrite and Nitrate, I am finding myself asking some basic questions again. Also the large differences in the various brines that are quoted (on here and in published curing books) is adding to my unease.

When using an immersion cure there is relatively so much nitrite added to the brine that the potential for exceeding the maximum permitted levels would at least seem a possibility. The calculations all seems to depend on a figure that is being quoted that says you only get a 10-12% take up of cure from the brine into the meat.  I am not currently disputing this is fact but I am just looking for a credible scientific source where this has been quantitatively demonstrated. 

It is probably staring me in the face and I have just missed it, but if any of you can point me to a credible document/paper where this has been shown to be the case I will feel much more comfortable.

Thanks

Wade

 

[diggingdogfarm]

Use an equilibrium brine and you won't have to worry about it.

http://www.smokingmeatforums.com/t/124590/universal-cure-calculator#post_833396

 

[wade]

That is an option certainly - even if a little patronising. I think what is more important than me personally worrying about it is that we need to fully understand the brining calculations being quoted on here, and so it would be good to have some credible quantitative evidence that show that the 10-12% figure being used is a valid assumption. If it is there will be some credible published evidence out there somewhere to support this. I am just asking for a link to it.

 

[diggingdogfarm]

As I explained in the other thread, the only way to know for sure is to weigh.
The 10% that was used in the equation IS NOT an assumption of what actual pick-up or gain will be, but in that example, we know that, AT 10% gain, we're within the limit.
The greater the gain. the higher the ppm nitrite.

So, either pull it at 10% or calculate the maximum amount of gain that's within the 200ppm limit and pull it then.

 

[diggingdogfarm]

Maximum % pick-up (or gain) = (200ppm x total weight of the brine solution ÷ weight of the nitrite x 1,000,000) x100

So, using the numbers from the other thread.....

200 x 14456=2891200
24.8 x 1000000=24800000
2891200 ÷ 24800000= 0.11658064516
0.11658064516 x 100=11.67% gain, maximum, to stay within the 200ppm nitrite limit.

 

[wade]

OK Martin. I understand what your calculations are saying. They do assume though that the 10% gain weight is equivalent to a corresponding 10% uptake of Nitrite, and that there is no active accumulation of Nitrite within the cells themselves nor selective blocking from it crossing the cell membranes.

If you are assuring us that the diffusion throughout the meat mass is uniform then that is great - but some published quantitative conformation that this is the case would be reassuring.

 

[diggingdogfarm]

Simply put, it's the government's nitrite limit and the government's equations to determine compliance with that limit.
They set the limits based on science.

 

[wade]

That's great to hear. If you can post up the link to the government site where this calculation is specified then that would be great and my question will be answered. 

Cheers

Wade

 

[bama bbq]

Wade,

I have found over the years, information is passed down as factual knowledge.  When someone wants to question the knowledge to determine if they are truly facts they run into resistance.  (e.g. The World is FLAT!)

Len Poli has some pretty good stuff on the subject.  About 3/4 of the way down on the linked page the discussion on pickling cure starts.  He cites his sources for your own investigation.  I hope this helps.  Enjoy!  http://lpoli.50webs.com/page0001.htm

I normally dry cure my bacon.  What I find interesting is if only 10% of the cure is absorbed in a pickling cure that sounds like an awful lot of wasted cure (90%).

 

[atomicsmoke]

 
I am just looking for a credible scientific source where this has been quantitatively demonstrated. 

Me too.

The only official source referenced ad nauseam everywhere I looked was the Processing Inspectors Handbook. Which surprise-surprise lists two formulas/methods for the same immersion process - see at the bottom. One is the intuitive formula, the other one uses the mysterious pickup factor. So...same process can give you two different nitrite levels in meat. Which is malarkey obviously. 

The first method (the one using the 10% pickup) is meant for large pieces of meat that will not reach equilibrium in the short time the assembly line processors afford. The second one is a equilibrium method, where the meat stays in brine until the nitrite level in meat equalizes the level in the brine.

So if you use the a brine like in the other thread and leave the meat in long enough you could reach over 1000ppm in the meat. That would be a nice red piece of meat. Ofcourse someone could argue: don't wait for equilibrium, pull the meat out at 10% weight gain.  The assumption being the only nitrite in meat is in the 10% brined absorbed. That is nonsense. The cells have absorbed salt and cure ions at a rate that cannot be easily correlated with the amount of water absorbed. Osmosis is a beetch.

Here it is the excerpt from the handbook:

Nitrite in Immersed Products

In immersion curing, the submerged meat or poultry absorbs the cover pickle solution, slowly,

over a long period of time. There are two recognized methods for calculating the allowable

ingoing amount of nitrite in immersion cured products. The method used depends on the

mechanism of movement of nitrite within the meat and/or poultry/pickle system and into the meat,

meat byproduct, or poultry tissue itself.

! 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.

< Calculation Formula (using % pick-up)

lb nitrite × % pick-up × 1,000,000 = ppm

lb pickle

! Method Two

The second method assumes that the submerged meat, meat byproduct, or poultry and the

cover pickle act as a single system. Over time, the ingredients in the pickle, such as nitrite

and salt, migrate into the meat, meat byproduct, and poultry until levels in the tissue and in

the pickle are balanced. This system is actually very complex and dynamic, with

components in constant motion, but it will reach and maintain a state of equilibrium.

Therefore, the calculation for ingoing nitrite is based on the green weight of the meat

block, using the percent added as a relevant amount.

< Calculation Formula (using the green weight and pickle weight)

lb nitrite × 1,000,000 = ppm

green weight (lb) meat block + lb pickle

 

[diggingdogfarm]

Procesing Inspectors Calculations Handbook

One must be VERY careful when using the handbook, it's intended for inspection personnel only and not the general public so it's incomplete in terms of some critical information.
Unfortunately, that has led to a LOT of folks misinterpreting some of the information in the handbook.

 

[diggingdogfarm]

As I said, It's easy to find instances of folks not understanding the handbook. :biggrin:

 

[atomicsmoke]

Yeah, this is not about the handbook. Please explain why in an equilibrium (weak) brine the meat picks up a lot more nitrite than the weight gain would explain, but in full strength brine won't. The only difference is the concentration of curing salt, which would even accelerate the osmosis process for the full strength brine.

 

[diggingdogfarm]

Let's see your examples.

 

[atomicsmoke]

Use the case discussed in the Prague Powder #1 thread yesterday.

 

[diggingdogfarm]

Yeah, we used the ingoing nitrite limit set by the government and the government's equation to determine compliance with that limit.
The equation is just as important as the limit, they go hand in hand.

 

[wade]

 
The assumption being the only nitrite in meat is in the 10% brined absorbed. That is nonsense. The cells have absorbed salt and cure ions at a rate that cannot be easily correlated with the amount of water absorbed. Osmosis is a beetch.

I am happy with Martin's logic and his calculation however you have hit precisely on one of the areas that worries me. It does make the assumption that the Nitrite is absorbed by uniform passive diffusion. Many years ago I worked in pharmaceutical research and am aware just how selective cells can be with what they actively take up and what they can block. I only worked with living cells though and I have no idea what the situation will be with a slab of "dead" pork. Some quantitative reassurance that there is no active biological mechanism where Nitrite is selectively accumulated within the cells would be comforting.

 

[wade]

 
Wade,

I have found over the years, information is passed down as factual knowledge.  When someone wants to question the knowledge to determine if they are truly facts they run into resistance.  (e.g. The World is FLAT!)

Len Poli has some pretty good stuff on the subject.  About 3/4 of the way down on the linked page the discussion on pickling cure starts.  He cites his sources for your own investigation.  I hope this helps.  Enjoy!  http://lpoli.50webs.com/page0001.htm

I normally dry cure my bacon.  What I find interesting is if only 10% of the cure is absorbed in a pickling cure that sounds like an awful lot of wasted cure (90%).

Thanks Bama - I will take a look. It may be in there. 

 

[diggingdogfarm]

I think the issue here boils down to a fundamental misunderstanding of the concept of an ingoing nitrite limit.
Obviously, every piece of meat is different, every piece of meat may absorb ingredients differently. I don't think anyone will argue with that.
The reality is that you can't do an indepth scientific analysis of every piece of cured meat.
So, with that in mind and for practicality, the government has set an ingoing nitrite limit (that it has deemed safe) and the method to calculate compliance with that limit.

 

[daveomak]

 
I am happy with Martin's logic and his calculation however you have hit precisely on one of the areas that worries me. It does make the assumption that the Nitrite is absorbed by uniform passive diffusion. Many years ago I worked in pharmaceutical research and am aware just how selective cells can be with what they actively take up and what they can block. I only worked with living cells though and I have no idea what the situation will be with a slab of "dead" pork. Some quantitative reassurance that there is no active biological mechanism where Nitrite is selectively accumulated within the cells would be comforting.

OK.... now put your head around a previously frozen piece of meat where the cell walls have been ruptured from ice crystals....