# Nitrite levels:  assumptions and calculations



## PolishDeli (Oct 9, 2018)

Hi,

I have a question about calculating nitrite levels in meat.  I know this isn’t a new topic, but I’ve not seen a detailed discussion of the calculations or the physical assumptions that go into the calculations.

According to the USDA’s Processing Inspectors' Calculations Handbook, nitrite levels are calculated using the following equation for meats cured by immersion or pumping:

ppm = (weight nitrite * % pick-up / weight water)*1000000. 
If pumping, %pick-up=%pump.

(https://www.fsis.usda.gov/wps/wcm/c...4da3-905b-fa240974a5a9/7620-3.pdf?MOD=AJPERES)


Comparing two popular sources; vastly different assumptions seem to be made regarding the value (and meaning) of % pick-up. Details are below.  In my example calculations, I assume a 20 pound ham, and 1 gal of water, and I am seeking to obtain 150ppm nitrite in the meat.  

Source 1 says 91g Cure #1.
Source 2 says 31g Cure #1.

Can anyone provide some insight, an academic reference, or an industrial reference?

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Source 1:  S. Marianski.  Author of several books, and a web site. I can’t find any information about his formal training/education/career.


Ham:  20 lb (9072g)
Water:  1 gal = 8.36 lb (3792 g)
*Cure # 1:  0.2lb (91g)*
Nitrite:  0.2*0.0625 = 0.01 lb (6g)

ppm nitrite in water = (6g / 3792 g)*1000000 = 1500ppm

If the ham is pumped with 2 lb (907g) of cure (i.e., 10%):
ppm nitrite in meat = 1500*0.10 = 150ppm

If not pumping, Marianski says 4%pick-up is a reasonable assumption: 
ppm nitrite in meat = 1500*0.04 = 60ppm

So, according to Marianski, the amount of nitrite in the meat, is proportional to the amount of curing solution it absorbed (or was pumped with).  This seems consistent with the USDA’s Calculations Handbook:  “…assumes that the meat or poultry absorbs not more than the level of nitrite in the cover pickle.” (Page 22)


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Source 2:  G Blonder PhD.  Professor of mechanical engineering at BU.  PhD in physics.  Lots of peer-reviewed publications, and is highly cited (h-index 48) – but not in the field of food science.  So, although he’s a very accomplished academic, he’s not technically a food scientist.

The amount of cure #1, was obtained from a nitrite calculator he developed and has posted on his web site. His calculator assumes no pumping.  To get 150ppm nitrite, Blonder’s calculator says you need:

Ham:  20 lb (9072g)
Water:  1 gal = 8.36 lb (3792 g)
*Cure # 1:  0.07lb  (30.9g)*
Nitrite:  0.07*0.0625 = 0.004 lb (1.9g)

Therefore;
ppm nitrite in water = (1.9g / 3792 g) * 1000000 = 509ppm
To get 150ppm, the calculator must be assuming a 30% pickup?

There is no way that the meat absorbs 30% of its weight in water.  Blonder must therefore be saying that the meat is filtering the nitrite out of the water.  This seems contrary to the USDA guidelines.  Unfortunately, I can find no explanation or justification for this calculation.

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Thanks for reading,


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## chef jimmyj (Oct 9, 2018)

I could not find the Blonder Calculator. Please post a link...JJ


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## daveomak (Oct 9, 2018)

You are correct...  Dr. Blonder is out of his field of expertise...

Polish, afternoon...   Having worked at a meat plant, as a private contractor, and knowing the owner and having many tours, % pick up is calculated at the needle curing injection station...  
Let me explain....  
The particular plant had a supplier of pork bellies...  They are allowed to inject the bellies to the point the finished weight, after processing, does not exceed the original weight...  There was a classification that the bellies fell into if they were within a certain % of original weight...   That is a critical number for sales and profit margin calculations...  The % pickup was used in the final pricing / per pound...   That number is used per batch for for a long period in a small processing plant....   Well, I was there when losses on bacon were noted and the owner explained to me how much money they lost...  The supplier had, for some reason, changed the standards for bellies that were supplied...  They were thinner bellies...  The owner showed me...  and he explained their needle injector was not correct for the thickness of the meat... very little pickup was experienced at all....   Therefore, after processing the bellies they weighed about 7% less than they did originally...   They had the original assumption calculated into the processed bellies they weighed what they did originally...  Subsequently, they were losing 7% on bellies....
% pickup in commercially processed meat is NOT a subjective thing...   Every ounce of meat is accounted for in a processing plant..


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## daveomak (Oct 9, 2018)

Polish.....  That is your first post... Why did you not querie Meat Head...


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## daveomak (Oct 9, 2018)

How is the percent solution pickup calculated? Does the establishment need to weigh the meat prior to being marinated/injected and then weigh it after to see how much was absorbed?

A; Determining the percent pick up involves weighing the raw meat or poultry before
solution is added, weighing the raw meat or poultry after adding solution, and
performing a calculation to determine the percent solution pick up in accordance with
9 CFR 317
.2(e)(2)(i) and 9 CFR 381.117(h)(1): “
The percentage of added solution
(total weight of the solution ingredients divided by the weight of the raw meat without solution or any other added ingredients multiplied by 100).”

https://www.fsis.usda.gov/wps/wcm/c...46/Q-A-Added-Solutions-122415.pdf?MOD=AJPERES


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## PolishDeli (Oct 10, 2018)

JJ, Here is the link:
https://www.genuineideas.com/ArticlesIndex/nitritecuringcalculator.html

Dave, 
Thanks for all the info and the FSISD link.  That all seems to be in line with Marianski's treatment of the topic.
I did reach out to Meathead about this. Maybe he was trying to be reassuring, but I didn't find his response helpful:  
"We put a LOT of effort into this calculator and Prof Blonder has checked it many times. It works."
I followed up, trying to pry out a more technical reply.  Nothing yet.

I used the Marianski math for thanksgiving ham last year.  All went well, and will do it again this year.  
Unless someone can convince me otherwise.


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## daveomak (Oct 10, 2018)

This makes some pretty good ham....

https://www.smokingmeatforums.com/threads/ham-from-fresh-picnics-update-10-21-money.236375/

...


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## chef jimmyj (Oct 11, 2018)

The Blonder calc, like DiggingDogs calc used here with success, are both Equilibrium Calculators. They determine how much cure is needed to get the entire system to say 150ppm. The total weight of water and meat is 12864g. Adding 30.9 (Blonder), 30.82 (Doggy) grams of Cure #1 will eventually. give 150ppm. The water alone contains all the Nitrite, at first, at 509ppm but over time,  Blonder uses 5 days per inch thick, diffusion will push the cure from the high concentration water into the low concentration Ham. Lets say we have a 12" diameter ham. At the end of 60 days, equilibrium will occurr and the ham and water will both be at 150ppm. Risky, bone sour, ropy  brine, undesirable bacteria, mold, or yeast invades, and impractical,  ties up refer space for 2 months, but these numbers will totally work to give the desired result, a Ham cured to 150ppm...JJ


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## PolishDeli (Oct 13, 2018)

Dave,
Nice recipe.  Thanks to JJ, I was able to juggle some numbers, and conclude that your method (pumping a 10% solution and bagging it) gives roughly equivalent nitrite levels, weather calculating according to Marianski or Blonder (see bottom of the post).  I’m not brave enough to start adding phosphates yet though. 

JJ,
Thanks for the perfect explanation. 

I think the cure time would be based on radius and not diameter though, since cure is entering along the entire circumference of the cylinder?  In any case, this method is indeed described in the USDA handbook:   It is “Method two” in the section on “Nitrite in Immersed Products.”  I had originally ignored this calculation because “Note: Method One is used for hams, shoulders, bellies, etc., because it takes weeks for these large items to reach equilibrium. Method Two is primarily used with small items with large surface areas such as pigs' ears, tails, snouts, etc.” (page 23) 

So, I’ve learned a lot.  In summary:
Source 1: S. Marianski uses USDA method one for nitrite calculation in immersed products.
Source 2: G Blonder uses USDA method two for nitrite calculation in immersed products.

That is a very broad range of “acceptable” Cure#1 weights. And the discrepancy increases with larger pickle volumes.

For example, If we immerse *20lb ham in 5 gal of pickle:*
Method 1:  454 g Cure#1 are needed for 150ppm.
According to Method 2 though, the meat is actually at 1013ppm.  This means if you eat 1kg of ham (2.2 lb) you consume 1g of nitrite, and that is a potentially toxic dose.
[2.2 g of sodium nitrite is considered lethal to a 100kg (220lb) person according to “GRAS (Generally Recognized as Safe) Food Ingredients: Nitrates and Nitrites (Including Nitrosamines),” 1972

Method 2:  67 g Cure#1 are needed for 150ppm.
According to Method 1 though, the meat only has 22ppm nitrite in it – too low for a suitably safe cure. Both Marianski and Blonder say ~50ppm is the minimum for any preservative effects to take place. 

The calculated weights of Cure#1 required for 150ppm according to  method 1 and method 2 cross over at 0.25gal (945g) for a 20lb (9072g) ham; i.e., a pickle weight ~ 10% of the ham weight.  That’s not enough solution to fully immerse the meat, so pumping is a must. Put it in a bag to trap whatever leaks out, and this the same as Dave’s method.


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## chef jimmyj (Oct 13, 2018)

There is some variation in recipes for relatively circular meats . Some use 5 days per inch total thickness or say 5 days per 1/2 inch of the radius. I have seen 7 days per inch thick as well...JJ


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