Musings on Nitrate/Nitrite Conversions

[Oddley]

Using the tried and tested recipe of Maynard Davis. Assuming that this will be within the current FSA regulations. I have come to the following conclusions. all comments welcome.

Conclusions.

1: 75% potassium Nitrate will be converted into Nitrites leaving a residue of 25%
2: There will be a decomposition over the curing period of 80-90% of the Nitrites leaving a residue of 10-20%

Using the calculation I did for the cure Here The Results being

Results

Total weight cured meat = 108 lb or 48987.936 gm
% of Saltpetre in Cure = 1.234%
Nitrates ingoing ppm = 1157
% of sugar In Meat = 1.851%
% of salt In Meat = 7.407%

Conversion Calculation Results

Nitrates ingoing ppm = 1157
75% Conversion to nitrites = 867.75 ppm
Remaining nitrates = 1157 - 867.75 = 289.25 ppm
80% nitrites decomposition = 173.55 ppm

Remaining Potasium nitrates = 289.25 ppm
Remaining Potasium nitrites = 173.55 ppm

I would like to know your thoughts on this.

[Parson Snows]

Oddley wrote

I have come to the following conclusions. all comments welcome

With Christmas/New Year just about caught up "paper work wise" I'll have a look over your calculations in the next day or so and get back to you. Thanks for sharing them.

kind regards

Parson Snows

[Parson Snows]

Oddley
You wrote

Conclusions.
1: 75% potassium Nitrate will be converted into Nitrites leaving a residue of 25%
2: There will be a decomposition over the curing period of 80-90% of the Nitrites leaving a residue of 10-20%

As you can see from the information below this won�t be the case unless isoascorbate is present . As I mentioned before numerous studies have been done on this and continue to be done.

ENCYCLOPEDIA OF FOOD SCIENCE AND TECHNOLOGY
Second Edition (2000) VOLUME 1
By Frederick J. Francis
Published By John Wiley ISBN 0-471-19285-6



dissociate
Definition: [v] (chemistry) to undergo a reversible or temporary breakdown of a molecule into simpler molecules or atoms; "acids dissociate to give hydrogen ions"

NITRATES AND NITRITES IN FOOD AND WATER
Editor MICHAEL HILL D. Sc., F.K.C. Path., F.R.S.C., C. Chem.
European Cancer Prevention Organisation, Hampshire, UK

6.2.4 Monitoring of nitrate and nitrite levels
There is no general agreement whether the nitrite added (at time of formation) or the residual nitrite (post process) reflects more closely the ability of the product to control growth of C. botulinum (Christiansen et.al. 1973, Hustad et al 1973, Pivnick and Chang 1974, Johnston et al. 1969; Christiansen et al. 1978, Tompkin et al. 1978d) (summarized by Roberts ef al. 1981a). The �time to zero residual nitrite�, which was literally the time to <10 fg/g (Gibson, et al. 1984) proved useful in illustrating the effect of heat treatment, storage temperature and chemical additives (isoascorbate/nitrate/polyphosphate) on residual nitrite in experimental pasteurized cured meats.
Several general conclusions could be drawn. In �low� pH slurries the rate of loss of nitrite fell with reducing storage temperature, and, although less residual nitrite remained after the higher heat treatments, the rate of loss of that nitrite during storage slowed with increasing heat treatment. If nitrate (500 fg/g) had been added, residual nitrite levels remained higher for longer, especially at initially low-input nitrite levels (100 fg/g). This was more obvious as the heat treatment increased and at low storage temperatures (20�C or below). At 35�C storage, the addition of nitrate had little effect on residual nitrite levels. In some instances residual nitrite increased during storage, particularly after the higher pasteurization treatments and when storage temperature was low. Nitrate-reducing organisms were isolated from many packs but there was insufficient data to relate rise in residual nitrite levels to their presence. Addition of isoascorbate in the absence of nitrate caused residual nitrite levels to fall rapidly and to become undetectable within 20 days irrespective of initial heat treatment, or subsequent storage temperature. If both isoascorbate and nitrate were present, residual nitrite fell at rates similar to those when isoascorbate was present and nitrate absent. Polyphosphate had relatively little effect on the rate of loss of nitrite.


The rise can be quiet dramatic though as it takes a while to get tables etc. onto this forum (something which should be addressed), I'll post them when I get some time.

Kind regards

Parson Snows

[Oddley]

In some instances residual nitrite increased during storage, particularly after the higher pasteurization treatments and when storage temperature was low. Nitrate-reducing organisms were isolated from many packs but there was insufficient data to relate rise in residual nitrite levels to their presence. Addition of isoascorbate in the absence of nitrate caused residual nitrite levels to fall rapidly and to become undetectable within 20 days irrespective of initial heat treatment, or subsequent storage temperature.

I can see what you are saying but as you can see these studies were carried out with pasteurised meat. As we know it is bacterial action that Contributes significantly to nitrite decomposition.

As This particular recipe is well known and tested and maynard Davis is a respected curer I would think that this recipe is safe so therefore I would conclude the nitrite/nitrate levels are within safety levels as the process and mature times are completed.

I will calculate a few more of his recipes to see indicative levels of nitrate. But as a general rule I think that with no extreme conditions we must come to the conclusions that the nitrite/nitrate levels must be in the region I suggested.

Or would you disagree with that assumption.