Allowable Nitrite/Nitrate levels in the UK

[Parson Snows]

Oddley

Thanks a lot for the Xmas wishes. I have just posted some additional information on this subject under "Curing/Techniques/Nitrite Determination"

hope that this is of some use to you

kind regards

Parson Snows

[Oddley]

Thanks again for posting this I have just had another look at it and is this right.

Indicative nitrate = (converted nitrate + unconverted nitrate)

Or should it be:

Indicative nitrite = (converted nitrate + unconverted nitrate)

just making sure I understand this

[Parson Snows]

Oddley

you wrote

Or should it be:

Indicative nitrite = (converted nitrate + unconverted nitrate)

I originally wrote

A simple relationship between Indicative and residual amounts of nitrates/nitrites can be expressed thus.

For the nitrate example.

If nitrate is used as the curing agent, it must first be converted (reduced) to nitrite by micro-organisms (bacteria) such as Micrococcus spp. present on the meat or poultry.

as we were explaining ingoing/indicative NITRATE that's what I kept it as to try and explain apples with apples etc. I hope that below might make it clearer for you.

To further try and clarify nitrites and the ingoing/indicative and residual amounts please find below



This is taken from Wiley Encyclopedia of Food Science and Technology (2nd Edition) Volumes 1-4
Edited by: Francis, Frederick J. � 1999 John Wiley & Sons

and



This is taken from Nitrates and Nitrites in Food and Water
Edited by: Hill, M.J. � 1996 Woodhead Publishing

I hope that this is found to be of some use to you

kind regards

Parson Snows

[Oddley]

Yes this does clear things up a bit. I am still having a problem with the term.

Indicative nitrate = (converted nitrate + unconverted nitrate)

The problem I cannot get my head around is if nitrate is converted then it is no longer nitrate so how can it = Indicative nitrate.

I'm sorry if this is getting on your nerves. Some people have likened me with a problem to a terrier with a rat. I just can't leave it alone.

I do appreciate your time as I suppose does everyone who reads these conversations but don't get involved. I'm actually keeping an archive of these conversations so I can refer back to them later.

[aris]

Oddley,

Perhaps you should consider a degree in food technology?

[Oddley]

Funny you should say that aris I was offered the chance to do an HNC in food science when younger which takes two years of full time study. Unfortunately I was to busy earning a living for my young family.

[Parson Snows]

OK Oddley Try THIS

You are going to the petrol station to fill up your car,
We�ll assume that as you pull into the petrol station the tank is completely empty (0) as you were almost out of petrol when you started out.

Petrol ADDED (indicative) = Petrol in tank (as tank was Empty)

KEEPING IT IN VERY SIMPLE TERMS
You now start your car and the petrol is combusted within the engine (converted to carbon monoxide and water). You then drive home though when parking your car you back over a rake a put a small leak in the petrol tank. You don�t notice it and turn off the engine. The petrol in the tank is now less than when you filled it up as some has been converted to carbon monoxide and water � powering the car home, and some is now being lost through the small leak.

WHEN YOU PARKED THE CAR

Amount of Petrol ADDED (indicative) = (used PETROL + Petrol still in tank)

OR

Petrol ADDED (indicative) = (converted PETROL + unconverted PETROL)

The converted PETROL has become, energy, carbon monoxide and water but it was still originally PETROL.

Amount of PETROL left in tank = (Amount of Petrol ADDED � Amount of Petrol used � amount of PETROL lost due to leak)

OR

Residual PETROL = (Petrol ADDED (indicative) � converted PETROL - amount of PETROL lost due to leak)

As there is a small leak eventually residual PETROL would also equal 0

Hope that this makes it clearer.

Same principle as mass balance calculations � everything must add up to 100 %

Kind regards

Parson Snows

[Oddley]

Thank you all becomes clear...

Don't get me started on mass balance calculations...

I used to drive the lecturers to distraction...

[Parson Snows]

Oddley

I do plan on touching on mass balance calculations pertaining to sausage formulations, assuming that we ever get through "Nitrates/Nitrites 101"

kind regards

Parson Snows

[Oddley]

Oh well now you know what you are getting yourself into...

BTW when you have finished your treatise on curing let me know and I'll let you have my email address so you can send it to me. When writing a program understanding the calculations is very important so the right results are obtained. I'll do my best to do it justice.

[Parson Snows]

Oddley

You wrote

When writing a program understanding the calculations is very important so the right results are obtained. I'll do my best to do it justice.

As I quoted before a lot of this subject is empirical, for example

The fate of nitrite can be roughly summarized as follows: 1-5 % is lost as nitric oxide gas or becomes bound to lipids, 1-10 % is oxidized to nitrate, 5-10 % remains as free nitrite, 5-15 % reacts with sulfhydryl compounds or myoglobin, and 20-30 % becomes bound to proteins. In addition, nitrosation of amino compounds (nitrosamine formation) may occur as well as the formation of organic nitrites and nitrates.

I�ll certainly post what I have and you�re welcome to program what you can, off the top of my head the brine formulations etc. would probably be the most beneficial.

As to the mass balance calculations, I have some pretty simple examples to post, we�ll just have to see how it turns out.

kind regards

Parson Snows

[Oddley]

If I have this right then the following is the most telling.

The chemistry of interactions involving nitrite in food products is
complex, owing to the highly reactive nature of nitrite. In cured meat
products, a rapid decrease to about 50% of the initially added nitrite
concentration occurs during processing.

If I am right we can say that if I add nitrite to a piece of meat at a

indicative rate of 200 ppm
then the Residual would = 100 ppm after processing (slighty more or less).

Is this right?

[Oddley]

Hello again parson I have just received this as part of a .pdf file from Andy at the FSA.

This may sound like a stupid question but in your opinion if I were making
dry cure bacon do the rules allow for.

E 250 Sodium nitrite* Dry cured bacon and ham 175 mg/kg as a residue
And
E 251 Sodium nitrate Dry cured bacon and ham 250 mg/kg as a residue

Or only one of them. I want to be sure.

And Oh have a look at the brisket would 10 mg/kg apply to Salt beef made with brisket

[Parson Snows]

Oddley

I have just sent you a PM with my email address enclosed

kind regards

Parson Snows

[Oddley]

e:mail sent.