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Dimensions in the Analysis Certificates

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nerea

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Posted 03 October 2012 - 12:25 PM

Hi all,
I have two questions.
1. What does "NPN/g"?
2. How to calculate dimention "NPN/g" into "CFU/g"?

Thanks!
Nerea



nerea

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Posted 03 October 2012 - 01:13 PM

Hi all,
I have two questions.
1. What does "NPN/g"?
2. How to calculate dimention "NPN/g" into "CFU/g"?

Thanks!
Nerea



Sorry, I have a mistake: it isn't NPN, it is MPN


George @ Safefood 360°

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Posted 03 October 2012 - 07:59 PM

Hi Nerea

I was just about to ask to check whether you meant MPN and not NPN. If my applied microbiology serves me well i believe it means Most Probable Number. I0 tis used for a specific testing method whereby dilutions of a sample are prepared and added to a specific reagent which produces a colour change over time when incubated at a particular temperature. This is an indicator of the most probable numbers of bacterial cells present. A calculation is conducted from the various dilutions prepared. I used it for a number of years while testing milk products for Coliforms. It does not measure directly the number of colony forming units like traditional plating methods but instead relies on a rate of a chemical reaction.


Anyway my memory is a little sketchy on this but this might be enough to get you started on researching it further. I'm sure the laboratory who is conducting the testing will provide with a more comprehensive explanation.


George



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nerea

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Posted 04 October 2012 - 07:29 AM

Hi Nerea

I was just about to ask to check whether you meant MPN and not NPN. If my applied microbiology serves me well i believe it means Most Probable Number. I0 tis used for a specific testing method whereby dilutions of a sample are prepared and added to a specific reagent which produces a colour change over time when incubated at a particular temperature. This is an indicator of the most probable numbers of bacterial cells present. A calculation is conducted from the various dilutions prepared. I used it for a number of years while testing milk products for Coliforms. It does not measure directly the number of colony forming units like traditional plating methods but instead relies on a rate of a chemical reaction.


Anyway my memory is a little sketchy on this but this might be enough to get you started on researching it further. I'm sure the laboratory who is conducting the testing will provide with a more comprehensive explanation.


George




Hi, George

Yes, I meant "MPN".
Thanks for this information, it's useful for me.

Nerea


Charles.C

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Posted 04 October 2012 - 10:18 AM

Hi all,
I have two questions.
1. What does "NPN/g"?
2. How to calculate dimention "NPN/g" into "CFU/g"?

Thanks!
Nerea


Dear nerea,

Can try these links for CFU/g and MPN/g respectively -

http://www.fda.gov/F...M/ucm063346.htm

http://www.fda.gov/F...M/ucm109656.htm

Rgds / Charles.C

Kind Regards,

 

Charles.C


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