19 replies to this topic

[hygienic]

Dear Aii:

I have a quick question in microbiological tests field. Is it require to do the TPC test for cheese and cheese products ? if no why ?

Thanks for your input.

hygienic

[Foodworker]

Interesting point.

With cheeses, depending on the variety, you are often actively encouraging micro growth to develop flavour and texture.

Not sure where you are in the world but in the EU the primary legislation is 2073/2005 and this does not have a requirement for a specific total count for cheese, just the normal pathogens.

That said, there is also in the UK a commonly used set of guidelines for ready to eat foods, of which cheese is obviously one. These guidelines have an aerobic colony count of above 10⁴ being unsatisfactory for cheese.

Enforcement officers tend to use these PHLS Guidelines as a starting point for further investigations. Customers often use them for setting specification limits.

My advice would be to monitor the total count as a routine to get a baseline. Sudden peaks beyond this baseline can often be an indicator of a process problem.

I am attaching the 2000 PHLS Guidelines (There is a 2003 update which I don't have) and also a more recent micro guide, which doesn't include cheese, but has some useful info.

Attached Files

•  uk microbiological guidelines 2009 RTE1.pdf   1012.42KB   151 downloads
•  phls guidelines 2000.pdf   138.24KB   126 downloads

[hygienic]

Interesting point.

With cheeses, depending on the variety, you are often actively encouraging micro growth to develop flavour and texture.

Not sure where you are in the world but in the EU the primary legislation is 2073/2005 and this does not have a requirement for a specific total count for cheese, just the normal pathogens.

That said, there is also in the UK a commonly used set of guidelines for ready to eat foods, of which cheese is obviously one. These guidelines have an aerobic colony count of above 10⁴ being unsatisfactory for cheese.

Enforcement officers tend to use these PHLS Guidelines as a starting point for further investigations. Customers often use them for setting specification limits.

My advice would be to monitor the total count as a routine to get a baseline. Sudden peaks beyond this baseline can often be an indicator of a process problem.

I am attaching the 2000 PHLS Guidelines (There is a 2003 update which I don't have) and also a more recent micro guide, which doesn't include cheese, but has some useful info.

Dear Foodworker:

Thanks for your input , I have answer for my enquery but I am not sure if its right , so I need advice .

What I know , that TPC test that only earobic microorganisms will grow, but in cheese which is a fermented products , that anerobic bacteria only cause the illness or food poisoning .
bacteria can be occure in cheese such as clostridum botulinum , salmonella , E.coli all these bacteria anerobic that mean (no need oxygen ), for this reasone TPC not required in cheese

please correct me if I am wrong .

Regards

Edited by hygienic, 02 February 2011 - 03:55 PM.

[Charles.C]

Dear hygienic,

yes, you are wrong (or perhaps more accurately, you may be wrong). And likely even more so if unpasteurised milk is used.

try this link (and subsequent parts) -

http://www.ontarioch...se_safety_2.php

or maybe -
http://www.uwstout.e...3/2003zhaom.pdf

Rgds / Charles.C

[hygienic]

Dear hygienic,

yes, you are wrong (or perhaps more accurately, you may be wrong). And likely even more so if unpasteurised milk is used.

try this link (and subsequent parts) -

http://www.ontarioch...se_safety_2.php

or maybe -
http://www.uwstout.e...3/2003zhaom.pdf

Rgds / Charles.C

Dear Charles:

thanks for the useful links and for correcting me , but still i didnt get the precise answer . why TPC test not required for cheese ?

Regards
Hygienic

[Charles.C]

Dear hygienic,

It's not my area but here is one simple literature comment –

The total number of bacteria has been counted in cheese, but the results are not very meaningful in terms of the care taken in manufacturing the cheese because most of the bacteria in the cheese will be either starter or NSLAB. (added ie part of the process)

(NSLAB = non-starter lactic acid bacteria)

As one example of possible size of the numbers, see attachment below –

 cheddar cheese.png   37.16KB   12 downloads

and here is a cheese micro.survey 2002 (note no plate count specs )
(Foodworker's previous reference to EC standards is even more up to date of course [2005])

http://www.health.ac...&pid=1063347263


Rgds / Charles.C

[DAVE84]

Hey
hygienic,

Please provide me the source from where you learned that TPC is not required in cheese. Here is what my understanding is.

TPC is a total plate count. Which includes counts of E.coli, salmonella, and a number of other pathogens + spoilage causing organisms (which are not pathogens).

So consider this event. If your sample is negative for salmonella and E.coli, but your TPC is too high (height than recommended) than the shelf life of cheese will reduce. It will also give you the idea of how smooth your operations are. IF you decide not to do TPC on regular basis that's fine, but prefer to do randomly. FDA can not ask you why you are not doing TPC count, if you are doing salmonella and listeria count on your product and show they are negative. Its just a matter of checking your product quality and shelf life. I guess for milk and milk product industry whole different body is working to create standards and whole milk industry follows that standards. You will easily find standards online. If you have hard time please let me know i will try to help you out.


Hope this will help you.

[hygienic]

Hey
hygienic,

Please provide me the source from where you learned that TPC is not required in cheese. Here is what my understanding is.

TPC is a total plate count. Which includes counts of E.coli, salmonella, and a number of other pathogens + spoilage causing organisms (which are not pathogens).

So consider this event. If your sample is negative for salmonella and E.coli, but your TPC is too high (height than recommended) than the shelf life of cheese will reduce. It will also give you the idea of how smooth your operations are. IF you decide not to do TPC on regular basis that's fine, but prefer to do randomly. FDA can not ask you why you are not doing TPC count, if you are doing salmonella and listeria count on your product and show they are negative. Its just a matter of checking your product quality and shelf life. I guess for milk and milk product industry whole different body is working to create standards and whole milk industry follows that standards. You will easily find standards online. If you have hard time please let me know i will try to help you out.


Hope this will help you.

Thanks for helpping , but I saw many standards where I found Coliform( there is a standard limit in the fermented products , bacillus , staph and listeria but under TPC test it mentioned like this ____ or N/A that mean it is not required . Is it ?

Hygienic
Regards

[DAVE84]

It meas that it is not required (mandetory) but its good to include.

Take example of coliform:

Coliform test will give you reading of E.coli and other coliform.

100 Coliform/10 gm does not mean that you have 100 E.coli in your porduct
But if you have result like 100 colifor/10 gm and 5 e.coli/10 gm for same sample (e.coli is not pathogen. only E. coli O157 H7 is pathogen)
than its clear that 95 is non pathogenic coliform.

When the mention staph, Listeria, salmonella this are pathogens (illness causing organisms). So each manufacturer are bound to test product for this bacteria. TPC is for shelf life and idea of process. So thats why they do not mendate that.

So if you test your product for E. coli and salmonella. you found 10 e coli and 20 salmonella. If you do TPC and you found TPC count of 50 than that 50 will include 10 e coli and 20 salmonella

so 50 TPC= E.coli (10) + salmonella (20) + spoilage cuasing bacteria (20)

but with the TPC you will not be able to identify which are e coli and which are salmonella

Am i clear?

[Charles.C]

Dear Dave,

Some interesting bacteriological theory.

Not disagreeing with yr interpretation but sometimes N/A also means Not Applicable, ie not appropriate for the specific product. I believe this can be the case for cheese (but not always perhaps).

Rgds / Charles.C

[DAVE84]

Yes charles,

But again it depends on who wrote that limits. I doubt that this N/A will be not applicable. Because if its not applicable for TPC than it will be not applicable for salmonella and other pathogens too.

Dave

[Charles.C]

Dear Dave,

This was the intended meaning of my earlier post #6. Sorry if it was unclear.

Rgds / Charles.C

[DAVE84]

No charles

actually it was my mistake. I was at work and i saw the post when i was in rush... I apologize for that.


Regards

Dave

[Charles.C]

Dear Dave,

No problem. I admire yr posting enthusiasm.

Have to say that i much prefer to eat cheese than to analyse it.

Rgds / Charles.C

[Vijayanthi]

If you add starter cultures during the manufacturing process there is no purpose of getting TPC counts.

[agwanda]

Hey
hygienic,

Please provide me the source from where you learned that TPC is not required in cheese. Here is what my understanding is.

TPC is a total plate count. Which includes counts of E.coli, salmonella, and a number of other pathogens + spoilage causing organisms (which are not pathogens).

So consider this event. If your sample is negative for salmonella and E.coli, but your TPC is too high (height than recommended) than the shelf life of cheese will reduce. It will also give you the idea of how smooth your operations are. IF you decide not to do TPC on regular basis that's fine, but prefer to do randomly. FDA can not ask you why you are not doing TPC count, if you are doing salmonella and listeria count on your product and show they are negative. Its just a matter of checking your product quality and shelf life. I guess for milk and milk product industry whole different body is working to create standards and whole milk industry follows that standards. You will easily find standards online. If you have hard time please let me know i will try to help you out.


Hope this will help you.

dEAR Hygienic,

I do agree with Dave84, TPC takes into account a wider group of microbes and thus setting limits on this may be fairly tricky. Cheese as a product depending on varieties have critical microorganisms that have to be totally absent or present in minimal counts. Pathogens such as S. aureus, E. Coli etc should normally be absent. TPC thus can only give you an idea of the probable shelf life but the presence of pathogen becomes a real danger.

Thus I consider pathogen detection in cheese more critical than other microbes...... atleast from the consumers perspective.

Agwanda

[clover]

Hi all,

 

Great discussion here. I'm gonna veer slightly off the topic here.

 

Today, I was told that it would be better to test for Listeria (rather than) Salmonella in cheese items. Why is that so? Anyone got any idea? Of course, ideally it would be great to test for all pathogens, but we are only limited to choosing one test parameters. 

[clover]

Bump..

[Guitardr85]

Great convos above!

 

I actually had a question on this myself.  I recently started at a cheese manufacturer and noticed this thread could (hopefully) help me out with some questions I have.  

 

I recently (about 15 minutes ago  ) received a COA that contains, what I consider, a high APC number (limits not established).  This seems at least somewhat redundant as we also tested coliform, E. Coli, Listeria, Salmonella, and Staph.  I know that this could threaten shelf life but would this really be considered a food safety issue?  Obviously I will conduct an investigation into why the levels are so high (e.g. cleaning efficacy, supplier review, etc.).

[Charles.C]

Great convos above!

 

I actually had a question on this myself.  I recently started at a cheese manufacturer and noticed this thread could (hopefully) help me out with some questions I have.  

 

I recently (about 15 minutes ago  ) received a COA that contains, what I consider, a high APC number (limits not established).  This seems at least somewhat redundant as we also tested coliform, E. Coli, Listeria, Salmonella, and Staph.  I know that this could threaten shelf life but would this really be considered a food safety issue?  Obviously I will conduct an investigation into why the levels are so high (e.g. cleaning efficacy, supplier review, etc.).

 

Hi Guitardr,

 

Intrinsically No but an astronomic level will obviously pose further "suspicions" regarding the detailed micro.profile, and possibly the sampling procedure/transport/analysing laboratory also).

 

No smoke without ....?