Aerobic germcount

Hi everybody,

I've received the microbiological analyse results of two products, deer burger and turkey beef stew.

The results that got my attention are:

Deer burger, aerobic germ count 30°C: 1.400.000 CFU/g (standard is 1.000.000)

Turkey beef stew, Aerobic germ count 30°C (shelf life test): 6.000.000 CFU/ g (standard for shelf life test is 5.000.000)

I've contacted the lab who did the analyses and asked about the turkey beef stew and he replied that it was pretty normal for shelf life tests that the aerobic germcount is too high.

He emphasized that the pathogenic bacteria we're all within the norm.

Can someone confirm his reaction?

I've a gutfeeling that this isn't exactly right, since the norm is already raised from 1.000.000 to 5.000.000 for shelf life tests.

Second opinions?

Thanks!

Kind regards,

Michiel

Hi everybody,

 

I've received the microbiological analyse results of two products, deer burger and turkey beef stew.

The results that got my attention are:

Deer burger, aerobic germ count 30°C: 1.400.000 CFU/g (standard is 1.000.000)

Turkey beef stew, Aerobic germ count 30°C (shelf life test): 6.000.000 CFU/ g (standard for shelf life test is 5.000.000)

 

I've contacted the lab who did the analyses and asked about the turkey beef stew and he replied that it was pretty normal for shelf life tests that the aerobic germcount is too high.

He emphasized that the pathogenic bacteria we're all within the norm.

 

Can someone confirm his reaction?

I've a gutfeeling that this isn't exactly right, since the norm is already raised from 1.000.000 to 5.000.000 for shelf life tests.

 

Second opinions?

 

Thanks!

 

Kind regards,

Michiel

Hi Michel,

Not sure what the red-marked comment means.

I assume these products are RTE.

I assume the samples were correctly transported and handled.

I assume the incubation was for 2 days.

I assume the results were directly made on the received samples.

One sample is inadequate to comment reliably.

Regardless, IMO the results are very high. And IMO so are  yr specifications/tolerances.

Some suspicions for cause of high numbers might be such as undercooked, slowly cooled, contaminated after cooking, stored incorrectly.

What were results of other data ?

addendum

If the items are not RTE the comments will be different.

Hi Michel,

 

Not sure what the red-marked comment means.

First off, thanks for the response.

Concerning the red-marked comment; The lab contacted me saying that it was pretty normal for the aerobic germ count to be so high since it was a shelf life test. However, since the norm for shelf life is already set higher then the norm for fresh meat,

 

 

I assume these products are RTE

No, these are raw meat products.

 

Regardless, IMO the results are very high. And IMO so are  yr specifications/tolerances.

Specifications and tolerances are based on UGent professor Dr. Ir. Mieke Uyttendaele. I'm working on to get the research paper. These tolerances were set up by the previous QA.

 

What were results of other data ?

Other data were:

Turkey beef stew: 79.000 CFU/g

Rabbit back: 730.000

Marinated turkey strips: 31.000

Marinated turkey strips: 93.000

Our company has a cold and minced preparation of poultry, turky and wild game.

Hi, Michiel.

I also think the limit is too high,  AFAIK, most regulation have n= 5, c = 3, m = 500.000, M = 5.000.000 as the limits. As for the shelf-life, provided that food is handled properly (frozen temp and thawing condition followed), the microbiological result should be expected not to exceed norms nor atleast to have exponential growth.

Since you also have data for other analysis, suggest to review processing and storage condition for those samples that exceeded that norms.

Hi Michel,

thks for info.

The typical requirement IMEX is that the micro.data at end shelf life meet the specification.

The lab comment may mean they were doing incubation at an elevated temperature (ie > 30degC) specifically for shelf-life testing. If so the data will not be directly correlatable to the specification.

Perhaps you can confirm whether above is correct or not ?

 

 

The lab comment may mean they were doing incubation at an elevated temperature specifically for shelf-life testing. If so the data will not be directly correlatable to the specification.Yes

Yes correct. The turkey beef stew shelf life test was executed at 30°C. (mentioned in the first post)

However, then we still have the deer burger who has counted 1.400.000 aerobic germs.

I'm planning to contact the lab again and explain my concerns.

Yes correct. The turkey beef stew shelf life test was executed at 30°C. (mentioned in the first post)

However, then we still have the deer burger who has counted 1.400.000 aerobic germs.

 

I'm planning to contact the lab again and explain my concerns.

Hi Michiel,

Sorry, my bad.  i meant to say that perhaps lab have been storing product at an elevated temperature(s) which is one standard methodology for doing accelerated shelf life testing. (30 degC is one of the usual settings for doing APC counts). This would result in an increase of APC level above the usual condition. (I assume these items were (normally) intended to be stored either chilled or frozen ?).

If so it is unclear whether reported data are at beginning or end of test run.

Hi Michiel,

 

Sorry, my bad.  i meant to say that perhaps lab have been storing product at an elevated temperature(s) which is one standard methodology for doing accelerated shelf life testing. (30 degC is one of the usual settings for doing APC counts). This would result in an increase of APC level above the usual condition. (I assume these items were (normally) intended to be stored either chilled or frozen ?).

 

If so it is unclear whether reported data are at beginning or end of test run.

These items are normally chilled (2°C).

The item is produced at 11/07 and tested on 16/07. 

I should've be more clearer in my intitial post. :)

These items are normally chilled (2°C).

 

The item is produced at 11/07 and tested on 16/07. 

 

I should've be more clearer in my intitial post. :)

Hi Michiel,

So when did lab receive samples ?

did the lab report that shelf-life was satisfactory ?

i forgot to ask as to the duration of labelled shelf life ?

did you actually request a shelf-life evaluation ?

Offhand I can only see  2 explanations -

(1) the lab received the samples and directly analysed them. IMO this does not enable any comment regarding shelf life compliance except a negative one if the result was already outside specification. As per yr data in OP, both samples did give a result > your specification so out of compliance (ignoring the caveat of only 1 sample). maybe that was the intended meaning of the lab comment to you as quoted  in OP ?

Regarding Post 4 -

The lab contacted me saying that it was pretty normal for the aerobic germ count to be so high since it was a shelf life test. However, since the norm for shelf life is already set higher then the norm for fresh meat,

The red ^ makes no sense to me if sample was directly analysed.

(2) the lab did a acc.shelf-life test at elevated temperature but to finish <= 5days sounds rather improbable (but not impossible). Unable to speculate further.

I think you will have to revert to lab with some more queries as to what they actually did, especially if they have claimed to have done a shelf-life test. It may be that the lab were more interested in the other indicator/pathogen data such as E.coli,S.aureus,Salmonella, E.coli O157

PS - I'm rather intrigued by all the limits you have quoted. Difficult for me to even guess how such numbers could be obtained, especially as APC  measurements are notoriously inaccurate. (Hence the 10x factor in the nmMc system exampled in Post5).

Hi Michiel,

 

So when did lab receive samples ?

They picked the samples up the day of production. (11/07) And tested them on 16/07.

 

did the lab report that shelf-life was satisfactory ?

I asked if they advised a corrective measure, but they did not.

 

 

i forgot to ask as to the duration of labelled shelf life 

For the Turkey beef stew it is 4 days.

 

   did you actually request a shelf-life evaluation ?

We have an agreement on a specific frequency where they do tests on the shelf-life, so yes.

 

 

PS - I'm rather intrigued by all the limits you have quoted. Difficult for me to even guess how such numbers could be obtained, especially as APC  measurements are notoriously inaccurate. (Hence the 10x factor in the nmMc system exampled in Post5).

I'm going to look further in depth regarding this comment. I'll keep you posted.

I know he used Afnor 3M 01/1-09/89, this was stated next to the analyse result.

( https://nf-validatio...01-09-89_en.pdf )

Thanks Charles.

Hi Michiel,

Ok, I think that makes things a bit clearer.

So for TB stew, the analysis was at end of shelf-life and storage temperature was presumably ca 2degC.

Is shelf life for deer burger the same ?

I deduce the APC specification for the 2 products @ 30degC/Xdays is that -

TBS < 5M cfu/gram

DB < 1M cfu/gram

(strictly the limits should be part of a sampling scheme)

So the APC counts at end shelf life are both > spec.

The lab don't seem to attach much importance to APC  in comparison to the other results. This is a question of Regulatory / Customer Requirements (if any) .

I don't quite understand the meaning of the last comment in OP that APC is raised from 1M to 5M for shelf-life ??.

addendum

Did the lab check for generic E.coli / any other indicators ?

Just as a general comment, it is worth reiterating that the APC levels reported are high / very high respectively.

Whether these  APC's are typical of the meat products you refer i do not know but micro. textbooks suggest that, in general,  "quality"  may often  significantly deteriorate at a level of 6000 cfu/g.

To add to Charles points, it's interesting that the lab didn't also test the same sample on the day of production. Were the counts that high initially and stayed steady, or were they low at production and then grew? A proper shelf life study should give you a curve, but at minimum those two data points would show how things progressed as the product aged.

Is shelf life for deer burger the same ?

Shelf life deer burger is 6 days.

 

 

I don't quite understand the meaning of the last comment in OP that APC is raised from 1M to 5M for shelf-life ??.

The criteria on production date is 1.000.000 cfu/g and at the end of shelf-life 5.000.000 cfu/g.

To add to Charles points, it's interesting that the lab didn't also test the same sample on the day of production. Were the counts that high initially and stayed steady, or were they low at production and then grew? A proper shelf life study should give you a curve, but at minimum those two data points would show how things progressed as the product aged.

Well I feel kinda stupid now but I guess I'm learning.

I've contacted the lab regarding this and it seems they actually did.

Me not seeing this was a combination of trying to be too fast and not working focused enough.

I have analyse results for the Turkey Beef stew on 12/07, a day after production. However there isn't one for the deer burger.

Results Turkey Beef stew 12/07:

Aerobic germ count: 79.000 (<1.000.000 = good)

Results Turkey Beef stew 16/07:

Aerobic germ count 30°C: 6.000.000 (>5.000.000 = not good)

Hi Michiel,

It's always a learning curve.  I deduce you are effectively the QA function .

I agree with 3F's comments.

I deduce E.coli generic was not checked. Unusual. How about S.aureus ? (are there specs for these species ?)

My experience is mainly with frozen (non-meat) goods so, offhand, i found the change in data in Post 16 extremely high (sort of unbelievable) but as illustrated in the attachment below the range is maybe not atypical. I wonder why the "as received"  case was only carried out for the TBS ?. Maybe the lab. considered only (safety-related) pathogen data was really significant to shelf life.

 meat chilled storage APC profile.png   132.51KB   0 downloads

Unfortunately the data also illustrates the necessity to supply more than one sample.

There might also be some benefit in comparing results from another lab.
 

 

The criteria on production date is 1.000.000 cfu/g and at the end of shelf-life 5.000.000 cfu/g.

OK, thks, now I understand.

Seems my interpretation in Post 12 was incorrect. Specification for TBS to the customer is presumably  APC < 5M cfu/gram

This figure seems a rather high level for a routine spec. but maybe not so unusual for raw beef/poultry meat.

PS - i  should have initially also asked if products are vacuum or MAP packed since can alter the microbial storage characteristics.

Hi Michael,

Take some time to do some searches on the forum for "meat shelf life", this topic has come up a bunch of times. What it comes down to is at what point a certain level of microbial growth causes flavor/smell/taste/texture issues when cooked. You can only determine that yourself or by industry standards (which are many and inconsistent).

I also covered some basic principals that Charles alluded to in his replies about the need for multiple samples in this article. The error bars on quantitative micro are huge and hard to interpret without a ton of data. The info in the article may help your future conversations with the labs.

 

PS - i  should have initially also asked if products are vacuum or MAP packed since can alter the microbial storage characteristics.

MAP. O2 value of 70% and 30% N2.

 

Take some time to do some searches on the forum for "meat shelf life", this topic has come up a bunch of times. What it comes down to is at what point a certain level of microbial growth causes flavor/smell/taste/texture issues when cooked. You can only determine that yourself or by industry standards (which are many and inconsistent).

 

I also covered some basic principals that Charles alluded to in his replies about the need for multiple samples in this article. The error bars on quantitative micro are huge and hard to interpret without a ton of data. The info in the article may help your future conversations with the labs.

Thanks.

I've read your article. Really interesting, especially your example with the ice cream recall. However, your article asks myself the question, how do you find out what your initial risk of contamination is? Do you always use 5% as initial risk (2sigma)? Anyhow, this is another subject.

When I find some spare time I will inform myself more on meat shelf life, especially from topics on this forum.

Been a few busy days and would like to find out more about this subject, however I need to priortize other things now.

Thanks everybody to help me out!