23 replies to this topic

[RitaV]

Hi there, I have a problem with Listeria monocytogenes in a ready-to-eat meal. In 5 samples, 2 turned out positive (and european regulation orders all negative). What are the main corrective actions in these case? I´m thinking of sampling some RTE contact surfaces as well as other batches.
Thanks for your help.

[Charles.C]

Dear RitaV,

Welcome to the forum!

A few initial routine queries -

Product = ?
Basic Process = ?
Cooking Conditions = ?,eg time / temp
Typical L.mono levels in raw materials (if known) = ?
All samples from same batch, eg same day of production ?

Rgds / Charles.C

[Tony-C]

Hi there, I have a problem with Listeria monocytogenes in a ready-to-eat meal. In 5 samples, 2 turned out positive (and european regulation orders all negative). What are the main corrective actions in these case? I´m thinking of sampling some RTE contact surfaces as well as other batches.
Thanks for your help.

Hi Rita,

Please post the info Charles has requested as this will help us understand the situation.

Retest unopened product if you have samples available.

You need to consider:

- If you should stop production and complete a deep clean of all areas, particularly food contact surfaces, take swabs (before and after cleaning) and material samples to investigate the source.
- If you need to withdraw the product.

Regards,

Tony

Edited by Tony-C, 11 October 2010 - 05:43 AM.

[GMO]

Step 1 - if it's still in your control stop it from going out!!!!! If not, then by law you have to contact the "compitent authority" which in the UK would be the environmental health officer. This is before any corrective actions....

[RitaV]

Hi,
in response to Charles C. queries, here are the answers:

Product = Turkey with potatoes
Basic Process = traditional cook-chill (cook-pack-chill)
Cooking Conditions = 95º/ 1 hour (oven)
Typical L.mono levels in raw materials (if known) = not known, but i suspect of post-cook contamination
All samples from same batch, eg same day of production= all samples from tha same batch

It is not possible to withdraw, because use-by date was already expires whwn the lab report arrived.
Thanks,
Rita V.

[biber]

Hi,
in response to Charles C. queries, here are the answers:

Product = Turkey with potatoes
Basic Process = traditional cook-chill (cook-pack-chill)
Cooking Conditions = 95º/ 1 hour (oven)
Typical L.mono levels in raw materials (if known) = not known, but i suspect of post-cook contamination
All samples from same batch, eg same day of production= all samples from tha same batch

It is not possible to withdraw, because use-by date was already expires whwn the lab report arrived.
Thanks,
Rita V.

1. Do not use rest of raw materials for further processing,
2. isolated them and do the sampling on Listeria
3. You should inform somehow customors or autoritis


R.

Biber

[Charles.C]

Dear RitaV

Thks yr data.

Cook-chill is not a familiar area to me but it is well-known to be a relatively high-risk food scenario. I think there are some experts here who know a lot more than me on this topic and who will hopefully hv more experience-based comments however I anticipate they may require some more info. due to the various possible failure points in such a process, eg what is your presentation of tukey? (eg weight, whole, breast, stuffed), type of business (eg complete integrated production facility starting from whole bird), have you validated core temperature reaches min.2min / 70degC or equivalent), shelf life etc.

I am rather surprised that your requirement was nil detection/5x25g for L.mono in the marketed product since the EC regs seemed to be max 100cfu/g in 2004 version unless certain other specified aspects occur. The situation in USA is AFAIK far more strict.

Basically, if you can validate that yr cooking process complies with official requirements, it seems to me that either yr input is extremely highly contaminated with L.mono or contamination has then subsequently occurred (somewhere / any of the possible stages) as you suspect but this statement is made within my previous comment about limits. The reason for the limits was of course due to the difficulty met by manufacturing facilities to comply with zero tolerance regulations / safety risk assessment of setting a positive tolerance.

From yr data, it obviously makes sense to check other batches. Do you normally do any routine microbiological sampling of the final production ? Results ?

I used this document as a guide for above comments, rightly or wrongly -

 Shelf life of RTE foods in relation to Lm FINAL v1.1.1 23 3 10.pdf   574.61KB   119 downloads

Rgds / Charles.C

[poppysnoss]

Hi Rita.

Did the lab carry out enumeration alongside the detection test for L. monocytogenes? If so, and the count is <100 cfu/g at end of life, then for the product that has gone out, it is less of a worry. If not, it may be useful to request enumeration alongside a detection test for future samples.

However, you do need to get to the bottom of how/where it's getting in.

[RitaV]

Charles C., thanks for the publication. In relation to validation, i´ve validated cook-chill process as well as product shelf-life. I do rotine testing on the final product, and it´s the first time a final product doesn´t comply with EC regs (and you´re right, it´s less than 100 UFC/g while the product is in the market). Answering to your other questions, the turkey is chopped in small squares and cooked along with potatoes in a tomato sauce in the oven.

Poppysnoss, the lab did enumeration (I miswrote my first post) and i do need to get to the point of how/where it is getting in.

So, i need some help about corrective actions.
Thanks,
Rita V.

[Charles.C]

Dear RitaV,

The labelled shelf-life seems critical from the document I posted ? <=5days?

Any suggested corrective actions may depend on the actual L.mono findings to which you refer, eg >100/g means, for example, 105 or 10005/g ? (I appreciate such data may be confidential but equally difficult to deduce much on zero info.)

If you have any balance of the suspect lot / access to same lot, i suggest you do further testing. If yr results are negative, and yr routine results are also always negative, I sincerely hope you hv fully validated yr lab procedure including use of known contaminated samples (for sure yr raw materials must give some significant positive data, <10/g?<1000/g? ).

If all your other (validated) internal tests / external tests(?) on finished product are routinely negative, IMO, this would suggest a one-off incident, eg something like cook process failure or abnormal ingredients / packaging (seems unlikely) etc so it may be necessary to look back and do further checks on possible overlapped batches (if any)(I presume you hv done traceability checks already). An environment failure tends to usually hit a range of lots IMEX but this also depends on yr production frequency / internal data checking.

As you can see, a lot of variables. Assuming you are convinced that machinery or environment is problem then some detailed investigative work will obviously be involved / examination of yr flow system. Hopefully there are people here who routinely do L.mono Production environment checking ???

Rgds / Charles.C

PS you may find this ref. of some interest although getting rather old, 10yr+ -

 l.mono in poultry facilities - 4600.pdf   1.05MB   59 downloads

added - PPS - It is also possible that if there was either (a) a short time process failure and/or (b) a contaminated raw material lot of small size mixed within one batch code, you may never locate the original problem due sampling limitations. This is one reason why people sometimes like to resample as part of the verification process.

[Tony-C]

So, i need some help about corrective actions.
Thanks,
Rita V.

Hi Rita

You may find this guidance from CODEX useful:

Guidelines on the Application of General Principles of Food Hygiene to the Control of Listeria monocytogenes in Foods
CAC/GL 61 - 2007

Kind regards,

Tony

[GMO]

Yep it's common for cook chill requirements to be nil Listeria and ime acheivable.

If you have Listeria in the product you describe, there are two probable causes; poor cooking step not achieving the time / temperature combination and / or post cooking recontamination.

I would investigate as follows. I would check how cooking temperatures are monitored and see whether they can be revalidated (using a datalogger for example). It is possible that a cooking programme which worked last week fails due to blocked gas jets (due to poor cleaning) or a mechanical failure so you should not assume that previously validated programmes are safe. Also remember if you're cooking to 70 degrees for 2 mins, a quick temperature probe does not confirm that has been achieved as the time held is critical as well, it may be prudent to aim for a higher temperature / shorter time combo (oh and check all temperature probe calibrations including ones in the oven.)

I would swab, swab, swab! Hands and equipment mainly. Also audit cleaning processes to check they are being performed to standard. Also check high / low risk barriers (quick tip, engineers are the ones who normally break the rules ime!)

From the description of your product I'm surprised it has such a short shelf life. Having worked in ready meals it sounds like a prime candidate for a 10 day shelf life. If you've not been able to acheive that due to spoilage, it would indicate to me that there is a weakness in your process which has been there since the design stage. It might be worth starting from scratch!

[GMO]

Note the temperature of the oven does not reflect core temperature. Are you taking core temperature readings post cook?

[Charles.C]

Dear GMO,

I don't think Rita has revealed the shelf-life yet. My own post probably misled you. Sorry.

@Tony

Thks for the interesting document. Certainly covers a wide range of Codex Hygiene Guidelines.

I noticed two curious ( to me) items –

1. No mention anywhere of the potential benefits of in-plant chlorination. I suppose this reflects a current European trend. I wonder if the Americans hv the same attitude, I suspect not. Quats seem to be the Codex preferred method which I also find slightly underwhelming.
2. The micro.treatment appears to follow their “own” concept and seems (although unmentioned as far as I could see) not aligned to the current EC Food RTE micro.directive. Their method also looks difficult to apply in practice to me (nasty maths for a starter ).

Rgds / Charles.C

[RitaV]

Hi there!
Thanks for the good documents, references and help.
The product shelf-life is 3 days.
Rita V.

[GMO]

Youch! 3 days! Why so short? Is that due to spoilage?

[Snitzel]

I absolutely agree with GMO about the efficiency of the heat treatment or any possible post cooking contamination.
Is the product rehandled after cooking/ chilling, or is it cooked in a cook-in tray?? Still you have to make sure that the core temperature is sufficient to eliminate the threat... IMEX (processed meat) 72C/ 2 mins is sufficient to reduce LMO about 6-7logs

PS: the shelf life is suprisingly small!!!

[Charles.C]

Dear Snitzel,

Hi There !

Is the product rehandled after cooking/ chilling, or is it cooked in a cook-in tray??

From the earlier post -

Basic Process = traditional cook-chill (cook-pack-chill)

I assume this means cook > pack > chill so that the method of packing may be relevant I guess this process has some analogies to hot-fill procedures except for the product orientation / final control parameters.
And presumably much more problematic than pack > cook > chill
(too many variations in this business!)

Rgds / Charles.C

[RitaV]

Hi everyone,

product' shelf-life is a client specification (it´s validated for 1 week).
The cooking procedure was accomplished, so it seems like a post-contamination...
But my original question was about corrective actions...

[Charles.C]

Dear RitaV,

There are typically several stages within an overall corrective action. A precise evaluation depends on knowledge of items like - the complaint, process flow-chart, process data, machinery, workers, environment, QA Records, etc which only you know in detail. The previous posts represent the authors’experiences of some frequently found defect opportunities.

A possible generic corrective action scheme (some elements in parallel) could be something like -

1. Deciding if the complaint is justified.
2. If yes, deciding if it was an isolated incident or covered a range of production lots / deciding if segregation of further lots / raw material is necessary.
3. Deciding on disposition of suspect lots, eg resampling / rejection / reprocess
4. Deciding on the most likely step / location / cause of the contamination
5. Deciding how to eliminate the contamination.
6. Validating the elimination.

If you are convinced the fault is post cooking contamination, IMO at least 3 steps will be necessary – (a) a risk assessment to prioritise sampling / testing at suspect locations, (b) appropriate hygienic procedures to apply overall and particularly where the location considered high risk, © a sampling/testing stage to validate effectiveness.. Some examples of procedures for (b) are in Tony’s post but the implementation via (a) and © obviously demands detailed knowedge of yr system.

I hope you have on-site micro.lab facilities.

Rgds / Charles.C

PS - for sure I hv forgotten some things

[RitaV]

Hi there!
Thanks for all your help! I will procede with the investigation. If i have any news, i´ll let you know!
Bye,
RitaV.

[Charles.C]

Dear RitaV,

Came across this document (slightly old maybe ca 2000) which you might find interesting -

 Listeria - Cleaning-Smoked-Fish.ppt   5.41MB   33 downloads

Rgds / Charles.C

[mesophile]

Hi there, I have a problem with Listeria monocytogenes in a ready-to-eat meal. In 5 samples, 2 turned out positive (and european regulation orders all negative). What are the main corrective actions in these case? I´m thinking of sampling some RTE contact surfaces as well as other batches.
Thanks for your help.

We found listeria in a few areas within our factory, and unfortunately within our product (<10/g L.innocula). After some investigations we found some cracks in the flooring to be the bone of contention. Contaminated water got underneath and the little bugs decided to populate wildely. Following some heavy deep cleaning we purchased two fogging machines - only £250 each, these screw on to 25litre chemical drums. The drums were filled with a 2% sanitiser solution and the room is now fogged on a weekly basis. Since then, no more listeria and general micro swabbing has greatly improved.

I understand fogging isn't for everyone, however it worked wonders on our site.

Good luck, what ever you decide. Listeria can be a nightmare to eradicate so you need to act quickly.

Simon

[Tony-C]

We found listeria in a few areas within our factory, and unfortunately within our product (<10/g L.innocula). After some investigations we found some cracks in the flooring to be the bone of contention. Contaminated water got underneath and the little bugs decided to populate wildely. Following some heavy deep cleaning we purchased two fogging machines - only £250 each, these screw on to 25litre chemical drums. The drums were filled with a 2% sanitiser solution and the room is now fogged on a weekly basis. Since then, no more listeria and general micro swabbing has greatly improved.

I understand fogging isn't for everyone, however it worked wonders on our site.

Good luck, what ever you decide. Listeria can be a nightmare to eradicate so you need to act quickly.

Simon

Thanks for that and a lesson learned - Controlling Listeria in the environment is fundamental in preventing product contamination.

Regards,

Tony