Listeria monocytogenes on Slicing Equipment

Advice & opinions needed please!

Routine enviro swabbing detected the presence of listeria mono.  on a smoked fish slicing machine (2 out of 4 key inspection points) including the slicer blade. Swabs were taken AFTER cleaning the previous day. While samples were sent to the lab, 2 batches of product were sliced. 

When the positive result was received, both batches were put into quarantine (none had been released)

5 samples of each product batch were then sent for testing (approx 300 units in a batch run)

We received test result this morning and ALL 10 samples of product show listeria NOT detected in 25g

Would you release these batches for sale?

The product is vac-packed, 28 day shelf life, cold smoked fish - there are no listericidal process steps

Hi,

how are you?

You did a qualitative or quantitative analysis in the sample detected?

I think that you can do a risk assessment to analise the presence of that contaminant on your product considering that the fish will be cooked our fried (according to their intended use).

Other important think that you can considering is the current laws of your country...

(Sorry for the bad english)

Advice & opinions needed please!

 

Routine enviro swabbing detected the presence of listeria mono.  on a smoked fish slicing machine (2 out of 4 key inspection points) including the slicer blade. Swabs were taken AFTER cleaning the previous day. While samples were sent to the lab, 2 batches of product were sliced. 

When the positive result was received, both batches were put into quarantine (none had been released)

5 samples of each product batch were then sent for testing (approx 300 units in a batch run)

We received test result this morning and ALL 10 samples of product show listeria NOT detected in 25g

 

Would you release these batches for sale?

 

The product is vac-packed, 28 day shelf life, cold smoked fish - there are no listericidal process steps

Hi Dralex,

A few queries.

All samples including machine  analysed by same external lab.?

Sampling done by external lab ?

(Probably should have done quantitative sampling/analysis ?)

I presume this is chilled RTE ?

So what does yr haccp plan say ? - I assume the situation/specification will have been analysed via a typical (quanttative) L.mono decision tree.

Is there a Regulatory L.mono requirement in Ireland or destination for this process/product? (eg similar to USA)

I would not. Period

The presence of l mon POST sanitation is proof that you have listeria in your plant (somewhere) that is contaminating your equipment

Did you continue to process product on that equipment after the positive result?

I have to add that I was employed by a large Canadian company that had a massive L mono recall that lead to 8 deaths

The facility was having sporadic positive tests, and at the time, that did not require action by any producer. HOWEVER, it was later discovered that the listeria was in fact, hiding very deep inside a slicing machine, and following the manufacturers cleaning procedure, could not possibly rid the machine of the contamination.

Hence, for me since then, and forever more, hard NO

https://www.swlawyer...n-Stevenson.pdf

I would not. Period

 

The presence of l mon POST sanitation is proof that you have listeria in your plant (somewhere) that is contaminating your equipment

 

Did you continue to process product on that equipment after the positive result?

 

I have to add that I was employed by a large Canadian company that had a massive L mono recall that lead to 8 deaths

The facility was having sporadic positive tests, and at the time, that did not require action by any producer. HOWEVER, it was later discovered that the listeria was in fact, hiding very deep inside a slicing machine, and following the manufacturers cleaning procedure, could not possibly rid the machine of the contamination.

 

Hence, for me since then, and forever more, hard NO

 

https://www.swlawyer...n-Stevenson.pdf

Hi Scampi,

Thks above Post/comments.

The text in pgs 55-59 of Post 4's attachment summarizes elements considered to have significantly contributed to the 2008 L.mono. disaster. The various cross-references included to the full Investigation report  are also illuminating and can be read in the attachment below.

 Investigator Report into 2008 Listeriosis Outbreak.pdf   3MB   27 downloads

I agree that it is insufficient to assess product safety based solely on isolated sets of microbial data. Contextual knowledge of the data itself and the associated Process/Process Environment/FS Program is equally important.
 

JFI I include an interpretation tree to the EC Regs on L.monocytogenes in chilled RTE products. This should ideally be complemented by trend analyses  from an associated environmental monitoring program (EMPG).

 Decision Tree, L.monocytogenes.pdf   593.56KB   32 downloads

Here is the CFIA/Health Canada guidance on L mono positives enviro samples

https://inspection.c...4/1528201904208

It suggests you hold ALL product until the FCS tests negative

"

If two or more FCS samples from the same production line are found positive for Listeria within a short timeframe, this is considered persistent contamination and an indication that the sanitation procedures or Listeria control measures are inadequate."

Advice & opinions needed please!

 

Routine enviro swabbing detected the presence of listeria mono.  on a smoked fish slicing machine (2 out of 4 key inspection points) including the slicer blade. Swabs were taken AFTER cleaning the previous day. While samples were sent to the lab, 2 batches of product were sliced. 

When the positive result was received, both batches were put into quarantine (none had been released)

5 samples of each product batch were then sent for testing (approx 300 units in a batch run)

We received test result this morning and ALL 10 samples of product show listeria NOT detected in 25g

 

Would you release these batches for sale?

 

The product is vac-packed, 28 day shelf life, cold smoked fish - there are no listericidal process steps

Hi Dralex,

This type of product has a long history of being "troublesome" micro-wise. It's a (particularly) high risk RTE food category.

For example, this was one of IFT's conclusions in 2001 in a Report for FDA -
 

Conclusions

The following conclusions are based on a thorough analysis and evaluation of the current science on control methods of human health hazards that may be associated with the con­sumption of cold-smoked fish.

Listeria monocytogenes

(1) Given the ubiquitous nature of L. monocytogenes, the lack of listericidal steps in the cold-smoking procedure, and the abili­ty of the organism to become established in the processing envi­ronment and recontaminate products, it is not possible to pro­duce cold-smoked fish consistently free of L. monocytogenes.
This is not unique to cold-smoked fish because this microorganism can be isolated from a wide range of ready-to-eat (RTE) foods.

 (2) By  adhering  strictly  to  Good  Manufacturing  Practices (GMPs) and Good Hygienic Practices (GHPs) it is possible to pro­duce cold-smoked fish with low levels of  L. monocytogenes, preferably at < 1 cell/g at the time of production.
etc

 IFT,Processing-Parameters-Needed-to-Control-Pathogens-in-Cold-Smoked-Fish.pdf   941.03KB   5 downloads

More recently (2020) -

 L.mono statistics in cold smoked fish.png   207.71KB   1 downloads

 Growth potential L.mono in some Salmon products.pdf   941.38KB   6 downloads

JFI I also noticed this comment in a comprehensive review -

Skinning/slicing
Slicing and skinning are major steps in making VP smoked fish products. Studies have revealed that the slicing and skinning
areas can also be major points of L. monocytogenes contamination. L. monocytogenes serotypes 1/2a and 1/2b were repeatedly
detected in slicer belts, distribution trays, slicing machines, and slicing covers for 3 y in a smoked-salmon production facility (Di
Ciccio and others 2012). The slicing machines (37%) and working tables (43%) had the highest contamination out of the 95
environmental samples tested. In another study, Dass and others (2010) isolated MLVA types Lm c and Lm b of L. monocytogenes
in the slicer/skinner machines over a 1-y survey. Contamination was, however, much lower with just 1 or 2 samples out of the 36
samples tested. Johansson and others (1999) also found L. monocytogenes contamination in smoked (cold and hot) and smoked-salted whitefish and rainbow trout samples from skinning and slicing areas of a VP fish-processing plant
.  Review - L.mono in VP,smoked fish products,routes contam.poss.interventions.pdf   942.84KB   5 downloads

 

Hold/Test/Release Options

The query stated in the OP can in Principle  be answered via the specific LEMPG (listeria monocytogenes environmental monitoring program) in use. A variety of  programs have been developed for this purpose although one can see similar logics within their constituent procedures/corrective actions. As examples three systems are referred below -  (1) Canadian,(2) GMA,(3) USFDA/NFI

(1)

The Canadian link of post 6 offers considerable product/process advice via its Fig 1/Table 1 (see following "Canadian" pdf). The text details appropriate corrective actions/test procedures (as probably indicated in any associated HACCP plan), etc,. The potential release options given in Fig 1/StepB seem slightly divergent to the info stated in StepC and later updates (eg note the "HRA")..

(the sample sizes of Table 1 would likely be considered inadequate by USFDA)

 Canadian Policy on L.monocytogenes in RTE Foods,2011.pdf   1.34MB   13 downloads
 

PS - Note that Canada has also issued a separate document on RTE smoked fish (2018) -

https://inspection.c...4/1528201904208

Systems (2-3) are zone based and contain detailed corrective actions which have analogies to (1). Files are attached below. The FDA proposed sampling/testing schemes are partially borrowed from the equivalent FSIS manual for meat which I have additionally attached below JFI. The FDA/FSIS sample sizes can in some cases be considerably larger than in Systems (1,2) which may require some compromises.

 GMA,L.mono,Guidance on envi.monitoring-2.pdf   334.07KB   11 downloads

 FDA,2017,Draft-Guidance-for-Industry--Control-of-Listeria-monocytogenes-in-Ready-To-Eat-Foods-(PDF)-2.pdf   795.29KB   11 downloads

 NFI, RTE-Manual-Second-edition-April-2018.pdf   4.5MB   12 downloads

 FSIS,l.mono - Controlling-Lm-RTE-Guideline-1.pdf   1.03MB   10 downloads

(see especially  pg 115 et seq)

(The FSIS manual is extremely detailed and may be of some direct value where its procedures overlap those of FDA).

@Dralex - Based on the above analysis, a critical initial query related to yr OP is as to whether you have implemented a LEMPG ? if not, should do so asap

As you can see the LEMPG (s)  (and an equivalent haccp plan) answers yr OP  query via a  corrective action scheme (eg stripping/cleaning/sanitizing) followed by further (appropriate) sampling and evaluating the L.mono status of suspect FCS and related product. New results are then entered into the LEMPG to determine the possibility  for onward processing and disposition of related product on hold. And so on. 

I work for a facility that had a Listeria recall several years before I got here (based only on product and environmental testing; luckily no illnesses).  We have a hard policy of not releasing any product that could potentially have been affected by a piece of processing equipment that could have been contaminated with Listeria.  The recall cost us about $1.3 million (US) and would have bankrupted us if we had not had a multinational company behind us.  I recommend that you discard the product in question.

I work for a facility that had a Listeria recall several years before I got here (based only on product and environmental testing; luckily no illnesses).  We have a hard policy of not releasing any product that could potentially have been affected by a piece of processing equipment that could have been contaminated with Listeria.  The recall cost us about $1.3 million (US) and would have bankrupted us if we had not had a multinational company behind us.  I recommend that you discard the product in question.

Hi Fishlady,

With all due respect, such disasters as you quote are somewhat "hearsay" without additional context.

Are you suggesting that official procedures and published texts on environmental monitoring programs have all got it wrong ?

Hi, Charles
To better explain, our recall stemmed from a FDA swabathon which occurred the same week that our internal environmental monitoring program found Listeria in a drain. Because FDA also found positive results in drains and other areas, we were forced to recall products that were produced during the time that the positives were found. It was before my time, so there may have been some other factors that played into the recall decision. But ever since then, especially because FDA has a zero tolerance policy for L. Mono in RTE product, our company will not release product if there is a positive result on a good contact surface or even a zone 2 surface in the finished product area.

Hi, Charles
To better explain, our recall stemmed from a FDA swabathon which occurred the same week that our internal environmental monitoring program found Listeria in a drain. Because FDA also found positive results in drains and other areas, we were forced to recall products that were produced during the time that the positives were found. It was before my time, so there may have been some other factors that played into the recall decision. But ever since then, especially because FDA has a zero tolerance policy for L. Mono in RTE product, our company will not release product if there is a positive result on a good contact surface or even a zone 2 surface in the finished product area.

Hi Fishlady,

Thks details. One additional significant element is regarding the results of product samples.

As I understand, the lengthy and laborious  FDA Program (often, I think, derived from FSIS's Meat/Poultry analog)  which is attached in Post 5 offers highly detailed interpretations / corrective actions (including destruction) based on product type, series of results of (EMPG +  Product) samples, etc. I can appreciate that specific circumstances/experiences/potential consequences might prompt a facility to take "preemptive" actions.

Hi, Charles,

True, the product can be cleared by testing, but it requires so many tests that it is likely not worth the bother (at least that is how we have looked at it).

Hi, Charles,

 

True, the product can be cleared by testing, but it requires so many tests that it is likely not worth the bother (at least that is how we have looked at it).

Hi Fish Lady,

Yes,as per Salmonella,  FDA do like to be statistically rigorous. I guess the ICMSF use similar logic eg, IIRC, already need 15 negative samples just to achieve a 95% confidence level that contamination is below 20%. .And 60 samples for a level of 5%. The latter is obviously impractical for many (most?)  labs.

Nonetheless rapid screening for the genus  now seems quite accessible although cost I don't know. I guess it ultimately  comes down to factors like value of goods, cost of time, availability of internal micro.lab (or not),etc,

PS - CFIA use smaller sample sizes than FDA but also not negligible.