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Corrective Actions - Presumptive Positive Listeria Spp. in Processing


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nlamers

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Posted 20 May 2019 - 11:38 PM

Hey All,

 

I've recently begun an environmental monitoring program for our facility, and our initial round of sampling has returned several presumptive positives for Listeria spp. (thankfully no monocytogenes) in our wet processing environment. All presumptive positives came from floors and drain perimeters; all equipment surfaces swabbed so far have come back negative. The wet processing room where these presumptive positives were obtained, which has one entrance/exit, is separated from the warehouse portion of the facility by the employee break room. The break room floors also returned several presumptive positive hits for Listeria spp, and it's also come to my attention that the three basin sink in the break room shares some plumbing with the trench drains in the wet processing room. Based on the facility layout and our results observed so far, I suspect that Listeria is being tracked into the break room from outdoors and proliferating into the processing room either by foot traffic or by the shared drainage between the two rooms.

 

Obviously there are some fundamental issues with how this portion of the facility is designed, but as a new employee at a fairly small company I don't have a tremendous amount of leverage to suggest completely overhauling its layout. I'm meeting with management tomorrow to discuss potential corrective actions, so I'm hoping to get some additional perspective on possible solutions that might not break the bank.

 

Your insights and experience are greatly appreciated!



Ryan M.

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Posted 20 May 2019 - 11:49 PM

Not surprising or shocking results really.  Seems like your greatest ROI in correcting the issue is employee training and practices to better control the foot traffic, and mitigation steps between the areas.  Regular sanitation of floor and drains is up there on ROI as well.

 

Do you have any footwear sanitizing / cleaning steps between the areas?

 

Where there any positives found in the warehouse floor and drains?  Did you check those?

 

There's a few cleaning chemical and sanitizer solutions that won't break the bank.  If you don't have door foamers at the processing to break room then use dry quat granules.  Some people use the floor mat basins you fill, but those need regular maintenance.  The quat granules you just spread on the floor.  Sure, it doesn't look pretty and gets tracked around, but that's also the point.

 

Also, look into ECOLAB's BOOST 3200/3201.  This is a fantastic product to eliminate any biofilms on surfaces.  In our facility we initially had listeria positives in drains and floors in several areas.  Our drains and floors are in pretty poor condition and regular cleaning / sanitizing didn't work very well (we kept getting repeat positives even after cleaning).  We brought in the BOOST and listeria went away.  We haven't had a positive since we've used it consistently.  I'd use this stuff on everything if it wasn't so expensive, it is truly magic.

 

I don't think the shared drainged between break room and processing is an issue unless that's backing up into your breakroom, OR you have an open drain in the break room.  Is the triple sink piped in directly?



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Charles.C

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Posted 21 May 2019 - 04:02 AM

Not sure what you mean by "Presumptive positives for Listeria". It should be "Confirmed"

 

If this is a RTE product/process with a thermal lethality stage, pre-thermal drain areas would be of secondary importance compared to post-thermal.


Kind Regards,

 

Charles.C


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HokeyPokey

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Posted 21 May 2019 - 01:48 PM

Remember you need to get to the root cause of each Presumptive positives.  Seek and destroy.  Each presumptive positives need to be treed as positive.  You need to do corrective action on each and everyone.   



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CMHeywood

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Posted 21 May 2019 - 03:07 PM

I work in a manufacturing plant that makes food contact packaging.

 

When we first started our SQF food safety program, when detected Listeria (not mono) near entrances, around drains, and in areas where people had walked.  We do not have a shoe capture program.

 

We have a lot of birds in the area.  We believe that people were stepping in bird droppings in the parking lots, etc. and picking up the Listeria on their shoes.

 

We put quat foot baths by the exterior entrances and by other areas such as bathrooms and locker rooms.  This controlled the presence of Listeria that was coming in through the exterior entrances.

 

Then we started seeing Listeria in other areas like the machine shop.  The Listeria was being picked up by fork trucks that were going into a wash area located in the basement.  The wash area was basically an corner in the basement that had a hose and a drain.  The area had never been sanitized.  The fork trucks picked up the Listeria on the tires and then spread it to other areas where they went.

 

We eventually changed the wash area and included it in our monitoring.  We also started checking fork truck tires and cleaning by wiping with a quat solution.



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zanorias

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Posted 21 May 2019 - 03:15 PM

What product and risk are you working with nlamers? If, for example, your facility is low risk raw meat products, I would be surprised if listeria wasn't found in places, especially floors and drains. It's the number and type I'd be concerned it. My facility has a low risk raw meat zone and we see some typical non-pathogenic species here and there, and authorities/BRC are fine with this. Excessive numbers or particularly mono would be another story. That said, I'd still recommend taking reasonable steps to improve hygiene as much as possible. I use Hygiena InSite listeria swabs (outside of EMP) to investigate listeria, the swabs are cheap and you can incubate on-site (in seperate building from production ofc) for quick results so it's ideal for efficiently tracking possible entry points for listeria.



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nlamers

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Posted 21 May 2019 - 05:11 PM

Hey all, thanks for your thorough and insightful replies! In response to some of your questions:

 

The product in question is RTD cold brew coffee (no additives, just water and coffee). No thermal processing, pH around 5.0, and packaged primarily in nitrogen-flushed kegs. A competing brand commissioned a challenge study a while back that pointed towards the product not supporting the growth or survival of vegetative pathogens, but on paper the processing method and intrinsic characteristics of the finished product make it a pretty hospitable environment for Listeria. 

 

With the exception of the room this product is brewed in, the remainder of the facility is a dry operation (roasting and packaging coffee), so no other floor drains to speak of in production or storage areas. It has, however, come to my attention that there is an open drain in the break room (beneath the garbage can of all places!), so separating the plumbing between the two rooms is a must. 

 

We don't yet have a captive footwear program. All cold brew-related operations are carried out by a single employee who currently has to walk from the brewing room through the break room in order to move finished product into refrigerated storage, which they do several times a day. So long as we're maintaining this current layout, I'm thinking dry quat granules at the brewing room/break room entrances along with disposable boot covers will be the most practical solution to minimize contamination of the brewing room by foot traffic.

 

I will definitely be pushing my swabbing further out into the facility, as well as looking into the in-house monitoring options and the BOOST cleaners recommended by zanorias and Ryan M, respectively. 

 

Thank you all again! 



Charles.C

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Posted 22 May 2019 - 05:27 AM

Remember you need to get to the root cause of each Presumptive positives.  Seek and destroy.  Each presumptive positives need to be treed as positive.  You need to do corrective action on each and everyone.   

 

Sorry but I totally disagree.

 

IMO Each presumptive needs to be confirmed. Negative results imply no "immediate" concern.

 

I recommend the OP to urgently seek a professional microbiologist.

 

PS - One can find opposite opinions to the above in the Literature. Offhand i suggest these are "alarmist".

 

For example  -

Myth 6

There is no need to further analyze samples after a positive test result

All commercially available rapid methods are screening tests and require cultural confirmation after a “presumptive positive” test result. Confirmation requires streaking the enriched test portion to selective agars in order to isolate a typical colony based on morphological and biochemical characteristics. This is especially true when testing end-products or foodstuffs. For environmental samples, cultural confirmation is seldom performed as added sanitation practices are often put in place [!!!]. There are several options for selective agar plates, with the most common ones found in the USDA Microbiology Laboratory Guidebook (MLG), FDA Bacteriological Analytical Manual (BAM), or ISO reference guides (see Table 1).

 

https://www.romerlab...thogen-testing/

 

Positive pathogen detections

It is a legal requirement for licensed businesses to notify the Food Authority about positive pathogen detections. Notification should be given by phone within 24 hours of receiving the laboratory result, and in writing within seven days. Once the laboratory advises that a presumptive positive result has been recorded, there is usually a 24-hour delay before the result is conclusive.  
Businesses should use this time to plan a product recall or withdrawal, in the event that a positive result is confirmed.

Attached File  NSW - presumptive_Listeria_positive.pdf   288.99KB   121 downloads

 

from BAM -

Alternate Screening Methodologies

The following alternative screening methodologies may be used to screen samples for the presence of Listeria. Follow the manufacturers' package insert making certain they have not deviated from the approved versions of the AOAC INTERNATIONAL Official Methods Manual protocols (Section F1). The kits are only approved for the specified food matrices, claimed in the OMA method, which vary from kit to kit. For other food matrices that are not validated a matrix extension validation is necessary. Negative results obtained with the products are considered definitive and no further testing is required. Presumptive positive results with these rapid screening methods must be confirmed by streaking to the selective agars and confirming isolates to the species level by the procedures described in sections G-I.

 

 

PPS - one caveat to my opinion could be perhaps where published data exists that, say, 95% of the presumptive positives typically found for environmental samples do confirm positive (might also relate to nature of business). This would depend on the degree of specificity of the particular screening test. I have as yet not seen any such data for Listeria kits but perhaps it exists (?).

 

P3S - I have previous experience of a rapid Salmonella test kit for which, over a period of approx 2 years, every positive presumptive it found  failed to confirm. Kit was not expensive but was simply insufficiently selective for the type of product I was handling.

 

Out of curiosity, what do FSIS recommend in their encyclopedic testing programs for Listeria Control ? Anyone ?

 

added - I guess this may answer my query -

Presumptive positive results must be confirmed according  to  the  confirmation  procedure outlined  in  the  USDA-FSIS  MLG  8.09  (Isolation and  Identification  of  Listeria  monocytogenes from  red  meat,  poultry,  egg  products,  and environmental  samples)  or  the  FDA’s Bacteriological  Analytical  Manual  (or  BAM Chapter  10:    Detection  and  Enumeration  of Listeria monocytogenes in Foods).

 

Attached File  RapidChek-Listeria-NextDay-Food-Package-Insert_Original_76564.pdf   346.17KB   69 downloads


Edited by Charles.C, 22 May 2019 - 06:48 AM.
expanded

Kind Regards,

 

Charles.C


MsMars

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Posted 22 May 2019 - 02:11 PM

If I understand correctly, we are talking about environmental non-contact surface samples here. If these positives were on food contact surfaces or in your product, you would indeed want to take immediate corrective action for each positive result, possibly including confirmation depending on what tested positive and if it involves product that has been shipped. But for non-food contact surfaces, I don't see the need for formal corrective actions for each and every positive swab. Seek and destroy - to me, this doesn't necessarily involve immediate formal corrective action, but initially an investigation that includes radial swabbing and extensive cleaning. Sometimes positives are just a one-off, and cleaning that area will eliminate the harborage.  If you do find an extensive problem after performing focused swabbing and investigation, then that is the time to do a corrective action.  I don't think confirmation is necessary in most cases - you shouldn't wait for confirmation to take action, and that means you will indeed be treating every presumptive as a positive, especially if it involves a food contact surface or product testing.  

 

Sounds like OP is on the right track, knows root cause, and once area is cleaned and preventive measures put in place such as quat granules (my recommendation) and captive footwear, then should re-swab to confirm preventive measures are effective. I think one corrective action should suffice, as there looks to be one root cause. 

 

FSIS's guidelines only pertain to meat and poultry but some good information generally, they can be found here: https://www.fsis.usd...pdf?MOD=AJPERES


Edited by MsMars, 22 May 2019 - 02:12 PM.


Ryan M.

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Posted 23 May 2019 - 01:58 AM

In my experience with listeria environmental swabs I've only seen one swab in my entire career be presumptive, but failed confirmation test.  I've always treated presumptives as positive results and take action regardless.  In my last two companies we didn't bother confirming because it added cost and we were taking action on the presumptives anyhow.  Always used third-party lab testing.

 

I understand if it is Zone 1 (FCS) or product that's a different story, you'll want to always confirm.

 

Salmonella or e.coli may be different, as well as, the test methodology in terms of presumptive versus confirmation.

 

I would recommend the OP makes a map of all the presumptive / confirmed positive results and date each hit.  This gives you a good visual in terms of how traffic flow and your actions from the results impact the overall results over time.



The Food Scientist

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Posted 04 November 2020 - 08:28 PM

Going back to this post.... 

 

Started in Juice Manufacturer 3 months ago..

 

We do these non-food contact swabs for Listeria as well AND treat a Presumptive Positive as it is a positive test.

 

We swabbed a certain area (no humans walk there or touch it or anything) , it came out as presumptive positive, so then we corrected it by spraying with Quat. A month or so later that area was swabbed again and it was presumptive positive. Also corrected by spraying with Quat and reswabbed to be negative. 

 

Management (and me a little) are getting frustrated about it. always having a positive test, spraying, reswabbing and all over again. I feel like a preventive measure should be taken here. What did everyone do?


Everything in food is science. The only subjective part is when you eat it. - Alton Brown.


kfromNE

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Posted 04 November 2020 - 08:57 PM

Going back to this post.... 

 

Started in Juice Manufacturer 3 months ago..

 

We do these non-food contact swabs for Listeria as well AND treat a Presumptive Positive as it is a positive test.

 

We swabbed a certain area (no humans walk there or touch it or anything) , it came out as presumptive positive, so then we corrected it by spraying with Quat. A month or so later that area was swabbed again and it was presumptive positive. Also corrected by spraying with Quat and reswabbed to be negative. 

 

Management (and me a little) are getting frustrated about it. always having a positive test, spraying, reswabbing and all over again. I feel like a preventive measure should be taken here. What did everyone do?

Are you doing any additional swabs. So farther out from the spot. This is what is suggested in the Listeria guidelines. That should be your next step. It may be caused by water over spray. The ceiling?



Ryan M.

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Posted 04 November 2020 - 09:28 PM

I echo the statement on more swabs to pinpoint where it is coming from.  Is there any sanitation that happens in the area if you do not get a presumptive positive?  Humans are not the only source of listeria.

 

 

Going back to this post.... 

 

Started in Juice Manufacturer 3 months ago..

 

We do these non-food contact swabs for Listeria as well AND treat a Presumptive Positive as it is a positive test.

 

We swabbed a certain area (no humans walk there or touch it or anything) , it came out as presumptive positive, so then we corrected it by spraying with Quat. A month or so later that area was swabbed again and it was presumptive positive. Also corrected by spraying with Quat and reswabbed to be negative. 

 

Management (and me a little) are getting frustrated about it. always having a positive test, spraying, reswabbing and all over again. I feel like a preventive measure should be taken here. What did everyone do?



The Food Scientist

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Posted 04 November 2020 - 09:43 PM

I echo the statement on more swabs to pinpoint where it is coming from.  Is there any sanitation that happens in the area if you do not get a presumptive positive?  Humans are not the only source of listeria.

 

Now it is suspected that some traffic is bringing the Listeria to that spot. Possibly water from when cleaning


Everything in food is science. The only subjective part is when you eat it. - Alton Brown.


The Food Scientist

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Posted 04 November 2020 - 09:44 PM

Are you doing any additional swabs. So farther out from the spot. This is what is suggested in the Listeria guidelines. That should be your next step. It may be caused by water over spray. The ceiling?

 

The area is underneath a machine (debagger). So it is hard for anything to reach there. Possibly some water from cleaning.


Everything in food is science. The only subjective part is when you eat it. - Alton Brown.


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Posted 04 November 2020 - 09:50 PM

Sounds like a great area where a biofilm can develop.  If it is hard to reach under there I question frequency and effectiveness of cleaning.

 

 

The area is underneath a machine (debagger). So it is hard for anything to reach there. Possibly some water from cleaning.


Edited by Ryan M., 04 November 2020 - 09:51 PM.


nlamers

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Posted 04 November 2020 - 10:05 PM

You'll definitely want to collect additional swabs in the radius of the area that returned the presumptive positive; I'd sample spots on the floor a few feet out in every direction from the problem spot, as well as the legs/bases of any equipment over or adjacent to the affected area. I agree with Ryan M. that this sounds like a great spot for biofilm buildup. I'm not sure what product availability is like at the moment, but we haven't had a single presumptive positive in our brew room since we started using this product on a weekly basis: https://www.sterilex...vator-solution/

 



The Food Scientist

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Posted 05 November 2020 - 01:24 PM

Sounds like a great area where a biofilm can develop.  If it is hard to reach under there I question frequency and effectiveness of cleaning.

 

Actually not really for biofilm development. The area is almost always DRY. 


Everything in food is science. The only subjective part is when you eat it. - Alton Brown.


The Food Scientist

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Posted 05 November 2020 - 01:36 PM

In addition to being almost always dry its an open space that is easy to clean under it. Its not a tight, enclosed space.


Everything in food is science. The only subjective part is when you eat it. - Alton Brown.


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Posted 05 November 2020 - 05:35 PM

You'll definitely want to collect additional swabs in the radius of the area that returned the presumptive positive; I'd sample spots on the floor a few feet out in every direction from the problem spot, as well as the legs/bases of any equipment over or adjacent to the affected area. I agree with Ryan M. that this sounds like a great spot for biofilm buildup. I'm not sure what product availability is like at the moment, but we haven't had a single presumptive positive in our brew room since we started using this product on a weekly basis: https://www.sterilex...vator-solution/

 

Hi nlamers,

 

I was unable to determine what the active ingredient is from link info. (albeit EPA approved). ?


Kind Regards,

 

Charles.C


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Posted 05 November 2020 - 06:28 PM

Hi nlamers,

 

I was unable to determine what the active ingredient is from link info. (albeit EPA approved). ?

Hi Charles! 

 

Fair point, as I just took a closer look at the product information page and didn't find it particularly helpful either. Sterilex is a two-part quaternary ammonium compound - please see the attached SDS for the disinfectant cleaner and activator solutions. 

Attached Files






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