7 replies to this topic

[Kurdelak]

Has there been any discussion in this forum of the Jan 6th Keith Loria article in Food Quality & Safety regarding new strains of quat resistant L. innocua and L. welshimeri that are exhibiting pathogenic behaviors? 

 

Text of article is attached as pdf, and here is the URL:

 

https://www.foodqual...haracteristics/

 

 

If the food industry is now facing two newly pathogenic types of Listeria and neither one minds quat sanitizers, what are our next steps in terms of product safety, environmental monitoring programs, regulatory expectations, audit readiness etc?  It's important for the food safety community to stay ahead of all these considerations when microbes start behaving in ways they have not behaved before. If we're seeing new risks to human health, we'll need to meet it the threat head on and protect our customers.

 

It will be quite helpful to hear thoughts and perspectives of microbiologists, sanitation experts, and other parties that can help outline a practical plant-level response to the concern raised in the article.

 

Erik Kurdelak

[SHQuality]

Hi Erik, 

 

What type of product do you produce and what mitigation factors do you already have in place to avoid Listeria now?

My initial thought would be to avoid causing conditions that make good growth conditions for any Listeria strain, but that may not be practical for your case.

[Scampi]

I think something everyone will have to consider is a chemical rotation, not just on the sanitizer, but cleaning agents as well.  Also, we may need to look at the number of hours sanitation has available to them in order to increase deep cleaning hours

 

Re: SHQuality--any facility that has either A) a wet clean process and/or B) raw agricultural commodities (including non heat treated flour) are at risk,  so impractical for most food manufacturers to avoid creating ideal conditions

 

Hopefully, this will spurn a new design for drainage systems whereby a sanitation process, much like CIP is installed when drains are

[Kurdelak]

We produce a wide range of raw and fully cooked frozen bakery products.  Our sanitation protocol, environmental monitoring, and other preventative controls are designed to prevent any listeria species.  This is validated by a 3rd party accredited lab that checks our EMP as well as actual product samples.  We use a standard  3wk-1wk rotation with sanitizers, being 3 weeks on quat-based sanitizer followed by one week of chlorine-based sanitizer to knock out any possible resistant strains. Then we go right back to quat fort he next 3 weeks.. 

 

If quat-based sanitizers might allow two strains of potentially harmful Listeria to exist, it's a very concerning matter for the food industry.  In working with our chemical supplier, they were unaware of the results of the French study or the corroborating study out of Johannesburg so they did not have an immediate solution available.  I am thinking we may need to re-evaluate our chemical sanitizers that are used in our plant sanitation. But I need to consider other alternatives and possible solutions before undertaking the process of changing our primary sanitizer.

 

ESK

[Charles.C]

Information peer reviewed ?

[Kurdelak]

Microbiology Spectrum is an ASM Journal (American Society for Microbiology) that is publishes peer reviewed content.  Included below is their statement with some additional details. 

 

Also here is a link to the research mentioned in the article.

https://journals.asm...ectrum.01189-22

 

 

Microbiology Spectrum^® (Spectrum) is an online-only, fully open-access journal that publishes research from all domains of basic, applied, and clinical microbial sciences. Rather than making subjective evaluations of potential impact, Microbiology Spectrum publishes research studies that are of high technical quality and are useful to the community. All decisions are made by an international and diverse editorial board that fully represents the microbiology research community. The journal provides authors with fair, rapid, and rigorous peer review. The journal offers rapid publication and wide dissemination of excellent research at no cost to readers.

 

In addition to studies that advance our collective understanding of microbial life, the journal will also consider:

• Replication studies that are useful to the field
• Findings that are of primary interest to smaller sub-fields within microbiology
• Technically robust datasets that contradict published findings
• Negative results of interest to microbiologists
• Descriptive datasets that would serve as a community resource
• Methodological advances and detailed experimental protocols that are of interest to microbiologists
• Re-analyses of large datasets that provide additional insights
• Experimental validation screening hits from previous reports

[Charles.C]

 

Microbiology Spectrum is an ASM Journal (American Society for Microbiology) that is publishes peer reviewed content.  Included below is their statement with some additional details. 

 

Also here is a link to the research mentioned in the article.

https://journals.asm...ectrum.01189-22

 

 

Microbiology Spectrum^® (Spectrum) is an online-only, fully open-access journal that publishes research from all domains of basic, applied, and clinical microbial sciences. Rather than making subjective evaluations of potential impact, Microbiology Spectrum publishes research studies that are of high technical quality and are useful to the community. All decisions are made by an international and diverse editorial board that fully represents the microbiology research community. The journal provides authors with fair, rapid, and rigorous peer review. The journal offers rapid publication and wide dissemination of excellent research at no cost to readers.

 

In addition to studies that advance our collective understanding of microbial life, the journal will also consider:

• Replication studies that are useful to the field
• Findings that are of primary interest to smaller sub-fields within microbiology
• Technically robust datasets that contradict published findings
• Negative results of interest to microbiologists
• Descriptive datasets that would serve as a community resource
• Methodological advances and detailed experimental protocols that are of interest to microbiologists
• Re-analyses of large datasets that provide additional insights
• Experimental validation screening hits from previous reports

 

Hi Erik,

 

Thanks for the links. It's an interesting topic.

I imagine that Genome was a virtually unrecognized word to the general public prior to Covid. S.Africa seems to have (fortuitously from a Covid POV)  been one of the frontrunners in the development/use of sequencing techniques.

 

There is a veritable Encyclopedia of studies investigating L.mono's sensitivity to Sanitisers, etc, particularly/predictably perhaps in USA. Less so for the other hitherto assumed virtually 100% human non-pathogenic Listeria spp although I daresay this may increase on the back of the link in Post 1.

 

It's not my direct area of expertise but a quick Literature skim of recent publications/reports yielded a few which seemed interesting - 

 

(1) One study (Lis1) of L.innocua (as a [ironically?] non-pathogenic surrrogate to L.mono) sensitivity to various sanitisers.

(2) One study (Lis3) seemingly demonstrating the need for careful scrutiny of  reports on decreasing efficiency of various Sanitisers against Listeria spp and also the predictive use of certain so-called quat-resistant genes.

(3) one study pro-rotation of Sanitisers, one saying not effective, and one against it (Lis 1, 2,3 respectively).

 

Hopefully, some food for thought.

 

 Lis 1.pdf   1.76MB   15 downloads

 Lis 2.pdf   1.7MB   10 downloads

 Lis 3.pdf   702.72KB   11 downloads

[Kurdelak]

Thank you Charles.C for the additional insight.  The Cornell study is very encouraging.  Looks like we have little to be concerned about provided sanitizer concentration levels are correct.

 

 

I have included a key excerpt from Cornell's work below.

 

 

 

Project Title
Listeria develops reduced sanitizer sensitivity but not resistance at recommended sanitizer use
levels
Project Period
January 1, 2020 – December 31, 2020 (extended to March 31, 2021)
Principal Investigator
Martin Wiedmann
Cornell University
Department of Food Science
341 Stocking Hall
Ithaca, NY 14853-7201
 

 

Considerable concerns havebeen raised about quat resistance and presence of quat resistance genes in Listeria; our data suggest that previously reported quat or oxidative stress resistance genes, e.g., bcrABC, qacH or SSI-2, do not predict Listeria survival at use-level concentration of sanitizer. In addition, increased resistance at low concentrations of benzalkonium chloride (BC) is due to genetic adaptation but does not confer a survival advantage at use level concentrations. Our findings suggest that quat resistance of Listeria is not a major issue for the produce industry and that concerns about “quat resistant Listeria superbugs” may not be warranted. Our data also indicate that caution should be warranted before implementing sanitizer rotation or changes that reduce use of quats, as quats provided for more consistent Listeria reduction as compared to PAA and NaOCl.