Listeria - Proper Eradication

Hello Everyone,

I am revamping our environmental program and corrective actions. As far as Listeria is concerned, what is the best means/sanitizer to eradicate this pathogen. Currently our facility uses bleach at a max of 200ppm as a sanitizer. Is this sufficient as a corrective action for eradication and preventative measures? Are there any sanitizers that would prove to be more effective?

Thanks in advance!

EmmE

Dear EmmE,

As you have realised,listeria can be a menace and hard to get rid off once they get in the production areas.I would occasionaly use the fogging technique with QAC based sanitisers e.g those containing Alky dimethyl benzyl ammonium and ethy alcohol on the production areas and all equipments.Also ensure that all equipments,walls ,etc are sanitised after cleaning.

Regards,
Kamwenji Njuma

There are three main species of listeria but only monocytogenes is the pathogenic type - if one of the non harmful ones is detected then its recommended that you still carry out corrective actions as if it was a postive for monocytogenes. Listeria can produce a biofilm which gives it a resistance to sanitizer - so if you rotate between two types of sanitizer with different active ingredients then this will give you a good means to deter and reduce it. Within your sampling program make sure you check floor machines, drain covers and other areas which come into contact with dirty and/or sitting water.

Although foggers are very useful I personally do not like them as the fog can errode parts of machine such as the aluminium coils in the fridge blowers.

The key to eliminating Listeria is proper cleaning. Listeria species produce a biofilm that deactivates sanitisers allowing them to re-colonise the area.
In the past, I organised series of deep cleans with the maintenance department where equipment were opened up and cleaned with a chlorine based detergent (this had the added benefit of killing mould spores as well). Prior to the sanitising process, I took ATP swabs to verify the cleaning.

Using a chlorine based detergent reduces the risk of chemical contamination posed by the use of bleach.

Hope this helps

Emme,
Sounds like our facility does a similar sanitizing procedure:12.5% Bleach at <200ppm(if >200 ppm we have to clear rinse after sanitizing) for 20 minutes-though not sure of all your details. Our sanitizing water runs onto the floor enroute to the drains, and our Listeria tests of the floors and drains are always negative. It's one of the least expensive and effective sanitizers we've researched, and kills the biofilm. It's good for sanitizing and preventive maintenance --not sure if it's realistic to write into an action plan for total irradication-rather control of! I'll leave that to the scientists-just caution not to set yourself up for failure. Good Luck

Hi EmmE,
May I add that Listeria can not be eradicated completely.
The best that one can hope for is to monitor and control.
Listeria species swab samples should be routinely taken on Food Contact Surfaces and in the processing Environment if you are producing RTE, (Ready-to-Eat) products, this will verifiy the effectiveness of your Sanitation program and any sanitizer you use.
If a Positive sample is identified by a certified lab, Corrective action must be taken immediately to target the problem area and all effected product should be held and recooked or discarded.
Good Luck, Ray

Hello Everyone,

I am revamping our environmental program and corrective actions. As far as Listeria is concerned, what is the best means/sanitizer to eradicate this pathogen. Currently our facility uses bleach at a max of 200ppm as a sanitizer. Is this sufficient as a corrective action for eradication and preventative measures? Are there any sanitizers that would prove to be more effective?

Thanks in advance!

EmmE

Hi EmmE
First of all you have to verify the effectiveness of your current sanitizer by the swabbing results from the food contact surfaces as well as environmental swabs "put in mind that the concentration of sanitizer can be doubled on the non-food contact surfaces; as drains ..", then you can see if the bleach is sufficient or you need to change it.
Best wishes ,
Youssef

Hi EmmE,

I'm following up the query you posted in May this year. How did the listeria erradication go? We have the same problem with Listeria spp in a ready to eat food production environment; whave identified L. welshimeri and recently monocytogenes. The cleaning regime has been constant though I think not sufficient, I discovered that the drains only being bleached twice weekly (unknown to the factory owner, as the operative whose job it was found that the drain led back into the high risk fridge and filled the place with chlorine odours, so stopped doing it!).

How did your process improve?

Cheers


Richard

Hi EmmE,

You can consult with your chemical sanitiser supplier and they can recommend the right sanitiser for you. As Kamwenji mentioned that a Broad Spectrum Quaternary ssuch as Sanimmax supplied by Ecolab will do the trick. I am sure there are many other QUAT based sanitisers that you can use. You need to apply it at a dilution of 1/500 9200pppm) and at 500ppm in hard water areas. contact time needs to be 60 seconds at 25°C. It has a 99.99% kill rate.

Regards

Dear EmmE,

So are you environmentally listeria free these days ??

Rgds / Charles.C