Neogen Kit for L.monocytogenes Testing
Hi all,
We are an RTE Facility that produces Poultry Products, recently they have started using the NEOGEN ANSR kit to test for Listeria Monocytogenes on the production lines but they have been taking the samples while the lines are Running & have product on it.
When I was checking the NOGEN manual, the following was mentioned in the intended use:
"This environment test can be used on stainless steel, sealed concrete, ceramic tiles, rubber and plastic. It was validated by the AOAC for stainless steel and sealed concrete surfaces. It is not designed for soiled samples or food matrices testing."
I do not have a lot of experience in microbiological & environmental sampling, and it is the first time for me to see samples taken from lines with products on it.
We take samples for the line after sanitation & from the product and send them to external laboratory, they do the NEOGEN samples for internal monitoring.
My question is: Is this a correct way to take the sample and to ensure the results are reliable?
Thank You!
The intention of an environmental monitoring program is to validate the effectiveness of your sanitation program. We know that Listeria exists in raw foods, most certainly in raw poultry products, and in places such as floor drains, ect.
The point of testing for such pathogens is to make sure that you have cleaned the surfaces properly so that pathogens are not present after you have completed the sanitation process. Swabbing in the middle of production is not proving anything. I suppose, you can test during production times as a way to indicate how long you can run between cleanings. Overall, you know that if there is raw material on the surface you will most likely have a positive listeria count.
You want to make sure the production areas are clean before you start and you want to make sure that if you have a high risk process you are cleaning enough in between runs to reduce the listeria and/or other pathogens. So clean the surfaces, let them dry, then swab for environmental pathogens. If you have a positive count then your sanitation program does not work.
Technically, if you have a positive count on a filler line, in the middle of production, then you are running production too long and need to shorten your runs and CIP more often.
Thank you for your reply.
The thing is the swabs sometimes touch the product when taking it (because it is hard to avoid touching chicken with a running belt)
We take the samples on sites after the cooking steps (which is our CCP), maybe they expect it to indicate the efficiency of the CCP?
Which would be weird because we are following the international temperature guidance for cooking & we have a CCP monitor who takes samples every 10 minutes when the line is running.
And we take samples from the product too, so what does these samples serve?
And we stop the lines every 4 hours to clean them during production.
I am asking because I feel it is not serving any purpose, it is a waste of time & money..
And does the sentences on the user guide mean that the results are not reliable? I like to have a reference if I am going to say something about that.
Thanks again !!
My question is: Is this a correct way to take the sample and to ensure the results are reliable?
This way you can take the sample and get a result but that does not serve the purpose.
Hello,
AHJ is right, you usually take swab samples to see if the sanitation program works. Even after the cooking process.
If you take samples from the cooking process lines and they end up clear, that doesn't mean that the CCP works. The poultry may still have surviving microorganisms in the center if the correct temperature-time is not followed.
In my opinion, because you send samples to external laboratory, you can minimize the internal evaluation.
"This environment test can be used on stainless steel, sealed concrete, ceramic tiles, rubber and plastic. It was validated by the AOAC for stainless steel and sealed concrete surfaces. It is not designed for soiled samples or food matrices testing."
This means that if you test a product with this kit and turns up clear, you can't trust it. The kit is not tested on food matrices therefore it may have false-positive or false-negative results.
Also, do you only take swab samples for listeria? Do you test it for salmonella too?
"This environment test can be used on stainless steel, sealed concrete, ceramic tiles, rubber and plastic. It was validated by the AOAC for stainless steel and sealed concrete surfaces. It is not designed for soiled samples or food matrices testing."
This means that if you test a product with this kit and turns up clear, you can't trust it. The kit is not tested on food matrices therefore it may have false-positive or false-negative results.
Also, do you only take swab samples for listeria? Do you test it for salmonella too?
what is "Food Matrices testing" ?
Yes we test samples for salmonella too from the product, and for E.coli, Satph. Aureus (along with ACC & TC)
And from the lines we take ACC and Listeria swabs after sanitation & send them to external lab.
The Neogen methodology is apparently also AOAC approved for certain foods -
what is "Food Matrices testing" ?
Yes we test samples for salmonella too from the product, and for E.coli, Satph. Aureus (along with ACC & TC)
And from the lines we take ACC and Listeria swabs after sanitation & send them to external lab.
Food matrices are all the consumable feedstuff. But from what i saw in the link Charles C posted, it says this
"The approval covers the use of the ANSR system to detect L. monocytogenes in the following sample types: hot dogs, Mexican-style cheese, cantaloupe, guacamole, pasteurized liquid egg, sprout irrigation water, and sponge samples from stainless steel surfaces."
I don't see the rational behind running any food contact surface testing WHILE running. IMO this is a waste of time and money.
Since you say you shut down every 4 hours (seems excessive to me too) to clean, that's when you should be swabbing surfaces. Post clean PRE sanitizer to verify that your sanitation process is working
L mono also is widely known for it's ability to hide, IF you ever get a positive hit on a belt running during production with product on it, I hope you're prepared to shut down the entire facility and recall everything from the last full weeks production. If it shows up on food contact BELTS you better believe you have a massive problem
I personally see value in collecting sponge samples during production. However these samples should only be taken in RTE processing areas. These samples show that you do not have an issue with pathogens getting from raw processing areas to RTE processing areas, whether on product or through the environment. It is common practice for RTE meat product producers to take these swabs during production. Some USDA inspectors may question you if your facility does not as likely most other plants they inspect do take operational LEM (listeria environmental monitoring) swabs, in my experience.
Bit OT
Actually, some widescale projects on surface micro. data in the Literature have utilised on sampling within Production. Such data can be interesting but difficult to compare with other studies, eg
assessing microbial performance FSMS systems.pdf 952.28KB 11 downloads
On the other hand, even for "just cleaned" data, other potential factors are often not detailed, for example (a) the precise method/duration of cleaning which must surely have some potential effect, (b) the production activity related to the surface investigated, eg slaughterhouse or RTE preparation table.
The net result is that a considerable range of opinions result as what level of, for example, APC value corresponds to a "best practice" in the general case. One Literature "rule of thumb" suggestion was that a just cleaned/sanitised surface should exhibit less than than 10% of its typical Production APC level.