Listeria testing requirements for RTE products

Hi!

I got the service of a third party laboratory to test for Listeria in our food sample and environmental swab. My questions are:
1. What food sample do we submit for testing? Our product ranges from RTE hotmeal, RTE Coldmeals and RTE desserts. Also, due to cost constraints, i can only submit 3 samples. Any recommendations what is best to submit?
2. Where could be the best swab point for environment swab? Our areas include raw preparation area, the cooking area, the RTE coldmeal area, the RTE hotmeal area and the RTE dessert area. Do we conduct swab on the floor, walls or ceilings or is it better to conduct swabbing on food contact surfaces(e.g. preparation tables, utensils like food pans, cutting boards etc.)?
3. What is the industry frequency of testing for Listeria both in food and environment? Is it acceptable to conduct testing on a semi-annual basis (2x per year)? We conduct in-house microbiological test like E. coli, coliforms, TPC, S. aureus, B. cereus, Salmonella, Vibrio and Anaerobic bacteria but we do not have the capacity to test for listeria.


Thanks in advance!

Can anyone help Majoy?

Hello Majoy,



In your case you should have strict environmental monitoring after your lethality step. But you can not ignor environmental monitoring in pre lethality steps as accesive microbes in that area will be a problem.


now talking about frequency. It will depend how much positive results your are getting. When you will start your program you need to send huge amount of samples. Once you have idea where you are finding pathogens all the time that area should be monitored weekly. If every week you are getting positive than increase to twice in a week. May be you will end up with daily. But there is not perticular frequency. You have to decide accoding to your product risk level and number of posivie results you get.



Hope this will help. If you need some referance material let me know. I can provide you with few links.



Dave

Here is a guidline for almonds..... you can use this as a base line............ very nice document...



http://ucfoodsafety....files/26483.pdf

Hope these documents can help you.

http://www.foodautho...ent-program.pdf
http://www.foodautho...emes_Manual.pdf

Here is a guidline for almonds..... you can use this as a base line............ very nice document...



http://ucfoodsafety....files/26483.pdf

Hi SZY,


excellent links!

I'll wait for the result of the 3rd party test and from there i can move forward with the info on the link you gave me.

Thanks thanks,

Hope these documents can help you.

http://www.foodautho...ent-program.pdf
http://www.foodautho...emes_Manual.pdf

Listeria swabbing is a necessary evil in the RTE food industry, unfortunately

First of all, the majority of your Listeria swabs should be focused on post-cooking processes; the only Low Risk swabs that may be necessary are the transfer points of ingredients from Low to High Risk. Listeria is easily killed off by proper cooking controls so swabbing in preparation and cook areas is not really necessary and I have yet to come across an auditor who thinks otherwise.

Main points of focus in High Risk
Low/High Risk transfer points (including sanitising tunnels)
Processing equipment (particularly hard to clean equipment and anything that involves any cutting or mixing)
Undersides of equipment directly over exposed product (particularly where prone to condensation)
Drains (particularly any close to processing equipment)
Refrigeration Units
Storage Bins, Trays, Crates
Scales
Anywhere water can accumulate (Listeria grows really well on wet surfaces)
Employee footwear, aprons, gloves
Bootwashes or Footbaths
Door handles


In the beginning you would need to do a lot of swabbing over a period of a month and if you can show that swabs are coming back negative, you should be able to cut it back and continue to carry out surveillance on a planned frequency; we do it weekly but that may not be within the buget of a small organistaion.

Samples of product is quite important; each product would ideally need to be sampled a minimum of monthly; if you start to get positive results, then you could look at the processes that are used for that product e.g. if you were making ham sandwiches which came up positive, the first thing you would want to swab is the ham slicer. Also don't forget about raw materials that are brought in cooked; your supplier should be giving you certificates of analysis for cooked raw materials anyway but some extra sampling by yourself may still highlight problems

One last thing, if you do get postives either from swabbing or food sampling, make sure that all corrective actions are recorded including any resamples as an auditor will certainly want to see how you dealt with any postives

I have attached a guide by the FSAI, the food safety body here in Ireland; it is very comprehensive and easy to follow

1. If its 3 samples, I prefer one hot meal, one cold meal and green salad, if you have
2. Swabs- Butchery room, packing room of all types of foods, production area
3. If you identified listeria as a micro hazard, you might have identified the out breaks reported due to listeria. Its easy for you identify the frequency of analysis based on the occurence levels. Refer
http://www.fsis.usda...ics/lmguide.htm
http://www.fda.gov/d...t/UCM197330.pdf

Regards
Jomy Abraham

Hi!

I got the service of a third party laboratory to test for Listeria in our food sample and environmental swab. My questions are:
1. What food sample do we submit for testing? Our product ranges from RTE hotmeal, RTE Coldmeals and RTE desserts. Also, due to cost constraints, i can only submit 3 samples. Any recommendations what is best to submit?
2. Where could be the best swab point for environment swab? Our areas include raw preparation area, the cooking area, the RTE coldmeal area, the RTE hotmeal area and the RTE dessert area. Do we conduct swab on the floor, walls or ceilings or is it better to conduct swabbing on food contact surfaces(e.g. preparation tables, utensils like food pans, cutting boards etc.)?
3. What is the industry frequency of testing for Listeria both in food and environment? Is it acceptable to conduct testing on a semi-annual basis (2x per year)? We conduct in-house microbiological test like E. coli, coliforms, TPC, S. aureus, B. cereus, Salmonella, Vibrio and Anaerobic bacteria but we do not have the capacity to test for listeria.


Thanks in advance!

Dear All,

I don't understand the apparently prevalent opinion that "Listeria" is a pathogen. Just like E.coli apparently.

Rgds / Charles.C

Hi All!

Thanks for all the reply and very good references.

Hurray! results were in - all samples were negative, foods and environmental swab!

I didn't know petrifilm can be used to test for the enviro swab! Next time we will do the swab test in-house and just buy the petrifilm. I can even increase my sample size and include other areas as what has been suggested above and not spend $35 on each swab test.


Thanks!

Majoy