Drains APC Listeria

Hello all, 

 

Does Aerobic Plate Count include Listeria Monocytogenes?  Is there any correlation between the two?  Would having a Less Than 1000 cfu/gram specification correlate to negative Listeria Monocytogenes?  I am particular about swabbing drains and our manufacturer only tests for Y&M and APC, not Listeria.  This is for a dietary supplement manufacturer.  Thank you in advance.  

Depends on your program. Listeria is usually the organism of concern for drains.

Hello all, 

 

Does Aerobic Plate Count include Listeria Monocytogenes?  Is there any correlation between the two?  Would having a Less Than 1000 cfu/gram specification correlate to negative Listeria Monocytogenes?  I am particular about swabbing drains and our manufacturer only tests for Y&M and APC, not Listeria.  This is for a dietary supplement manufacturer.  Thank you in advance.  

 

Based on the Literature, the generic answers to your 3 questions are sometimes, rarely, rarely.

Hi there.  I am a Microbiologist at a food plant in USA.  There is no direct correlation between APC counts and Listeria.  It would be best to swab and monitor the drains for Listeria species in general.  If there is a sanitation/cleaning issue you will pick up a positive for Listeria sp.  When a pos. is observed, have sanitation clean and sanitize (prefer a Quat. or a peroxyacid Sanitizer) the drain, then re-swab for Listeria sp.  A pos. for Listeria species indicates that conditions may be favorable for L. monocytogenes growth.

 

Test the environmental swab samples for Listeria species.

 

Test the finished products for L. monocytogenes.

 

I hope this helps.

No.  Swab for target of Listeria (genus).  Any presumptive positives you should have some sort of corrective action for.  This errs on the side of caution which should always be used for Listeria.

 

Some people target Listeria M. specifically, and some only worry about confirmed results.  It is entirely up to you.

Agreed- test for Listeria species (and speciate any positives to determine if they are L. Monocytogenes). And when you find a positive, take additional swabs from surrounding areas to determine whether it has spread. These additional samples can also help you determine if you have a transient Listeria incident or a resident colony. Late last year we found the same strain in multiple locations, indicating it had spread from the drain around the production facility (thankfully not to zone 1 areas!). After 5 months of intensive testing and fine-tuning of our sanitation procedures, we were finally able to feel confident that we have the situation under control- and we continue to monitor aggressively.

Note that the locational focus on specific Drains may also (risk) relate to the Process, eg RTE with a thermal "kill" step.