Cleaning verification using E-Coli VS a Listeria check?
We have added an extra cleaning and sanitizing of the entire production line zones 1-3 if an employee is found to be at risk of the virus and confirms a test positive.
Normally, we verify cleaning by zone-2 swabbing for dry ATP.
It was mentioned to use the E-coli for verification during the crisis. Can you clarify with respect to cleaning verification during the crisis- would Genus Listeria be acceptable in place of testing for E-coli for a cleaning verification to capture against a virus?
- We use Microsnap swabs and already have Listeria swabs in house with incubators. E-coli would be a different swab we'd need to purchase.
Also- immediately after the extra cleaning, prior to the sanitizing- is it still acceptable for verification using zone-2?
Dear Kristine,
We have been lead by some of the laboratory people saying that if you make area or surface clean, this means that area or surface is not adequate for virus to be found there.
Since virus is different from the bacteria, virus needs living cells to change their information like DNA or RNA, if you remove the living cells or bacteria, there is no area for virus to develop.
This is the main reason behind, why we mentioned E. Coli. If you can prove that your cleaning process was successful enough to remove bacteria, than it must be that cleaning is also sufficient to have virus free area or surface. In this case it would mean also if you prove that Listeria is removed, this is sufficient to have virus free area or surface. Also i think that verification from zone-2 is sufficient.
Does this make sense to you? Do you have any other opinion, since we are not microbiology specialists and this is only some logical thinking based on conversation with laboratory people?
Dear Kristine,
We have been lead by some of the laboratory people saying that if you make area or surface clean, this means that area or surface is not adequate for virus to be found there.
Since virus is different from the bacteria, virus needs living cells to change their information like DNA or RNA, if you remove the living cells or bacteria, there is no area for virus to develop.
This is the main reason behind, why we mentioned E. Coli. If you can prove that your cleaning process was successful enough to remove bacteria, than it must be that cleaning is also sufficient to have virus free area or surface. In this case it would mean also if you prove that Listeria is removed, this is sufficient to have virus free area or surface. Also i think that verification from zone-2 is sufficient.
Does this make sense to you? Do you have any other opinion, since we are not microbiology specialists and this is only some logical thinking based on conversation with laboratory people?
Hi Vladimir,
I rather doubt that failure to detect (generic)E.coli or Listeria proves there is a total absence of bacteria. APC data might be informative.
I'd keep with ATP, and tighten your parameters if anything to ensure that "extra" cleaning has been effective. Whilst viruses don't generate ATP themselves, it will be a clearer general indicator of cleanliness than a bacteria-specific test; an absence of E-coli would surely be expected as standard anyway without extra cleaning. ATP is
also an instant result - presumably your incubator is 48hr to confirm negative?
Considering that most hospitals in the US have been using ATP testing to verify terminal cleaning of a COVID positive patient room, I don't see why it wouldn't be sufficient for food manufacturing as well. Also, Coronavirus is a very weak virus outside of a host cell. It does not take much to "inactivate" the virus (compared to other viruses). Proper cleaning procedures in the food industry should be more than sufficient to remove any coronavirus on the surface.
Listeria and E. coli are very tough compared to Coronavirus. If those aren't present then you are more than good.
Side note - You mention verifying cleaning using Zone 2 swabbing for ATP. I would recommend swabbing zone 1 with ATP also. Those are the surfaces most at risk of contaminating your product. If you are concerned about the swabs introducing something onto the Zone 1 surface, this is not going to happen. The swabs have multiple lysing agents on them to break through biofilms and release ATP from living cells so they can be detected. These agents also ensure the swabs themselves don't contain any living cells. They also must be manufactured under strict ISO guidelines.
I'd have to agree with Charles that the lack of e.coli or listeria on a test would not really translate to show cleaning efficacy since more often than not there isn't any listeria or E.coli to begin with. It just doesn't make a lot of sense to me. I would stick to ATP/ACP testing to verify cleaning efficacy.
We have added an extra cleaning and sanitizing of the entire production line zones 1-3 if an employee is found to be at risk of the virus and confirms a test positive.
Normally, we verify cleaning by zone-2 swabbing for dry ATP.
It was mentioned to use the E-coli for verification during the crisis. Can you clarify with respect to cleaning verification during the crisis- would Genus Listeria be acceptable in place of testing for E-coli for a cleaning verification to capture against a virus?
- We use Microsnap swabs and already have Listeria swabs in house with incubators. E-coli would be a different swab we'd need to purchase.
Also- immediately after the extra cleaning, prior to the sanitizing- is it still acceptable for verification using zone-2?
Hi Kristine,
I deduce you wish to increase "cleanliness" in the event of encountering a Covid-19 (CV19) positive event, This action is presumably based on the assumption/premise (A) that increased "cleanliness" will minimise the likelihood of residual virus on contact surfaces.
Here are a few ATP caveats from Hygiena -
- ATP systems do not detect viruses directly. However, COVID-19 infected material that contains biological residues will be detected by an ATP system.
- Hygiena does not produce a virus test
- Performing ATP CleaningVerification does not guarantee removal of viruses on surfaces
- ATP Cleaning Verification should be used in conjunction with CDC recommendations and guideline
afaik, there is as yet no commercial kit for detecting the CV19 virus on contact surfaces.
Viruses do not contain ATP so are not directly estimatable by this measurement.
I have not seen any reported evidence of quantitative relationships between any indicator/pathogenic bacterial species and the CV19 virus.
If one chooses to accepts premise (A), it becomes necessary to implement/validate a quantitative method to estimate the increase in cleanliness from any additional introduced cleaning procedure.
(a) One option would be to compare ATP data as you mention (eg file cl1)
(b) A second (micro) option might be to compare APC data.(compiled "standards" exist here).
(c) Use fluorescent marking (eg -
https://pubmed.ncbi....h.gov/22080657/
(d) Use mycometer (eg file cl2)
The difficulty with (a,d) may be accuracy of measurements/procedural repeatability.
cl1-evaluation cleaning- bioburden of frequently touched surfaces with ATP.pdf 704.24KB 6 downloads
cl2 - COVID19, ATP, Mycometer for assessing cleanliness.pdf 305.83KB 5 downloads
@cjewell- not swabbing in zone 1 is a debatable but sort of "accepted" fudge to avoid draconian actions due the processing material itself.