The Wash Podcast: Understanding Efficacy Studies

Welcome to The Wash, your trusted resource for the latest and greatest in public health and hygiene, where we will tackle topics like hand hygiene, best practices in footwear sanitization, creating an employee hygiene program, and more!

On this week's episode, we invite Meritech CTO Paul Barnhill as a return guest to help listeners understand efficacy studies for handwashing. Mr. Barnhill goes into detail explaining how these studies are performed, how to interpret results and general information about handwashing efficacy.

You can listen to the podcast using the media player or read the podcast transcript below:

Podcast Transcript: Understanding Efficacy Studies

Joe: Hello and thank you for joining us for another episode of the wash, your trusted resource for the latest in public health and hygiene. This podcast is brought to you by Meritech, the leader in automated hygiene technology. I'm your host today, Joe Johnson, and I'm joined by Paul Barnhill, the chief technology officer and head engineer here at Meritech. Thanks for joining us, Paul.

Paul: Thank you for having me.

Joe: Today we are going to talk about efficacy and how exactly we prove the efficacy of hand-washing events. Meritech has been performing lab studies to test the efficacy of clean tech, automated hand washing stations for over 30 years. Over that time, we have performed over 50 studies to prove just how well our stations work. Paul, could you walk us through at a high level, how we perform these studies?

Paul: Well, most of our studies that we do are performed in in laboratories, and we actually use a specific laboratory, a company called bio-science laboratories. They are probably one of the premier labs within the country that studied both topical antimicrobials and the science of hand hygiene.

Joe: I noticed in the study overview that there are two different methodologies used. Could you explain the differences between the types?

Paul: So we have really two different types that we work with. One that really focuses, an ASTMs standard. It's around viruses and an ASM standard that we focus really around general hand hygiene or bacterias. So if we look at E1838 we're really focusing on a virus there, the noroviruses, things like that. And then if we're looking at the E1174 we're really focused on things like bacteria or other pathogens like E coli, serratia marcescens, maybe a staphylococcus aureus or something like that.

Joe: Are there other methodologies?

Paul: There's a lot of other people that kind of do different methodologies, but not typically performed at an ASTM level. So you may, somebody may perform what is called a total plate count. And one of the difficulties with that is that you're really collecting the pathogens of everything that's on the hands. And that really doesn't give you specifics like you do when you're looking at a, an other ASTM method where I'm literally doing what it's called pathogen specific testing. When I'm pathogen specific testing, I'm truly putting on a pathogen on my hands, either a virus or bacteria. I'm measuring what that known amount is creating a baseline and then I'm applying it again and again and again over again to then remove that to see what that reduction level is, so I'm not getting that outside noise of other pathogens that already reside in the skin and so forth. That we, we have. So yes, you have other methods. You may have a, again, at total plate count, you may have a finger swab or a finger plate. Again, with those three methods, a little bit more challenging because you do not get the competence level with the results and you get varied human results just because the methodologies are somewhat flawed. And what are some of the pathogens that we have tested CleanTech against, and how did we go about selecting them. Well, I mean, we, we select various paths depending on, you know, kind of what we know is really important. So, for example, in the ASTM E1174 standards, really to follow the protocol, the standards, you have a couple of different pathogens test. Obviously you test either serratia marcescens or E coli. We have tested both of those, but really one of those within our core industry is food manufacturing. E coli is very prevalent within that industry and we want to focus on those pathogens that people easily recognize and know. We've also tested things like a norovirus. We use a surrogate called feline calici, but again, it's a surrogate for noro. And so that's very common. Wherever you have sequestered individuals and your longterm health care, cruise ships, incarceration or prisons are areas where norovirus, and even sometimes schools and universities can be exposed to that as well as we tested other pathogens like staphylococcus aureus and, and those things to be able to just kinda get a general broad spectrum of pathogen reduction.

Joe: So of the pathogens we have selected to test, would you say that it's given us a good coverage of all the possible pathogens out there?

Paul: That's a really, really good question. There are so many pathogens out there. It would really be a, it would take a lifetime to really test them all. And some of them we can apply to human skin and some of them we can't. So when we do all of our testing, all of our test methods are really testing on human skin or testing on, on human subjects, applying the true pathogen. Yes, we're testing a good variety and there's always more that we can test as new pathogens come along that become in the media and things that we have to focus on. So we are testing both transient as well as resident, pathogen. So for example, e coli is a transient, staphylococcus aureus is more of a resident pathogen. So we are looking at broad spectrum as well as then we're looking at bacterias as well as viruses.

Joe: Could you go into a little bit more detail about the differences between resident and transient pathogens?

Paul: Great question. A lot of people get confused about this because they wonder, why can I not get, you know, like a hundred percent reduction of a pathogen, so understanding that that, you know, the body's largest organ is actually skin and it's a living, breathing organism and on our skin, which is a little bit pH, a little bit acidic. on the lower side and that helps fight off pathogens. They're also what a resident pathogens. Pathogens that live on the skin, those pathogens are help, there to, uh, take care of the quality of the skin, as well as fight off transient pathogens. So those are coming from within my body. 95% or greater of these pathogens are inert. They're harmless to me or to others. And then you have transient pathogens. Let's call that our, our noroviruses or, our E coli, things like that. These are the things that we pick up from others. They may be coughing, sneezing, they may have touched a doorknob or an elevator button or a handrail, and we picked that up. So those are the differences between those two pathogens.

Joe: So now that we have a little bit of background on the studies, let's look at some of the results. I see in the studies, the results are recorded as log reductions. Could you explain a little more detail what a log reduction is?

Paul: It's funny, you know, I have this conversation a lot in different trade shows and so forth, and to friends, and people go, well, can you help me understand what log10 is, it really is simple math. When you think about it The log, 10 reduction that we're doing is actually just a scientific log reduction that we're majoring in log 10, math. So logarithmic math. But to boil that down in a simple, easy method, if you want one log is a 90% reduction. You want a two log, it's 99% reduction. Three log is nine 9.99, 4 log is 99.99 and then it just exponential from there. Just keeps going and going and going, beyond 99.99 is really difficult because again, we're dealing with a living, breathing organism like skin, very difficult to attack beyond a 4 log reduction. Let's dive into a few of the specific studies that we've done, just to hear about that process as well as the results that were delivered. So we've studied a lot of those and kind of just picking a couple of them off the top of my brain. Really, the norovirus is, is again, a very, well-known pathogen. Uh, very common. Uh, when, again, it's a question of areas we're showing with our technologies, with the Meritech automated hand washing systems, a 99.99% removal every single time with that. Now we say that removal, we don't say that it's killed. There's a big difference when we're washing the hands cause we are saying we're removing. Yes we're using a detergent antimicrobial product at the same time, but we want to make sure that we're saying that we are removing that pathogen from the skin. Cause I can't very well say I'm killing it every time. But we're showing that 4 log where that 99.99% removal. And we did do that with the E1838 study, which is really for viruses. Now if you look at something like an e coli that's very common within the food environments that we work within. We're showing a 99.9% reduction on that. Differences in those two pathogens is very, one is bacteria, one is a virus. They adhere to the skin differently. The quantity of pathogens making you ill is vastly different between the two and one is a little bit harder to remove from the skin and so forth. That being e coli. We've also then studied things like, um, staphylococcus aureus. Staphylococcus aureus is a little bit more challenging. We're showing a 99.5% greater reduction of that. The reason that pathogens, a little bit more difficult to remove, again from the skin is because the fact is it is a resident pathogen. So we don't, you know, we're trying to remove that and we don't, you don't always get that as 99.99 or 999 greater than that for that reduction. Again, because it's a resident pathogen.

Joe: Could we, uh, talk a little bit about what the actual differences between a 99.5 or a 99.9 and 99.99?

IPaul: t's funny, let's see if I can describe this in a podcast. Something I taught, uh, not that long ago to a group of individuals. And the very question came out, and so I brought out an experiment that I have. So if you take literally 9,999 red hot candies. And you really take that number and if you want to understand the difference, so you take 9,900 of those and that's your 99% and then if you want your 9,990 you have a 99.9 and then if you really want 99.99 you really are at literally nine more red hots to get to that number. And that number just keeps going down and down and down and down. So that really is a very simple way of looking at it. And a lot of people say, well, why can't I get to 100% reduction over time? Again, we're dealing with a living, breathing organism, skin. We do not want total eradication. If we had total pathogen kill or overkill, the skin, you're going to get degraded skin quality and skin health, which is going to lend itself to greater pathogens, greater cracks and crevices. People will wash less. If you're literally destroying the skin, you want to wash it. You want to do a really good job of washing it, but you want, you want to keep that skin intact and, and viable for the person going forward.

Joe: So now that CleanTech removes more than 99.9, and in cases like norovirus 99.99% of the harmful pathogens, that seems like the epitome of clean hands. Would you, what would you say is next for the development of the technology?

Paul: You really, you really, you're, you're exactly where it needs to be. You can't really go beyond 99.99 for human skin. It's very, very difficult to show that you beyond a 4 log reduction. You don't want to do that too often as well. You don't want to degrade again, the skin health, you cannot separate the two things. You cannot separate clean hands and skin health from each other. They are absolutely related. So if you're overusing a product that's incredibly drying to the skin, incredibly damaging to the skin long term, you're going to get, again, higher levels of pathogens, both in the resident and or the transit loads that are going to live and reside in the skin. There's really not much to go beyond that, other than you continue to work as new pathogens arrive in the world that we look at and see, we look at ways and technologies to deal with, how do we address that pathogen what is the best way to either remove it, to kill it, how do we do that to continue to protect skin health and make sure that we are doing what is right for the individual. In regards to Meritech, how can we do that quickly, efficiently, um, where we remove a lot of that human behavior aspect. That's what Meritech is about, is how do we make this process the same every single time as quickly as possible while making sure that we protect against skin health?

Joe: Paul, thank you so much for that insightful information. If you would like to learn more about employee hygiene, you can always find more Paul, thank you so much for your time and expertise. It was a pleasure spending time with you today.

Paul: Thank you very much. Glad to be here.

This podcast is brought to you by Meritech, the leader in automated employee hygiene. Meritech offers a complete line of fully-automated hygiene equipment that provides the only clinically-validated, technology-based approach to human hygiene in the world. Meritech’s line of CleanTech® Automated Handwashing Stations perform a fully-automated 12-second hand wash, sanitize and rinse cycle, removing over 99.9% of dangerous pathogens while wasting zero water or solution. Meritech delivers employee hygiene, contamination control, and infection prevention programs within a wide variety of markets, including food production, food service, cleanroom, healthcare, medical, theme parks, and cruise lines. For more information call 303-790-4670.

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