This episode features Emily Hale, a Produce Safety Technician with the Blue Water Conservation District, and Chris Callahan, who runs the Agricultural Engineering Program within University of Vermont Extension. They discuss the difference between cleaning, sanitizing, and disinfecting, along with where and how often these activities should occur on the farm.
A Guide to Cleaning, Sanitizing, and Disinfecting for Produce Farms: This guide, developed by Chris Callahan, helps to further explain the differences between cleaning, sanitizing, and disinfecting.
Introduction to Selecting an EPA-Labeled Sanitizer: The Produce Safety Alliance created a guide to help growers better understand what to look for in a sanitizer label.
Introduction: Hello and welcome to the Agrifood Safety Produce Bites podcast, where we discuss all things produce safety and dive into the rules and regulations surrounding the Food Safety Modernization Act Produce Safety Rule.
Emily Hale: My name is Emily Hale. I am a Produce Safety technician with the Blue Water Conservation District and I assist produce growers in Southeast Michigan.
Chris Callahan: I'm Chris Callahan with the University of Vermont Extension. I run the Agricultural Engineering Program within Extension here. My work has focused on post-harvest handling, washing storage, with a focus on equipment and hygienic design most recently. And my role in the produce safety world, in addition to the post-harvest side of things and hygienic design, is I am the director of the Northeast Center to Advance Food Safety, which is one of four FDA and USDA supported regional centers focused on training and outreach related to the FSMA Produce Safety Rule and Preventive Controls for Human Foods Rules, and I am a PSA lead trainer.
Alison Work: And I am Alison Work. I am the Digital Media Designer with Michigan State University Extension for the Produce Safety team. Today we are going to be talking a little bit about cleaning, sanitizing and disinfecting-- why it's important, and when and where you should do it on your farm. The first question here is what is the difference between cleaning, sanitizing and disinfecting?
Emily: So cleaning is the physical removal of dirt from a surface, and usually this includes using a detergent and clean water, usually like scrubbing.
Chris Callahan: Yeah, and then sanitizing is really, you know, I tend to lean on the CDC definitions for these things, and then also the PSA curriculum. So when we think about sanitizing, we're actually talking about going beyond cleaning, beyond the physical removal of germs, dirt, impurities, and actually getting into chemically lowering the number of germs on a surface, or on objects to a safe level, and that's judged by public health standards or requirements.
Emily Hale: And then we have disinfecting, which is the treatment of a clean surface to destroy pathogens on that surface. And this is really done to non-food contact surfaces.
Alison Work: And so what areas on the farm should you clean, sanitize and disinfect? And are there any areas that often get missed or overlooked when it comes to cleaning sanitizing and disinfecting?
Chris Callahan: In terms of areas on the farm that should be cleaned and different ones that might be sanitized, and other ones that might be disinfected, I think of it in terms of, getting back to those different zones, zone one through four, with a primary focus on food contact surfaces. So zone one surfaces, surfaces that we know in normal practice will come into contact with food and making sure that we have an appropriate cleaning plan and schedule for those surfaces. And in my experience, even surprisingly, many of those surfaces do get missed. And sometimes it's just an accessibility or a visibility issue, and one of the things we've been working on a lot is bringing hygiene design principles increasingly to produce operations. And that's a key part of it, is making sure with these food contact surfaces that we can actually see and reach them so that we can at least get them effectively cleaned. And, by and large, they should also be getting sanitized. So again, going back to Emily's introduction to cleaning, we want to first remove any, physically remove germs, dirt, soil, other things, and then follow up with sanitizer to lower the number of germs on the surface, and pathogens on the surface, using some sort of chemical sanitizer or antimicrobial solution. So, zone one for sure. Zone two is definitely considered a best practice to do the same sort of thing with, and maybe on a slightly different schedule depending on the operation. And then I think, you know, going beyond that, zones three and four will likely have a different schedule and different approach but also are very, very important for being maintained with cleaning and at times sanitizing. Emily, do you want to add anything to that before we get into disinfecting?
Emily Hale: Yeah, so I would say when I first start working with a grower who's looking to develop food safety on their farm, I often like to sit down and kind of go through their food contact surfaces, and list those and then how they’re going to clean them and what's the frequency? How often do they plan on cleaning those? And it's definitely going to change depending on what the surface is and how frequently it's going to be used. So that's something I've also found.
Chris Callahan: Great idea, walk through it together and identify all the food contact surfaces. I also think in terms of, when deciding between cleaning, sanitizing and disinfecting, I think it really comes down to what's your intent and what's the trigger for doing this activity? So, you know, cleaning can be triggered by just some visible impurity that needs to be removed. It can also be triggered by a schedule or the need for a clean break between lots or between crops that are being handled. Sanitizing much the same way. I think I may differ with some people on where I'm going next, so I welcome a conversation on this but I do think there are times when we should be considering disinfecting food contact surfaces. And I think the difference between the two for me is if you have a known hazard, we should be considering disinfection. So, if there's something that is clearly a human pathogenic hazard you know, we may want to be looking into disinfection doses and times and application details going beyond sanitizing. And I'm happy to talk more about that but I do think there's another level that may be important beyond just sanitizing, and that's disinfection.
Emily Hale: So if you were to go to the next level from sanitizing to disinfecting food contact surfaces, are you just following a label on that, as far as your steps to disinfecting that food contact surface? And are you finding labels that are addressing disinfection of food contact surfaces?
Chris Callahan: Yeah, I recently went through the labels for common antimicrobial solutions that are used in our area. Everything from sodium hypochlorite-based solutions to peroxyacetic acid and hydrogen peroxide based products. And they, with the exception of one common brand, they all include labeled applications and labeled uses for both sanitizing surfaces but also disinfecting food contact surfaces. And the differences that I noted are the level of the concentration of the product used when mixed for use, and then the amount of time, the amount of contact time. And products also differ, of course, based on what the final step is. You know, some indicate draining, some indicate air drying and some indicate rinsing. But yeah, there are definitely labeled applications that provide for that.
Emily Hale: And what if you were advising a grower to choose disinfection? When would it be better to use a disinfecting step than a sanitizing step?
Chris Callahan: So for me it comes down to the difference between… I mean, what we're trying to address here are the risks of hazards being present. And so to me, what it comes down to is the probability that you have a hazard, and so I think of it in terms of if it's a possibility of a hazard, you know, so for example, we grow in an open environment. And so, there are human pathogens in the open environment. We don't necessarily know that we have a human pathogen on the produce. But there's a possibility of it. And so that points to the need for sanitizing. If we have a known or probable hazard, for example, maybe we have a worker who is diagnosed with a communicable disease, and they have been in contact with a food contact surface in a way that might transmit that. That, to me, is a known hazard. And that really calls for disinfection. So, to me, it's the likelihood of the hazard, and that would determine what approach to take.
Emily Hale: Is this something that you've kind of moved towards recently based off the current climate or is this something you've always advised people to maybe choose disinfection?
Chris Callahan: So my current thinking on this came about as a result of growers asking about what to do in the face of increasingly likely hazards. So, hazards that we haven't been dealing with using traditional training curricula necessarily, and hazards primarily involving labor and work crews. And so yeah, it definitely has introduced a new level of consideration for farms and for growers and as a result for educators like myself, so trying to provide some guidance that will help people decide, you know, when to do either of these things so that on the one hand, we're not, you know, overdosing food contact surfaces unnecessarily, but at the same time, the growers have some peace of mind that they're addressing what could be a known hazard.
Emily Hale: Interesting. Yeah, I guess they hadn't really discussed disinfection like they are now. And then just with the last few, or the amount of information I've gotten, it's always been for non-food contact surfaces. So that's interesting. I've never heard them talk about disinfecting food contact surfaces.
Chris Callahan: Yeah, it is. It's interesting. And I think, you know, I think what we're seeing is a blending of medical practice, or hospital practice with commercial practice, farm practice and home practice. And you know, including to the point where the CDC recommendations for using germicidal bleach isn't even on the label for germicidal bleach for disinfection, so, you know, it's, it's interesting to me, we're kind of in a in a new land.
Alison Work: So then how should a grower decide what detergent sanitizer or disinfectant to use?
Emily Hale: So mostly when I'm talking to growers about using sanitizers, I'm focusing on making sure they have EPA labels for their sanitizers, and they know what the label says and that they're using it how the label directs. That's mostly what I discussed with growers when choosing a sanitizer or determining if the sanitizer they're currently using is safe to be used.
Chris Callahan: Yeah, for a lot of the growers I work with it, it comes down to issues of things like access and availability. So, there are a handful of sanitizers in particular that are readily available through supply chains that they’re accustomed to. We also have a significant number of new or emerging farms, and they've learned what they know working on other farms and so a lot of it comes down to what they've been exposed to and what other folks have used. So there's a lot of sort of peer learning that happens. But absolutely, regardless of all that, I completely agree with Emily's point about being grounded in the label, and understanding why the product is being used, what is the intent, and making sure that intended application is a labeled use and is being carried out in accordance with the label. They can be incredibly confusing with labels. And so I think starting with a very clear idea of why am I using this and to what end and then making sure you ground that application with the label.
Alison Work:So then lastly, what are the Food Safety Modernization Act requirements when it comes to cleaning, sanitizing and disinfecting? For example, what is required versus what is recommended?
Chris Callahan: So, under the FSMA Produce Safety Rule, cleaning and sanitizing are covered primarily under 112.123 and that section asks what general requirements apply regarding equipment and tools subject to this subpart. And in D 1 under that section, sort of the framing requirement is as follows: “you must inspect, maintain and clean and when necessary and appropriate. sanitize all food contact surfaces of equipment tools used in covered activities as frequently as reasonably necessary to protect against contamination of covered produce.” That's a mouthful. But a couple of key things, there's a “must” in there. So, you must do something and that something is inspect, maintain and clean and when necessary and appropriate, sanitize. And then what they're talking about are food contact surfaces of equipment and tools, specifically those used in covered activities. How frequently? As frequently as reasonably necessary to protect against contamination uncovered produce. So this this is a very, very flexible statement in and so as a result, it's also a somewhat vague statement, but it does provide for a consideration of risk at the farm level and the development of not only sop’s, standard operating procedures, but also schedules that makes sense for that farm based on the specific risks. That's how I summarize. That's how I would summarize this. And the rest of it, I think depends incredibly on the individual operation, and the specific line or piece of equipment. But Emily, how do you how do you approach this?
Emily Hale: Yeah, so I usually approach it as you're required to clean and then that line that says, sanitizing is required when necessary and appropriate. So that, we kind of talked about this earlier, is developing those schedules of when you'll be cleaning and then sanitizing is going to help you either move to a different commodity, or maybe establish your clean breaks. And that might be the “when necessary and appropriate”. But it's all, like you said, going to be based off your operation.
Alison Work: Awesome. Well, thank you guys so much for your time today and for coming out and doing this podcast.
Chris Callahan: Yeah, you're welcome. I do have one resource that may be helpful. That's go.uvm.edu/clean-sanitize-disinfect. And one of things that's there is a label comparison between four common products used in our in our area. So that provides a, you know, a summary of the CDC definitions of the different things, but also the labels may be helpful to folks.
Conclusion: Links or definitions to anything referenced in this episode are provided in our show notes, which can be accessed on the website at canr.msu.edu/agrifood_safety. You may also visit the Agrifood Safety website for additional produce safety resources, trainings, and assistance offered by MSU Extension. Thank you to everyone for listening, and don't forget to tune in next month for another episode of our Produce Bites podcast.