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Managing Food Safety Risks with Apples
79 Plays9 months ago
This episode features Faith Critzer, Associate Professor at the University of Georgia studying fresh produce in the realm of food safety, and Phil Tocco, On-Farm Produce Safety Educator at MSU Extension. They talk about all of the surfaces apples touch from the time they are picked off the tree until they get to the grocery store and how to keep these surfaces clean.
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Transcript
Introduction to Agri-Food Safety Podcast
00:00:00
Speaker
Hello and welcome to the Agri-Food Safety Produce Bytes podcast, where we discuss all things produce safety and dive into the rules and regulations surrounding the Food Safety Modernization Act Produce Safety Rule.
00:00:14
Speaker
My name is Phil Toko. I'm with Michigan State University Extension and I work in on-farm produce safety across the state. Today we're going to talk a little bit about apples.
Exploring Apple Harvest Surfaces
00:00:24
Speaker
We're in the middle of apple harvest here in Michigan and I know there's a lot of
00:00:30
Speaker
surfaces that apples come into contact with. And I thought we could maybe talk with an expert on apple harvest surfaces. So I've invited Faith Bryster here to talk with me about those surfaces.
00:00:46
Speaker
How are you Faith? Pretty good. How are you doing Phil? Cool. I'm doing good. Doing good. I was wondering if you wanted to kind of tell us a little bit about who you are and sort of your history and your provenance and how some of you in Georgia know something about apples. Yeah. Um, thanks a lot for having me on. I really appreciate it. My name is Faith Kreitzer and I'm an associate professor of food microbiology and I study fresh produce specifically in the realm of food safety.
00:01:16
Speaker
And I've been doing this for 15 years now. And while I'm at the University of Georgia currently, previously I was at Washington State University, where I was their produce safety extension specialist. And I really enjoyed working with the tree fruit industry out there, which is pretty large. And they were really great partners. And so throughout that partnership,
00:01:42
Speaker
You know, we kind of identified some of the key things they had questions about in the, you know, world of food safety. And we did projects together and collaborated. So that's some of the work that we'll talk about here, some of the questions they had. And, you know, while Washington's not Michigan or New York or anywhere else, so where they grow tree fruit, you know, a lot of the same issues still come up when it comes to food safety.
00:02:07
Speaker
how to manage risk and put your resources in the best places so that you can keep all the balls in the air.
00:02:15
Speaker
Yeah, Michigan right now is in the throes of apple season. I have a feeling that the people that are going to benefit the most from hearing this are not going to hear it until December or later. But definitely I think it was important to call you and talk to you a little bit about some of the stuff that you've done and really some of the work that you continue
From Orchard to Grocery: The Apple Journey
00:02:36
Speaker
to do. So I'm wondering if you can talk a little bit about the journey that apples take from the time that they're picked off the tree until they get to the grocery store.
00:02:46
Speaker
for those that are in the industry, I think that we're really segmented even. So you're either in the field or you're on the post-harvest side and the packing house side, and also for just normal people who like to eat apples who may be listening in. There are a lot of surfaces that apples will come in contact with once they're harvested. So there's
00:03:10
Speaker
hand that will pick them. And, you know, we're moving towards automation. So maybe in the future, there's going to be equipment that would pick them. So anything that that, you know, Apple touches, we're going to call a food contact surface going forward. So think about anything that has physical contact with that Apple. And then we're going to go into a picking bag. We're going to talk a lot about picking bags today, but they are pretty standardized across the tree fruit industry. Most of
00:03:38
Speaker
us will be using a type of nylon. It's called Cordura. But these are very common within the industry. We also see some canvas use. But inevitably, that is something that we are more, by far and away, more nylon. And then after they get into the bag, they will then get packed into a bin. And I would say that the bin is the surface that the apples are going to spend the most time in.
00:04:07
Speaker
because they are going to essentially ride in that bin from the field all the way to the packing house. And from the packing house, the packing house will assess their quality characteristics and determine how long they're likely to survive in storage.
Apple Storage and Bin Importance
00:04:23
Speaker
Because in order for us to have tree fruit year round,
00:04:27
Speaker
we're going to need to have that apple crop that's harvested right now in the fall, make it in late summer, all the way through, even in spring of next year and things along those lines.
00:04:39
Speaker
So you're telling me that they don't harvest apples year round in Washington? They don't, just like in Michigan, right? So it is a storage crop and we're really lucky that it's a storage crop and actually stores really well. Yeah. And so in that bin, they can remain ultimately for like a year, right? Until essentially they are purchased and there's different types of storage they can go into, but essentially it's a refrigerated storage and sometimes will modulate the atmosphere.
00:05:08
Speaker
I would argue that that been as one of the most important food contact surfaces, given the length of time they're in it. Do you want me to go into some of the post-harvest things? I mean, essentially they're run across a line where they are put in water and washed off. Um, they will go through various systems to clean off, you know, any residue that may be there. Then they'll many times be waxed, not all the time though.
00:05:35
Speaker
Within that system, they'll also go through really high speed automated systems that will both determine their size and color and interior, look for quality defects that you can't see with the naked eye. And they'll be sorted by class or grade and also by size. And essentially that's what the grocery store puts an order in for. And if you're ever wondering, why do all the apples in the grocery store look
00:06:02
Speaker
relatively same size and colorables because that's how they're purchasing them. That's not how they are on the tree, of course. But all of the surfaces, you know, from the water through the brush beds, through the conveyor belting, through those sorters, all the way until that apple ultimately makes it into a case or into a bag are all still considered through contact surfaces.
00:06:26
Speaker
Cool.
Wood vs Plastic Bins: Pros and Cons
00:06:27
Speaker
So back to the bins. I mean, I've seen bins out in the field that are plastic and some that are wood. And it seems to me the growers, when I talk to them about the bins, they talk about the price of plastic bins being about three times the cost of wood bins. And the nice thing about a wood bin is if one of the staves breaks, they can repair it.
00:06:51
Speaker
Whereas they can't necessarily repair a plastic bin when it breaks. So I mean, are either one, are those interchangeable surfaces or is there differences between those two in terms of cleanliness? Yeah. Um, I would say, you know, from the growers perspective, they have to look in from the packing house perspective that may be supplying the, they're usually supplying the bins. We really think about a lot of factors, right? So food safety is one of those things.
00:07:20
Speaker
But inevitably, for them, we need to acknowledge, right, that they have a lot of things, economics being one of the key things, right? Because inevitably, they are running businesses. When it comes, though, from the realm of food safety, right, and looking at things, we normally look in and assess how easy it is to clean a surface. And we know that wood doesn't hold a candle to plastic because plastic is a solid surface.
00:07:48
Speaker
in the plastics that we use for bins. And therefore it's much easier to get dirt and, you know, decay residue and things along those lines off of it. And including in that would be bacteria. Now, why is a wood surface not quite as good? It's because it's porous, right? And that's just because of its natural, its nature. Does that mean it's a total no-go? No, we still see a lot of wood bins used
00:08:17
Speaker
I think that the growers just have to keep in the back of their mind. It's going to be harder to clean them, typically. And that may not only affect food safety, but it may also affect things around decay that can carry over. If that's in the bottom or the sides of the bend, then most likely you're going to be inoculating when you put things in there. So we like to really still talk about, no matter what surface you're working with, still having that same frame of mind that you still need to get them.
00:08:47
Speaker
clean. But by far and away, what's a harder, much harder task to get to that point.
Ensuring Cleanliness of Storage Bins
00:08:55
Speaker
Okay, so now I'm really curious, how do you recommend a grower keep these surfaces clean? Yeah, I think, you know, most commonly, and I don't know what it's like in Michigan, but ultimately, that was the packing house managing that for many of our growers.
00:09:11
Speaker
And so I think from the growers perspective, really thinking about the timing of when they're having the bins placed in the field, right? Because ultimately we want to give them as little, you know, time in the field where they could get mucked up or you could have animal intrusion or other things along those lines coming in and impacting them.
00:09:34
Speaker
I would say that for growers, they should also be really cognizant. You're going to get bins potentially that are visibly not clean. And I would really make a push to have a practice in place where you're evaluating those bins before you start to pack out in them and have a game plan for what you're going to do on site when you find a dirty bin.
00:09:57
Speaker
And yeah, yeah, I think that the options for me are naturally just setting it to the side, right? And not using it and returning it back to the packing house. You can also have something onsite for kind of an as needed basis looking at how am I going to have resources out there? Many times you're going to need at least water. You're going to need to have some detergents out there, which is how we clean.
00:10:22
Speaker
you're going to need to have that water that you're draining off these bins not create a worst problem, like a mud pit right in the middle of the field for this water application. So having a gravel area that you can do this in or a concrete pad would be even better. And then essentially you have to have a sanitizer on hand that then after everything's cleaned and washed off, you can apply that sanitizer. For the cleaning part, some people use high pressure in these applications.
00:10:51
Speaker
similar to how we wash off our cars, you would have something of that nature on hand. Other people will go with the more, you know, manual cleaning and brushes. But it's really hard for a special cause to have all those things at the ready every day that you're picking when there's so many other things going on, like managing a harvesting crew and keeping your eye on everything else. So I would say that
00:11:17
Speaker
That's kind of a question. As far as how they get cleaned on the packing house side, you know, a lot of people will be saying like when they get immersed down in the water, they'll be evaluated. A lot of them have gone to using bin washers after they come out of the dump tank. And then they go through those bin washing systems, which is essentially like a dishwasher that's created for cleaning harvest bins. I would say that that's a much more controlled method of trying to get that bin clean again.
00:11:46
Speaker
And then it's kind of what happens on the storage part in between, between after it comes out of the packing line, and then when they ultimately get burned out again for the next year's harvest. Yeah, I mean, I've heard a lot of growers when they store them, they often find the raccoons get inside of them and
00:12:05
Speaker
and nest over the winner in them and things occasionally. That kind of thing happens. So it definitely the idea of a pre-harvest assessment, making sure that they didn't get dirty in the meantime makes a lot of sense. Yeah, I think that a lot of times, like that makes common sense, right? But it's just like making sure that you impress upon people who may be managing harvest that this is a really key aspect.
00:12:31
Speaker
that they need to not shortchange is always really pivotal for management, I think.
00:12:38
Speaker
One thing I heard you say that I think is really important, maybe even just to reiterate, you mentioned detergent. So it sounds like rinsing with water is not washing or not cleaning. The cleaning requires some kind of an agent that helps to basically remove the dirt. Would that be a fair assessment? Yeah, I would say a detergent is necessary when you can visibly see something's not clean.
00:13:04
Speaker
Um, not that water does nothing. It definitely does. It helps, right? And physical removal, especially the higher the pressure, which, you know, even some other people would say like, you're still just redepositing things and all that spray that you're producing. Um, you know, there's, there's pluses in my, but I think on the realm of bins, it is, uh, something that can easily be utilized, um, for field cleaning.
00:13:30
Speaker
You know, as far as detergents go, they are just designed to entrap soil, which tends to actually be a little bit hydrophobic, which means it doesn't like water. So by allowing that detergent to come in, it can interact with that soil. And when I say soil, it's, you know, plant matter, decay, microorganisms, everything, and allow it to be removed from that surface, which typically is really tightly adhered to. So that anything we can do that helps in that process is going to get us a clean bin.
00:13:59
Speaker
So we can apply more physical kind of pressure and mechanical cleaning. We can allow for reagents to come in like our detergents. We can allow for more time. You know, typically the more time something sits, the easier it is to get clean again.
00:14:14
Speaker
And so those are the sort of things that we're really thinking about when we're trying to say, okay, if we're going to do this, how are we going to do it? That's why I say a detergent is usually money well spent because it will allow you to clean more effectively and faster.
00:14:30
Speaker
Cool, cool. Okay, so I'm curious about pick
Managing and Cleaning Picking Bags
00:14:33
Speaker
bags now. We've got all of these apples going into pick bags. What I've seen harvest workers do is once they fill the pick bag, they go over to a bin and then they drop the bottom of the pick bag onto the surface of the apples in the bin and then they gently allow the apples to roll out.
00:14:51
Speaker
So you basically, I mean, my head, I see two food contact surfaces. I see that outside of the canvas part. And then I see the inside of the canvas part. How do you recommend a grower keep those surfaces clean? Yeah, I would say that first off, get those surfaces on your list of food contact surfaces of something that you're assessing. Cause we even found a lot of times they were really flying under the radar.
00:15:20
Speaker
And the reason they were flying under the radar is that a lot of the harvest crews actually brought their own picking bags to Washington orchards. And I don't know really what the practice is in Michigan or in other states, but once FSMA came into play, right, we had to start thinking about the produce safety rule. It's not that that's not allowable, right? But as far as the growers concern, what they have to be cognizant of is that they need to pack into
00:15:50
Speaker
things that are clean, right? And if you're not controlling that surface, cause you don't know where it was yesterday or a month ago, right? Um, then it's really hard to control that surface. So I would say that is definitely one thing to think about and one reason why they were kind of flying under the radar. But once we started to really evaluate, it's like, yeah, these are really important if they happen to be contaminated with, and it doesn't always have to be microorganisms. It could also be a chemical or something along those lines.
00:16:20
Speaker
Because people I think sometimes just don't think and these things are like riding around in trunks and everything. So I think, you know, really, it's not always microorganisms that can make people sick. Really, it made sense then for the growers to definitely provide those bags because then they could start controlling the rate at which they were cleaned and sanitized, you know, the timing of that. Because the other thing that is really going to kill morale is if you give people
00:16:46
Speaker
soaking wet picking bags to pick in, you know, early in the morning. So we need to think about doing this at an interval where these things can actually get dry and all the padding get dry and things along those lines. And then, you know, just really thinking through where are we going to clean them at where and also thinking about definitely the outside and even the leather that many times binds the top and in trying to get all those surfaces while they're not like what we typically design through contact surfaces to be.
00:17:15
Speaker
They're there for really important reasons for durability and working within those systems, similar to how we can work between wood and plastic. And it just may be a little bit harder to get those surfaces clean. I think that, you know, most people would, if they really thought about their own farm, they would say, yeah, we could probably make some improvements here. Uh, and, and, you know, maybe do things a little bit different. So that's why I would challenge everybody to do is like, how frequently are things getting clean? Can you answer that question at a minimum?
00:17:43
Speaker
And then what sort of sanitizers are you using after you clean them? And then, you know, hopefully that's happening on an interval so that these surfaces don't become a risk factor as far as getting dirty over time. And then if they are, try and make that frequency happen more commonly so that you can achieve both your food safety goals and your worker comfort goals and get a high quality crop packed out.
Sanitizers' Efficacy on Food Surfaces
00:18:07
Speaker
So one last question, I'm curious if you can tell us a little bit about your research around these food contact surfaces. Yeah, we had a Center for Produce Safety funded project with collaborators at Kansas State University that evaluated the efficacy of different sanitizers on common surfaces that we talked about. So we looked at the Cordura nylon and we actually used picking bags because
00:18:34
Speaker
Everybody knows that there's a bit of a different coating on the interior of the bag versus what's on the exterior of the bag. So we actually use picking bags. We used wood that was from men's. And then we also use plastics that was from men's. And we essentially inoculated all of those surfaces with foodborne pathogens. And then we evaluated how well
00:18:58
Speaker
different sanitizers worked on inactivating that target microorganism. So we looked at listeria and salmonella and sugar-toxigenic E. coli also. And the takeaway was, high level, we talked about that wood's hard to clean and it's hard to sanitize and get the similar microbial reduction because it's so porous. What we also found is that honestly, the weave of the nylon provides a very similar protective environment
00:19:28
Speaker
And many times we got relatively similar in activation on wood and nylon versus plastic. And it's not like the house is on fire or anything, just like we're still using wood. It's just something to be cognizant of. And so we may need to take more time to clean those picking bags. And we may want to, usually on a label for a sanitizer,
00:19:55
Speaker
there's a range of concentrations you can select from for food contact services. And I would say probably go with the higher concentration would be really, you know, probably a good move for somebody who's looking at those picking bags. Other people have started to look at the accuracy of liners, which are essentially like a plastic liner that covers the inside of picking bags. And you can find those at supply companies.
00:20:23
Speaker
because they just weren't a hundred percent sure if they're going to be able to reach the food safety goals they had set for themselves. Of course, that's a lot of plastic potentially in your field that you have to manage. And it still doesn't take away the fact that you still need to have a clean surface and the exterior of the back is still not covered. And clearly that's coming in contact with Apple. So it's not like you can just forego cleaning and sanitizing those surfaces.
00:20:53
Speaker
because you're using a liner, right? So that's one thing, though, that we saw some people start to evaluate for their harvest crews. I'm wondering, too, if they use the liners, if they have to worry about ethylene, extra ethylene getting caught inside the bag and maybe lower post-harvest quality faster. Definitely a bin liner. I would really think about
00:21:14
Speaker
you're covering up those vents, right? And even though the top's still open. And for the picking bags, to me, it just seems like it's a lot of potential trash in your field and you still have to manage the surface no matter what. Right. Thank you so much for your time today. I appreciate it.
00:21:31
Speaker
Yeah, thank you!
Additional Resources and Show Notes
00:21:33
Speaker
Links to anything referenced in this episode are provided in our show notes, which can be accessed on the website at canr.msu.edu slash agri-food underscore safety. Thank you to everyone for listening, and don't forget to tune in next month for another episode of our Produce Bites podcast.