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Emily Davenport: 0:15

Welcome to Cultivating Curiosity, where we get down and dirty with the experts on all the ways science and agriculture touch our lives, from what we eat to how we live. I'm Emily Davenport.

Jordan Powers: 0:27

And I'm Jordan Powers. And we're from the University of Georgia's College of Agricultural and Environmental Sciences.

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Jordan Powers: 0:36

We are here with Carla Schwan, assistant professor and Extension food safety specialist. Carla, thank you so much for joining us today.

Carla Schwan: 0:43

Good morning. Thank you for having me. I appreciate the opportunity to connect.

Jordan Powers: 0:47

Absolutely. We are really excited for this episode, especially ahead of the very quickly approaching holiday season.

Emily Davenport: 0:53

Mm-hmm.

Jordan Powers: 0:54

Before we dive into some of the holiday related food safety questions. Tell us a little bit about your background and how you got started in food safety.

Carla Schwan: 1:01

I majored in food science and technology. So I'm originally from Brazil, and majored in food science and technology. And during my undergrad, I wanted to do an internship to learn more which area I wanted to go, and food microbiology, especially bacteria, always fascinated me. So goes back to when I was a little kid and I had an infection with E. Coli. And I got really, really sick was in the hospital for a month. And it turned out I had Shiga toxin-producing E. coli, which is a strain of bacteria that produces toxin in your intestines, and it can lead to severe consequences. One of them shutting down your kidneys, so I was on dialysis, and doctors didn't think it was going to make it. And usually when you have this type of bacteria, they do not give you antibiotics, because if the bacteria is resistant, then likely you're going to die from it. But in last resort, they give you the antibiotic because that's the last thing they can do. So they gave gave me the antibiotics. And here I am. So the bacteria thankfully was not resistant, and I made it. And since then I was about 12 years old, I couldn't even pronounce the name of the bacteria back then, my doctor would tell me and I'd be like, wow, this is a mouthful, I cannot even say that name. And just so fascinating on how something that you cannot see with the naked eye can make you so sick. And so when I started food science technology, one of the areas that I could do an internship was food microbiology, and I loved my professor, I loved the classes, you know, food micro 101, I approached him and said, hey, can I, you know, intern in your lab and just learn more about this and see if I like it? And that's how it all started. And I did an internship work with him with bacteria. And then I had the opportunity to come to the US to do a Science Without Borders program that the Brazilian government had at the time. And I did one year of internship at Kansas State University with Dr. Randall Phebus, working in his lab, and he really guided me on more the advanced technologies on food safety and equipment that we didn't have access back home. So then I was able to be exposed for one year in his lab and learn a lot of different things. So I went back to Brazil to graduate with my undergraduate degree. And he had recently got a USDA grant to work on Shiga toxin-producing E. coli, the same bacteria that nearly killed me. And he emailed me saying, hey, I have this grant, would you like to come and do your Master's with me? And I'm like, wow, yeah, of course. I was, you know, I was super excited. So I came back to the US and then did my Master's with him investigating E. coli. It was not intentional, you know, because I had the infection when I was 12. And here I am working with this bacteria, identifying interventions for the beef industry. It kind of came full circle, not intentionally, but I think I can tell my story and tell people how and why food safety is so important, because I'm a living example of something that really went wrong when I ate a burger back then when I was a kid, and it really affected me for my whole life. We always in food safety, talk about short term disease, which is you have your diarrhea, vomiting, headache, maybe low grade fever, things like that. And then you have long term disease or chronic disease that you can develop that we have seen research on. And one of the examples is irritable bowel syndrome, and within that category have Crohn's disease as well. So then you fast forward, I'm about 28 years old, and I start getting really sick again, and the doctor has diagnosed me here in the US with Crohn's disease. And even though we cannot exactly pinpoint that specific event, because it was so intense, and I had toxin formation in my intestine, and my kidneys were shutting down, it was such an intense event, and it changed my gut microbiome. Now I have a chronic disease that I develop later on. And so the doctors think that had an effect on it. But of course, we cannot say 100% that that's the only thing that causes it, but a contributing factor potentially on top of having the genetics for it and some environmental stressors. I like to give this example because we talk about short term illness, the immediate symptoms that you can see and then long term disease is hard to track but people sometimes forget and don't see it and now you have a chronic disease that potentially came from a foodborne illness that was preventable, and now you have this disease for the rest of your life. Crohn's disease specifically is an autoimmune disease that there is no cure for it. So being on infusions and doctor's appointments, and you know, the cost of that associated with a foodborne illness too, is so high There's just so many facets to it. So I always like to give this example and share with people because it's real. And it can happen to anyone. And probably everybody has already had experience a foodborne illness, but just didn't realize, but it's preventable. So that's the great thing. It's preventable. We can work together to prevent things like that.

Jordan Powers: 5:33

I think it's probably easy for a lot of people who have maybe experienced that short term illness, right, those couple of hours to a couple days where you're regretting some decisions, but then you get past it, and you don't think about it again. And for a lot of people, I think that's the way that it goes. So it's really fascinating to hear you talk about that long term repercussion that might not even happen for, you know, your case another more than a decade.

Carla Schwan: 5:54

More than a decade, yeah.

Jordan Powers: 5:55

But it's it's out there, and it's real. So that makes me really excited to dive into some of our topics today. So turning to the, like I mentioned earlier, very quickly approaching holidays, we do know that many people love to make homemade gifts around the holidays, whether it's homemade vanilla, infused oils, homemade caramels, etc. What are some considerations that gift givers should have in mind, if they go that route?

Carla Schwan: 6:17

I think the first thing I would say depending on the recipe, if it's a recipe that could pose more risk, and I'm referring to here, infused oils, definitely find a validated, tested recipe that somebody has validated in their lab, because then you know that the procedures you're going to follow are safe. And even though it's a higher risk product, you can feel confident that you are following the steps and you're gifting someone with something that is safe. So for example, the concern with infused oils is that you are creating an anaerobic environment. So there's no oxygen because of the oil and you are adding maybe garlic or herbs or different things that are low acid, meaning there is not enough natural acid in those foods that could prevent the growth of bacteria. And in this case, we are talking specifically about Clostridium botulinum, which is a bacteria that produces a toxin that causes a disease called botulism. So botulism poisoning, it can be a deadly disease. And so we are mostly worried in the case of infused oils with botulism and how it could, if the spore is present, germinate in the right conditions, and then produce that toxin. So the infused oil piece, people sometimes assume that just because you're adding garlic, or you're adding herbs, because it's oil, you can just leave it out at room temperature and it will be fine. So by doing that, We'll link to that and the Newswire article in the show without following a validated tested recipe, you're really creating a perfect storm of conditions for that bacteria to produce a toxin. So you have no oxygen, you have a low acid food that you are adding into that oil, and you're leaving it at room temperature. So those conditions are perfect for Clostridium botulinum to germinate. If the spore is present to germinate and then produce that toxin. However, there is a safe way of doing that. So we have validated recipes, we have research that was on to understand before you even add the garlic or you add the herbs that you should be adding some acid and letting that acid infuse into the garlic or into the herbs before you add that into your oil. So we have a publication on that and steps on how you can do that safely. So you can feel confident that if you want to do that, number one it's going to be safe. And it also can stay on the counter and is a piece of decoration, right, that people like to show and it looks beautiful. So you want to display that. And there is a safe way of doing this. So we have an Extension publication that we talk about that and the steps on how much acid and what is the thickness of the garlic and how many herbs you can put and things like that. notes so that our listeners can go that route if they'd like to use an infused oils safely.

Emily Davenport: 8:47

Well, between the holidays and then right after, the Super Bowl, for those who celebrate. We're definitely in the season of large gatherings. So how can party hosts or maybe people who are attending and bringing a dish take steps to keep guests safe?

Carla Schwan: 9:03

There are several measures that we can take in order to prevent foodborne illness and contamination. So first, I would say when you are preparing your dish at home making sure the counters are clean, that you have cleaned them and you will wash your hands and you have a clean surface to work with. And if you have raw meats and raw vegetables, separating them, so having separate cutting boards or if you only have one cutting board, preparing the vegetable first that is not going to be cooked so there is no intervention really to kill anything if it was cross contaminated with the meat. So you prepare your vegetable first, washing really well your cutting board and then you prepare your meat that is raw and is going to be cooked so there is an intervention step there to take care of any bacteria if they were present. So that's one thing. When you are cooking your meats, making sure you're cooking it to the correct temperature internal temperature using a food thermometer, storing the foods in the refrigerator and making sure they are below 40 Fahrenheit and when you're transporting your food to the party that you're going to utilizing containers that will keep your food either cold or hot. So if your food is cold, you can use ice packs to make sure that it's padded around the food and then transporting it to the place that you're serving it, making sure that when you arrive to the party and you're serving food or if you're hosting the party, you're serving food and you keep hot foods hot and cold foods cold. So for hot foods, you want to keep it above 140 Fahrenheit. And for cold foods, you want to keep it below 40 Fahrenheit. Also being aware and making sure that your guests are aware if you have any allergens. So right now, FDA declares nine big allergens, so we call the big nine. And obviously, that's for regulation purposes. Being in your house, you're not being regulated by the FDA. So you don't necessarily have to do all the guidelines that they offer. But I highly encourage that if you have allergens that you make sure you tell people what dishes have what allergens, because the last thing you want is somebody with an allergy coming in and eating a food and then having an anaphylactic reaction to it. That will ruin your party and maybe their friend will never come over again, because

Everyone: 11:05

[laughter]

Jordan Powers: 11:05

There's a risk.

Carla Schwan: 11:05

There is a risk. So labeling your allergens. Sometimes also when you're serving and there's a big gathering of people, using single use items. So people are not mixing maybe the spoons they are using in different dishes and cross contaminating that way. Also, hand washing, maybe before you start a party, you can encourage the guests to hand washing and having stations available. So bathrooms or in the kitchen and having soap and paper towels available for the guests who wash their hands and hand sanitizers as well throughout the space. Those are some tips when you are preparing or bringing food or serving food. But also when the party is wrapping up and you have leftovers. Of course, you don't want to waste food. So making sure that you kind of keep a timeline on when that food was put out. So usually, we recommend that if the food has been left out for two hours or more, you should throw it away. But if the temperature for example, in the summertime is above 90 Fahrenheit, then only one hour because bacteria multiply really fast when it's a little bit more warm and cozy for them to multiply. So that's the general recommendation for storage. And then let's say next day, or in the next two days, you want to reheat that food and you want to eat that food that was leftover from the party, making sure that you are reheating it to a safe temperature and using a thermometer to make sure that the internal temperature of that food has reached at least 165 Fahrenheit. And that should be good. Something else that I also like to mention is sometimes we have recalls. So if there's a contamination, USDA or FDA, or even a voluntary recall from the company, they will recall recalling your product due to contamination of X, Y, or Z. So being aware that foods that maybe you have at home, stored at home, or that you might have served were recalled so you can let your guests know or even in the front end, if you know that something that you have in your pantry has been recalled, you can avoid serving that. And there is a great app that USDA has, it's called Food Keeper that you can get alerts and follow recalls in different items. So it's not only USDA regulated food products, but also FDA. So it's a really great resource that people can have and check periodically or even set up alerts to receive information.

Jordan Powers: 13:14

Yeah, that's fantastic. We will link to that in the show notes.

Emily Davenport: 13:16

Definitely. So.

Jordan Powers: 13:17

I didn't know that existed.

Emily Davenport: 13:19

I know, I love that they've made that accessible to people.

Carla Schwan: 13:21

Yeah, and it's free. Yeah.

Emily Davenport: 13:23

That's great. And I appreciate all the great tips that you shared. And if our listeners want to know more about food safety and keeping their guests safe, we will link to another episode that we did about food science and safety with Manpreet Singh who's department head of Food Science and Technology.

Jordan Powers: 13:39

Those are some really incredible tips to keep guests safe. Like we talked about earlier, it's really easy to forget the basics or to rush through the basics. I know that in my family we've been guilty of going oops, we forgot to thaw XYZ in time and then we're debating do we take the easy route of just leaving it on the counter while we go run errands and come back or do we do it the right way and maybe postpone that meal another day or cold water thaw which we've learned about. I know that I have gotten a little stricter in my household about how we do these things after talking to people like Manpreet and yourself and reading all of this research. One I will admit that I'm still guilty of a little bit, Emily and I are both very avid bakers and we know that eating raw cookie dough is supposed to be a no-no. I say "supposed to" because I'm still learning. It's commonly thought that the issue is eggs, raw egg, but we know that there's another culprit and it's the flour. Can you give us the scoop on why we should avoid eating raw flour before it's been baked?

Carla Schwan: 14:39

Yes. And I love that you said raw flour and the key word here is raw. Because at the store there's two different types of flowers you can buy. You can buy just regular general flour that is not heat treated, but there's also heat treated flour that you can use for raw cookie dough and so there is a safe way of making raw cookie dough, so using heat treated flour and using pasteurized eggs because, as you said, salmonella in eggs. It goes back to when the food industry is developing a process or looking at the food safety plan that they have for a specific product. They think about what is the intended use of that product, right? And so in this specific case, flour is not intended to be eaten raw generally. So the food safety plan is matching that intended to use piece that we have when we do a risk analysis or develop a food safety plan. And so because flour is not to be intended to be eaten raw, there is less precautions taken at the industry side of things. And so when people are consuming it at home, you're going to have an intervention step you're going to bake it or you're going to cook it or you're going to make a dish that there's going to be cooked and so you recover from that side. But then if you're using general flour that the intention is not to be eaten raw, and you're eating it raw, you're misusing it for the purpose that it's serving, right? And that's kind of where the problem comes in. There is heat treated flour at the grocery store. But you can also do that at home. We have some guidelines that we offer. And through research again, we are able to determine how much time and what is the thickness you should spread that flour in a baking sheet and for how many minutes you should bake that at what temperature. And we have also publication on that, that explains step by step how you can heat treat flour at home. You can make safe raw cookie dough and you can confidently eat it. Something else that we sometimes forget that we use flour for is where, when kids are making crafts. And they're making play dough at home with raw flour. And so that's something else that when you're handling that raw flour with kids especially, which is a population that is mostly susceptible to foodborne illness due to their immune system being still formed. Also want to make sure that if you're using flour for crafts at home with kids or with anyone you heat treat that flour before you use it. The recommendation for heat treating flour at home is that you're going to preheat your oven to 400 Fahrenheit. And then you're going to spread about 3/4 inches deep or less in a baking sheet of flour. And you're going to bake it for five minutes. But we have specific steps and you don't have to memorize this for me see there right now. You can look that publication up and do it yourself at home,

Jordan Powers: 17:14

We will absolutely link to that in the show notes. And what an easy way so I can get out of my shame of nibbling raw cookie dough occasionally, keep myself safe. I mean, those are those are those moments. I'm like, I grew up with homemade playdough. I've grown up eating raw cookie dough. And I've gotten, knock on wood, very lucky. But there's an easy fix here if people take the time to access all of these amazing resources out there to do the things that we want to do, but do them in a safer manner, so.

Carla Schwan: 17:40

Yeah, and it's flour, you think about it, there's no really moisture. So the water activity of that product is super, super low. And recently we have been learning different pathogens can survive. They don't necessarily grow in flour, but they can survive and just hang it there. And then once you add water and you add eggs and you add whatever the other ingredients are, now you're making a really good party for that bacteria that is just hanging in there. Now you have water, you have nutrients and then it's able to grow and multiply. And so that's when the problem becomes real.

Emily Davenport: 18:12

I didn't think about that. But that's what microorganisms are good at doing is surviving for a long time if they have to.

Jordan Powers: 18:19

They're just lingering in waiting.

Everyone: 18:21

[laughter]

Carla Schwan: 18:22

Yeah.

Jordan Powers: 18:23

Eugh.

Emily Davenport: 18:26

Now you can get yourself some pasteurized eggs, Jordan, make a whole bowl of raw cookie dough if you want to.

Carla Schwan: 18:30

Exactly. This is a game changer, Carla. Guilt free.

Jordan Powers: 18:35

I even have a tofu cookie dough recipe. I can skip the eggs entirely.

Carla Schwan: 18:39

Oh wow.

Jordan Powers: 18:40

And now do it with safe flour and be completely set to go.

Carla Schwan: 18:43

You might have to share that recipe with us.

Jordan Powers: 18:45

There we go. I will. It's a good one.

Emily Davenport: 18:47

All right. Well, another thing that people are probably doing a lot of right now is putting up food from their gardens because it's fall and everybody's reaping the spoils of their gardens if they're so lucky. My garden was not that lucky, but.

Jordan Powers: 19:02

Maybe for some other people.

Emily Davenport: 19:03

So how do people make sure they stay safe when preserving homegrown goods?

Carla Schwan: 19:07

Yeah, that's a great question. And I think something that I like to start off by saying that quality in is quality out. So people think that, oh I want to, you know my tomatoes are going bad. I'm going to just harvest them really quick and I'm going to can them and they're going to be good. And yeah, if you follow a validated recipe in the steps, they're probably going to be fine but there is no magic happening when you are preserving that food when you are, for example in this instance, canning so make sure that you always start with good quality produce. Even the slightest indication of mold growing in that tomato or in you know, whatever fruit you're using or vegetable, you should discard that and avoid using that for for canning because quality in is quality out and probably a little bit even less quality out because you're applying heat and you're applying treatment to that food. So it's going to be safe, but the color might have changed,the texture might have changed. So that's the first thing that I talk about, using good quality produce when you are preserving. Specifically for canning, using a validated recipe. There is other food preservation methods that we also have guidelines and validated recipes, but for the sake of time today, focusing on canning because I think through the National Center of Home Food Preservation right now, the high volume of questions that we are getting is canning tomatoes. And I think tomatoes are wrapping up and everybody wants to quickly extend their shelf life by canning. And so I'm going to be focusing on that for the episode, but making sure that you have a validated, tested recipe. And I cannot emphasize that enough. And sometimes when people think about, oh, it's just a recipe, what could be that is so fancy about the recipe? And the research and the time, the equipment, the expertise that goes behind developing a recipe in the lab, it's immense. There's just a lot that goes behind the recipe. And so sometimes you see recipes on different social media, and they look great, and the photos are beautiful. And when you start making it, then people call me and they say, well, I found this recipe. I don't know, I have a weird feeling. Do you think it's safe? Can I still eat it? Well, unfortunately, after the fact, I cannot really tell you because just by looking at a recipe, there is no way I can tell that recipe is safe. So there are several things that we measure in the lab to make sure that the steps that we give the consumer are steps that you're going to follow and are going to be safe. And specifically for canning, again, it goes back to the infused oils, the same concept. For canning, the high risk, the bacteria that we are mostly worried about is Clostridium botulinum, again, botulism. And so for canning, what you're really doing, you are preserving that produce, your, let's say tomatoes, you're putting that tomato in your jar, and you did either a raw pack or a hot pack. And now you're, you know, you close your jar and you are processing that depending on the recipe, let's say you had a recipe that called for citric acid or lemon juice or vinegar, whatever the recipe calls for, and it allows you to process that tomato using a boiling water canner. So once you do that, basically what happens the air that is inside the jar is driven out because of the heat and then that air is driven out, you have the lid on, and once that jar is cooling during the cooling process, that vacuum seal is formed preventing air from coming from the outside coming in, recontaminating your food, and also from your food drying out because then the air is out right. And so if you do that, when you're canning and you don't follow a validated recipe, you could be creating a scenario where Clostridium botulinum would be just happy to come out of the spore. I like to compare it with a seed. So it's like a seed that is just there. It's not doing anything. It's not harmful by itself, but at the right conditions it's going to germinate. In this case for canning, the right conditions are no oxygen, ambient temperature, so room temperature, and not enough acid. So most vegetables, some fruits, meats, seafood, they don't have enough natural acid present on them. So either the recipe is going to call for acid as I mentioned earlier, lemon juice, vinegar, citric acid are some of the common ones we use. It's going to call for that and you're going to acidify that food, or it's not going to call for acid but you're going to process that jar in a pressure canner because the pressure canner is going to be able to drive that temperature really, really high, up to 250 Fahrenheit and be able to destroy that spore. So we are not able to destroy the spore if present at boiling water temperatures and that's why we have recipes and methodologies that either call for boiling water canner when that food is naturally acidic or has been acidified because then we are controlling that pH to a lower level that we are not worried about Clostridium botulinum anymore, we are worried about other things, potentially salmonella, E. coli, spoilage organisms, too, that could spoil and ferment your food. So that's one of the methodologies we use for canning. And then on the pressure side of canning. So pressure canning, we have low acid foods and we want to extend the shelf life but also want to make sure it's safe. By using a pressure canner, you are able to raise that temperature that you are able without pressure to 240, 250 Fahrenheit. And so a lot of people think that the pressure is what kills the spore and destroys the spore, and it's really not. The pressure is just helping the temperature rise to 240, 250 Fahrenheit, and then it's the temperature that is destroying that spore because the sport is really heat resistant. So you really need to make sure that one, you have good quality produce. You have validated recipes, you know what methodology you're using. For specifically canning you could be using boiling water canning, you could be using steam canning, or you could be using pressure canning. So those are the three approved methods that we have research based information on that we recommend through the National Center.

Jordan Powers: 24:34

And we have even more resources through that Extension publication that you mentioned and through a Newswire story we did on canning precautions that we will absolutely link in the show notes because we have seen even just a spike in press around canning. I think it was partially COVID that people kind of were at home and diving back into the sourdough breads and the canning and the different preservation techniques, which is wonderful. I mean, I have so many memories as a kid, my mom was huge into food preservation, and I still have memories of falling asleep to the cans popping

Everyone: 25:03

[laughter]

Jordan Powers: 25:03

as they were vacuum sealing. So it's a super fond memory for me, but making sure we're doing that safely and using the resources that are out there.

Carla Schwan: 25:10

Definitely, yeah, and our website has many resources and recipes for free, so there is no need for you to find recipes out of social media that we are not sure have been validated or tested and just put your family and yourself at risk for something that is such a preventable thing, right? Because we have the recipes available and they are free access. They're on the website, we also have a book too, that we offer through Extension.

Jordan Powers: 25:34

Absolutely. And we will link all of that in the show notes. So it is right at the fingertips. I think this might be one of the most highly resourced episodes we've done of just all of these tools. I have a million more questions, so I could go on for hours here.

Emily Davenport: 25:47

Yup, me, too.

Jordan Powers: 25:48

But in the interest of time, what have we

Carla Schwan: 25:50

So I would say that for you that are listening, missed, Carla? don't forget your local Extension office and the local experts that you have in your community, so your Extension agents, and we have Family and Consumer Science agents, we also have ag agents that are available to help you. So if you have questions, you're not sure where to find resources, or you need a recommendation on something that you did at home, especially consumer food safety, reach out your local Extension office to those experts, and they're going to be able to help you and guide you in the right direction. So it's easy to go to the internet right away. And of course, we have our websites through UGA Extension, but also giving them a call or just going to your local extension office to connect with the person and ask for help is a good reminder, and we are here to help we are here to serve. We are happy to connect with you. So don't feel shy. We welcome questions, and we welcome the concerns and needs that you have. And we do our best to help you.

Jordan Powers: 26:43

That's such an important reminder, because now that I'm in this job, I know that these things, but I will admit until I started in this role, the amount of times I would do research and whether it was when I was in Iowa and it was Iowa State Extension or even in first moving to Georgia and UGA Extension, you don't realize how much those resources are, one, popping up in your Google searches, which is fantastic. But also that you can go talk to your local Extension agent and, I sound like a broken record, but we have a great tool on the UGA Extension site to just go to your county and it pops up who your local agents are. So we will absolutely link that in the show notes in case our listeners don't know who their local Extension agent is.

Carla Schwan: 27:21

Exactly. And also some classes that we offer. So, home food preservation classes or classes for retail food safety for restaurants and things like that. It's on the calendar so you can easily see the nearest class to you and you can sign up and, you know, be part of that as well. So great resources out there.

Jordan Powers: 27:37

Well, Carla, we have covered a lot in a short period of time. I know I have some new tools in my toolbox to keep myself and my family safer this holiday season and beyond. So we are incredibly grateful for your time today.

Carla Schwan: 27:50

Thank you both so much. I just enjoyed this conversation and connecting with you both. Thank you for the opportunity and for allowing me to come to your studio and record this.

Emily Davenport: 27:58

Thank you so much. We had fun.

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Emily Davenport: 28:01

Thanks for listening to Cultivating Curiosity, a podcast produced by the UGA College of Agricultural and Environmental Sciences. A special thanks to Mason McClintock for our music and sound effects. Find more episodes wherever you get your podcasts.