Language selection


Food poisoning trivia with 2 epidemiologists

In this podcast episode, we bust popular myths about food poisoning with 2 epidemiologists, Tanis Kershaw and Courtney Smith, from the Public Health Agency of Canada.

Food poisoning trivia with 2 epidemiologists – Audio transcript

Courtney Smith (guest): By the book, you might see an epidemiologist defined as someone who investigates patterns and causes of disease and health-related events in a population. But more informally, we often explain the role of an epidemiologist as sort of a disease detective. And I'm doing air quotes. (laughs) But yeah, epidemiologists are searching for the cause of a disease, identifying which members of the population are most at risk, and finding ways to prevent or mitigate illness.

Greg Rogers (co-host): Hi, I'm Greg.

Michelle Strong (co-host): And I'm Michelle. And this is Inspect and Protect, the Canadian Food Inspection Agency's official podcast.

Greg: All about food safety, animal health and plant health.

Michelle: Hi, Courtney. Hi, Tanis. Do you want to introduce yourselves?

Tanis Kershaw (guest): Sure. Thank you so much for having us. I'm Tanis Kershaw. I'm currently an Acting Manager with the Outbreak Management Division, and we are part of the Centre for Foodborne, Environmental and Zoonotic Infectious Diseases at the Public Health Agency of Canada.

Courtney: Yes, hi. Happy to be here as well. My name is Courtney Smith. I'm a Senior Epidemiologist and I work right alongside Tanis in the Outbreak Management Division

Greg: Tanis and Courtney, thanks for joining us today. I have a really simple question. What is an epidemiologist?

Courtney: Yes. So a great question, and one that many people have. Especially pre-pandemic, more than post-pandemic. But one of the more obvious examples of an epidemiologist at work is from the COVID-19 pandemic, which everyone knows super well. So you probably both heard a lot about this term, flattening the curve. And epidemiologists or "epis", as we call each other. We're the ones working behind the scenes to make that curve, to track cases, to assess trends and recommend strategies to reduce illness. But, of course, epidemiologists are working on a really, really wide range of health issues. So, for example, epis are working in areas of mental health and addiction, diabetes, breast cancer, environmental health. Basically for any health-related issue, there's an epidemiologist working away behind the scenes trying to understand better how the issue is impacting the population and what can be done about it. And of course, Tanis and myself specialize in enteric disease epidemiology, which is why we're here today. And our bread and butter each day is investigating foodborne outbreaks.

Greg: I have a question: what does enteric mean?

Tanis: Enteric is essentially a gastrointestinal illness.

Michelle: Is it like IBS?

Courtney: Anything related to the intestines. Yeah, I'd say you're referencing intestinal disease of some sort. So we call it enteric illness, or enteric epidemiology, with our focus being on the foodborne aspect of that. Because of course there are other things that can make you sick, digestively speaking.

Greg: I keep thinking of that "don't you put it in your mouth".

Tanis: (laughs)

Courtney: (laughs)

Michelle: That's an old commercial!

Greg: "Because it might not be good to eat".

Michelle: I thought you were going to talk about the Pepto-Bismol song.

Greg: So we hear that you guys have prepared a little true or false kind of test for us. Is that true?

Tanis: That is true. It is not false. Indeed. (laughs)

Michelle: Should we play?

Greg: I love trivia.

Tanis: We thought we could go over some of the statements, kind of common beliefs or misconceptions that we often hear, either from the people we interview or just also our own friends and family, and see what you think about them. So I can start us off with the first one.

So true or false: it's often the last thing you ate that made you sick.

Michelle: False. What do you think, Greg?

Greg: I'd say false.

Tanis: That is correct, yes. So this is probably the one I hear. I would say I hear the most, especially from people I know. And I've been guilty of it myself. So you start to feel some symptoms that you think might be foodborne related and you're immediately going to the last thing you ate, or something you ate a few hours ago. But what I think shocks people or surprises them is that the incubation period, which is the time from when you are exposed to the contaminated food to when you actually get sick, can be quite long for some pathogens. So for E. coli, it's anywhere from about 1 to 10 days. Salmonella for up to 7 days. Something like hepatitis A is actually 15 to 50 days. So 5-0. Listeria, especially severe listeria, can even be up to 70 to 90 days. So you think about … no one's thinking about something they ate two months ago is what's causing their symptoms today, right. So that can be really hard to kind of explain to cases sometimes, thinking about those challenges. A common challenge we have is a case will be convinced it's the last thing they ate. And so they have trouble kind of going through the rest of the interview because they keep coming back to saying, you know, it was this, it was definitely this. And we have to say it could be anything you ate in whatever that time period is.

Michelle: Now you have me second guessing… I had a scenario years ago where we were driving from Ottawa to Toronto and we stopped for lunch and we got a coffee and a sandwich and all that. And I got sick once we got to Toronto, for like 3 days, and I was convinced it was the milk in the coffee. So now I'm thinking I could be wrong.

Courtney: Yeah, that poor milk is probably innocent. (laughs)

Greg: Wrongly accused.

Courtney: Okay, next question. If you shared a meal with your family and that meal had a contaminated food item, everyone will get sick.

Michelle: Oh, that's tough.

Courtney: True or false.

Greg: I think false.

Michelle: I'll go true.

Greg: I'm thinking maybe some people have better systems than others, maybe?

Courtney: Okay. We're divided.

Michelle: Oh, you think you're immune?

Courtney: So the answer is false. If you share a meal, for example, like with your sister or friend, and that meal is contaminated, all options are really on the table. So, you can get sick and your sister, for example, can be totally fine. She can get sick and you can be fine. You can both be sick or neither of you can be sick. So every option is available. And this is because of a variety of factors. So the first is sporadic contamination, which is more or less exactly how it sounds. So sometimes when a product is contaminated, it can be the case that some parts of that product may contain the bacteria or virus of concern, while another part might be totally safe. And it just might be kind of luck of the draw as to which part of that product or meal that you eat.

Michelle: Interesting.

Courtney: And another factor is kind of what Greg was saying, is these individual vulnerability factors. So if someone is more vulnerable than another because of their health status or their age, for example, they may become sick from a contaminated food, while another person who eats that exact same food, they might be totally fine and unaffected. And of course, some food handling can also play a role. So, for example, a family might share a meal that unknowingly has a contaminated ingredient, but the only person who gets sick might be the person who prepared that meal. For example, if the contaminated ingredient was a raw product that was cooked prior to consumption and was safe after cooking. So all in all, we do hear a lot from our cases like, oh no, I shared that meal with my husband and he feels totally fine. So that's definitely not it. But for us, everything is still on the table.

Michelle: That would have been me. I'd be like, I'm fine. Oh, interesting.

Tanis: Okay, we have another one for you.

Greg: I'm winning so far.

Tanis: Okay. Number 3: most people who get a foodborne illness do not become severely ill.

Michelle: I don't know.

Greg: True?

Michelle: (laughs) True?

Tanis: You both sound very confident in your responses. It is true. But we wanted to add some context. So, yes, most people who get foodborne illness will recover at home, usually better within a few days, up to a week, depending who you ask. They might say it was still the sickest they've ever been but they're recovering at home. But it is a misconception. We will hear people say foodborne illness is no big deal, and that's not true. So some people do get quite ill from foodborne illness. They can be hospitalized. And unfortunately, we do also see deaths. And it really depends on the severity of the pathogen as well as individual factors, again. So something like E. coli can cause kidney failure. Something like listeria can be very serious for pregnant people. It can cause miscarriage, stillbirth, and premature birth. And even salmonella can have long-term implications once your infection is over. It can cause joint pain, so severe arthritis. And so people that are more at-risk are children 5 and under, pregnant people, those with a weakened immune system already. And those kind of that 60 to 65 and older age. So we do take it very seriously, as we said, because we do not want people to get seriously ill. Thankfully, most people do recover at home, but we just like to kind of crack that misconception that it's no big deal because it can be a very big deal for some people.

Michelle: And if somebody thinks they're super sick, like is… and I don't know if this is your realm… Should they call their doctor? Should they call a specific phone number in their area or some of them just go straight to the emerg[ency]? What would you recommend?

Tanis: Yeah, I think just like any illness, go see your medical professional right away if you're unwell. So definitely go to the doctor, go to the hospital if that's appropriate. And then when public health will come into play is when that laboratory confirmation comes in. Or if you've gone out, say to a restaurant and your whole dining party has become sick and you're suspecting maybe it was the restaurant, you can call your local public health unit to put in a complaint there and they will do more investigation. So that's something you can do as well.

Michelle: Smart.

Tanis: Okay. Do we have one last one, Courtney?

Courtney: I have another one if there's time, yeah.

Greg: Oh, yeah.

Courtney: Okay. Next one. It's more likely to be the fast food or restaurant meal that made you sick than something you made at home.

Greg: Depends on how much fast food you eat, I guess.

Michelle: I'll say false (laughs).

Courtney: Okay, we got a false. And one "It depends on the quantity of fast food consumption".

Greg: I'll say false too.

Courtney: Okay. This one is an epidemiologist's favourite answer. The answer is: it depends! So often the most memorable foodborne outbreaks are often those that are tied to fast food chains or restaurants, and that's because they tend to get a lot of media attention. But in reality, one scenario is not necessarily more likely than another. Contaminated foods can come into the home via grocery stores just as easily as they can be delivered to restaurants or fast food establishments. And that's why it's always great to pay close attention to recalls announced by the Canadian Food Inspection Agency and the public health notices posted by the Public Health Agency of Canada. So you can stay up to date on outbreaks and ways to avoid foodborne illness. And I'll just plug very quickly that you can subscribe to both the CFIA recalls and PHAC public health notices. So that way no news is good news. But if you do get an email, you'll be fully in the know about how to protect your health and the health of your family.

Greg: That's good advice.

Michelle: Lots of stuff I didn't know. That was fun. Are there any foods that you avoid now because of certain outbreak situations that you've worked on?

Courtney: Oh gosh, yeah. We live and learn definitely through our jobs. I don't know, Tanis, you want to take that one first?

Tanis: I think it's, you know, we learn a lot of good lessons. So for me, I am one of those people who's not eating the raw dough. I took that investigation pretty seriously. There were some people with serious illnesses in that one. And I do not eat kind of those raw products that should be cooked. I do follow all those food safety rules on my end.

Courtney: Yeah, the raw dough. It was interesting because it's something that I didn't know about before joining the team and the job that I have now. I always assumed that raw dough was a risk because of the salmonella from eggs, which I think a lot of people know about, but wasn't aware of the risk from E. coli in flour. So I definitely take heed of this when considering whether or not to eat raw dough. I'm trying to think of other foods that I might avoid. For me, I've worked on a few outbreaks of norovirus associated with consumption of raw oysters. And our recommendation is to cook your oysters before consuming them. So that's…

Michelle: Really?

Courtney: Yeah. So that's definitely something that I've put in practice in my life. So I recommend oysters Rockefeller to anybody who would like to enjoy an oyster but would like to do it in a food-safe way.

Michelle: Is that a baked oyster with cheese on it?

Courtney: Yes. Yeah, exactly.

Michelle: I still like raw oysters… And you're talking to Greg here in the Atlantic area, which I'm sure is a seafood fanatic.

Courtney: Oh no! I hope I'm not offending any Atlantic listeners here. But you know, try baked oyster, add some cheese, add some breadcrumbs. It's delicious.

Greg: Yeah, I don't think I could give up raw seafood, no.

Michelle: I'm with you.

Courtney: No, that's a common comment that we get. People are diehard oyster lovers. So we put the message out there. But of course, everyone makes the decisions best for them. But we know people are oyster lovers for sure.

Michelle: Absolutely. And what made you want to become a foodborne outbreak epidemiologist? Like what got you into this?

Courtney: Okay. So even back when I just started my graduate training in epidemiology, I was always super drawn to outbreaks. To me, it was always the most exciting part of the field and I really liked the fast pace and high-stakes nature of it. And I would also be lying if I didn't say that the movie Contagion played some role in that journey for me. I don't know if we have Contagion fans here amongst the 2 of you.

Greg: Yeah, yeah.

Michelle: I love the pop culture reference.

Courtney: Yeah. I was a big fan when it came out myself, which is surprising, all the way back in 2011 now. But I worked in some different areas of public health before landing this gig as a foodborne outbreak epidemiologist and honestly, I loved it immediately. In public health, we often operate on much longer time scales. So it often takes years or even decades to see the impact of our work in public health. But in the world of foodborne outbreaks, that rewarding feeling of preventing illnesses comes in much shorter intervals.

Michelle: What an impact. Very cool.

Greg: What about you Tanis?

Tanis: So I didn't dream of being a foodborne outbreak "epi" when I was growing up. Mostly because I didn't know it existed. So I didn't really know about the field of public health or epidemiologists at all. And it wasn't until I started working after my undergrad degree in public health that I learned about epidemiology. I found it really interesting. But I really had a love for the outbreak investigation specifically. I really love working on outbreaks because it's very diverse. So no outbreak is the same. I also really love helping to prevent people from getting sick from food. So I do think of us like detectives. I'm not sure if real detectives would appreciate the analogy. But I really do feel like we are looking for clues and pieces of evidence and trying to put that all together.

Michelle: Tanis and Courtney aren't the only ones who consider themselves detectives when it comes to foodborne illness outbreaks.

Greg: As a bit of bonus content for this episode, here's a story from Fred Jamieson, Food Investigation and Recall Specialist at the Canadian Food Inspection Agency.

Michelle: Fred was working in this field before the [Canadian] Food Inspection Agency even existed. His first outbreak investigation happened in… well, I'll let Fred tell you the story.

Fred Jamieson (guest): Yeah, it's hard to believe the first large outbreak I was involved in was exactly 25 years ago. So in March and April of 1998, I was working... I wasn't at the Office of Food Safety and Recall, because it didn't exist at that time. So I was working in Toronto with the staff down there, and this was just a year after the Agency was created. So I was working on an outbreak with Salmonella Enteritidis and it was in a prepackaged, ready-to-eat lunch type product. And at the time, it was considered to be one of the largest outbreaks in Canadian history. There were over 800 reported cases with an estimate about 10 times more. So you're looking at, like that could be up to about 8,000 impacted individuals. 60 of these individuals went to the hospital. And over 80% of these cases were under the age of 15 because this particular product was targeted for children. So this is where I'm saying, like the pressure on, because and it was national. So there's a lot of pressure and we all have children and we should all expect it.

Michelle: That's scary.

Fred: Years ago I'd go, you know: what did you eat? "I'm not sure." And so you'd have to see if they could find their paper receipt or their memory.

And so it was very hard. Like sometimes they didn't know the product. They knew: "Oh, I ate a burger." Well, that didn't really help. So now with debit cards, credit cards, loyalty cards, a lot of social media applications, it makes it easier and faster to trace back foods. I had an issue where there were high school children and they had been getting E. coli O57H7. And the issue here, and usually you associate that with meat. So when we got all their debit cards and all that, we found they would go in the morning, they would go to get breakfast at McDonald's, then they'd go to other different chains. And the issue here was trying to find what was common. And we ended up with…it was a donair product. Right. That was actually linked in. So the idea here is that when a person was consuming 5 or 6 different unique ground beef products in a day, it was a huge issue. But because of the debits and the tapping, we focused in on a single location, and that's what helped us do the investigation.

This is why, often when we do investigations, we often would ask you, "What did you eat for the last 3 days?". And it's very hard for people to remember what they've eaten if they're just home. You know, with COVID and people at home, you'd think it'd be more memorable, but now, when you look at people outside and you go get a coffee and a bun with it, and they do something else. You have your breakfast, and your snacks, and between your snacks, and you have your lunch, so many people may visit 7 or 8 different locations.

For us, it was tracing back, so there's been a lot of improvements in the system, technologically and again, going back, the most important is that just working with all the different departments, there's been the analysis of previous issues and how to improve it. So it doesn't make it faster in many cases because of the microbiological, but communications are key. And that was one of the big issues is that information is important. Just the technology and a lot of the updates and the Internet has made our investigations much quicker.

Michelle: Foodborne illness outbreak investigations are a team effort across Canada. Local, provincial, territorial and federal public health units work together to identify the issue and recall all related products.

Greg: If you aren't currently receiving food recalls and alerts, you should really sign up for them. We've put the link in our description or in the "Learn more" section on our web page.

Michelle: This was Inspect and Protect, the Canadian Food Inspection Agency's official podcast.

Greg: Thanks for listening!

[End of recording]

Listen on Apple Podcasts

Listen on Google Podcasts

Listen on Spotify

Learn more

Get more Inspect and Protect

Date modified: