PULLMAN, Wash. — Yuan Su is a doctorate student at the School of Food Science, focusing on microbial safety of fresh produce. He is graduating this spring with his PhD. Yuan Su was also one of the winners of the 3-Minute Thesis Competition held earlier this year.
Congratulations on being one of the winners for the 3-Minute Thesis competition! Can you tell me what that whole experience was like? All the way from preparation to deliberation?
Preparation was pretty challenging. I was pretty anxious, especially on that day. I didn’t have too much free time to prepare. I was in the industry and was wrapping things up for the last chapter of my dissertation. I had to make the slides and the scripts in the hotel, and, luckily, I have my colleague, Edmund Afari. He’s also a Ph.D. student in the school of food science, and he was helping me at the standpoint of an audience and giving me suggestions on the details.
The biggest challenge is how to convey so much research precisely in three minutes while also thinking that there is a general audience who are not in research, or not in the food safety field. Really what I had to do was explain “why” to the audience, like why I’m doing this while using a lot of content. I’ll say that’s probably two out of three minutes and then I only get the last minute to show my findings.
I actually had to teach for Dr. Zhu for one of her classes as a guest lecturer on that day too. That was from 1pm to 2pm and then the competition kind of started at two. There were so many things happening. Luckily, I think I did good. I never thought I’d win a prize to be honest.
How did it feel to be nominated as one of the winners?
I was thrilled. My [jaw dropped] for a couple of seconds. I was there with my fiancée and my colleague, Edmund, and we were like, “okay, let’s go after they announce everything,” but then, I heard I was in first place, and I was thrilled and also a little bit shocked… That was a good day.
Can you tell us a bit about your background – professional and/or personal?
I’m a PhD candidate in the School of Food Science at WSU. I did both my masters and PhD here. I graduated in 2019 as a Coug in this department. I also participated in the 3-Minute [Thesis competition] back then when I was wrapping things up for my masters. I didn’t win anything then, so that’s kind of the original push for me to register again [this year] because it was the last chance I get, since I’ll be out of school as a student.
For my PhD, my work is to control Listeria monocytogenes, that’s a very dangerous foodborne pathogen. My goal is to control during dump tank processing of fresh apples, a critical step on commercial apple packing lines. My work integrates general microbiology to discover sanitizers’ efficacy during that step. It also integrates some statistical tools, for example, mathematical modeling to predict efficacy during dynamic conditions. Ultimately, my goal is to is to provide information for apple packers as much as possible with scientifically obtained data… and to ensure fresh apple safety and consumer health.
As a consumer myself, my mind usually goes to chicken or lettuce when it comes to outbreaks, and not so much apples. How did you learn about these outbreaks and what made you pursue this direction?
If we’re talking about when I started my PhD, I knew it was important. When I started as a master’s, that’s a whole different story.
L. monocytogenes is a rarer kind of case. With apples, there is only one confirmed outbreak in listeriosis. So, compared to lettuce or chicken, or even some ground meats, they are more frequently involved with pathogens such as Salmonella, E. coli O157: H7. You know, even TV shows knows these names. But L. monocytogenes has higher mortality rate, especially in certain susceptible groups. For example, the apple outbreak in [2014 to 2015] caused seven deaths and 35 hospitalizations, involving the consumption of both fresh and caramel apples. So, when I started doing my PhD, I knew it was a unique challenge and the importance of ensuring fresh apple safety to prevent L. monocytogenes contamination.
To make things harder, there is more of a struggle to control L. monocytogenes. It still grows during refrigeration, and they grow at low temperatures. Also, there’s no killing step, the packers are heavily relying on sanitizer washing. There’s no cooking, there’s no pasteurization, for the purpose of freshness and all those kinds of things that are guaranteed to kill bacteria. That’s part of what makes it such a unique challenge.
But, you know, things were totally different when I started my master’s. I’m Chinese and I traveled here back in 2017 to do my master’s. For my bachelor’s, I also studied food science, but it was more towards the engineering or food storage part instead of food safety. Back then, I did learn about Listeria in classes, but I didn’t know why it was so important across the Pacific. I didn’t know whether it was a major thing in the US or not, because I know it’s not that of a major thing in China. Different countries have different habits in eating and have different eateries. They have their different styles of cooking. The Chinese stir fry and pressure cook a lot and that kind of kills Listeria almost instantly. Here [in the U.S.], when people are eating salads and, you know, ready to eat foods, that’s more serious of a scenario. So, I didn’t know all of this back then, but I got a much better idea throughout my master’s and PhD.
What drove you to pursue food science?
My uncle is a professor in food medicine, so he uses food as a medical treatment to help people adjust their diet and obtain certain health standards nutritionally. When I grew up, he kind of introduced me to a lot of basic research that he did… I think that was the original push for me to study food science.
People always have different needs in their diet and safety problems are still emerging now. It’s a subject that needs continuous support, and continuous effort to address these issues and to bring out more data and convey them to the industries and consumers. Ultimately, we are human, we need to eat and we need to stay healthy.
What has been one of your favorite accomplishments during your time here at WSU?
Last year, I was awarded the Center for Produce Safety (CPS) Professional Development Award. They are a big nonprofit organization that funds research in the produce safety field. They paid all the expenses for me to go to their annual symposium in Denver. I had never been to Denver, never even to Colorado, and so it was a really lovely visit. It was special to me and has been a great honor for me because, you know, that’s a national award and only a few students/postdocs could get it annually across all CPS funded research teams.
Looking ahead, what are you hoping to do after you graduate?
My passion lies in research while also sharing my findings to the public to kind of the extension side or teaching side of things. I’ll do a postdoc after this and I’ll go from there.
Any advice for undergraduate students looking to pursue a graduate degree?
The biggest suggestion I have is to step into a lab and actually feel it, [to have a good idea of what to expect for the future.] Build connections with the professors, so if there’s a position open somewhere it will make it a lot easier for you to get in. During your undergrad is such a wonderful time to explore and I think you can take classes, and you can be in the clouds. Undergrad is the best time to grow. To thrive.