Welcome back to our FSHN Research Journeys series, which follows graduate students’ research in the Food Science and Human Nutrition program at The University of Florida. In this article, first-year food science master’s degree student Nalanda Doddi describes her research into the methods of preventing norovirus infection resulting from the consumption of oysters. Read on to learn about the harmful results of norovirus infection, how cooking oysters may not eliminate norovirus, and Nalanda’s mission to make oyster consumption safer for everyone.
Nalanda:
Prepare to dive into the intriguing world of microorganisms as our research unfolds like an exhilarating adventure! Imagine these tiny creatures as explorers of an ever-changing thermal landscape, their secrets waiting to be uncovered. My goal? To delve deep into the complex relationships between viruses and oysters at diverse temperatures. This endeavor is essential to elevating food safety standards.
The captivating fusion of scientific inquiry, practical significance, and the potential for better public health outcomes define the mesmerizing field of thermal processing and norovirus inactivation in oysters.
Oysters and Norovirus: A Culinary Conundrum for Food Safety
Human norovirus (HNV) significantly contributes to foodborne illnesses and is the primary cause (49%) of gastroenteritis cases.1 Annually, it results in 19–21 million infections, leading to approximately 109,000 hospitalizations and tragically claiming about 900 lives, as reported by the Centers for Disease Control and Prevention (CDC).2
Most outbreaks are associated with the consumption of raw or undercooked oysters and can trigger a host of symptoms, including sudden onset of stomach pain, nausea, diarrhea, and vomiting, often accompanied by fever, headaches, and body aches.3 These symptoms greatly increase the disease’s burden on public health.
While the U.S. Food and Drug Administration (FDA) recommends specific cooking methods like boiling for three minutes, frying in oil at 375°F (191°C) for ten minutes, or baking at 450°F (232°C) for ten minutes, there is substantial evidence suggesting that these approaches may not completely eliminate the virus, emphasizing the need for further research and enhanced food safety measures.4 However, thermal processing shows promise.
We need further research to determine the optimal temperature-time combinations for successfully inactivating norovirus without compromising the oyster’s enjoyable taste and texture.5
From Culinary Curiosity to Community Commitment: Charting a Course for Oyster Safety at UF
My journey into the realm of food science and safety began with a profound fascination for the culinary world and a deep commitment to community service through my active involvement with the National Service Scheme and the Rotary Club. I engaged in initiatives that addressed food safety and nutrition awareness in the community. These experiences, which included organizing educational workshops and participating in health camps, not only honed my leadership skills but also solidified my resolve to pursue a career where I could make a substantial impact on public health, particularly through enhancing food safety standards.
Within the innovative environment of the University of Florida, renowned for advancing food technology, I’ve found a supportive place that aligns with my aspirations. My mentor is Dr. Andrew MacIntosh, an esteemed food engineering professor and an expert in establishing thermal processes and modeling heat transfer dynamics in oysters. I’ve dedicated my research to finding ways to deactivate HNV in oysters, with the ambition of delivering a significant positive impact on our society.
Oyster Odyssey: Unveiling the Secrets of Norovirus Inactivation and Ensuring Food Safety
This collaborative project is supervised by two mentors: Dr. Naim Montazeri, who specializes in virology, and Dr. MacIntosh. In alignment with USDA FSIS guidelines, the study will use thermocouples, which are essential for recording precise detection and monitoring of cooking temperatures, internal temperature, and oven humidity. This system facilitates continuous oversight of temperature variations, tracking the internal temperature of oysters during cooking methods like steaming, baking, and roasting. The data will be used to develop virus inactivation and risk assessment models.
In my experiment, I will insert thermocouples through the shell into the oyster. Taking temperatures will allow me to identify areas of concern for thermal inactivation. Half-shell oysters will undergo heat treatment with cooking temperatures, internal temperature, oven humidity, and come-up times (time required for the internal temperature of food to reach the level necessary to begin the inactivation of pathogens). We will assess the physical properties of raw oysters via optical scanning, shell density, and internal characteristics.
Instead of studying the highly contagious norovirus in our lab, we will examine surrogates like the Tulane virus as they mimic the actual virus’s behavior while simplifying and securing lab studies. This practice allows researchers to explore norovirus treatments without direct handling. Successful outcomes are applied to norovirus-contaminated oyster samples, testing heat inactivation kinetics. We will assess virus reduction using the Weibull model and first-order kinetics to detect logarithmic reductions in viral surrogates.
The study offers vital insights into effectively neutralizing HNV in oysters through cooking. These results apply to various thermal processing methods, presenting a model to assess the heat response of resilient pathogens. Additionally, it reduces the economic impact of food recalls for businesses and healthcare expenses associated with outbreak-related illnesses.
From Heat to Eat: Safeguarding Oysters Against Viruses
The intricate composition of oysters can lead to insufficient cooking and virus clustering. Some viruses may withstand heat processing, and the health risks of consuming oysters containing heat-resistant viruses remain uncertain. Moreover, a lack of in-vitro models for norovirus adds to the challenges.
To address the challenges associated with oysters’ thermal processing and virus survival, a comprehensive approach is necessary. By exploring the complex structure of oysters through experiments that help us understand thermal simulation, which is crucial in viral inactivation studies, we can refine our cooking methods to optimize safety and taste. Exploring varied cooking durations, temperatures, and approaches might ensure complete heat penetration, minimizing virus survival.
Furthermore, investing in research to develop in-vitro models for norovirus will be pivotal in comprehensively gauging the risks and refining cooking processes. This diligent approach aims to transform cooking practices by blending deliciousness with top-tier safety, ensuring that every oyster is tasty and secure, and instilling trust in culinary experts.
Nalanda is a food technologist who worked as a nutrition officer trainee at Nestle India Pvt. Ltd. and a research and development executive at Kountry Kitchen Pvt. Ltd. (an organic food manufacturing facility). She developed instant breakfast mixes with millet. She is currently pursuing her master’s degree in food science at the University of Florida.
References
- Centers for Disease Control and Prevention (CDC). (2017).: Retrieved from http://www.cdc.gov/foodsafety/fdoss/
- Centers for Disease Control and Prevention (CDC). (2023). Retrieved from https://www.cdc.gov/norovirus/burden.html
- Li, J., Predmore, A., Divers, E., & Lou, F. (2012). New interventions against human norovirus: progress, opportunities, and challenges. Annual review of food science and technology, 3, 331-352.
- Centers For Disease Control and Prevention (CDC). Date, 2022, Norovirus prevention. Available at: https://www.cdc.gov/norovirus/about/prevention.html.
- Gyawali, P., Fletcher, G. C., McCoubrey, D.-J., & Hewitt, J. (2019). Norovirus in shellfish: An overview of post-harvest treatments and their challenges. Food Control, 99, 171-179. Doi: https://doi.org/10.1016/j.foodcont.2018.12.049
Looking for more posts exploring graduate research projects in the FSHN Department at the University of Florida?
Dive into the Research Journeys of other graduate students below.
M.S. Food Science
M.S. Nutritional Sciences
Ph.D. Food Science
Ph.D. Nutritional Sciences
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