Ep. 191. Dr. Edward Dudley: Wastewater Monitoring for Foodborne Pathogen Surveillance
Apr 8, 2025
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Dr. Edward Dudley, a leading expert in foodborne bacteria at Penn State, discusses innovative wastewater monitoring methods to track foodborne pathogens like Salmonella and E. coli. He highlights a study showing how genome sequencing links pathogens in wastewater to human illnesses. Patrick Schneider adds insights on chlorine dioxide's effectiveness in food plant sanitation, showcasing its advantages as a biocide. Together, they explore challenges in food safety, the implications for public health, and the importance of early pathogen detection.
Wastewater monitoring proves effective for tracing foodborne illnesses, linking salmonella in wastewater to clinical cases in Pennsylvania.
Chlorine dioxide is emphasized as a sustainable sanitation solution due to its effectiveness at lower concentrations without harmful byproducts.
Whole genome sequencing is revolutionizing outbreak surveillance but faces challenges in linking genomic data to direct human illness causation.
Deep dives
The Importance of Chlorine Dioxide in Sanitation
Chlorine dioxide is presented as a crucial component in effective sanitation protocols across various industries. It is recognized as a powerful oxidizing agent that serves as a biocide, viricide, and fungicide. Unlike traditional chlorine and chlorine bleach, chlorine dioxide is highlighted for its effectiveness at lower concentrations without producing harmful byproducts, making it more sustainable. Its application spans food processing, water treatment, and animal husbandry, underscoring its versatility in maintaining health safety standards.
Wastewater Surveillance for Foodborne Pathogens
Research indicates that monitoring wastewater can be significantly beneficial in tracing foodborne illnesses, with findings linked to salmonella outbreaks in Pennsylvania. A project led by Dr. Edward Dudley's team utilized wastewater samples to successfully isolate and identify salmonella, establishing genetic connections to known clinical cases. The study emphasized the value of composite sampling techniques, which provide a more accurate representation of pathogen presence over time. This innovative approach not only adds depth to public health monitoring but also suggests a new avenue for preventing foodborne outbreaks.
Regulatory Developments in Food Safety
Recent regulatory changes announced by the FDA include a 30-month delay in the compliance date for the food traceability rule under FSMA section 204D. Despite the delay, FDA remains committed to enforcing the traceability requirements aimed at improving food safety and enhancing the speed of responding to potential outbreaks. Consumer advocacy groups have voiced concerns regarding the impact of the delay on public health, highlighting the necessity for precise compliance timelines. The contradictory views from industry stakeholders reveal the complexities as they navigate food safety regulations while ensuring consumer protection.
Emerging Concerns with Microplastics
A study reveals that microplastics may contribute to antimicrobial resistance in pathogens like E. coli, posing a new threat to food safety. The research indicates that bacteria residing on microplastics can develop stronger biofilms, leading to increased resistance levels, even after halting antibiotic exposure. The alarming presence of microplastics in various food products underscores the need for comprehensive strategies to address this issue. These findings are pivotal as they illustrate the potential health risks associated with environmental pollutants and their interaction with foodborne microorganisms.
The Future of Whole Genome Sequencing in Food Safety
Whole genome sequencing (WGS) is revolutionizing the field of food safety, enhancing outbreak tracing and surveillance. As sequencing technology advances, it allows for rapid identification of pathogens, significantly improving outbreak response times and public health outcomes. However, challenges arise in linking genomic data to direct causation in human illnesses, emphasizing the need for further investigation. Researchers continue to explore how to efficiently interpret sequencing data to maximize its utility in foodborne outbreak investigations, demonstrating WGS's transformative potential in food safety practices.
Edward G. Dudley, Ph.D. is the Director of the E. coli Reference Center and a Professor of Food Science at the Pennsylvania State University. He has a broad background in molecular biology, physiology, and foodborne bacteria genomics, with expertise in both beneficial and pathogenic species. His current research program focuses on factors that drive the virulence of Escherichia coli O157:H7 and the development of DNA sequence-based methods for tracking pathogen spread during foodborne illness outbreaks, including wastewater monitoring.
Dr. Dudley is a past Chair of the Food Microbiology Division of the American Society of Microbiology (ASM), the Food Microbiology Representative to ASM's Council of Microbial Sciences, and a previous member of ASM's Microbe Program Committee. In 2019, he was appointed an ASM Distinguished Lecturer and Co-Editor of the Evolution and Genomics domain for ASM's online journal, EcoSal Plus. He was also elected to the American Academy of Microbiology in 2023. Dr. Dudley holds a Ph.D. in Bacteriology and an M.S. degree in Food Science, both from the University of Wisconsin–Madison.
In this episode of Food Safety Matters, we speak with Dr. Dudley [35:17] about:
A study conducted by Dr. Dudley’s lab that investigated the usefulness of wastewater monitoring for surveillance of foodborne Salmonella illnesses
How whole genome sequencing (WGS) was used to link Salmonella isolates from wastewater systems in central Pennsylvania to an existing salmonellosis outbreak
The significance of discovering the rare S. Baildon serotype in the wastewater samples
How wastewater monitoring activities could fill gaps created when foodborne illnesses go underreported by infected people, as well as the potential limitations of wastewater monitoring for foodborne illness surveillance
Other foodborne pathogens besides Salmonella that could be surveilled via wastewater monitoring
Apart from the Salmonella wastewater monitoring study, various research projects carried out by Dr. Dudley’s lab related to E. coli.
Before we speak to Dr. Dudley, we also hear from Patrick Schneider [25:37], Vice President of Operations and Engineering (Chlorine Dioxide) at CDG Environmental LLC. In his interview, he discusses the usefulness of chlorine dioxide for food plant sanitation, and what makes CDG Solution 3000TM the “gold standard in chlorine dioxide solutions.” Prior to joining CDG Environmental, Mr. Schneider spent 35 years holding various global roles in the oil and gas industry. He holds a B.S. degree in Petroleum Engineering from Penn State University.
