Events Calendar

Astani Civil and Environmental Engineering Seminar

Speaker: Adam Simpson, Ph.D. Candidate, Stanford University

Talk Title: Predicting Initial Transformation of Food-Based Bio-Polymers and -Molecules During Food Disinfection

Abstract: Foodborne pathogenic outbreaks still occur 100x more frequently than waterborne pathogenic outbreaks from municipal/community water supplies in the US, despite the passing of the Food Safety Modernization Act of 2011. To kill pathogens, food packaging facilities must treat fruits, vegetables, and meats with high dosages of chemical sanitizers-”most frequently free chlorine-”for ready-to-eat and triple washed foods. Food chemists and engineers have looked to water disinfection byproduct research to predict and measure contaminants (i.e., trihalomethanes, haloacetic acids and chlorates) formed in food disinfection washwaters as potential chemical exposures to consumers. However, my research demonstrates that this is fundamentally incorrect as the boundary conditions of food disinfection and water disinfection processes
are incongruent. First, I will introduce current food disinfection processing techniques and conditions and compare with water disinfection to encourage a new way to predict initial transformation products formed during food disinfection. Second, I will demonstrate the formation of chlorotyrosines isolated inside of chlorine washed spinach and lettuce in comparison to volatile disinfection byproducts isolated in the washwater to prove where true toxic exposure risks are. Third, I will introduce a new class of food-based disinfection byproducts measured inside of chlorine treated vegetables, namely fatty acid chlorohydrins,and compare the cumulative toxic potencies of these chlorine treated vegetables to a poor-quality water at EPA regulated limits to demonstrate the relative magnitude of these exposures. I will end the seminar with a glance of my future research involving this uncharted field.


Biography: Adam Simpson is a PhD candidate at Stanford University, in the Civil and Environmental Engineering Department advised by Professor William Mitch. His research involves using organic chemistry and complex analytical chemistry techniques to synthesize and isolate new classes of food-based disinfection
byproducts that are toxic and affect most consumers. To advance his depth of knowledge and experience with postharvest crop treatment, he is also undergoing a stint at the United States Department of Agriculture-”Agricultural Research Service in Parlier, California, where he is also advised by the
Environmental Chemist, Dr. Spencer Walse. His work has been supported by multiple fellowships including a Stanford Graduate Fellowship, a National Science Foundation Graduate Research Fellowship, and a Diversifying Academia, Recruiting Excellence Fellowship. He will receive his PhD in Civil and Environmental
Engineering in May-2022 and received his M.S. degree in Civil and Environmental Engineering from Stanford University, and B.S. degree in Chemical Engineering from Carnegie Mellon University. Beingpassionate about diversifying academia, Adam is also a science communicator through his YouTube Channel, where he aims to humanize academia with a focus on Science, Technology, Engineering, and Math Education, while uplifting underrepresented voices. With an ambition of being a tenure-track assistant
professor of Civil and Environmental Engineering-”he hopes to continue his work to make a more inclusive
academia.

Host: Dr. Daniel McCurry

Webcast: https://usc.zoom.us/j/94682875854 Meeting ID: 946 8287 5854 Passcode: 090068

Location: Michelson Center for Convergent Bioscience (MCB) - 102

WebCast Link: https://usc.zoom.us/j/94682875854 Meeting ID: 946 8287 5854 Passcode: 090068

Audiences: Everyone Is Invited

Contact: Evangeline Reyes