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Graduate Defense: Dalton Miller

May 31 @ 1:00 pm - 2:00 pm

Thesis Defense

Thesis Information

Title: Antimicrobial And Chemical Characterization Of Cold Atmospheric-Pressure Plasmas

Program: Master of Science in Chemistry

Advisor: Dr. Ken Cornell, Chemistry and Biochemistry

Committee Members: Dr. Don Warner, Chemistry and Biochemistry and Dr. Jim Browning, Electrical and Computer Engineering

Abstract

Microbial contamination of food processing facilities is a major cause of human disease and economic loss. There are approximately 9,000,000 cases of foodborne illness in the United States annually, leading to 56,000 hospitalizations and 1,300 deaths. The total economic damages are estimated at $36 billion each year, including productive hours, medical expenses, and the disposal of contaminated foodstuffs. Current methods to reduce contamination on food processing surfaces utilize steam or concentrated chemicals (hydrogen peroxide, hypochlorite, strong acids, strong bases) that are hazardous to workers and required large volumes of water to remove prior to resuming contact with food. Ongoing outbreaks of foodborne disease, coupled with these hazards, suggest the need for improved methods of sanitization. One proposed alternative is cold atmospheric-pressure plasma (CAP), which has been demonstrated in numerous studies to exert antimicrobial effects. CAP inactivation of microbes is mediated by reactive oxygen and nitrogen species (RONS), which can cause oxidative damage to biomolecules. However, the impact of different plasma treatments on their antimicrobial effects is not well-understood due to limited prior characterization of the contribution of different plasma parameters the production of RONS. In this work, we characterize the antimicrobial effects and RONS production by single linear CAP discharge and multiple linear array CAP discharge devices, focusing on pathogens relevant to food processing facilities. Importantly, we demonstrate powerful and rapid antimicrobial effects against both gram positive and gram-negative bacteria, and multiple viruses. Additionally, we quantify the production of six different RONS, allowing for a comparison between RONS production and the antimicrobial effects observed with the different CAP treatments.