Survival, Biofilm Formation, and Control of Foodborne Pathogens in Hydroponic Systems

Author

Sai Rithin Reddy Kothur Thirupathi, The University of Texas Rio Grande Valley

Date of Award

5-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Agricultural, Environmental, and Sustainability Sciences

First Advisor

Veerachandra K. Yemmireddy

Second Advisor

Manohar Chakrabarti

Third Advisor

Amit Raysoni

Abstract

The growing global population and increasingly unpredictable weather patterns have intensified the demand for sustainable food production methods. Hydroponics, a form of Controlled Environment Agriculture (CEA), has gained attention as a viable solution due to its efficient use of resources such as land and water. Although hydroponic systems are perceived as safer alternatives to conventional farming, recent foodborne outbreaks associated with these systems have raised significant public health concerns. This thesis research investigated the food safety risk in hydroponic, particularly the survival and persistence of foodborne pathogens. Chapters I and II provide a comprehensive overview of hydroponics and the microbial hazards associated with nutrient solutions. In Chapter III, the study evaluated the survival of Salmonella Typhimurium, Listeria innocua, and E. coli 0157:H7 in Hoagland's nutrient solution circulated through a CDC biofilm reactor. The pathogens/surrogates were inoculated to reach 106-7 CFU/mL and monitored for 7 days for planktonic survival and biofilm formation on polycarbonate coupons. Results showed that Salmonella persisted in the solution for 7 days with minimal reduction, while L. innocua and E. coli exhibited 3.5 and 1.25 log reductions, respectively. To identify effective interventions, the study examined antimicrobial light treatments such as UV-A, UV-C, and antimicrobial blue light alone and in combination, as well as ultrasound (20 kHz at varying amplitudes) and peroxyacetic acid. Among the treatments, UV-C showed the highest efficacy in pathogen reduction and combination treatments further enhanced microbial reductions in nutrient solutions. Finally, Chapter IV summarizes the major findings, limitations, and future research directions.

Comments

Copyright 2025 Sai Rithin Reddy Kothur Thirupathi. https://proquest.com/docview/3240623850

Recommended Citation

Kothur Thirupathi, S. R. (2025). Survival, Biofilm Formation, and Control of Foodborne Pathogens in Hydroponic Systems [Master's thesis, The University of Texas Rio Grande Valley]. ScholarWorks @ UTRGV. https://scholarworks.utrgv.edu/etd/1713