Disinfection of Foodborne Bacteria using the Contamination Sanitization Inspection and Disinfection (CSI-D) Device

<p>Foodborne pathogens, including <em>Escherichia coli</em>, <em>Salmonella enterica</em>, and <em>Listeria monocytogenes,</em> are major causes of gastrointestinal disease globally. The Contamination Sanitization Inspection and Disinfection (CSI-D) device is a new handheld fluorescence-based imaging system designed to disinfect food contact surfaces contaminated with microorganisms using ultraviolet-C (UVC) illumination. This study aimed to determine the optimal parameters for the disinfection of foodborne bacteria using the CSI-D device. The following bacterial strains were tested: generic <em>E. coli; </em>enterohemorrhagic <em>E. coli </em>(EHEC) O157:H7; enterotoxigenic <em>E. coli</em> (ETEC) O78:H11;<em> S. enterica</em> serotypes Enteritidis, Newport, Typhimurium, and Javiana; and <em>L. monocytogenes </em>serotypes 1/2a, 1/2b, and 4b<em>.</em> Each bacterial strain was spread-plated on non-selective agar and exposed to high-intensity (10 mW/cm²) or low-intensity (5 mW/cm²) UVC for 1 s, 3 s, or 5 s or were not exposed to UVC (control). The plates were then incubated overnight at 37℃ and the resulting colonies were counted. Three trials for each bacterial strain were conducted on separate days. The average of the trials showed that exposure time of 3-5 s at either intensity (high: 10 mW/cm² or low: 5 mW/cm²) resulted in effective and consistent inhibition of <em>E. col,</em> <em>S. enterica, </em>and <em>L. monocytogenes</em> growth. The minimum reduction at 3 s and 5 s exposure for both intensities was 99.95-100% for <em>E. coli</em>, 98.36-100% for <em>S. enterica</em>, and 99.24-100% for <em>L. monocytogenes</em>. The 1 s exposure time resulted in lower efficiency in reducing bacterial growth, with survival rates of 0.48-6.95% for <em>E. coli</em>, 0.29-17.40% for <em>S. enterica</em>, and 1.95-31.8% for <em>L. monocytogenes</em>. The results of this study show that, in pure culture conditions, exposure to UVC with the CSI-D device for at least 3 s is required to achieve 98-100% reduction of <em>E. coli, S. enterica, </em>and <em>L. monocytogenes</em>.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Food Science

Year dc:date.available

2023

Author dc:creator

• McCoy Sanders, Jennifer

Contributors dc:contributor

• Rosalee Hellberg, Ph.D.
• Lillian Senger, Ph.D.
• Anuradha Prakash, Ph.D.

• Contamination Sanitization Inspection and Disinfection (CSI-D)
• disinfection
• foodborne bacteria
• light-emitting diode (LED)
• ultraviolet (UV)
• Food Microbiology
• Food Science

Repository record dc:identifier

https://digitalcommons.chapman.edu/food_science_theses/32

OAI identifier oai:identifier

oai:digitalcommons.chapman.edu:food_science_theses-1032