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CC BY V4.0, Open Access
Thesis
ESTABLISHING CRITICAL LIMITS FOR COMMERCIAL ANTIMICROBIALS AGAINST FOODBORNE PATHOGENS IN SIMULATED WATER IMMERSION SYSTEMS
Washington State University
Master of Science (MS), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000002399
Handle:
https://hdl.handle.net/2376/120112
Abstract
The increasing number of foodborne illness, outbreaks and recalls associated with fruits and vegetables due to cross-contamination has highlighted the need to develop and implement better food safety practices in the produce industry. While cross-contamination can occur during any stage of production, surveillance data from past whole produce outbreaks have repeatedly found contamination within the packing facility. Previous studies have established the risk of cross-contamination in produce recirculating water systems (e.g., dump tanks and flumes) if concentrations of commercial antimicrobials are not properly maintained. However, most Environmental Protection Agency (EPA) labels for commonly used antimicrobials in these systems control for spoilage organisms rather than organisms that are a public health concern, creating challenges when trying to establish concentrations to effectively mitigate and manage food safety risks. Therefore, the goal of this research was to determine the efficacy of two commonly used antimicrobials [sodium hypochlorite (NaOCl) and peroxyacetic acid (PAA)] against Shiga-toxigenic Escherichia coli (STEC), Listeria monocytogenes, and Salmonella enterica in water with similar quality characteristics seen in these types of systems. Water quality parameters were collected throughout production in three different apple packing facilities in Washington State to establish industry-relevant water conditions for in-lab experiments. Organic load was varied to simulate wash water with organic loads of 30, 500 and 2500 ppm of chemical oxygen demand (COD). Target concentrations of NaOCl (10 to 100 ppm) or PAA (25 to 80 ppm) were added to water. Water was portioned into 500 mL samples and inoculated with a five-strain cocktail of STEC, Listeria, or Salmonella. Aliquots were taken over a duration of 60 seconds, neutralized, serially diluted, and enumerated to determine inactivation. Keeping concentration and time constant, increasing organic load resulted in a significant (p<0.05) reduction in microbial inactivation of PAA and NaOCl for all organisms. Overall, efficacy of microbial inactivation was highly dependent on COD level, sanitizer concentration and exposure time for STEC, Listeria, and Salmonella. Free chlorine was most impacted by increasing organic load. This research highlights the need to set antimicrobial limits based upon expected COD in order to manage risk of cross-contamination within these postharvest washing systems.
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Details
- Title
- ESTABLISHING CRITICAL LIMITS FOR COMMERCIAL ANTIMICROBIALS AGAINST FOODBORNE PATHOGENS IN SIMULATED WATER IMMERSION SYSTEMS
- Creators
- Kory Marlane Anderson
- Contributors
- Faith Johnson Critzer (Advisor)Stephanie Smith (Committee Member)Gulhan Unlu (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Food Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 121
- Identifiers
- 99900606653301842
- Language
- English
- Resource Type
- Thesis