Thesis
Bactericidal effects of Cecure against Listeria monocytogenes on fresh apples
Washington State University
Master of Science (MS), Washington State University
12/2019
DOI:
https://doi.org/10.7273/000004027
Handle:
https://hdl.handle.net/2376/124922
Abstract
Listeria monocytogenes, one of the most challenging foodborne pathogens, has raised a health concern of fresh apples recently through multistate listeriosis outbreaks and numerous recalls. However, ensuring fresh apple safety is challenging because apples are transported and processed in an open environment and the effective kill step is limited. Thus, there is an urgent need for alternative sanitation methods. In this study, Cecure was tested for its antimicrobial efficacy and surfactant role against L. monocytogenes inoculated on fresh apples. Applying 0.8 or 1.6% Cecure for 30 sec or 2 min wash led to 1.3 or 2.0, and 1.8 or 2.6 Log10 CFU/apple reductions against L. monocytogenes on granny smith apples (GSA), respectively. Cecure eliminated the bacteria in spent wash water or sanitizer solutions and prevented the cross-contamination of L. monocytogenes between apples. Cecure had higher antimicrobial efficacy against apple resident microflora than peroxyacetic acid (PAA). 1.6% Cecure led to the maximum reduction of 1.5 and 2.6 Log10 CFU/apple against the total plate counts (TPC) and yeast and molds (Y/M) on GSA, respectively. In addition, the incorporation of Cecure enhanced the antimicrobial efficacy of PAA against L. monocytogenes. PAA at 80 ppm containing Cecure at 100 or 500 ppm reduced L. monocytogenes on GSA by 2.2 and 3.2 Log10 CFU/apple respectively after a 2 min wash, as comparison to 1.6 Log10 CFU/apple reduction achieved by PAA-only treatment. The combinations of PAA and Cecure also eliminated the bacteria in spent solutions. Furthermore, Enterococcus faecium NRRL B-2354 was tested to be a good surrogate for L. monocytogenes on GSA as affected by Cecure (0.8 or 1.6%) intervention or the combinations of PAA and Cecure. In summary, Cecure is effective in inhibiting L. monocytogenes on GSA and preventing bacterial cross-contamination, its efficacy is dependent on concentration and contact time. Cecure enhanced the antimicrobial efficacy of PAA against L. monocytogenes. E. faecium B-2354 is a suitable surrogate for L. monocytogenes on GSA as affected by Cecure interventions with or without PAA.
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Details
- Title
- Bactericidal effects of Cecure against Listeria monocytogenes on fresh apples
- Creators
- Yuan Su
- Contributors
- Meijun Zhu (Advisor) - Washington State University, School of Food Science
- Awarding Institution
- Washington State University
- Academic Unit
- School of Food Science
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900890795301842
- Language
- English
- Resource Type
- Thesis