Thesis
Environmental monitoring programs to assess food safety risks from food contact surfaces in Washington state apple packinghouses
Washington State University
Master of Science (MS), Washington State University
12/2020
DOI:
https://doi.org/10.7273/000004218
Handle:
https://hdl.handle.net/2376/125215
Abstract
Washington State is the leading producer of apples in the United States. The increasing association of foodborne outbreaks and recalls of fresh apples caused by cross-contamination with the pathogen Listeria monocytogenes within packing facilities, coupled with new regulations from the Food Safety Modernization Act (FSMA), have emphasized the focus on food safety interventions within the apple packing industry. As a result, implementing a robust environmental monitoring program (EMP) is warranted to mitigate the risk of potential contamination with foodborne pathogens. Five apple packinghouses located in Washington State were sampled for the quantification of populations of indicator organisms such as aerobic plate count, Enterobacteriaceae, coliforms and Escherichia Coli, the detection of Listeria species (spp.), and rapid tests such as ATP swabs and glucose and lactose residue swabs on food contact surfaces (FCS). Given that apples are stored up to 12 months in cold storage rooms, packinghouses were visited quarterly to obtain data representing different storage time points. Rapid tests were assessed to evaluate their accuracy in predicting microbial loads on packing surfaces after sanitation procedures over the 2018 packing season. Rapid tests were neither suitable to assess microbial populations nor to detect Listeria spp. Moreover, populations of indicator organisms were not related to the detection of Listeria spp. To assess the prevalence of Listeria spp., 2,988 sample sites were tested after sanitation and after three hours of packinghouse operations over the 2018 and 2019 packing seasons. Among all tested samples, 4.6% were positive for Listeria spp. The wax coating unit operation was associated with the highest frequency of detection of Listeria spp. Several niche points for Listeria spp. were identified, including polishing brushes, brushes and dividers under fan/air blowers, and dryer rollers. An increase in the prevalence of Listeria spp. was observed throughout crop storage time. The results of this research provide a better understanding of the use of rapid tests and indicator organisms testing for the implementation of effective EMP's. Correspondingly, based on the most Listeria-prevalent FCS, strategies to mitigate the risk of contamination with L. monocytogenes can be designed to prevent future outbreaks and recalls.
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Details
- Title
- Environmental monitoring programs to assess food safety risks from food contact surfaces in Washington state apple packinghouses
- Creators
- Bianca Elia Ruiz Llacsahuanga
- Contributors
- FAITH JOHNSON CRITZER (Advisor)
- 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
- Identifiers
- 99900896436201842
- Language
- English
- Resource Type
- Thesis