Thesis
Assessment of bacterial water quality in an irrigation drainage and delivery system and adoption of good agricultural practices among Pacific Northwest produce growers
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/101144
Abstract
Agriculture drives Washington’s diverse economy. Fresh produce outbreaks are increasing; on-farm food safety is imperative to prevent economic losses and reduce illnesses. Irrigation water is an important pathogen vehicle; regulatory and industry bacterial water quality criteria exist, including WA-Department of Ecology (WADOE), Leafy Greens Marketing Agreement (LGMA) and proposed Food Safety Modernization Act (FSMA) rules. A study examined 17 sites over 12 dates from 2008-2009 in an intensively-utilized Washington water system, comparing total coliform, fecal coliform and generic E. coli levels to current criteria and examining Salmonella spp. and E. coli O157 prevalence . Indicator organism levels were quantified using the Most Probable Number method. Salmonella and E. coli O157 were isolated using FDA-BAM methods. Data were analyzed to examine sampling date within year and site; data were compared with regulatory and industry criteria. Fecal coliform levels increased (p<0.05) from May to the highest levels in July, 2008 with significant decreases in August and September. Generic E. coli levels followed different trends, with significantly higher levels in May, 2008 and June, 2009 with levels declining for the remainder of the season. Salmonella spp. were detected in 4% and E. coli O157:H7 in 3% of samples. All samples exceeded WSDOE fecal coliform criteria; only canal site 16 met proposed FSMA generic E. coli standards. Sampling sites more frequently met LGMA generic E. coli guidelines; however, over half of pathogen positive samples were observed when LGMA guidelines were achieved. In another study, Good Agricultural Practices (GAPs) workshops were conducted to increase Pacific Northwest food safety practices. Session one provided a lecture-based overview, and a discussion-based Session two format focused on implementation. Participant evaluations (330) determined impacts from 10 Session one and 9 Session two workshops from 2008-2009. Between workshops, almost half of the participants’ status changed on implementation of GAPs and recordkeeping (45.6% and 42.6%, respectively). Fecal coliform and generic E. coli results did not align for overall conclusions; however, water quality monitoring is necessary to establish baselines for comparison. Growers implementing GAPs tended to focus on recordkeeping and hygiene training; however, interest in water testing was specifically expressed in follow-up workshops.
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Details
- Title
- Assessment of bacterial water quality in an irrigation drainage and delivery system and adoption of good agricultural practices among Pacific Northwest produce growers
- Creators
- Katherine M. Sandoval
- Contributors
- Karen M. Killinger (Degree Supervisor)
- 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; [Pullman, Washington] :
- Identifiers
- 99900525123401842
- Language
- English
- Resource Type
- Thesis