title: Multifactorial effects of ambient temperature, precipitation, farm management, and environmental factors determine the level of generic Escherichia coli contamination on preharvested spinach.
abstract: A repeated cross-sectional study was conducted to identify farm management, environment, weather, and landscape factors that predict the count of generic Escherichia coli on spinach at the preharvest level. E. coli was enumerated for 955 spinach samples collected on 12 farms in Texas and Colorado between 2010 and 2012. Farm management and environmental characteristics were surveyed using a questionnaire. Weather and landscape data were obtained from National Resources Information databases. A two-part mixed-effect negative binomial hurdle model, consisting of a logistic and zero-truncated negative binomial part with farm and date as random effects, was used to identify factors affecting E. coli counts on spinach. Results indicated that the odds of a contamination event (non-zero versus zero counts) vary by state (odds ratio [OR] = 108.1). Odds of contamination decreased with implementation of hygiene practices (OR = 0.06) and increased with an increasing average precipitation amount (mm) in the past 29 days (OR = 3.5) and the application of manure (OR = 52.2). On contaminated spinach, E. coli counts increased with the average precipitation amount over the past 29 days. The relationship between E. coli count and the average maximum daily temperature over the 9 days prior to sampling followed a quadratic function with the highest bacterial count at around 24°C. These findings indicate that the odds of a contamination event in spinach are determined by farm management, environment, and weather factors. However, once the contamination event has occurred, the count of E. coli on spinach is determined by weather only.
authors: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA Center for International Health Research, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA dvm.spark@gmail.com.
authors: Sangshin
authors: http://orcid.org/0000-0003-2407-0962
authors: S
authors: Park
authors: Department of Animal Sciences, Colorado State University, Fort Collins, Colorado, USA Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA.
authors: Sarah
authors: S
authors: Navratil
authors: Department of Horticultural Sciences, Texas A&M AgriLife Extension Service, Weslaco, Texas, USA.
authors: Ashley
authors: A
authors: Gregory
authors: Department of Horticultural Sciences, Texas A&M AgriLife Extension Service, Weslaco, Texas, USA.
authors: Arin
authors: A
authors: Bauer
authors: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA Tarleton State University, Stephenville, Texas, USA.
authors: Indumathi
authors: I
authors: Srinath
authors: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
authors: Barbara
authors: B
authors: Szonyi
authors: Department of Animal Sciences, Colorado State University, Fort Collins, Colorado, USA Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas, USA.
authors: Kendra
authors: K
authors: Nightingale
authors: Department of Horticultural Sciences, Texas A&M AgriLife Extension Service, Weslaco, Texas, USA.
authors: Juan
authors: J
authors: Anciso
authors: Department of Statistics, Texas A&M University, College Station, Texas, USA.
authors: Mikyoung
authors: M
authors: Jun
authors: Department of Epidemiology and Biostatistics, School of Public Health, Texas A&M Health Science Center, College Station, Texas, USA.
authors: Daikwon
authors: D
authors: Han
authors: Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
authors: Sara
authors: http://orcid.org/0000-0001-9154-8909
authors: S
authors: Lawhon
authors: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
authors: Renata
authors: R
authors: Ivanek
mesh_terms: D000822:Animal Husbandry; D058491:Bacterial Load; D003120:Colorado; D003430:Cross-Sectional Studies; D004777:Environment; D004926:Escherichia coli / Q000302:isolation & purification*; D005506:Food Contamination; D005516:Food Microbiology; D015233:Models, Statistical; D011891:Rain; D018724:Spinacia oleracea / Q000382:microbiology*; D013696:Temperature; D013781:Texas
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