title: Contamination of Fresh Produce by Microbial Indicators on Farms and in Packing Facilities: Elucidation of Environmental Routes.
abstract: To improve food safety on farms, it is critical to quantify the impact of environmental microbial contamination sources on fresh produce. However, studies are hampered by difficulties achieving study designs with powered sample sizes to elucidate relationships between environmental and produce contamination. Our goal was to quantify, in the agricultural production environment, the relationship between microbial contamination on hands, soil, and water and contamination on fresh produce. In 11 farms and packing facilities in northern Mexico, we applied a matched study design: composite samples (n= 636, equivalent to 11,046 units) of produce rinses were matched to water, soil, and worker hand rinses during two growing seasons. Microbial indicators (coliforms,Escherichia coli,Enterococcusspp., and somatic coliphage) were quantified from composite samples. Statistical measures of association and correlations were calculated through Spearman's correlation, linear regression, and logistic regression models. The concentrations of all microbial indicators were positively correlated between produce and hands (ρ range, 0.41 to 0.75;P< 0.01). WhenE. coliwas present on hands, the handled produce was nine times more likely to containE. coli(P< 0.05). Similarly, when coliphage was present on hands, the handled produce was eight times more likely to contain coliphage (P< 0.05). There were relatively low concentrations of indicators in soil and water samples, and a few sporadic significant associations were observed between contamination of soil and water and contamination of produce. This methodology provides a foundation for future field studies, and results highlight the need for interventions surrounding farmworker hygiene and sanitation to reduce microbial contamination of farmworkers' hands.IMPORTANCEThis study of the relationships between microbes on produce and in the farm environment can be used to support the design of targeted interventions to prevent or reduce microbial contamination of fresh produce with associated reductions in foodborne illness.
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Faith E
authors.initials: FE
authors.lastname: Bartz
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Jacquelyn Sunshine
authors.initials: JS
authors.lastname: Lickness
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás, Nuevo León, México.
authors.forename: Norma
authors.initials: N
authors.lastname: Heredia
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Fabiszewski de Aceituno
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Kira L
authors.initials: KL
authors.lastname: Newman
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Domonique Watson
authors.initials: DW
authors.lastname: Hodge
authors.affiliation: Department of Food Science, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Lee-Ann
authors.initials: LA
authors.lastname: Jaykus
authors.affiliation: Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás, Nuevo León, México.
authors.forename: Santos
authors.initials: S
authors.lastname: García
authors.affiliation: Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA juan.leon@emory.edu.|Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Juan S
authors.initials: JS
authors.lastname: Leon
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D000072480:Farms; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology / Q000295:instrumentation; D018857:Food Packaging / Q000295:instrumentation*; D006225:Hand / Q000382:microbiology; D006801:Humans; D008800:Mexico; D000078329:Workforce
keywords: environmental microbiology; food-borne pathogens; produce