Structural Equation Models Suggest That On-Farm Noncrop Vegetation Removal Is Not Associated with Improved Food Safety Outcomes but Is Linked to Impaired Water Quality

• Published in: Applied and environmental microbiology 2022-12, Vol.88 (23), p.e0160022
• Main Authors: Weller, Daniel L, Love, Tanzy M T, Weller, Donald E, Murphy, Claire M, Rahm, Brian G, Wiedmann, Martin
• Format: Article
• Language: English
• Subjects: Agriculture; Dissolved oxygen; E coli; Ecology; Ecosystem; Ecosystem services; Farms; Food availability; Food Microbiology; Food quality; Food Safety; Impaired water quality; Multivariate statistical analysis; Nutrients; Pathogens; Safety; Soil; Soil water; Soils; Structural equation modeling; Tradeoffs; Vegetation; Water Quality; Wetlands; Wildlife
• ISSN: 0099-2240; 1098-5336; 1098-5336
• DOI: 10.1128/aem.01600-22

While growers have reported pressures to minimize wildlife intrusion into produce fields through noncrop vegetation (NCV) removal, NCV provides key ecosystem services. To model food safety and environmental tradeoffs associated with NCV removal, published and publicly available food safety and water quality data from the Northeastern United States were obtained. Because data on NCV removal are not widely available, forest-wetland cover was used as a proxy, consistent with previous studies. Structural equation models (SEMs) were used to quantify the effect of forest-wetland cover on (i) food safety outcomes (e.g., detecting pathogens in soil) and (ii) water quality (e.g., nutrient levels). Based on the SEMs, NCV was not associated with or had a protective effect on food safety outcomes (more NCV was associated with a reduced likelihood of pathogen detection). The probabilities of detecting spp. in soil (effect estimate [EE] = -0.17; = 0.005) and enterohemorrhagic Escherichia coli in stream samples (EE = -0.27; < 0.001) were negatively associated with the amount of NCV surrounding the sampling site. Larger amounts of NCV were also associated with lower nutrient, salinity, and sediment levels, and higher dissolved oxygen levels. Total phosphorous levels were negatively associated with the amount of NCV in the upstream watershed (EE = -0.27; < 0.001). Similar negative associations ( < 0.05) were observed for other physicochemical parameters, such as nitrate (EE = -0.38). Our findings suggest that NCV should not be considered an inherent produce safety risk or result in farm audit demerits. This study also provides a framework for evaluating environmental tradeoffs associated with using specific preharvest food safety strategies. Currently, on-farm food safety decisions are typically made independently of conservation considerations, often with detrimental impacts on agroecosystems. Comanaging agricultural environments to simultaneously meet conservation and food safety aims is complicated because farms are closely linked to surrounding environments, and management decisions can have unexpected environmental, economic, and food safety consequences. Thus, there is a need for research on the conservation and food safety tradeoffs associated with implementing specific preharvest food safety practices. Understanding these tradeoffs is critical for developing adaptive comanagement strategies and ensuring the short- and long-term safety, sustainability, and profitabi