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

Weller, Daniel; Love, Tanzy; Weller, Donald E.; Murphy, Claire M.; Rahm, Brian G.; Wiedmann, Martin

doi:10.1128/aem.01600-22

Cited by 3 publications

(2 citation statements)

References 77 publications

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“…A 2020 review of agricultural water in the Southeastern United States noted that the geographical location of a water source played an important role in the prevalence and survival of foodborne pathogens ( 35 ). This conclusion is supported by other studies that compared microbial water quality between growing regions nationally ( 16 , 37 ) and locally ( 12 , 17 , 38 ), and between water types ( 32 , 39 – 41 ). Indeed, multiple studies have shown that this variability in water quality limits the efficacy of one-size-fits-all approaches to monitoring and mitigating microbial hazards in aquatic environments.…”

Section: Introductionsupporting

confidence: 77%

Methodological differences between studies confound one-size-fits-all approaches to managing surface waterways for food and water safety

Weller,

Murphy,

Love

et al. 2024

Appl Environ Microbiol

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Even though differences in methodology (e.g., sample volume and detection method) have been shown to affect observed microbial water quality, multiple sampling and laboratory protocols continue to be used for water quality monitoring. Research is needed to determine how these differences impact the comparability of findings to generate best management practices and the ability to perform meta-analyses. This study addresses this knowledge gap by compiling and analyzing a data set representing 2,429,990 unique data points on at least one microbial water quality target (e.g., Salmonella presence and Escherichia coli concentration). Variance partitioning analysis was used to quantify the variance in likelihood of detecting each pathogenic target that was uniquely and jointly attributable to non-methodological versus methodological factors. The strength of the association between microbial water quality and select methodological and non-methodological factors was quantified using conditional forest and regression analysis. Fecal indicator bacteria concentrations were more strongly associated with non-methodological factors than methodological factors based on conditional forest analysis. Variance partitioning analysis could not disentangle non-methodological and methodological signals for pathogenic Escherichia coli , Salmonella , and Listeria . This suggests our current perceptions of foodborne pathogen ecology in water systems are confounded by methodological differences between studies. For example, 31% of total variance in likelihood of Salmonella detection was explained by methodological and/or non-methodological factors , 18% was jointly attributable to both methodological and non-methodological factors. Only 13% of total variance was uniquely attributable to non-methodological factors for Salmonella , highlighting the need for standardization of methods for microbiological water quality testing for comparison across studies. IMPORTANCE The microbial ecology of water is already complex, without the added complications of methodological differences between studies. This study highlights the difficulty in comparing water quality data from projects that used different sampling or laboratory methods. These findings have direct implications for end users as there is no clear way to generalize findings in order to characterize broad-scale ecological phenomenon and develop science-based guidance. To best support development of risk assessments and guidance for monitoring and managing waters, data collection and methods need to be standardized across studies. A minimum set of data attributes that all studies should collect and report in a standardized way is needed. Given the diversity of methods used within applied and environmental microbiology, similar studies are needed for other microbiology subfields to ensure that guidance and policy are based on a robust interpretation of the literature.

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Section: Introductionsupporting

confidence: 77%

Methodological differences between studies confound one-size-fits-all approaches to managing surface waterways for food and water safety

Weller,

Murphy,

Love

et al. 2024

Appl Environ Microbiol

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“…At least 32% of leafy green growers in California's Central Coast reported removing non-crop vegetation on their farms in a survey following the 2006 E. coli outbreak (Beretti and Stuart, 2008). Nearly a decade after the incident, ∼45% of California produce growers still reported clearing vegetation to create or expand bare-ground buffers around their fields (Baur et al, 2016), despite evidence suggesting the practice is ineffective at mitigating food-safety risks (Karp et al, 2015;Sellers et al, 2018;Glaize et al, 2021;Weller et al, 2022). Thus, growers often perceive that hedgerows and windbreaks pose food safety risks in attracting and harboring wildlife, and additional supply chain requirements from processors or retailers may actually prohibit hedgerows in close proximity to crops like leafy greens (Carlisle et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Remote sensing of hedgerows, windbreaks, and winter cover crops in California's Central Coast reveals low adoption but hotspots of use

Thompson

Symonds

Carlisle

et al. 2023

Front. Sustain. Food Syst.

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Non-crop vegetation, such as hedgerows and cover crops, are important on-farm diversification practices that support biodiversity and ecosystem services; however, information about their rates and patterns of adoption are scarce. We used satellite and aerial imagery coupled with machine learning classification to map the use of hedgerows/windbreaks and winter cover crops in California's Central Coast, a globally important agricultural area of intensive fresh produce production. We expected that adoption of both practices would be relatively low and unevenly distributed across the landscape, with higher levels of adoption found in marginal farmland and in less intensively cultivated areas where the pressure to remove non-crop vegetation may be lower. Our remote sensing classification revealed that only ~6% of farmland had winter cover crops in 2021 and 0.26% of farmland had hedgerows or windbreaks in 2018. Thirty-seven percent of ranch parcels had cover crops on at least 5% of the ranch while 22% of ranches had at least one hedgerow/windbreak. Nearly 16% of farmland had other annual winter crops, some of which could provide services similar to cover crops; however, 60% of farmland had bare soil over the winter study period, with the remainder of farmland classified as perennial crops or strawberries. Hotspot analysis showed significant areas of adoption of both practices in the hillier regions of all counties. Finally, qualitative interviews revealed that adoption patterns were likely driven by interrelated effects of topography, land values, and farming models, with organic, diversified farms implementing these practices in less ideal, lower-value farmland. This study demonstrates how remote sensing coupled with qualitative research can be used to map and interpret patterns of important diversification practices, with implications for tracking policy interventions and targeting resources to assist farmers motivated to expand adoption.

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Ungrazed seminatural habitats around farms benefit bird conservation without enhancing foodborne pathogen risks

Olimpi,

Ke,

Baur

et al. 2024

Landsc Ecol

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Context Conservation in working landscapes is critical for halting biodiversity declines and ensuring farming system sustainability. However, concerns that wildlife may carry foodborne pathogens has created pressure on farmers to remove habitat and reduce biodiversity, undermining farmland conservation. Nonetheless, simplified farming landscapes may host bird communities that carry higher foodborne disease risks. Objectives We analyzed the effects of local farming practices and surrounding landscapes on bird communities and food-safety risks across 30 California lettuce farms. Specifically, we sought to determine how farmland diversification affects bird diversity, fecal contamination, and foodborne pathogen incidences, thereby identifying potential tradeoffs between managing farms for bird conservation versus food safety. Methods We surveyed birds at 227 point-count locations, quantified fecal contamination along 120 transects, and assayed 601 bird feces for pathogenic E. coli, Campylobacter spp., and Salmonella spp. We then used hierarchical models to quantify effects of farm management and landscape context on bird communities and food-safety risks. Results Surrounding ungrazed seminatural areas were associated with higher bird diversity, more species of conservation concern, and fewer flocks that may increase risks from foodborne pathogens. In contrast, on-farm diversification practices and surrounding grazing lands offered weaker bird conservation benefits. Surrounding grazed lands were associated with more potentially pathogenic bird feces in crop fields. Conclusions Our results suggest that habitat conservation around produce farms could support bird conservation without increasing foodborne pathogens, especially on farms further from grazing lands. Thus, interventions that diversify farming systems offer potential to simultaneously conserve biodiversity and provide safe food for human consumption.

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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

Cited by 3 publications

References 77 publications

Methodological differences between studies confound one-size-fits-all approaches to managing surface waterways for food and water safety

Methodological differences between studies confound one-size-fits-all approaches to managing surface waterways for food and water safety

Remote sensing of hedgerows, windbreaks, and winter cover crops in California's Central Coast reveals low adoption but hotspots of use

Ungrazed seminatural habitats around farms benefit bird conservation without enhancing foodborne pathogen risks

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