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Throughout the United States, diverse water sources and delivery systems are used in fresh produce production from pre-planting through post-harvest operations. These operations include soil preparation, irrigation, agrochemical mixing, microclimate protection from freeze injury and sunscald, dust abatement on farm roads, harvesting activities, and cleaning and sanitizing of field equipment. Water used in produce operations comes from groundwater, surface water, or collected rainwater and is accessed from wells, rivers, creeks, streams, reservoirs, ponds, lakes, irrigation districts, municipal supplies, and private purveyors. Human pathogens that have been detected in water include bacteria, parasites, and viruses, many of which can survive in water for extended periods of time posing a food safety risk when contaminated water is used on or near produce crops. To fulfill mandates in the Food Safety Modernization Act, the U.S. Food and Drug Administration (FDA) has proposed risk-based regulations for agricultural water that are expected to be finalized within 2024. This review, the first part of a series on agricultural water in produce production, gives an overview of how agricultural water is used during production activities throughout produce growing regions in the United States and summarizes recent and seminal research relevant to pathogen prevalence and persistence in agricultural water. [ABSTRACT FROM AUTHOR]

Environmental Monitoring Programs (EMPs) have been historically implemented in processing facilities, with more recent application in raw agricultural commodity packing operations. EMPs verify effectiveness of sanitation programs and reduce harborage/niches of microorganisms. While benefits of EMPs are well recognized, there has not been a formal survey of produce packers adopting these programs to determine their scope, including information on sampling targets and frequency of sampling by environmental zone. Approximately 62.5% of produce packers (40/62 packinghouse; 5/10 field-pack) who responded to the survey indicated they had an EMP. ATP was the most common monitoring technique used for zone 1 surfaces, followed by generic Escherichia coli, Listeria species, and aerobic plate counts. A shift was noted towards addition and greater reliance on pathogen targets (e.g., Salmonella) for zones 2-4. While 100% of produce packers with an EMP had corrective actions (CA) identified, 42% reported never needing to implement a CA, suggesting produce packers were always in conformance. This result indicates a potential shortfall in EMP rigor, as occasional failures are expected. Overall, survey findings can be used as a baseline to assess changes in EMPs over time and to emphasize potential points of confusion when conducting outreach to the fresh produce industry. [ABSTRACT FROM AUTHOR]

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 metaanalyses. 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 quant ified 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 difference s 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. [ABSTRACT FROM AUTHOR]