Evaluation of grower practices to mitigate risks of BSAAO use in leafy greens

Studies have shown a direct link between the industry practices of using Biological Soil Amendments of Animal Origin (BSAAOs) and increased pathogen prevalence in the farm environment. Furthermore, repeated observations have highlighted how storage and application strategies at the field level, coupled with environmental conditions, potentially exacerbate in-use amplification during or after a crop production cycle. To address this critical need, this proposal aims to fill the current knowledge gaps concerning the identification and resolution of microbial issues in on-farm practices surrounding the use and storage of BSAAOs. To achieve these goals, we propose a series of four objectives. First, we will work with producers to conduct assessments of finished inputs at appropriate volumes to assess pathogen/indicator loading. This will include testing final finished and cured compost, as well as thermal treated and pelletized manures to determine the baseline microbial load. Next, we will evaluate industry practices at field scale (e.g., stockpiling, temperature/moisture conditions, timing of incorporation/irrigation) that may cause pathogen/indicator persistence or re-growth. These assessments will provide actionable insights into how storage and application practices influence microbial risks and inform improvements in management strategies. Additionally, we will examine the impact of weather conditions (e.g., drought, soil moisture, seasonality, temperature, precipitation) on the persistence, regrowth, and movement of pathogens/indicators within the growing environment. Understanding the influence of weather variability will be critical to developing robust risk mitigation strategies and recommendations. Finally, the study will assess composting, generation and storage conditions associated with pathogen physiological state, particularly conditions that may induce a viable but non-culturable (VBNC) state. This research will uncover critical traits that influence microbial behavior and persistence in diverse agricultural environments. By integrating these efforts, the study will evaluate post-delivery grower management practices and environmental conditions to determine risk reduction strategies that support industry decision-making. This work aims to equip leafy green producers with science-based best practices for the use and application of BSAAOs at the field scale, reducing food safety risks and fostering confidence in fresh produce safety.