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March 15, 2022

Science: Agricultural Water Management Evolution

By Sonia Salas, WG Assistant Vice President of Science

The fresh produce industry exists to offer safe and nutritious food. Many investments and controls continue to be implemented with the goal of enhancing fresh produce safety. Contamination can come from different sources on and outside the farm, including agricultural water. Therefore, knowing how to manage water quality is critical to reducing produce safety risks during fresh produce production. However, questions remain regarding agricultural water management and where it is heading.

In addition to the risk associated with various water sources, the FAO/WHO committee also recognized the impact of irrigation timing on the fate of pathogens if they were introduced onto the crop via contaminated water. The committee noted that “pathogens have been shown to decline with time following cessation of irrigation before harvest,” and acknowledged that the influence of different irrigation systems was not well understood or studied but that overhead irrigation was likely riskier than any subsurface irrigation.

Food safety practices from the early 2000s to today have rapidly matured, consequently adding significant cost and complexity to food safety and irrigation management. Between April 2006 and April 2007, the leafy green industry’s approach to irrigation water safety moved from a voluntary system of recommended good agricultural practices to a mandatory system of measuring prior to use and monitoring during use to manage microbial water quality using science-based standards.

The leafy greens industry in California and Arizona has recognized the risk of contamination related to water sources along with the timing and method of irrigation and is committed to continuous improvement. The Leafy Greens Marketing Agreement (LGMA) members have adopted food safety metrics that are routinely reviewed and modified. The most recent modifications in 2019 and 2020 addressed agricultural irrigation water by implementing significant changes to further minimize the potential for irrigation water contaminating a field. Rather than only relying on testing and monitoring to ensure the safety of water sources, distribution systems and suitability for intended use, the LGMAs adopted a rigorous risk assessment protocol, limited the use of certain types of waters, enacted timing restrictions and required treatment of select waters in the field. Today, the LGMA-approved metrics embody the most stringent requirements for the use of agricultural irrigation water in the United States.

On Dec. 2, 2021, the U.S. Food and Drug Administration (FDA) announced the long-anticipated proposed changes to the agricultural water requirements (Subpart E) of the Produce Safety Rule. The agency is moving away from a prescriptive approach to a risk assessment-based approach for assessing agricultural water systems. This proposed approach provides flexibility but at the same time creates ambiguity when it comes to how each company conducts a hazard assessment.

As currently proposed, the new approach would require entities to comprehensively assess possible sources and routes by which known or “reasonably foreseeable hazards” are likely to be introduced in pre-harvest agricultural water and then apply mitigation measures. We expect diverse views on how entities define and manage “reasonably foreseeable hazards” and the burden to mitigate issues will fall heavily on the grower despite growers being unable to control adjacent land uses that can impact the quality and safety of agricultural water. We anticipate issues regarding what constitutes nearby areas, appropriate action(s), or mitigation measures that are not solely dependent on antimicrobial water treatments.

As the FDA moves towards a risk-based approach for managing agricultural water, we encourage the agency to work with federal, state and local agencies to support water quality and safety and consider their role and role of other users in water quality and safety. In addition, data-sharing and data analytics can play a key role in filling knowledge gaps and enhancing how farms manage agricultural water in the future. Western Growers will continue working with the produce industry to understand and address the risks associated with agricultural water through the use of data analytics, leading industry efforts and working with all stakeholders.

The role that data science and analytics play in filling knowledge gaps will provide insights and help improve the understanding of different aspects such as various water sources, application methods, and treatment and timing of water applications. Only through collaboration with agricultural neighbors in sharing knowledge, responsibility, and taking a holistic approach to managing water quality and safety can we support a sustainable and safe use of agricultural water.