Agricultural Water Use in U.S. Fresh Produce Growing Operations – Part III: Setting the Foundation for Practical Agricultural Water Testing

Since the adoption of good agricultural practices, produce growers have implemented various measures to reduce the likelihood of using agricultural water contaminated with human pathogens on their crops. Although the regulatory framework under the U.S. Food and Drug Administration’s Agricultural Water Rule recently shifted from mandatory preharvest water testing to risk-based assessments, testing agricultural water to ensure it is “safe and of adequate sanitary quality for its intended use” remains a critical monitoring measure and systems-based verification for the produce industry. This review, third in a series, recaps current agricultural water quality guidelines and standards; examines studies investigating sampling strategies, including location, frequency, timing, and sample volume; and provides an overview of commonly used microbial detection and quantification methods for assessing the microbial quality of agricultural water. For the produce industry, generic Escherichia coli remains the practical fecal indicator to assess microbial water quality, despite the exploration of alternative indicators and the body of research demonstrating its pathogen correlation is generally poor and inconsistent. This review aims to inform produce growers’ agricultural water management strategies by synthesizing research findings related to water sample collection and analysis.