Knowledge Transfer Task Force

Article 19 - Informing on the FSMA water quality rule

January 27, 2022

Related Resources:
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Ivanek - FSMA agricultural-water die-off compliance provisions benefit from condition-specific modifiers
Rock - Agriculture Water Treatment – Southwest Region
Rock - Assessment of E. coli as an indicator of microbial quality of irrigation waters use for produce
Sanchez Moragas - Occurrence and accumulation of potentially infectious viruses in process water and impact of water disinfection practices to minimize viral cross-contamination
Vellidis - Does Salmonella move through the irrigation systems of mixed produce farms of the southeastern United States?

This article originally appeared in Produce Processing, and is reprinted here with permission. © 2022 Produce Processing

While we’re waiting for the dust to settle around newly proposed changes to the Food Safety Modernization Act (FSMA) agricultural water requirements, let’s take a look at what we’ve learned about ag water safety in recent years — and the role that research-informed knowledge has played in driving regulatory change.

No surprise, the fresh produce supply chain has a necessary relationship with water. We rely on water to grow, cool, pack, process, and retail or serve our bounty. Yet we also know that water can efficiently introduce or transfer pathogens to our products at points all across that value chain.

So, answering industry’s questions about water safety — specifically, measuring and managing microbial water quality — has been the top priority at Center for Produce Safety (CPS) since it was founded in 2007, which it has done by focusing on produce-specific food safety research. To date, CPS has invested $9 million in industry and public funds to fund 41 ag-water research projects. Specific to wash water, the center has invested another $2.9 million to fund 17 additional projects.

CPS then transfers learnings to industry and other interested stakeholders via its annual Research Symposium (taking place virtually in 2020 and 2021), webinars, articles in trade press outlets and other channels. Additionally, CPS funded scientists publish their findings in respected peer-reviewed journals, largely in open-access sources.

Here’s a sampling of what we’ve learned from CPS’s water research.

CPS-funded research reported in 2020 shed much-needed light on another component of FSMA water quality regulations. FSMA allows growers to use water exceeding safety levels on a crop, if they wait a prescribed time before harvesting that crop. However, existing science didn’t agree on pathogen die-off rates. Cornell University’s Renata Ivanek, Ph.D., led an international team that set out to bring more surety to the subject. To test the relationship between weather conditions and pathogen die-off, she and her colleagues replicated the same field experiment in the same location multiple times, in locations here and abroad — collecting more than 5,000 produce samples in all. The team was able to develop a model to predict pathogen die-off as a function of bacteria type, produce type, dewpoint and relative humidity. The model appears to predict die-off rates substantially better than FSMA’s matrix, suggesting the rule should be updated.

The rest of the story

The original FSMA water-testing requirements were so complex and prescriptive that industry leaders asked CPS to host a summit of scientists, industry and regulators to review current science and consider options. After that colloquium in early 2017, the Food and Drug Administration announced it was reconsidering its approach to ag water safety and postponed compliance with the 2015 regulations. Four years later, the agency has now proposed replacement rules.

Center for Produce Safety research doesn’t just teach our supply chain how to better safeguard fresh produce, to protect consumers and our businesses alike. It also helps us to advocate for science-based legislation and regulation. To learn how you can benefit from and support CPS’s work, visit


— Dave Murray is a partner with GoodFarms, which grows and markets indoor and outdoor, conventional and organic berries and tomatoes from California, Baja and mainland Mexico. He is a member of Center for Produce Safety’s volunteer Board of Directors, which keeps CPS focused on its mission: to fund science, find solutions and fuel change in fresh produce food safety.