New Actions by FDA and the Leafy Green Industry Focus on Agricultural Water

Thanks primarily to E. coli O157:H7 outbreaks attributed to romaine lettuce, leafy green growers have been in the food safety spotlight for the past couple of years. Since agricultural water can potentially cause mass contamination if it contains human pathogens, a major portion of the spotlight has been on the microbial quality of ag water used directly on crops during growing and harvesting activities. To address the food safety risk this poses, FDA, in FSMA’s Produce Safety (PS) Rule, requires certain, more risky, ag water sources to be treated with antimicrobial agents (i.e., surface water used on crops during harvest). However, antimicrobial water treatments must be approved by the U.S. Environmental Protection Agency (EPA) for specific uses, and no treatment, as yet, has been approved for such purposes causing a dilemma for the growing community.

To address the issues surrounding ag water safety and, in general, to advance the safety of leafy greens, both FDA and the leafy green industry have taken decisive actions since the beginning of the year. In a July 30th webinar, FDA announced the 2020 Leafy Greens STEC Action Plan, and the leafy green industry recently published amended best practices that tighten up ag water requirements under Arizona’s and California’s Leafy Green Marketing Agreements. In addition, some companies in the buying community are also developing their own proprietary ag water requirements.

In their Action Plan, FDA addresses prevention, response, and knowledge gaps and how the agency plans to collaborate with industry stakeholders and other regulatory agencies. In general, the plan includes initiatives for enhanced inspection, auditing and certification programs; various data collection and analyses endeavors; improved technologies; increased monitoring of adjacent and nearby land use; and numerous research projects as well as additional outreach and communication programs.

As part of the prevention portion of the action plan, FDA developed a new protocol, in collaboration with EPA for registering antimicrobial treatments to control microorganisms of public health significance (foodborne pathogens) in ag water used for crop applications (i.e., irrigation, fertigation, chemigation, etc.). Under the PS Rule, surface water used in direct contact with crops must be treated to make it “safe and of adequate sanitary quality for its intended use and/or meet the relevant microbial quality criteria”. The rule also addresses methods that can be used to treat water including “pesticide devices” (as defined by the EPA), EPA-registered antimicrobial pesticide products, or “other suitable methods”. Ag water requirements for large growers subject to the PS Rule will be enforced beginning in 2022 with medium- to small-sized growers following in 2023 and 2024, respectively.

In conversations with the produce industry after the rule was published, FDA acknowledged its awareness that no antimicrobial treatment product currently on the market is registered for the intended purpose of controlling foodborne pathogens in water used on produce fields or for treating irrigation water systems or ponds. It was never clear to industry whether this was an oversight or if FDA was planning to deal with this issue after writing the rules. However, in the interim the industry has been using several antimicrobial treatment products that are approved for treating drinking water to control microorganisms of public health significance and for treating ag water to kill plant pathogens and to prevent weeds and algae growth (e.g., in irrigation equipment, reservoirs, etc.). Although these treatments would effectively provide water that would meet the PS Rule’s microbial quality criteria, their use to treat ag water for foodborne pathogens so it could be applied to produce crops may be considered off-label (i.e., unapproved, unauthorized, and thus, illegal). In lieu of no registered treatments authorized to eliminate foodborne pathogens in water used on produce crops, EPA agreed to not penalize off-label uses until treatment products could be registered as such. In the meantime, they worked with FDA to establish an approval process for evaluating the efficacy of antimicrobial pesticides against microorganisms of public health significance in ag water.

In their discussions with FDA and EPA concerning the approval process for antimicrobial ag water treatments, industry stakeholders appealed to EPA to consider allowing registration of generic chemicals or classes of chemicals used as a specific product’s active ingredient. Since registration process is cumbersome and expensive, this proposal would have made use of industry-compiled accumulative data and saved time and money. But EPA rejected the proposal and is requiring water treatment manufacturers to submit information and data for both amendments to current product labels and for each specific new product regardless if its active ingredient is the same as a previously registered product.

To-date, no antimicrobial pesticide treatment for foodborne pathogens in ag water has been EPA-approved, but growers continue to use antimicrobial pesticide treatments approved for drinking water and as a fungicide/bactericide/algaecide for irrigation water sources and equipment. Trade associations such as Western Growers serve as a liaison for growers as they navigate the regulatory issues surrounding ag water treatment. The industry is also working with chemical suppliers/service providers and extension specialists to optimize water treatments that are currently being implemented. In addition, researchers – many of whom are funded by the Center for Produce Safety are exploring new methods and procedures for treating ag water to control foodborne pathogens contamination of ag water sources.