Agricultural Water

NOTE: This text has been updated to reflect changes in the proposed FSMA rules as of October 2014.

Background

Farmers use water throughout their operations, for everything from irrigating crops and preventing frost damage to washing and cooling produce.  In the proposed Produce Rule, FDA has developed standards for agricultural water use on farms.

The Food Safety Modernization Act (FSMA) requires the Food and Drug Administration (FDA) to develop regulations aimed at improving the safety of produce.  Water used in agricultural operations has been identified as a potential source of pathogens that may contaminate produce, and Congress required FDA to include standards for water when developing new regulations for produce safety.

Also important to the water standards, Congress required FDA to take into consideration conservation practices and environmental standards such as those by USDA’s Natural Resources Conservation Service (NRCS) and the Environmental Protection Agency (EPA). Congress also specified that FDA could not propose requirements that conflict with or duplicate the requirements for certified organic production.

FDA’s initial proposed water standard caused great concern among produce farmers because the microbial standard, treatment requirements, and testing frequencies were overly prescriptive, inflexible, and insufficiently risk- and science-based.  In response to comments received on this issue, FDA has significantly revised its approach to agricultural water standards, as explained in more detail below.

Proposed Agricultural Water Standards

The proposed standards for agricultural water include:

• General water quality requirements;
• Water system inspection requirements;
• Water treatment requirements;
• Water testing requirements;
• Requirements for water used in harvesting, packing, and holding of produce; and
• Recordkeeping requirements.

The requirements apply to “agricultural water” – i.e., water that is used in the growing, harvesting, packing, or holding of “covered” produce (click here for the list of produce subject to the requirements of the Produce Rule).  FDA considers water to be “agricultural water” if it is intended to or likely to contact covered produce or food-contact surfaces.  Examples of agricultural water include irrigation water that is directly applied to the harvestable portion of a crop, water used for preparing crop sprays, and water used for washing or cooling harvested produce.

Broadly, the proposed agricultural water standards are aimed at minimizing the likelihood of produce being contaminated by pathogens in water used in the growing, harvesting, packing, and holding of produce.  Because the methods for detecting microbial pathogens in water are so limited, FDA is basing its proposed standards on monitoring for hazards and testing water for fecal contamination – specifically for generic E. coli, which FDA claims is a satisfactory indicator for determining fecal contamination.

What the Proposed — and Re-Proposed — Standards Require

General Water Quality Requirements

Generally, the proposed agricultural water standards require farmers to ensure that agricultural water is “safe” and “of adequate sanitary quality for its intended use.”  That means that water should not contain pathogens or contaminants and that it should be suitable for use.  This general requirement underpins the entire water standard.

If, through any of the scenarios discussed below, a farmer has determined or has reason to believe that the agricultural water is not safe or of adequate sanitary quality, generally the standards require the farmer to immediately discontinue use of that water on the farm.  The farmer must then take action to address the water quality problem in one of two ways:

1. Inspect the on-farm agricultural water system components that are under the farm’s control, identify any conditions that could be causing the problem, make any necessary changes to fix the problem, and retest the water to ensure the changes were effective; OR
2. Treat the water (see the water treatment section below).

Water System Inspection Requirements

The proposed standards require a farmer to inspect his/her agricultural water system at the beginning of a growing season.  In that inspection, a farmer must identify conditions that may result in hazards contaminating produce through water, and take into consideration:

• The nature of each agricultural water source (e.g., ground water or surface water);
• The extent of the farmer’s control over each source;
• The degree of protection of each source;
• Use of adjacent or nearby land; and
• The likelihood of hazards being introduced in the water by a farm upstream.

The standards require a farmer to adequately maintain all agricultural water sources under that farmer’s control and keep those sources free of possible sources of contamination such as debris, trash, or domesticated animals.  Farmers must also inspect and maintain equipment used in the agricultural water system, and minimize the amount of pooling water.

FDA’s revised or “supplemental” proposed Produce Rule does not change the general water quality requirements or the water system inspection requirements.

Water Treatment Requirements

The original proposed agricultural water standard presented chemical treatment of agricultural water as the only option if the agricultural water was not safe and of adequate sanitary use and the problem was not within the farmer’s control.  FDA has provide some clarity and flexibility on this issue by allowing farmers to modify their practices and continue using surface water for irrigation without treating it, as explained below in the Water Testing Requirements section.

For non-irrigation purposes, however, treatment is likely the only option for farmers with water that exceeds the applicable microbial standard.  If a farmer must treat the water, then FDA suggests treating water with an antimicrobial compound.  FDA notes, however, that any chemical used to treat water would need to be registered with the Environmental Protection Agency and that, presently, there is no such registration for chemical treatment of irrigation water.  FDA assumes that this issue will be addressed and a new registered product created before farmers must comply with the water standards (see compliance information below).

For water that is treated, FDA requires a farmer to make sure that the treated water is consistently safe and of adequate sanitary use, and to monitor treatment at an adequate, but unspecified frequency.

Water Testing Requirements

FDA is proposing to require testing of agricultural water when that water:

• Directly contacts the harvestable portion of a crop prior to, during, or after harvest;
• Directly contacts food-contact surfaces;
• Is used for hand washing during and after harvest;
• Is used to make agricultural teas; or
• Is used to irrigate sprouts.

A farmer would not be required to test his/her agricultural water if he/she:

• Uses water from public water systems and has public water system results or certificates of compliance;
• Uses an irrigation method that does not directly contact the harvestable portion covered produce (e.g. drip or furrow irrigation); or
• Treats the water according to the water treatment requirements (see above).

For farmers that have to test water, FDA is proposing three numerical standards for testing:

1. No detectible E. coli present per 100 ml of water:  This standard would apply to water used for an activity during and after harvest, water used to make agricultural teas, and water used in sprout irrigation.
2. A geometric mean of no more than 126 CFU per 100 ml: This standard would apply to untreated groundwater used to irrigate in a manner that directly contacts the harvestable portion of the crop.
3. A statistical threshold value of 410 colony forming units (CFUs) generic E. coli per 100 ml for a single water sample, and a geometric mean of no more than 126 CFU per 100 ml:  This standard would apply to untreated surface water used for growing activities (except for sprouts) that directly contact the harvestable portion of the crop.  If your water testing shows that you exceed these values, you can still use your water, as long as you apply an appropriate time interval between the end of irrigation and harvest (see the “Calculating Microbial Die-off” section below).

This is a significant change from FDA’s original approach, which set a limit of 235 CFU per 100 mL and prohibited the use of water that exceeded this limit.

FDA’s New Approach to Testing and Using Untreated Surface Water

FDA has proposed a new tiered approach to testing and using untreated surface water that is directly applied to the harvestable portion of the crop:

1. Conduct a baseline survey to initially develop the water quality profile of each of your water sources: FDA is proposing that you develop your water quality profile by calculating the geometric mean (GM) and the statistical threshold value (STV) of generic E. coli (in CFU per 100 mL) using at least 20 samples over at least two years.  You should sample the water as it’s used (e.g. at the end of the sprinkler), and collect the samples during a time period as close as practical to harvest.
   • If your water quality profile is above the STV and GM thresholds, then you are not required to stop using that water source.  Instead, you can still use the water in conformance with the microbial die-off provision (see “Calculating Microbial Die-Off” below).
2. Verify your water quality profile through annual sampling: Each year, you must take at least 5 new samples to verify the accuracy of your water quality profile.  If your annual survey is sufficiently different from your existing water quality profile, then you would have to update your water quality profile and make adjustments to your practices.
3. Re-establish your baseline: FDA is proposing that you re-establish your baseline survey every ten years, or sooner if your annual survey samples do not support your water quality profile, and then adjust your practices accordingly (e.g. wait another day or two before harvesting, based on the microbial die-off rate).

To develop a new water quality profile, you can use your 5 samples from the current year’s annual survey combined with past year’s samples (e.g. 15 samples from the last 3 years).  You can also use your 5 current samples and take 15 new samples to meet the 20 sample minimum.  However, if you know or have reason to believe that your water quality profile no longer represents the quality of your water due to significant changes in neighboring land use or other impacts outside of your control that could adversely affect the quality of your water source, then you must re-establish your baseline with at least 15 new samples, and modify your practices accordingly.

If you are using untreated surface water for other purposes, like post-harvest, to irrigate sprouts or make agricultural teas, for hand washing, or in direct contact with food-contact surfaces, then you must test the quality of each source of the water “with an adequate frequency to provide reasonable assurances that the water meets the required standard” (no detectable generic E. coli per 100 mL).  You must have adequate scientific data or information to support your testing frequency.

Calculating Microbial Die-Off

If you are using untreated surface water to irrigate in a way that directly contacts the harvestable portion of the crop, and your water quality exceeds the proposed STV and GM thresholds, you can still use that water as long as you wait enough time to account for the natural reduction in generic E. coli (“microbial die-off”) that would bring you below within the threshold.  If this confuses you, you aren’t alone.  This is a relatively complicated concept, and FDA recognizes that they will need to provide guidance and education to help farmers calculate the appropriate number of days that they need to wait between the end of irrigation and harvest.

FDA has proposed a die-off rate of 0.5 log per day that would apply to determine the number of days you must wait between irrigation and harvest.  This rate means that every day after you irrigate, you can assume a roughly 67% reduction in generic E.coli on the surface of the crop due to natural causes like sunlight, moisture, temperature, pH, etc.  FDA provides some examples of how applying the 0.5 log die-off rate allows you to use water that would otherwise exceed the standard.

You can also use an alternative die-off rate for the time between irrigation and harvest, and/or apply a die-off rate between harvest and end of storage.  In both instances, you are expected to provide documentation showing that the alternative method is supported by adequate scientific data indicating that the alternative would provide the same level of public health protection and would not result in adulterated produce.  This alternatives option is not applicable to water used during and after harvest, water used to make agricultural teas, and water used in sprout irrigation.

FDA’s New Approach to Testing and Using Untreated Groundwater

If you are using untreated groundwater, FDA has proposed a tiered testing approach like that for untreated surface water:

1. Conduct a baseline survey to develop a water quality profile: FDA is proposing to require at least four tests during the growing season or over the period of one year, using at least four samples collected as close as practical to harvest.
   • If the groundwater is for post harvest use, handwashing, sprouts, agricultural teas, or it contacts food-contact surface, the standard is no detectable generic E. coli per 100 mL
   • If you are using the water for irrigation and it will directly contact the harvestable portion of the crop, the standard is a geometric mean of generic E. coli of 126 CFU or less per 100 mL
2. Annual Verification: If you meet the applicable standard in your baseline survey, then you only need to test once annually.  But, you must resume testing at least four times per year (or growing season) if any annual test fails to meet the standard.

Sharing Water Testing Data

FDA has proposed new provisions that address the issue of whether and how farmers can use test results obtained by third parties.  You can use:

• Test results that you obtain, or by someone else or another entity acting on your behalf; or
• Data collected by a third party or parties, provided the water source(s) sampled adequately represent your water source(s), as long as the requirements above regarding testing are met.

Requirements for Water used in Harvesting, Packing, and Holding of Produce

For water used during harvesting, packing, and holding activities, FDA is requiring farmers to manage the water to maintain adequate sanitary quality and minimize the potential for contamination.  Farmers must visually monitor the quality of water for build-up of organic material, and must maintain and monitor water temperature to minimize the potential for infiltration of microorganisms into covered produce.

Recordkeeping Requirements

FDA is proposing that farmers keep the following records with respect to agricultural water:

• The findings of the inspection of the agricultural water system;
• Documentation of results of any analytical tests conducted to determine whether agricultural water is safe and of adequate sanitary quality;
• Scientific data or information to support the adequacy of a water treatment method used;
• Documentation of results of water treatment monitoring;
• Documentation of the results of water testing;
• Scientific data used to support the use of an alternative for agricultural water used during growing activities;
• Scientific data used to support the use of an alternative microbial die-off rate; and
• Annual documentation of the results or certificates of compliance from a public water system, if applicable.

All of these recordkeeping requirements are subject to the overarching recordkeeping requirements of the proposed Produce Rule, available here.