In response to industry feedback, the FDA is considering the simplification of the microbial quality and testing requirements for agricultural water established by the Food Safety Modernization Act’s (FSMA’s) (P.L. 111-353) produce safety rule while still protecting public health.
The FSMA’s produce safety rule (80 FR 74353) establishes two sets of criteria for microbial water quality of agricultural water, both of which are based on the presence of generic E. coli, which can indicate the presence of fecal contamination:
- No detectable generic E. coli are allowed for certain uses of agricultural water in which it is reasonably likely that potentially dangerous microbes, if present, would be transferred to produce through direct or indirect contact. Examples include water used for washing hands during and after harvest, water used on food-contact surfaces, water used to directly contact produce (including to make ice) during or after harvest, and water used for sprout irrigation. The rule establishes that such water use must be immediately discontinued and corrective actions taken before re-use for any of these purposes if generic E. coli is detected. The rule prohibits use of untreated surface water for any of these purposes.
- The second set of numerical criteria is for agricultural water that is directly applied to growing produce (other than sprouts). The criteria are based on two values, the geometric mean (GM) and the statistical threshold (STV). The GM of samples is 126 or less colony forming unit (CFU) of generic E.coli per 100 mL of water and the STV of samples is 410 CFU or less of generic E.coli in 100 mL of water.
If the water does not meet these criteria, corrective actions are required as soon as is practicable, but no later than the following year. Farmers with agricultural water that does not initially meet the microbial criteria have additional flexibility by which they can meet the criteria and then be able to use the water on their crops. These options include, for example:
- Allowing time for potentially dangerous microbes to die off on the field by using a certain time interval between last irrigation and harvest, but no more than four consecutive days.
- Allowing time for potentially dangerous microbes to die off between harvest and end of storage, or to be removed during commercial activities such as washing, within appropriate limits.
- Treating the water.
The produce safety rule bases testing frequency on the type of water source (i.e. surface or ground water).
Testing Untreated Surface Water
In testing untreated surface water that is directly applied to growing produce (other than sprouts), the FDA requires farms to do an initial survey, using a minimum of 20 samples, collected as close as is practicable to harvest over the course of two to four years. The initial survey findings are used to calculate the GM and STV (these two figures are referred to as the “microbial water quality profile”) and determine if the water meets the required microbial quality criteria.
Testing untreated ground water
For untreated ground water that is directly applied to growing produce (other than sprouts), the FDA requires farms to do an initial survey, using a minimum of four samples, collected as close as is practicable to harvest, during the growing season or over a period of one year. The initial survey findings are used to calculate the GM and STV and determine if the water meets the required microbial quality criteria.
For untreated ground water that is used for the purposes for which no detectable generic E. coli is allowed, the FDA requires farms to initially test the untreated ground water at least four times during the growing season or over a period of one year. Farms must determine whether the water can be used for that purpose based on these results.
Testing public water supplies
There is no requirement to test agricultural water that is received from public water systems or supplies that meet requirements established in the rule (provided that the farm has public water system results or certificates of compliance demonstrating that the water meets relevant requirements), or if the water is treated in compliance with the rule’s treatment requirements.
The feedback that the FDA has received in response to the produce safety rule is that some of these standards, which include numerical criteria for pre-harvest microbial water quality, may be too complex to understand, translate, and implement. These factors can be important to achieving high rates of compliance.
In response to these industry concerns, the FDA is considering how it might simplify the water standards. The FDA indicates it intends to work with stakeholders as these efforts related to the water standards proceed.