What is postharvest water?
Any water that is used during and after harvest, including during packing and holding activities. Postharvest water use includes:
- commodity movement
- ice making
- postharvest fungicide and wax
- cleaning and sanitizing
- any water that directly contacts food contact surfaces
Note: Although the Agricultural Water Standard under FSMA’s Produce Safety Rule is currently under revision, there are tools that produce growers and technical assistance providers can use to understand the general quality of a water source (surface, well or municipal) that is applied to fruit and vegetable crops during postharvest activities. Understanding and managing postharvest water quality is extremely important because it is often associated with the last processing/handling steps that produce receives before it reaches the end user.
The subsequent sections cover postharvest water testing and management under FSMA for agricultural water intended to or likely to contact covered produce (other than sprouts), in addition to some best practices for maintaining postharvest water quality.
FSMA water quality criterion for postharvest water, under the Produce Safety Rule
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Water used for harvest and postharvest activities must have no detectable generic E. coli per 100 milliliter sample. This means:
- Single-pass postharvest water is used at 0 CFU of generic E. coli/100 mL
- Recirculated and batch water begins with 0 CFU of generic E. coli/100 mL, and safe and sanitary quality is maintained throughout its use.
Although the Agricultural Water Standard under FSMA’s Produce Safety Rule is currently under revision, the following guidelines may be used to understand and maintain the quality of a water source (surface, well or municipal) that is applied to fruit and vegetable crops during postharvest operations.
Find a water testing lab near you
- Labs must use EPA Method 1603 or an equivalent method to test for presence of generic E. coli, see list of equivalent tests provided by the FDA.
- The labs on this map offer equivalent tests to EPA Method 1603. The map also has each lab’s address and sampling information.
Maintaining postharvest water safety
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When using recirculated, or batch water (water that will be reused over multiple batches of produce), consider variables that impact water quality and the use of antimicrobials in post-harvest wash systems.
- Overview, wash water sanitation systems (Washington State University)
- Visual guide for managing packinghouse wash water quality (Kansas State)
- Water temperature causing infiltration in fresh produce (University of MA, Amherst)
- Turbidity in post-harvest water (Michigan State University)
- Water pH and its impact on the effectiveness of chlorine-based sanitizers
- Guidance on Wash Water Discharge from Vegetable Pack Sheds – Advice on System Design (University of Vermont)
- Backflow prevention (CSU)
- For a comprehensive list of sanitizers labeled for use in post-harvest water on fruits and vegetables, food contact surfaces, and non-food contact surfaces, consult: Labeled Sanitizers for Produce (Excel tool) with accompanying Tutorial: How to Use the Excel Tool Labeled Sanitizers for Produce (Video)
- Any antimicrobial used must be labeled for use with fresh fruits and vegetables and used according to label instructions
- Develop processes and train employees on mixing antimicrobials according to label instructions
Using sanitizers in wash water video series:
- Using Sanitizers in Wash Water: Part 1 – Reasons for Washing Fresh Produce (English, Spanish)
- Using Sanitizers in Wash Water: Part 2 – Types of Wash Systems (English, Spanish)
- Using Sanitizers in Wash Water: Part 3 – Correct Use of Sanitizers (English, Spanish)
- Guidelines for the Use of Chlorine Bleach as a Sanitizer in Food Processing Operations (Oklahoma State University)
- Choosing and Using a Chlorine-Based Disinfectant During Postharvest Handling of Fruits and Vegetables (North Carolina State University)
- Chlorine Use in Produce Packing Lines (University of Florida)
- If you detect any generic E. coli in your postharvest water (either in single-pass water or recirculated water), you must immediately stop using that water. You cannot use that water for postharvest activities (including hand-washing, ice-making, produce washing or cooling, and cleaning or sanitizing of any food contact surfaces) until you determine the source of contamination and eliminate it.
- Once the source of contamination has been eliminated, sanitize your water distribution system, and then re-test your water to ensure that you successfully eliminated the presence of any generic E. coli in your water.
- Keep records of how you corrected the contamination issue and of any sanitizers that you used to clean the system.