Practical Food Safety Resources for the Produce Industry
Highland Fresh Technologies provides practical food safety, cleaning, sanitation, and antimicrobial resources for the fresh produce industry. This resource center is designed to help growers, packinghouses, and produce processors better understand produce wash water management, cleaning and sanitation practices, antimicrobial technologies, verification methods, and other factors that support effective food safety programs.
Explore Produce Food Safety Topics
Produce Wash Water Management
Effective produce wash water management is an important part of reducing the potential for cross-contamination during washing and handling. Antimicrobial concentration, organic load, pH, water temperature, contact time, product-to-water flow, and ongoing monitoring can all affect how a wash system performs. The resources below provide practical guidance and technical information for managing produce wash water and antimicrobial systems.
Sanitizer Concentration & Process Control
Maintaining the appropriate antimicrobial concentration throughout production is an important part of produce wash water management. The concentration needed depends on the antimicrobial being used, its EPA-approved label directions, the application, water conditions, and the amount of organic material entering the system.
A concentration established at startup should not be assumed to remain constant throughout production. Fresh produce, soil, plant material, and other organic matter can create sanitizer demand and affect the concentration available in the process water. Wash systems should therefore be monitored during operation using an appropriate method for the antimicrobial being used.
Authoritative Resources
Center for Produce Safety — Produce Wash Water Research
CPS-funded research, findings, and technical resources addressing produce wash water, sanitizer performance, cross-contamination, organic load, monitoring, and process control.
Organic Load & Sanitizer Demand
Organic material from soil, plant debris, damaged produce, and other contaminants can increase sanitizer demand in recirculated wash water. As organic load increases, the amount of active antimicrobial available in the water may decrease, depending on the chemistry being used.
Managing sanitizer demand requires more than simply adding additional chemical. Water turnover, filtration, product condition, incoming soil load, and antimicrobial monitoring should all be considered when managing process water. Understanding these factors can help maintain more consistent antimicrobial conditions throughout production.
Authoritative Resources
Center for Produce Safety — Organic Load & Chlorine Efficacy
Increasing organic load in produce wash water can reduce sanitizer efficacy. This CPS-funded research evaluated methods for assessing organic load and its relationship to free-chlorine performance during commercial lettuce processing
U.S. Food & Drug Administration — Fresh Fruit & Vegetable Food Safety Guidance
FDA guidance addressing processing-water quality, antimicrobial treatment, disinfectant monitoring, organic-material buildup, water temperature, and practices intended to reduce cross-contamination during produce washing and processing.
pH, Temperature & Contact Time
pH, water temperature, and contact time can influence antimicrobial performance and should be evaluated as part of the overall wash process. The importance of each factor depends on the antimicrobial chemistry, application method, produce being handled, and the product’s EPA-approved label directions.
pH can significantly affect the activity of some antimicrobials, while temperature may influence chemical reaction rates, produce quality, and process conditions. Contact time is equally important—a target antimicrobial concentration alone does not describe the complete treatment. Effective process control considers concentration, pH, temperature, contact time, and the physical design of the wash system together.
Authoritative Resouces
CPS-funded research examining the relationship between sanitizer concentration and contact time, including how pH, temperature, and organic load can affect the conditions needed to prevent cross-contamination in produce wash water.
U.S. Food & Drug Administration — Fresh Fruit & Vegetable Food Safety Guidance
FDA guidance explains that antimicrobial effectiveness can depend on treatment conditions including water temperature, pH, and contact time. It also recommends monitoring process parameters that affect antimicrobial performance.
Monitoring & Verification
Routine monitoring helps confirm that a produce wash system is operating within its intended conditions throughout production. Depending on the antimicrobial and process, monitoring may include sanitizer concentration, pH, oxidation-reduction potential (ORP), temperature, flow rate, water quality, or other relevant operating parameters.
Verification goes beyond simply taking a reading. Instruments and test methods should be appropriate for the chemistry being used, maintained and calibrated as needed, and results should be documented so changes can be identified over time. Verification may also include reviewing monitoring records, confirming instruments are functioning properly, and evaluating whether established operating procedures are being followed. Monitoring frequency should reflect the process, sanitizer demand, production conditions, and applicable regulatory or food safety requirements.
Authoritative Resources
Center for Produce Safety — Operating Standards for Produce Wash Systems
CPS-funded research evaluating practical monitoring standards, critical operating parameters, and test methods for produce wash systems. The project evaluated chlorine-based sanitizers and peroxyacetic acid (PAA), along with measurements such as sanitizer residual, pH, ORP, organic load, turbidity, and commercially available sensors and test kits.
Center for Produce Safety — Process Control: Produce Wash Systems
CPS synthesis of produce wash-water research highlighting the importance of monitoring and controlling wash systems to prevent cross-contamination. The resource addresses process variables including disinfectant concentration, contact time, organic load, pH, temperature, system design, product loading, and water replacement, as well as the role of process validation.
Water Quality & Source Water
The quality of water entering a produce operation can affect both food safety and the performance of antimicrobial treatments. Water source, microbial quality, mineral content, hardness, pH, turbidity, and other characteristics may influence how process water should be managed.
Water used for produce washing and other food-contact applications should meet applicable regulatory and food safety requirements for its intended use. Operations should understand their water source, establish appropriate testing and monitoring practices, and consider how changes in incoming water quality may affect antimicrobial performance and process control.
Authoritative Resources
U.S. Food & Drug Administration — Harvest & Post-Harvest Agricultural Water Requirements
FDA guidance outlining Produce Safety Rule requirements for water used during harvesting, packing, and holding activities, including produce washing and cooling. The resource addresses water quality, microbial criteria, testing, water-system inspection, recirculated-water management, treatment, monitoring, and recordkeeping.
Antimicrobial Technologies
Antimicrobial treatments are commonly used in produce washing, process-water systems, and spray applications to help control microbial cross-contamination during handling and processing. Available technologies include chlorine-based sanitizers, peracetic acid (PAA), chlorine dioxide, and other EPA-registered antimicrobial products approved for specific food and produce applications.
Each antimicrobial chemistry has different operating characteristics, including effective concentration ranges, sensitivity to organic load and pH, monitoring requirements, contact-time considerations, and compatibility with equipment and produce. Selection and use should be based on the specific process, water conditions, treatment objective, and the product’s EPA-approved label directions.
Application method matters. Antimicrobial technologies can perform differently in recirculated immersion systems compared with single-pass or non-recovery spray applications. HFT evaluates antimicrobial chemistry in the context of the specific process and application rather than treating all produce-wash systems as equivalent.
Authoritative Resources
Center for Produce Safety — Process Control: Produce Wash Systems
CPS research synthesis examining produce wash-water process control and antimicrobial technologies. The resource discusses commonly used disinfectants including sodium hypochlorite, peroxyacetic acid (PAA), and chlorine dioxide, along with factors such as sanitizer concentration, contact time, organic load, pH, system design, and product loading.
View CPS Antimicrobial & Process Control Resource
Explore Antimicrobial Technologies
Additional technical resources are being developed for the following antimicrobial technologies and applications.
Peracetic Acid (PAA)
Learn about produce applications, process-control considerations, monitoring, organic-load considerations, and the advantages and limitations of PAA.
Chlorine
Learn about free-chlorine control, pH, organic demand, monitoring, recirculated wash-water applications, and the advantages and limitations of chlorine.
Chlorine Dioxide
Learn about chlorine dioxide application methods, including single-pass and non-recovery spray applications, process-control considerations, monitoring, and the advantages and limitations of chlorine dioxide.
HFT Antimicrobial Technology Comparison
Compare chlorine, peracetic acid (PAA), and chlorine dioxide, including application methods, process-control requirements, monitoring considerations, and operational advantages and limitations.
Regulatory & Industry Guidance
Produce washing and antimicrobial treatment are subject to regulatory requirements that depend on the operation, commodity, water use, and antimicrobial product being used. FDA requirements and guidance address produce safety and agricultural water, while EPA registration and labeling establish approved uses and directions for antimicrobial pesticide products.
Operations should determine which requirements apply to their specific activities and use antimicrobial products according to their EPA-approved labeling. Regulatory requirements and guidance may change over time, so current information should be verified through the appropriate regulatory agency
Authoritative Resources
U.S. Food & Drug Administration — FSMA Produce Safety Rule
FDA information on the Produce Safety Rule, including standards for growing, harvesting, packing, and holding covered produce for human consumption.
U.S. Food & Drug Administration — Harvest & Post-Harvest Agricultural Water
FDA requirements specifically addressing agricultural water used during harvest and post-harvest activities, including water used in washing and other activities where water contacts covered produce or food-contact surfaces.
View FDA Harvest & Post-Harvest Water Requirements
U.S. Environmental Protection Agency — Pesticide Labeling Requirements
EPA information explaining pesticide labeling requirements and the role of the approved label in establishing directions for use, precautions, application requirements, and other conditions for registered pesticide products.