NOP Compliant Antimicrobial Rinses on Leafy Greens and the Effect on Foodborne Pathogen Indicator Presence

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2010: $14,944.00
Projected End Date: 12/31/2011
Region: Western
State: Washington
Principal Investigator:
Dan Hulse
Tahoma Farms

Annual Reports


  • Vegetables: greens (leafy)


  • Crop Production: food product quality/safety
  • Education and Training: extension, farmer to farmer, networking, on-farm/ranch research
  • Farm Business Management: risk management
  • Natural Resources/Environment: indicators
  • Production Systems: organic agriculture
  • Soil Management: soil microbiology
  • Sustainable Communities: new business opportunities

    Proposal summary:

    Our project will test the effectiveness of various antimicrobial treatments in reducing indicator organisms on leafy greens. The presence of foodborne pathogens in leafy greens has a higher rate of occurrence than any other fruit or vegetable, and with greater regulation of food safety in the fresh fruit and vegetable industry looming, producers need options to help minimize the risk of selling contaminated food. For organic producers in particular, who are prohibited from using chlorine in production or processing, there is a need for a viable alternative to the standard used in many conventional operations that use an antimicrobial rinse. There is not a more critical issue for small and medium-sized growers right now than that of food safety. For this project, heads of leafy greens will be assigned to one of 6 treatments (20 heads per treatment): pre-rinse, water rinse, chlorine antimicrobial rinse, lactic acid rinse, peroxyacetic acid rinse and a vinegar rinse. The pre- rinse treatment will provide an indication of initial microbial load on leafy greens prior to an antimicrobial intervention. After each rinse, heads will be sampled for microbial load to examine the effectiveness of the intervention on reducing indicator organisms. Each head of leafy greens will be enumerated for aerobic plate count (APC) and total coliforms. There will be two sampling events over the course of a two month period. The objective of this project is to determine if an antimicrobial rinse is effective in reducing indicator organisms and, if so, whether the application of an antimicrobial rinse on leafy greens can be an economical and practical addition to a farm’s food safety program.

    Project objectives from proposal:

    Test the effectiveness of anti microbial rinses for reducing pathogen indicator organisms on leafy greens. Compare current methods used in conventional production to those meeting organic certification guidelines. Allow adoption of an antimicrobial rinse in preparing leafy greens for marketing.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.