Skip to content Skip to navigation
UMass Collegiate M The University of Massachusetts Amherst
  • Visit
  • Apply
  • Give
  • Search UMass.edu
Center for Agriculture, Food, and the Environment
UMass Extension Vegetable Program
  • Vegetable Home
  • About
    • About the Vegetable Program
    • Faculty & Staff
    • Funding
    • Request a visit
    • Request a Crop & Pest Management Planning Meeting
    • Contact us
  • Publications
    • Vegetable Notes
    • New England Vegetable Management Guide
    • Northeast Vegetable and Strawberry Pest Identification Guide
    • Cucurbit Disease Scouting & Management Guide
    • Sweet Corn IPM Scouting Guide & Record Keeping Book
    • Nutrient Management Guide for New England Vegetable Production
  • Fact Sheets
  • Special Topics
    • Brassica Pest Collaborative
    • Heating Greenhouses with Locally Grown Corn
    • Winter Production and Storage
  • Resources
    • Food Safety for Farmers
    • Nutrient Management
    • Scouting Resources
    • Research Reports
    • Recursos en Español (Spanish-Language Resources)
    • Useful Links
  • Services
    • Disease Diagnostics
    • Soil and Plant Nutrient Testing
    • UMass Extension Bookstore
    • Hot Water Seed Treatment
    • Mentor Farm Program
    • Scouting Program
  • News & Events
    • Upcoming Events
    • News
    • Past Events
  • Make a Gift

Produce Wash Water Sanitizers: Chlorine and PAA

Food borne pathogens such as Salmonella and Escherichia coli O157:H7 may be present in raw or incompletely composted manure, and when manure is used as a crop amendment, runs off into fields or water, or is carried into fields or processing areas by workers or animals, these pathogens can be passed along to fresh produce. Using a sanitizer in produce wash water can help to maintain clean wash water free of microbial loads. However, choosing and sourcing a sanitizer can be difficult, especially on the small farm scale. This article provides an overview of two effective sanitizing agents – chlorine-based sanitizers and peroxyacetic acid – to help alleviate the stress of deciding which sanitizer is best for certain applications. Note that other types of sanitizers are available such as ozone and chlorine dioxide but the following have been chosen because they are the most readily available for small-scale Northeast growers.

Chlorine-based sanitizers

Chlorine is popularly used as a produce wash water sanitizer due to its documented efficacy and low cost. Though many different chlorine bleach products are available in stores, any product used for this agricultural purpose must be registered with the EPA and specifically labeled for fruit & vegetable washing (1). In the table below, two examples of Clorox bleach are given which are allowed for this use. Certain conditions need to be taken into account when using chlorine, such as the temperature and pH of the wash water as well as the presence of organic matter, since chlorine reacts with organic matter and becomes inactive. Bleach is inexpensive, but managing these factors can lead to added cost. Be aware that the Clorox label states that for fruit and vegetable washing, the concentration of available chlorine in the water may not be more than 25 ppm, and use rates are given accordingly. Fact sheets and other food safety resources may recommend preparing wash solutions at higher concentrations using household bleach, but be sure to follow the label for whichever product you are using. Using free chlorine test strips to measure ppms will help you determine product use rates to stay within the allowable limit. The FDA permits the use of chlorine for food contact, and the EPA regulates it as a general use pesticide.

Peroxyacetic acid

Peroxyacetic acid (PAA) is a combination of acetic acid and hydrogen peroxide. It is effective in reducing the microbial load of wash water by a variety of mechanisms (2). While on the more expensive side for initial cost, peroxyacetic acid does not react with organic matter in the same way chlorine does, and is active over a broad pH range, so dunking solutions don’t have to be changed as frequently between batches (1). The FDA does not permit PAA to exceed 80 ppm in produce wash water, and the EPA regulates PAA as a general use pesticide.

Considerations

This guide is intended to help you make a decision as to which type of sanitizer will work best for you. The total cost per use must take into account both the initial cost of each product, as well as the cost of frequent solution changes and monitoring for conditions such as pH. As discussed, chlorine is reactive to organic matter and may require more per use than indicated in the chart below. Further studies regarding this reactivity will be carried out in the future to compliment this document. You should have a standard protocol that all workers can follow for whichever method you choose, and keep a log book to document sanitizer use rates and conditions such as pH. An example of this kind of log is provided in the UMass GAP manual as a Word document which can be downloaded and tailored for use on your own farm.

Click on table for a larger view.
Produce Wash Water Sanitizers: Chlorine and PAA chart

Sources:

(1)  http://anrcatalog.ucanr.edu/pdf/8003.pdf

(2)  https://store.extension.iastate.edu/Product/Guide-to-Liquid-Sanitizer-Washes-with-Fruit-and-Vegetables

Author: Marie Lawton and Amanda Kinchla, UMass Extension Food Safety Specialist, and Lisa McKeag, UMass Extension Vegetable Program
Last Updated: September 30, 2015

The Center for Agriculture, Food and the Environment and UMass Extension are equal opportunity providers and employers, United States Department of Agriculture cooperating. Contact your local Extension office for information on disability accommodations. Contact the State Center Director’s Office if you have concerns related to discrimination, 413-545-4800 or see ag.umass.edu/civil-rights-information.

Ways to Connect

  • Ask a question
  • Request a Visit
  • Request a Crop & Pest Management Planning Session
  • Submit a Sample
  • Become a Mentor Farm
  • Join the NEVBGA
  • Make a Donation

Connect with us on Social Media

extension vegetable program facebook page  extension vegetable program instagram   extension vegetable program youtube channel

Center for Agriculture, Food, and the Environment

 

Stockbridge Hall,
80 Campus Center Way
University of Massachusetts Amherst
Amherst, MA 01003-9246
Phone: (413) 545-4800
Fax: (413) 545-6555
ag [at] cns [dot] umass [dot] edu (ag[at]cns[dot]umass[dot]edu)

 

Civil Rights and Non-Discrimination Information

College of Natural Sciences

Login for faculty and staff

CAFE Units

Mass. Agricultural Experiment Station

UMass Extension

UMass Research and Education Center Farms

UMass Cranberry Station

Water Resources Research Center

Interest Areas

Agriculture

Commercial Horticulture

Energy

Environmental Conservation

Food Science

Nutrition

Water

Youth Development & 4-H

Services

Pesticide Education

Plant Diagnostics Laboratory

Soil and Plant Nutrient Testing Laboratory

Hot Water Seed Treatment

Water Testing / Environmental Analysis Laboratory

Projects

Conservation Assessment Prioritization System (CAPS)

Extension Risk Management/Crop Insurance Education

Mass. Envirothon

Mass. Herp Atlas

Mass. Keystone

MassWoods

North American Aquatic Connectivity Collaborative

RiverSmart

UMass Design Center in Springfield

Resources

Extension Sales Portal

Agriculture & Commercial Horticulture Resources

Community & Economic Vitality

Disaster Preparedness

Food Safety

Home Lawn & Garden

Integrated Pest Management (IPM)

Land Conservation Tools

Pollinators

Tick testing

Resources for Faculty and Staff

Extension Programs

4-H Youth Development

Agriculture

Crops, Dairy, Livestock and Equine

Fruit

Greenhouse Crops and Floriculture

Landscape, Nursery and Urban Forestry

Pesticide Education

Turf

Vegetable

Clean Energy

Climate Change

Food Science

Nutrition Education

Value-Added Food

Seal of The University of Massachusetts Amherst - 1863
©2025 University of Massachusetts Amherst · Site Policies · Accessibility