Food Safety Tips for Washing Produce

Water can move a pathogen from one piece of produce to a large volume of produce. Keep these tips in mind to keep your produce safe.
Food Safety Tips for Washing Produce - Articles

Updated: August 27, 2017

Food Safety Tips for Washing Produce
  • The water source must meet EPA microbial standards for drinking water (potable).
  • Use a sanitizing agent in batch washing tanks.
  • Use test strips to regularly check concentration.
  • Change water when dirty.
  • Clean and sanitize tanks between uses.
  • Clean hands and equipment regularly!
  • Be sure sanitizers are EPA approved for food contact use.

Greens can be washed in single or multiple wash tank systems. Recently Vernon Grubinger from the University of Vermont did a study on ways to reduce bacteria in produce wash water. His group found that bacterial loads can be greatly reduced with the addition of a full-dose of sanitizer (SaniDate® 5.0, or similar product) in a single vessel system. This method requires less infrastructure and water. However, two separate rinses, each containing the sanitizer, was more effective for reducing grit. With sanitizer and double rinse bacteria were reduced by 99.6%. Triple washing was the best washing method for farms with appropriate infrastructure (e.g., triple bay sink, multiple stock tubs). Up to 98.0% reductions in bacteria were achieved without sanitizer and with triple rinsing. When triple washing, its best to add a sanitizer to the first wash tank. That's because one contaminated item can spread pathogens through the entire batch and the sanitizer in the next basin would have to work harder to decontaminate the water and the produce. If the greens are particularly gritty or muddy, it's a good idea to rinse the greens with non-recirculated spray water. No sanitizer is needed when using spray water.

There are several commercially available sanitizers used in wash water: two common ones are peroxyacetic acid and chlorine.

  • Peroxyacetic acid is a combination of hydrogen peroxide and acetic acid. It kills microbes through oxidation. In many commercial products, its strength is enhanced by pre-mixing with hydrogen peroxide. A few advantages to peroxyacetic acid formulations are that it has a relatively low reactivity with organic matter and soil and it is effective across a wide range of pHs. A few commercial examples are Sani Date, Oxidate, and Tsunami.
  • Chlorine is hypochlorous acid (HOCl). It is commonly used due to its relative low cost, however chlorine will react with organic matter and soil and is most effective at neutral pH (6.5-7.5). If you plan to use chlorine for your sanitizer it is critical that you test the levels frequently to ensure that the soil has not neutralized your product. Also keep in mind that household bleach often contains non-food grade additives. Additionally, under the Safe Drinking Water Act, you must ensure that you are not disposing wash water that is above the maximum residual disinfectant limit of 4 ppm hypochlorite.

Remember, whatever sanitizer you use, federal law requires that it be labeled for use in fruit and vegetable wash water. There are many sources of these and other food safe sanitizers. A few include EcoLab (Mark.Ivkovich@ecolab.com); AFCO (1-800-345-1329); and BioSafe Systems (1-888-273-3088 to find a local distributor).