Peroxyacetic Acid and Chlorine Reduce Escherichia coli in Agricultural Surface Water for Potential Produce Postharvest Uses

An increase in foodborne illnesses associated with fruits and vegetables has been observed in recent years, with several outbreaks linked to contaminated agricultural water. The effectiveness of peroxyacetic acid (PAA) and chlorine (Cl) at reducing Escherichia coli in rain barrel and creek water was evaluated in this study. Rain barrel and creek water (12 and 32°C overnight) were inoculated with ~5 log CFU/ml of an E. coli cocktail, reequilibrated to 12 and 32°C (30 min), and treated with 25 ± 2 ppm of Cl, 75 ± 5 ppm of PPA, or a water control (W). Samples were collected 0, 5, 10, 60, 1,440, and 2,880 min after treatment, neutralized in Dey–Engley broth, and enumerated using the Food and Drug Administration-approved IDEXX Colilert method, as well as E. coli/coliform (EC) Petrifilm, and enriched for the presence or absence of E. coli. E. coli was not detected in 12 and 32°C creek and rain barrel water 0 min after treatment with PAA and 60 min after treatment with Cl using Colilert. E. coli was not detected in samples treated with PAA or Cl at any time point using EC Petrifilm. These data allow growers and extension educators to explore the use of these treatments in surface water sources for postharvest uses in produce.