Factors Limiting the Efficacy of Hydrogen Peroxide Washes for Decontamination of Apples Containing Escherichia coli

Factors limiting efficacy of H 2 O 2 washes and alternative decontamination strategies were investigated with Golden Delicious apples, inoculated with nonpathogenic Escherichia coli. Post‐treatment rinsing decreased efficacy by eliminating residual H 2 O 2 . A 2‐stage wash incorporating a rinse to remove surfactant residues prior to H 2 O 2 application was developed. Rapid attachment of E. coli to apples prevented effective removal by washing with water. Surviving E. coli following a 5% H 2 O 2 wash were concentrated in stem and calyx areas. Survival was independent of the time interval between inoculation and washing. E. coli inoculation of punctured apple surfaces resulted in growth at 20 °C and greater survival after washing with 5% H 2 O 2 . Improved decontamination methods are needed.