title: Effect of copper hydroxide sprays for citrus canker control on wild-type Escherichia coli.
abstract: OBJECTIVE
  To show that application of copper hydroxide citrus sprays mixed with field source water (possibly contaminated) will not support Escherichia coli on plant surfaces. Environmental stresses of transient phyllosphere bacteria and presence of copper will eradicate these bacteria before harvest.
  
  
  RESULTS
  Studies were performed in vitro with bacteria grown in broth and then subjected to field spray copper hydroxide concentrations in the broth and on citrus leaves. Escherichia coli exposed to copper hydroxide in vitro were eradicated from the broth within 6-8 h depending on the broth pH. Even with near neutral pH (7·2), cells began to die immediately after exposure to copper. No E. coli survived on leaf surfaces sprayed with copper.
  
  
  CONCLUSIONS
  Copper field sprays mixed with water that may contain E. coli can help eliminate E. coli from plant surfaces.
  
  
  CONCLUSIONS
  HACCP mandates are becoming more restrictive because of the increased illness resulting from food pathogens on fresh produce. Use of potable water in fields, a proposed mandate, is not feasible for large grove owners. These data show that copper sprays aimed at reducing citrus canker also affect E. coli and may help to ease water quality mandates.
authors.affiliation: U.S. Department of Agriculture/Agricultural Research Service, US Horticultural Research Laboratory, Citrus and Subtropical Laboratory Unit, Fort Pierce, FL 34945, USA. jan.narciso@ars.usda.gov
authors.forename: J A
authors.initials: JA
authors.lastname: Narciso
authors.forename: C M
authors.initials: CM
authors.lastname: Ference
authors.forename: M A
authors.initials: MA
authors.lastname: Ritenour
authors.forename: W W
authors.initials: WW
authors.lastname: Widmer
mesh_terms: D000383:Agriculture / Q000379:methods*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002957:Citrus / Q000382:microbiology*; D003300:Copper / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000494:pharmacology*; D018515:Plant Leaves / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D006878:Hydroxides; C508959:copper hydroxide; D003300:Copper