Effect of copper hydroxide sprays for citrus canker control on wild-type Escherichia coli

Abstract

Aims: 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. Methods and 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. Significance and Impact of the Study: 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.

Egg masses treatment with micronutrient fertilizers has a suppressive effect on newly-emerged nymphs of the brown marmorated stink bug Halyomorpha halys

“…Copper was present in products (1), (3), and (4). The involvement of this element in plant pathogen control is widely recognized (Scheck & Pscheidt 1998;Narciso et al 2012), and our results confirmed a lethal effect on P. carbekii as well. Moreover, higher mortality, as a result of bactericidal effect, was exhibited when copper was used in combination with zinc and citric acid, while the application of copper hydroxide alone was less effective in reducing nymphal survival.…”

Effects of Chitosan‐Essential Oil Coatings on Safety and Quality of Fresh Blueberries

“…Southern highbush blueberries Vaccinium virgatum were purchased from a local store and used immediately after purchase or within 2 d storage at 5 °C. E. coli was a wild‐type culture isolated from citrus fruit as described by Narciso et.al (Narciso and others ). Penicillium digitatum Link was also isolated from citrus fruit (Narciso ).…”

Antimicrobial Activity of Controlled-Release Chlorine Dioxide Gas on Fresh Blueberries

“…Strains of Escherichia coli wild type and Colletotrichum acutatum Corda were isolated from citrus fruit surfaces (26) and stored at -8 0°C on E. coli agar and potato dextrose agar (PDA) plugs in cryoprotectant (10% glycerol), respectively. The E. coli agar plugs were recultured on E. coli agar at 34°C for a week, and the bacteria were checked on Levine eosin methylene blue agar (Sigma-Aldrich Co., St. Louis, MO).…”