title: Essential oils reduce Escherichia coli O157:H7 and Salmonella on spinach leaves.
abstract: The efficacy of cinnamaldehyde and Sporan for reducing Escherichia coli O157:H7 and Salmonella on spinach leaves was investigated. Spinach leaves were inoculated with a five-strain cocktail of Salmonella or E. coli O157:H7, air dried for ca. 30 min, and then  immersed in a treatment solution containing 5 ppm of free chlorine, cinnamaldehyde, or Sporan (800 and 1,000 ppm) alone or in combination with 200 ppm of acetic acid (20%) for 1 min or with water (control). After spin drying, treated leaves were analyzed periodically during 14 days of storage  at 4°C for Salmonella, E. coli O157:H7, total coliforms, mesophilic and psychrotrophic bacteria, and yeasts and molds. Treatment effects on color and texture of leaves also were determined. Sporan alone (1,000S), Sporan plus acetic acid (1,000SV), and cinnamaldehyde-Tween (800T)  reduced E. coli O157:H7 by more than 3 log CFU/g (P < 0.05), and 1,000SV treatment reduced Salmonella by 2.5 log CFU/g on day 0. E. coli O157:H7 and Salmonella populations on treated spinach leaves declined during storage at 4°C. The 1,000SV treatment  was superior to chlorine and other treatments for reducing E. coli O157:H7 during storage. Saprophytic microbiota on spinach leaves increased during storage at 4°C but remained lower on leaves treated with Sporan (800S) and Sporan plus acetic acid (1,000SV) than on control leaves.  The color and texture of Sporan-treated leaves were not significantly different from those of the control leaves after 14 days. Sporan plus acetic acid (1,000SV) reduced E. coli O157:H7 and Salmonella on baby spinach leaves without adverse effects on leaf color and texture.
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, 3102 Marie Mount Hall, College Park, Maryland 20742, USA.
authors.forename: Nadine
authors.initials: N
authors.lastname: Yossa
authors.forename: Jitendra
authors.initials: J
authors.lastname: Patel
authors.forename: Patricia
authors.initials: P
authors.lastname: Millner
authors.forename: Y Martin
authors.initials: YM
authors.lastname: Lo
mesh_terms: D002713:Chlorine / Q000494:pharmacology; D015169:Colony Count, Microbial; D003258:Consumer Behavior; D003257:Consumer Product Safety; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005506:Food Contamination / Q000032:analysis; D005511:Food Handling / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009822:Oils, Volatile / Q000494:pharmacology*; D012475:Salmonella / Q000187:drug effects* / Q000254:growth & development; D018724:Spinacia oleracea / Q000382:microbiology*; D013696:Temperature
chemical_list: D009822:Oils, Volatile; D002713:Chlorine