Inactivation kinetics of inoculated Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enterica on strawberries by chlorine dioxide gas.
Inactivation kinetics of inoculated Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enterica on strawberries by chlorine dioxide gas at different concentrations (0.5, 1, 1.5, 3 and 5 mgl(-1)) for 10 min were studied. A cocktail of three strains of each targeted organism (100 microl) was spotted onto the surface of the strawberries (approximately 8-9 log ml(-1)) separately followed by air drying, and then treated with ClO(2) gas at 22 degrees C and 90-95% relative humidity. Approximately a 4.3-4.7 logCFU reduction per strawberry of all examined bacteria was achieved by treatment with 5 mgl(-1) ClO(2) for 10 min. The inactivation kinetics of E. coli O157:H7, L. monocytogenes and S. enterica were determined using first-order kinetic models to establish D-values and z-values. The D-values of E. coli, L. monocytogenes and S. enterica were 2.6+/-0.2, 2.3+/-0.2 and 2.7+/-0.7 min, respectively, at 5 mgl(-1) ClO(2). The z-values of E. coli, L. monocytogenes and S. enterica were 16.8+/-3.5, 15.8+/-3.5 and 23.3+/-3.3 mgl(-1), respectively. Furthermore, treatment with ClO(2) gas significantly (p < or = 0.05) reduced the initial microflora (mesophilic, psychrotrophic bacteria, yeasts and molds) on strawberries. Treatment with ClO(2) gas did not affect the color of strawberries and extended the shelf-life to 16 days compared to 8 days for the untreated control.
Mahmoud
Barakat S M
BS
Department of Food Science, Purdue University, West Lafayette, IN 47907-2009, USA. bmahmoud@purdue.edu
Bhagat
A R
AR
Linton
R H
RH
D017606:Chlorine Compounds / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003258:Consumer Behavior; D003257:Consumer Product Safety; D004202:Disinfectants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development*; D005519:Food Preservation / Q000379:methods; D031985:Fragaria / Q000382:microbiology*; D006801:Humans; D007700:Kinetics; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development*; D008826:Microbial Sensitivity Tests; D010087:Oxides / Q000494:pharmacology*; D011786:Quality Control; D019779:Salmonella enterica / Q000187:drug effects / Q000254:growth & development*; D013649:Taste; D013997:Time Factors
D017606:Chlorine Compounds; D004202:Disinfectants; D010087:Oxides; C025109:chlorine dioxide