Response surface modeling for the inactivation of Escherichia coli O157:H7 on green peppers (Capsicum annuum L.) by chlorine dioxide gas treatments.
The effects of chlorine dioxide (ClO2) gas concentration (0.1 to 0.5 mg/liter), relative humidity (RH) (55 to 95%), treatment time (7 to 135 min), and temperature (5 to 25 degrees C) on inactivation of Escherichia coli O157:H7 on green peppers were studied using response surface methods. A four-factor, central, composite, rotatable design was used. The microbial log reduction was measured as a response. A direct membrane-surface-plating method with tryptic soy agar and sorbitol MacConkey agar was used to resuscitate and enumerate ClO2-treated E. coli O157:H7 cells. The statistical analysis and the predictive model developed in this study suggest that ClO2 gas concentration, treatment time, RH, and temperature all significantly (P < 0.01) increased the inactivation of E. coli O157:H7. ClO2 gas concentration was the most important factor, whereas temperature was the least significant. The interaction between ClO2 gas concentration and RH indicated a synergistic effect. The predictive model was validated, and it could be used to determine effective ClO2 gas treatments to achieve a 5-log reduction of E. coli O157:H7 on green peppers.
Han
Y
Y
Department of Food Science, Purdue University, West Lafayette, Indiana 47907-1160, USA.
Floros
J D
JD
Linton
R H
RH
Nielsen
S S
SS
Nelson
P E
PE
D002212:Capsicum / Q000382:microbiology*; D017606:Chlorine Compounds / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology*; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development*; D005516:Food Microbiology; D008954:Models, Biological; D010087:Oxides / Q000494:pharmacology*; D010946:Plants, Medicinal; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013696:Temperature; D013997:Time Factors
D017606:Chlorine Compounds; D004202:Disinfectants; D010087:Oxides; C025109:chlorine dioxide