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Effect of relative humidity on inactivation of foodborne pathogens using chlorine dioxide gas and its residues on tomatoes
Author(s) -
Park S.H.,
Kim W.J.,
Kang D.H.
Publication year - 2018
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.13002
Subject(s) - chlorine dioxide , chemistry , listeria monocytogenes , relative humidity , food science , escherichia coli , humidity , salmonella , bacteria , biochemistry , biology , organic chemistry , genetics , physics , gene , thermodynamics
The effect of relative humidity (RH) on the antimicrobial efficacy of chlorine dioxide (ClO 2 ) gas against foodborne pathogens on tomatoes was evaluated. Also, levels of ClO 2 residues on tomatoes after exposure to ClO 2 gas under different RH conditions were measured to determine the quantity of solubilized ClO 2 gas on tomato surfaces. Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes were inoculated on tomatoes and exposed to ClO 2 gas (5, 10, 20 and 30 ppmv) under different RH conditions (50, 70 and 90%). As ClO 2 gas concentration and treatment time increased, significant differences ( P < 0·05) were observed between inactivation levels under different RH conditions. Exposure to 30 ppmv of ClO 2 gas (50% RH) for 20 min resulted in 1·22–1·52 log reductions of the three foodborne pathogens. Levels of the three foodborne pathogens were reduced to below the detection limit (0·48 log CFU per cm 2 ) within 15 min when exposed to 30 ppmv of ClO 2 gas at 70% RH and within 10 min at 90% RH. At a given ClO 2 gas concentration, ClO 2 residues on tomatoes significantly ( P < 0·05) increased with increasing RH, and there were close correlations between log reductions of pathogens and ClO 2 residues on tomatoes. Significance and Impact of the Study This study reported on the correlation between the amount of ClO 2 residues on produce surfaces and the level of inactivation of pathogens after ClO 2 gas treatment. Variations in RH have great effect on the solubilization of ClO 2 gas on tomato surfaces considering that ClO 2 residues on tomatoes increased with increasing RH. Also, the amount of ClO 2 residues on tomatoes is positively correlated with the level of inactivation of pathogens. The results of this study provide insights for predicting inactivation patterns of foodborne pathogens by ClO 2 gas for practical application by the fresh produce industry.