Chlorine Dioxide Gas Treatment of Cantaloupe and Residue Analysis

Kaur, Simran. M.S., Purdue University, December 2013. Chlorine Dioxide Gas Treatment of Cantaloupe: Residue Analysis. Major Professor: Mark Morgan. Chlorine dioxide (ClO2) is a selective oxidant and powerful antimicrobial agent. Previous work has shown that treatment of cantaloupe with ClO2 gas at 5 mg/L for 10 minutes results in a 4.6 and 4.3 log reduction of E. coli O157:H7 and L. monocytogenes respectively. A significant reduction (p<0.05) in the initial microflora and an increase in the shelf life by six days without altering the color of the cantaloupe (as compared to the untreated control) were also reported. In the past two decades, cantaloupes have been associated with numerous foodborne illness outbreaks in the United States. The use of ClO2 treatment may help mitigate this problem, however, it could result in the presence of chloroxyanions residues (chloride (Cl), chlorite (ClO2), chlorate (ClO3) or perchlorate (ClO4)) in the treated product. These residues, at certain levels, are a toxicity concern. The objective of this project was to identify and quantify chloroxyanions in cantaloupes treated with ClO2 gas at the relevant conditions. Current analytical methods for ClO2 and chloroxyanions are only applicable to aqueous samples. Some of these methods have been used to determine surface residues in treated products by analyzing rinse-water. In order to quantify residues in the tissues of a more complex food matrix, while reducing interference from