Magnitude and Nature of Chemical Residues Present on Produce after Treatment with Chlorine Dioxide Gas
Animal Metabolism-Agricultural Chemicals Research
Project Number: 5442-32000-014-08
Start Date: Jun 01, 2011
End Date: May 31, 2016
Studies have conclusively demonstrated that treatment of a variety of commercial fruits and vegetables with low concentrations of chlorine dioxide gas (ClO2) increases produce shelf-life. In addition, ClO2 treatment decreases the incidence and concentrations of food-borne pathogens such as E. coli and Salmonella on produce. Although the chemical properties of ClO2 suggest that its presence on produce subsequent to treatment would be transient, studies proving such have not been conducted due to technical difficulties. The objective of this work is to determine the magnitude and chemical nature of residues in produce after treatment with radioactive ClO2 gas. The use of radioactive gas is necessary so that metabolites of ClO2 may be unambiguously identified and quantified.
Sealable Plexiglas chambers will be constructed to hold produce and a ClO2 generating system. Radioactive ClO2 will be produced by chemical reaction of sodium 36Cl-chlorite in the closed system. Produce will be bathed in 36Cl-ClO2 gas for a fixed duration period. Concentrations of gaseous 36Cl-ClO2 will be measured periodically. At the end of the reaction, radioactive gasses will be collected into chemical traps and exposed produce will be harvested. Harvested fruit will be analyzed for total radioactive residues by radiochemical techniques and the chemical identifies of radioactive metabolites will be identified and quantified by ion chromatography and radiochemical techniques, respectively. Some samples will be rinsed to determine the quantity of surface residues that are removable by water; surface residues will be speciated.