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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Animal Metabolism-Agricultural Chemicals Research » Research » Publications at this Location » Publication #308821

Research Project: METABOLIC FATE OF CHEMICAL AND BIOLOGICAL CONTAMINANTS

Location: Animal Metabolism-Agricultural Chemicals Research

Title: Distribution and chemical fate of 36Cl-chlorine dioxide gas during the fumigation of tomatoes and cantaloupe

Author
item Smith, David
item Ernst, William - Ica Tri-Nova Corporation, Llc
item Giddings, John

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2014
Publication Date: 11/19/2014
Publication URL: http://handle.nal.usda.gov/10113/60017
Citation: Smith, D.J., Ernst, W., Giddings, J.M. 2014. Distribution and chemical fate of 36Cl-chlorine dioxide gas during the fumigation of tomatoes and cantaloupe. Journal of Agricultural and Food Chemistry. 62:11756-11766.

Interpretive Summary: Bacteria that cause human disease may be present on fruits, vegetables, and melons after harvest. While washing is effective at removing some bacteria from vegetables or melons having smooth surfaces, it is very ineffective at removing bacteria from vegetable matter having rough surfaces or that may be damaged or scarred. Chlorine dioxide dissolved in waster is an excellent antibacterial agent that is currently used for many food applications; chlorine dioxide gas is also very effective at eliminating pathogens and rot organisms on fruits and vegetables. The use of chlorine dioxide gas, however, has not been approved by regulatory authorities for use on human foods. Data generated by this study strongly suggests that under the proper conditions chlorine dioxide may be used to treat tomatoes or melons without the formation of undesirable chemical residues.

Technical Abstract: The distribution and chemical fate of 36Cl-ClO2 gas subsequent to fumigation of tomatoes or cantaloupe was investigated as was major factors that affect the formation of chloroxyanion byproducts. Approximately 22% of the generated 36Cl-ClO2 was present on fumigated tomatoes after a 2-hour exposure to 5 mg of 36Cl-ClO2. A water rinse removed 14% of the radiochlorine while tomato homogenate contained ~63% of the tomato radioactivity; 24% of the radiochlorine was present in the tomato stem scar area. Radioactivity in tomato homogenate consisted of 36Cl-chloride (=80%), 36Cl-chlorate (5 to 19%) and perchlorate (0.5 to 1.4%). In cantaloupe, 55% of the generated 36Cl-ClO2 was present melons fumigated with 100 mg 36Cl-ClO2 for a 2-hour period. Edible cantaloupe flesh contained no-detectable radioactive residue (LOQ = 0.3 to 0.4 µg/g); >99.9% of radioactivity associated with cantaloupe was on the inedible rind, with <0.1% associated with the seed bed. Rind radioactivity was present as 36Cl-chloride (~86%), chlorate (~13%) and perchlorate (~0.6 %). Absent from tomatoes and cantaloupe were 36Cl-chlorite residues. Follow-up studies have shown that chlorate and perchlorate formation can be completely eliminated by protecting fumigation chambers from light sources.