Technical feasibility study for development of chlorine dioxide releasing packaging system and its application in decontaminating fresh produce

A feasibility study was conducted to develop chlorine dioxide (ClO 2) releasing packaging films for decontaminating fresh produce. Sodium chlorite and citric acid powder were incorporated into polylactic acid (PLA) polymer. Films made with different amount of PLA (100 and 300 mg), percentage of reactant (5-60%), and ratios of sodium chlorite to citric acid (1:2 or 2:1) were prepared using a solvent casting method. The release of ClO 2 from the resultant films was activated by moisture. Increase of reactants in the films produced more ClO2 while higher PLA content in the films resulted in less release of ClO2. The ratio of sodium chlorite to citric acid and activation temperature (22°C vs. 10°C) didn't affect the ClO2 release from the films. Antimicrobial efficacy of ClO2 released from the films was evaluated using grape tomato as a model food. The results indicate that the films were activated by moisture from tomatoes in the package and the released ClO2 reduced Salmonella spp. and E. coli O157:H7 inoculated on the tomatoes to undetectable levels (< 5 CFU/tomato), achieving more than 3 log reduction. The film-treated tomatoes did not show significant changes in color and texture as compared to controls during storage at 10°C for 21 days. This study demonstrated the technical feasibility for development of gaseous chlorine dioxide releasing packaging system to enhance microbial safety and extend shelf life of fresh produce.