Inactivation of SalmonellaNewport on blueberries by treatment with chlorine dioxide gas and its effect on blueberry qualities

The purpose of this study was to use chlorine dioxide (ClO2) gas to inactivate SalmonellaNewport on blueberries and observe quality changes of blueberries as affected by the treatment. Blueberries inoculated with S. Newport were treated with ClO2gas for 10 h ClO2gas was generated from either 1 or 2 mL of ClO2solution dropped in a sealed container and the container was hold at 12 °C or 25 °C. Within 30 min, Salmonellapopulations on blueberries treated with ClO2gas, regardless of treatment temperature and amount of ClO2solution, reduced below the detection limit (1.7 log CFU/sample) and the organism was eliminated within 30 min when 1 mL of ClO2solution was used to generate gas at 25 °C. After the ClO2gas treatment, blueberries were analyzed with an electronic eye. Color of untreated and ClO2-gas treated blueberries are composed of 12 and 11 color codes, respectively. Out of the color codes, 7 codes of both blueberries in control and treatment groups are the same. ClO2gas treatment did not cause significant changes in Hunter's L, a, and b-value of blueberries. Hardness (g) of blueberries treated with ClO2gas for 30 min significantly increased; however final values were not significantly different from the values of untreated ones. As a result of this study, the ClO2gas successfully reduced S. Newport on blueberries without significant changes in their color and hardness.