Inactivation kinetics of inoculated Escherichia coli O157:H7, Listeria monocytogenes and Salmonella Poona on whole cantaloupe by chlorine dioxide gas

The objectives of this study were to examine inactivation kinetics of inoculated Escherichia coli O157:H7, Listeria monocytogenes and Salmonella Poona inoculated onto whole cantaloupe and treated with ClO 2 gas at different concentrations (0.5, 1.0, 1.5, 3.0 and 5.0 mg l −1) for different times (0, 2.0, 4.0, 6.0, 8.0 and 10.0 min). The effect of ClO 2 gas on the quality and shelf life of whole cantaloupe was also evaluated during storage at 22 °C for 12 days. A 100 μl inoculation of each targeted organism was spotted onto the surface (5 cm 2) of cantaloupe rind (approximately 8–9 log CFU 5 cm −2) separately, air dried (60 min), and then treated with ClO 2 gas at 22 °C and 90–95% relative humidity for 10 min. Surviving bacterial populations on cantaloupe surfaces were determined using a membrane transferring method with a non-selective medium followed by a selective medium. The inactivation kinetics of E. coli O157:H7, L. monocytogenes and S. Poona were determined using nonlinear kinetics (Weibull model). A 3 log CFU reduction of E. coli O157:H7, L. monocytogenes and S. Poona were achieved with 5.0 mg l −1 ClO 2 gas for 5.5, 4.2 and 1.5 min, respectively. A 5 log CFU reduction of S. Poona was achieved with 5.0 and 3.0 mg l −1 ClO 2 gas for 6 and 8 min, respectively. A 4.6 and 4.3 log reduction was achieved after treatment with 5.0 mg l −1 ClO 2 gas at 10 min for E. coli O157:H7 and L. monocytogenes, respectively. Treatment with 5.0 mg l −1 ClO 2 gas significantly ( p