Integrated electron beam irradiation treatment with hydrogen peroxide aqueous solution to inactivate Salmonella on grape tomatoes

This study investigated the efficacy of integrated electron beam (e-beam) irradiation and hydrogen peroxide (H2O2) aqueous solution treatments to inactivate mixed strains of Salmonella inoculated in grape tomatoes. Whole grape tomatoes were inoculated with a mixed bacterial cocktail composed of five strains of Salmonella enterica corresponding to serotypes Rissen (SAL1449), Montevideo (SAL4599), Saintpaul (476398), and Typhimurium (ATCC 13311 and ATCC 700720), dried in a biological safety cabinet for 2 h at room temperature and then stored at 4°C for 24 h to facilitate bacterial attachment before treatment. Tomatoes in H2O2 (60 mg/L) aqueous solution were irradiated at 0.45, 0.60, 0.75, 1.0, and 1.25 kGy dose. The combined treatment of 1.0 kGy radiation dose and 60 mg/L H2O2 achieved 4-log reductions in Salmonella. The D10−average value of Salmonella in the present study was 0.25 ± 0.01 kGy. Regarding the effect of the treatment on tomato quality, the combined application of e-beam up to 1.25 kGy and H2O2 (60 mg/L) did not affect (p >.05) the color and texture of grape tomatoes compared to non-irradiated samples. Furthermore, the combined treatments of e-beam and H2O2 aqueous solution reduced the dose uniformity ratio (DUR) by 7%, a relevant finding regarding commercial applications of electron beam accelerators. Exposure of the tomatoes to e-beam and water wash with added H2O2 is a promising decontamination system for use in tomatoes and other produce processing. Further studies on the optimization of this integrated treatment are needed. Practical Applications: Electron beam irradiation of tomatoes immersed in hydrogen peroxide (H2O2) solution reduces the dose required to eliminate pathogens in the fresh produce. The integrated treatment ensures minimal changes to produce quality and increased treatment efficiency in terms of dose uniformity.