At the dose levels required to achieve a 5-log reduction in Salmonella, the shelf life of whole green onion can be extended. The 2.0 kGy samples maintained good visual quality for 17 d suggesting that irradiation can increase shelf life by reducing spoilage microorganisms but higher doses can be detrimental to quality. The control maintained good visual quality for about 13 d as compared to 15 d for 1.5 and 2.5 kGy samples. No significant difference was observed in color and texture between irradiated samples and control. Although the counts increased during storage, they did not exceed the initial counts of control. Irradiation reduced total plate counts and psychrotrophs by 3 logs. For the quality study, both varieties of green onions were irradiated at 0, 1.5, 2.0, and 2.5 kGy and evaluated for changes in microbial counts, color, texture, and visual quality during storage at 4 ☌. This indicated that a 5-log reduction of Salmonella can be achieved at a dose of 1.6 kGy. The D values were in the range of 0.26 to 0.32 kGy depending on variety but not on the method of inoculation. Two varieties of green onions, Banner and Baja Verde, were inoculated with a cocktail of 3 Salmonella strains using dip and spot inoculation and irradiated at 0, 0.3, 0.6, 0.9, and 1.2 kGy using electron beam. Salmonella survivors were enumerated using a XLD underlay/TSAYE overlay plating method.
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