Effect of the Combined Treatment of UV-C Light and Modified Atmosphere Packaging on the Inactivation of Escherichia coli Inoculated Watercress

Abstract

Minimally processed watercress is an alternative to increase vegetable consumption. However, at almost all stages from field production to processing the vegetables could be contaminated with pathogenic and spoilage bacteria. UV-C light can be effective in controlling bacterial growth, but limited information is available for watercress sanitation and storability. This study reports the effect of UV-C light (0-25 kJ/m(2)) on the quality of minimally processed watercress inoculated with a nonpathogenic Escherichia coli (ATCC 35218), and stored under active modified atmosphere (5% O-2-10% CO2) during 12 days at 5C. The application of UV-C treatments reduced E. coli counts between 2.6 and 4.4 log cfu/g. Moreover, the application of 15-25 kJ/m(2) increased the phenolic content and caused slight changes in the visual appearance and color. Therefore, high UV-C doses could be an effective tool to decrease bacterial growth and to extend shelf life of minimally processed watercress.