Surface Decontamination of Fresh Produce

摘要

This study was designed to assess the efficacy of dissolved ozone (O3) in its role in the decontamination of fresh produce in both one and two stage wash processes. Lettuce (‘Fiorella') was inoculated with a combination of Escherichia coli, Listeria monocytogenes, Salmonella choleraesuis and Bacillus cereus. The inoculated lettuce was treated at 1.5 ppm dissolved [O3]. The highest level of sensitivity was attributable to L. monocytogenes during a two-stage wash process resulting in a 4- log reduction in comparison with a 0.7 log reduction in the one-stage wash process. Population reductions of B. cereus also improved with the two-stage process with log reductions of 1.8. Log population reductions of 1.1 were achieved for S. choleraesuis. E. coli proved the most resistant with reductions of only 0.2 log in the two-stage process achievable. Though reductions in bacterial numbers are achievable with the use of a one-stage wash process, the efficacy of dissolved O3 is far greater when used in conjunction with an initial washing step to remove minimal amounts of bacteria and other organic debris.