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United States Department of Agriculture

Agricultural Research Service

Title: Washing Conditions Affect the Inactivation of Escherichia Coli O157:h7 on Fruit Surfaces

Authors
item Wang, Hua - UIUC
item Feng, Hao - UIUC
item Luo, Yaguang

Submitted to: Abstract of International Horticultural Congress
Publication Type: Abstract Only
Publication Acceptance Date: April 3, 2006
Publication Date: April 28, 2006
Citation: Wang, H., Feng, H., Luo, Y. 2006. Effects of washing conditions on escherichia coli o157:h7 reduction on fruit surfaces [abstract]. International Fresh-Cut Produce Association. Paper No. 007-06.

Technical Abstract: Washing with sanitizers is an important step to reduce microbial populations during postharvest handling of produce. The washing efficacy of sanitizers has been extensively studied in the contexts of produce-to-sanitizer ratio, washing time, and washing temperature. Little attention has been paid to the effect of flow conditions on the efficacy of a washing treatment. This study was undertaken to investigate effects of washing conditions such as flow rate, agitation rate, and treatment time on bacterial reduction on rough fruit surfaces. Cantaloupe and apple cylinders were prepared with and without skins respectively. The top surfaces of the cylinders were spot inoculated with E. coli O157:H7 before treatment with the sanitizer (Tsunami). Models were developed to determine the correlation between E. coli O157:H7 inactivation and the wash conditions. The results showed that the residual bacterial population decreased with increasing agitation rate, flow velocity, and treatment time. A quadratic regression function was found to best fit the flow velocity/agitation rate to normalized log reductions (N/N0, with N the final pathogen population and N0 the initial pathogen population). A logarithmic relationship was found to best correlate the treatment times to log N/N0 at each flow rate. It is therefore important to maintain the optimum flow velocity, agitation rate, and washing time to achieve the maximum reduction of bacterial populations and ensure food quality and safety.

Last Modified: 8/22/2014