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United States Department of Agriculture

Agricultural Research Service

Research Project: MICROBIAL ECOLOGY AND SAFETY OF FRESH ON-FARM ORGANICALLY GROWN PRODUCE Title: Improving Pathogen Reduction by Chlorine Wash Prior to Cutting in Fresh-Cut Processing

Authors
item Nou, Xiangwu
item Luo, Yaguang

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 9, 2010
Publication Date: August 2, 2010
Citation: Nou, X., Luo, Y. 2010. Improving Pathogen Reduction by Chlorine Wash Prior to Cutting in Fresh-Cut Processing. Meeting Abstract.

Technical Abstract: Introduction: Currently, most fresh-cut processing facilities in the United States use chlorinated water or other sanitizer solutions for microbial reduction after lettuce is cut. Freshly cut lettuce releases significant amounts of organic matter that negatively impacts the effectiveness of chlorine or other sanitizers for microbial reduction. Purpose: The objective of this study is to evaluate whether shifting the primary chlorine wash intervention to pre- cutting stage can significantly improve microbial reduction efficacy compared to traditional post- cutting sanitizer washing. Methods: Romaine lettuce was inoculated with E. coli O157:H7 strains and subjected to sanitizing washes in chlorinated water prior to or after cutting. Survival and transference of E. coli O157:H7 strains on lettuce shreds were determined by selective plating and MPN procedures. Results: Chlorine wash of cut lettuce reduced E. coli O157:H7 count by approximately 1.5 log10 units. Reversal of the cutting-washing sequence resulted in an addition one log10 unit reduction of E. coli O157:H7 counts. High level of E. coli O157:H7 transference was observed when inoculated and non-inoculated lettuce leaves were co-processed following the traditional cutting and washing sequence. This cross contamination was significantly reduced when chlorine wash was performed prior to cutting. Significance: Sanitizer wash performed at the whole-leaf stage significantly enhanced the efficacy of chlorine for pathogen reduction and cross-contamination prevention.

Last Modified: 8/27/2014
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