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Title: Assessment of sodium hypochlorite and acidified sodium chlorite as antimicrobial agents to inhibit growth of Escherichia coli O157:H7 and natural microflora on shredded carrots

Author
item ALLENDE - CEBAS-CSIC,MURCIA,SPAIN
item GONZALEZ, ROLANDO - DEHS,UM,SCH PUB HEALTH,MN
item McEvoy, James
item Luo, Yaguang - Sunny

Submitted to: Journal of Vegetable Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/29/2006
Publication Date: 2/7/2007
Citation: Allende, Gonzalez, R.J., Mcevoy, J.L., Luo, Y. 2007. Assessment of sodium hypochlorite and acidified sodium chlorite as antimicrobial agents to inhibit growth of Escherichia coli O157:H7 and natural microflora on shredded carrots. Journal of Vegetable Science. 13:51-63.

Interpretive Summary: The safety of fresh-cut produce such as shredded carrots is important to both fresh-cut processors and consumers. Since the typical sanitizing step during processing of carrots, a chlorine wash, is not completely effective in killing all harmful bacteria, it is critical to test the applicability of using newly available sanitizers. In this paper we report that the new commercial sanitizer, acidified sodium chlorite, is significantly more effective than chlorine in killing a human pathogenic bacterium as well as spoilage bacteria. This information will be of use to the fresh and fresh-cut produce industry in improving the safety of shredded carrots and similar products.

Technical Abstract: The influence of cold tap water, sodium hypochlorite (200 ppm) and acidified sodium chlorite (100, 250, 500 and 1000 ppm) washes on survival and growth of Escherichia coli O157:H7 inoculated onto shredded carrots was determined after treatment and 7 and 14 days of storage. Growth of total mesophilic and yeast and moulds were also evaluated. Product was stored under passive modified atmosphere at 5 ºC. It was observed that cold tap water did not reduce growth of E. coli O157:H7, total plate count and yeast and moulds. Spoilage and pathogenic microorganisms were reduced by two logs by using sodium hypochlorite or ASC at 200 and 100 ppm, respectively. Acidified sodium chlorite at the highest concentrations (500 and 1000 ppm) was very effective in reducing microbial growth by 6 logs. During storage, total mesophilic growth increased, as expected, in samples washed with cold tap water, sodium hypochlorite or ASC at 100 and 250 ppm. However, shredded carrots washed with ASC at 1000 ppm did not showed any microbial growth even after 14 days of storage at 5 ºC.