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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: Control of Escherichia coli O157:H7 contamination on green leaf lettuce using a bacteriophage cocktail

Authors
item Boyacioglu, Olcay -
item Sulakvelidze, Alexander -
item SHARMA, MANAN
item Ahmedna, Mohamed -
item Goktepe, Ipek -

Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2009
Publication Date: June 8, 2009
Citation: Boyacioglu, O., Sulakvelidze, A., Sharma, M., Ahmedna, M., Goktepe, I. 2009. Control of Escherichia coli O157:H7 contamination on green leaf lettuce using a bacteriophage cocktail. Annual Meeting of the Institute of Food Technologists. Institute of Food Technologists Meeting Technical Program Abstracts.

Technical Abstract: Unpredictable outbreaks caused by fresh produce contaminated with enterohemorrhagic Escherichia coli O157:H7 (EHEC) have raised concerns about the safety of fruits and vegetables. Since simple washing alone is not sufficient to keep the produce free of pathogens, there is a need for more effective methods to control and/or prevent pathogenic bacteria from growing on fresh produce. Lytic bacteriophages are natural enemies of bacteria and they represent logical candidates for the control of foodborne pathogens. This study investigated the effect of bacteriophage treatment on the survival of E. coli O157:H7 on green leaf lettuce. Small pieces (5x5 cm2) of lettuces were inoculated with E. coli O157:H7 strain RM1918 and air-dried for bacterial attachment. Phage cocktail (106 PFU/ml) was introduced on lettuce pieces contaminated with EHEC. Lettuce pieces were incubated at 4ºC for 24 h. E. coli O157:H7 counts were determined by standard colony counting on Sorbitol MacConkey (SMAC) agar. The phage treatment resulted in a 2 log reduction in E. coli O157:H7 compared to the control samples. Our results suggest that the EHEC-specific phage cocktail used in this study has the potential to control E. coli O157:H7 contamination in fresh produce. Ongoing research is aimed at determining the optimal phage treatment protocol for lettuce using various application methods relevant for real-life produce industry settings.

Last Modified: 8/27/2014
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