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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 on Leafy Greens Using a Phage Cocktail

Authors
item Boyacioglu, Olcay - NCA&T STATE UNIV
item Goktepe, Ipek - NCA&T STATE UNIV
item Sulakvelidze, Alexander - INTRALYTIX,INC. BALTO, MD
item Sharma, Manan

Submitted to: Interscience Conference on Antimicrobial Agents & Chemotherapy Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 24, 2008
Publication Date: October 25, 2008
Citation: Boyacioglu, O., Goktepe, I., Sulakvelidze, A., Sharma, M. 2008. Control of Escherichia coli O157:H7 on Leafy Greens Using a Phage Cocktail. Interscience Conference on Antimicrobial Agents & Chemotherapy Proceedings., p.187.

Technical Abstract: Enterohemorrhagic Escherichia coli O157:H7 (EHEC) outbreaks in fresh produce have raised concerns about the safety of fruits and vegetables. Since washing only is not enough to keep produce free of pathogens; there is a need for better and more effective methods to control and/or prevent pathogenic growth in fresh produce. Bacteriophages are natural enemies of bacteria, and therefore, 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 leafy lettuce. E. coli O157:H7 cultures at 104 CFU/ml were inoculated directly on both sides of 5x5 cm2 lettuce leaves. Contaminated lettuce leaves were air dried for bacterial attachment, followed by inoculation of EHEC-specific phage cocktail at 106 PFU/ml. Lettuce samples were incubated for 24 hrs at 4 and 37ºC. EHEC counts were performed on Sorbitol MacConkey (SMAC) Agar. Phage treatment resulted in a 2 log growth reduction compared to the phage-free controls kept at 4 and 37ºC. These results show that EHEC-specific phage cocktail used in this study has the potential to control E. coli O157:H7 in fresh produce. Ongoing research is aimed at optimizing phage inoculation on lettuce samples using different application methods.

Last Modified: 10/24/2014