Bacteriophage cocktail significantly reduces Escherichia coli O157

Abstract

Foods contaminated with Escherichia coli O157:H7 cause more than 63,000 foodborne illnesses in the United States every year, resulting in a significant economic impact on medical costs and product liabilities. Efforts to reduce contamination with E. coli O157:H7 have largely focused on washing, application of various antibacterial chemicals, and gamma-irradiation, each of which has practical and environmental drawbacks. A relatively recent, environmentally-friendly approach proposed for eliminating or significantly reducing E. coli O157:H7 contamination of foods is the use of lytic bacteriophages as biocontrol agents. We found that EcoShield™, a commercially available preparation composed of three lytic bacteriophages specific for E. coli O157:H7, significantly (p < 0.05) reduced the levels of the bacterium in experimentally contaminated beef by ≥ 94% and in lettuce by 87% after a five minute contact time. The reduced levels of bacteria were maintained for at least one week at refrigerated temperatures. However, the one-time application of EcoShield™ did not protect the foods from recontamination with E. coli O157:H7. Our results demonstrate that EcoShield™ is effective in significantly reducing contamination of beef and lettuce with E. coli O157:H7, but does not protect against potential later contamination due to, for example, unsanitary handling of the foods post processing.

Keywords: :

• EcoShield™
• Escherichia coli O157:H7
• bacteriophage
• beef
• food safety
• genomics
• ground beef
• lettuce
• phage
• phylogeny

Disclosure of Potential Conflicts of Interest

C.C., T.A., M.L., J.W. and A.S. hold an equity stake in Intralytix, Inc., a Maryland corporation involved with the development of phage preparations (including EcoShield™) for food safety applications.

Acknowledgments

Arnold Kreger is gratefully acknowledged for his editorial assistance. The E. coli strains, 2886-75, G5101 and 93-111, were obtained from the STEC Center at Michigan State University. The study was supported, in part, by SBIR award W911QY-07-C-0125 from the US Army (to A.S.).

Supplemental Materials

Supplemental materials may be found here: www.landesbioscience.com/journals/bacteriophage/article/22825