Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2010
Publication Date: 7/19/2010
Citation: Boyacioglu, O., Goktepe, I., Sharma, M., Sulakvelidze, A. 2010. Inhibition of E. coli O157:H7 on the surface of Fresh Spinach by bacteriophage ECP-100 and Modified Atmosphere Packaging. [abstract]. Annual Meeting of the Institute of Food Technologists. Interpretive Summary:
Technical Abstract: The last multistate Escherichia coli O157:H7 (EHEC) outbreak linked to bagged spinach in 2006 has raised concerns about the safety of ready-to-eat vegetables. Since washing alone or in combination with chemicals has been ineffective in completely killing EHEC, there is an urgent need for more effective and safe methods to control pathogens on fresh produce. One novel approach is to utilize lytic bacteriophages, which are natural enemies of bacteria and are promising candidates for the control of foodborne pathogens in fresh vegetables. This study investigated the effectiveness of an EHEC-specific bacteriophage cocktail (ECP-100) alone or in combination with modified atmosphere packaging on fresh spinach contaminated with EHEC. Pieces (3x3 cm2) of spinach were spot inoculated with EHEC strain RM1918 (initial population) and air-dried. Contaminated spinach pieces were sprayed with ECP-100 bacteriophage cocktail, and packaged under different atmospheres including 3, 5, and 21% (atmospheric) oxygen. All packages were stored at 4°C for 7 days.EHEC counts of phage-treated and untreated control samples were determined by standard colony counting on cefixime-tellurite Sorbitol MacConkey (CT-SMAC) agar on days. The phage treatment resulted in a 3-log reduction in EHEC counts compared to control samples during storage time. In all cases, the phage treatment reduced the EHEC populations below the detection limit (0.045 log CFU/cm2). Different modified atmosphere packaging did not show any significant effect on the number of EHEC counts. Our results suggest that EHEC-specific bacteriophage cocktail used in this study has the potential to reduce EHEC on fresh spinach.