Submitted to: Innovative Food Science and Emerging Technologies
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/15/2005
Publication Date: 5/10/2006
Citation: Podolak, R., Solomon, M.B., Patel, J.R., Liu, M. 2006. Effect of hydrodynamic pressure processing on the survival of Escherichia coli O157:H7 in ground beef. Innovative Food Science and Emerging Technologies 7:28-31. Interpretive Summary: Escherichia coli O157:H7 has been recognized as a major public health concern in the United States because it can cause severe illness and death. Hydrodynamic pressure processing (HDP), a non-thermal technology was evaluated as a method to reduce six pathogenic E. coli O157:H7 in ground beef. E. coli O157:H7 reduction in ground beef was marginal following HDP treatment. Our results indicate that the strains of E. coli O157:H7 used in this study may be pressure resistant to the HDP technology. A modification in some process parameters of HDP might increase its effectiveness in reducing E. coli O157:H7.
Technical Abstract: Hydrodynamic pressure processing (HDP), a novel non-thermal technology that uses a small amount of explosive (100g) to generate a supersonic-hydrodynamic shock wave in a water filled steel container (54 L) was evaluated for inactivation of Escherichia coli O157:H7 (EHEC) in a ground beef. The ground beef was inoculated with a six strain cocktail of E. coli O157:H7 at three different concentrations (103, 104 and 106 CFU/g). The following strains of E. coli O157:H7 were used in the cocktail: 3027-93, 3055-93, C7927, 43888, C9490, and green fluorescent protein-expressing E. coli O157:H7 B6-914 (GFP EC). Inoculated ground beef was wrapped in polyethylene wrap, vacuum packaged into multilayer barrier bags, heat shrunk and treated with the HDP. The initial concentrations of EHEC were 1.29 X 103, 2.88 X 104, and 2.19 X 106 CFU/g. After HDP treatment, the EHEC populations were reduced (P<0.05) to 9.12 X 102, 2.40 X 104, and 1.91 X 106 CFU/g, respectively. A similar trend was observed for GFP EC which was also enumerated from the cocktail. The GFP EC initial populations of 4.26 X 102 and 3.72 X 103 CFU/g were reduced to 3.47 X 102, and 3.09 X 103 CFU/g, respectively. Although the reduction in EHEC populations due to HDP treatment was statistically significant, the practicability of the reduction was marginal. Therefore, other hurdle parameters should be included along with the HDP treatment for more practical inactivation of EHEC in ground beef.