title: Differences in inactivation of Escherichia coli O157:H7 strains in ground beef following repeated high pressure processing treatments and cold storage.
abstract: High pressure processing (HPP) is a safe non-thermal processing method to effectively improve food safety. In this study, HPP treatment followed by cold storage was investigated to reduce Escherichia coli O157:H7 in ground beef. Experiments were conducted using ground beef contaminated with six E. coli O157:H7 strains one at a time or as a cocktail. Control and inoculated ground beef samples were HPP at 25 °C, 35 °C, and 45 °C, at 400 MPa and pre-determined number of pressure cycles totaling a holding time of 15 min. Optimum HPP parameters were 25 °C, 400 MPa at five pressure cycles of 3 min each which achieved a 5-log reduction of E. coli O157:H7 in ground beef. Storing HPP processed ground beef at 4 °C or -20 °C further decreased (P < 0.05) the E. coli O157:H7 population. An effective HPP treatment (5-log reduction) was developed that could be used post-processing to reduce the risk associated with E. coli O157:H7 contamination in ground beef.
authors.affiliation: Department of Food Science, Rutgers, The State University of New Jersey, 65 Dudley Road, New Brunswick, NJ 08901, USA.
authors.forename: Yijing
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Food Science, Rutgers, The State University of New Jersey, 65 Dudley Road, New Brunswick, NJ 08901, USA.
authors.forename: Mukund V
authors.initials: MV
authors.lastname: Karwe
authors.affiliation: Department of Food Science, Rutgers, The State University of New Jersey, 65 Dudley Road, New Brunswick, NJ 08901, USA. Electronic address: matthews@aesop.rutgers.edu.
authors.forename: Karl R
authors.initials: KR
authors.lastname: Matthews
mesh_terms: D000818:Animals; D002417:Cattle; D003080:Cold Temperature; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D019453:Escherichia coli O157 / Q000502:physiology*; D005506:Food Contamination; D005511:Food Handling; D005516:Food Microbiology; D061353:Food Storage; D005628:Frozen Foods; D050296:Microbial Viability; D011312:Pressure; D000069466:Red Meat / Q000382:microbiology*
keywords: Escherichia coli O157:H7; Ground beef; HPP; Pressure cycling