title: Effects of vacuum or modified atmosphere packaging in combination with irradiation for control of Escherichia coli O157:H7 in ground beef patties.
abstract: The efficacy of controlling Escherichia coli O157:H7 in ground beef patties by combining irradiation with vacuum packaging or modified atmosphere packaging (MAP) was investigated. Fresh ground beef patties were inoculated with a five-strain cocktail of E. coli O157:H7  at 5 log CFU/g. Single patties, packaged with vacuum or high-CO(2) MAP (99.6% CO(2) plus 0.4% CO), were irradiated at 0 (control), 0.5, 1.0, or 1.5 kGy. The D(10)-value for this pathogen was 0.47 ± 0.02 kGy in vacuum and 0.50 ± 0.02 kGy in MAP  packaging. Irradiation with 1.5 kGy reduced E. coli O157:H7 by 3.0 to 3.3 log, while 0.5 and 1.0 kGy achieved reductions of 0.7 to 1.0, and 2.0 to 2.2 log, respectively. After irradiation, the numbers of survivors of this pathogen on beef patties in refrigerated storage (4°C) did  not change significantly for 6 weeks. Temperature abuse (at 25°C) resulted in growth in vacuum-packaged patties treated with 0.5 and 1.5 kGy, but no growth in MAP packages. This study demonstrated that combining irradiation with MAP was similar in effectiveness to irradiation with vacuum  packaging for control of E. coli O157:H7 in ground beef patties during refrigerated storage. However, high-CO(2) MAP appeared to be more effective after temperature abuse.
authors.affiliation: Johnsonville Sausage, Sheboygan Falls, Wisconsin 53085, USA.
authors.forename: Li L
authors.initials: LL
authors.lastname: Kudra
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Sebranek
authors.forename: James S
authors.initials: JS
authors.lastname: Dickson
authors.forename: Aubrey F
authors.initials: AF
authors.lastname: Mendonca
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Larson
authors.forename: Armitra L
authors.initials: AL
authors.lastname: Jackson-Davis
authors.forename: Zheng
authors.initials: Z
authors.lastname: Lu
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D002417:Cattle; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004307:Dose-Response Relationship, Radiation; D019453:Escherichia coli O157 / Q000254:growth & development*; D005506:Food Contamination / Q000032:analysis; D005514:Food Irradiation; D018857:Food Packaging / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D008461:Meat Products / Q000382:microbiology*; D012034:Refrigeration; D014618:Vacuum
chemical_list: D002245:Carbon Dioxide