title: Survival of Pseudomonas fluorescens and Salmonella typhimurium after electron beam and gamma irradiation of refrigerated beef.
abstract: The radurization effects of gamma ray and electron beam irradiation at 1.5 and 3.0 kGy on beef steaks inoculated with Salmonella Typhimurium and Pseudomonas fluorescens were investigated during 8 days of storage at 5 degrees C. Total bacterial counts and numbers of Salmonella Typhimurium and P. fluorescens were analyzed at 2-day intervals. Total bacterial counts of samples irradiated by both gamma rays and electron beam were significantly (P < 0.05) reduced by 3.8 to 5.3 log CFU/g. Salmonella Typhimurium was not detectable during the experimental period. P. fluorescens counts of beef samples irradiated by gamma rays at both 1.5 and 3.0 kGy were not detected; however, P. fluorescens in samples irradiated by electron beam at 1.5 and 3.0 kGy was recovered after 2 days, and bacterial counts reached 7.8 and 6.9 log CFU/g, respectively. Both gamma ray and electron beam irradiation reduced total bacterial counts initially, possibly extending shelf life. Irradiation was very effective in destroying Salmonella Typhimurium; however, P. fluorescens was not completely eliminated by electron beam irradiation. Consequently, gamma ray irradiation was more effective than electron beam irradiation in the destruction of P. fluorescens.
authors.affiliation: Korea Health Industry Development Institute, Seoul. chungms@khidi.or.kr
authors.forename: M S
authors.initials: MS
authors.lastname: Chung
authors.forename: Y T
authors.initials: YT
authors.lastname: Ko
authors.forename: W S
authors.initials: WS
authors.lastname: Kim
mesh_terms: D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D005514:Food Irradiation; D005720:Gamma Rays; D008460:Meat / Q000382:microbiology*; D011551:Pseudomonas fluorescens / Q000528:radiation effects*; D012034:Refrigeration; D012486:Salmonella typhimurium / Q000528:radiation effects*