Sterilization of Escherichia coli O157:H7 Contaminated Beef by Gamma Irradiation

Escherichia coli O157:H7을 오염시킨 우육의 감마선 조사에 의한 살균효과

  • Kim, Sung (Department of Food Irradiation, Korea Atomic Energy Research Institute) ;
  • Yook, Hong-Sun (Department of Food Irradiation, Korea Atomic Energy Research Institute) ;
  • Lee, Ju-Woon (Department of Food Irradiation, Korea Atomic Energy Research Institute) ;
  • Choi, Cheong (Department of Food Science and Technology, Yeungnam University) ;
  • Byun, Myung-Woo (Department of Food Irradiation, Korea Atomic Energy Research Institute)
  • 김성 (한국원자력연구소 방사선식품공학연구실) ;
  • 육홍선 (한국원자력연구소 방사선식품공학연구실) ;
  • 이주운 (한국원자력연구소 방사선식품공학연구실) ;
  • 최청 (영남대학교 식품가공학과) ;
  • 변명우 (한국원자력연구소 방사선식품공학연구실)
  • Published : 1998.10.01

Abstract

The gamma-radiation sensitivity of four kinds of Escherichia coli O157:H7 was investigated in frozen cells $(-18^{\circ}C)$ with 0.1 M phosphate buffer and inoculated cells in beef. The maximum populations were observed at 12 hr when E. coli O157:H7 was incubated in the tryptic soy broth at $37^{\circ}C$. In the case of the frozen cells at logarithmic phase, the $D_{10}$ and $12D_{10}$ values of four kinds of E. coli O157:H7 were $0.09{\sim}0.15\;kGy$ and $1.08{\sim}1.80\;kGy$, and inactivation factors were $13.33{\sim}22.22$ and $20.00{\sim}33.33$ at radiation doses of 2 and 3 kGy, respectively. The radiosensitivity of inoculated E. coli O157:H7 in beef showed the $D_{10}$ value of $0.30{\sim}0.47\;kGy$, the $12D_{10}$ value of $3.60{\sim}5.64\;kGy$, and inactivation factor of $4.26{\sim}10.00$. The radiosensitivity of the frozen cells was higher than that of the inoculated E. coli O157:H7 in beef. Gamma irradiation at doses within the range of 1.5 to 3 kGy is considered to be an effective method to control E. coli O157:H7 in beef.

Keywords

Escherichia coli O157:H7;beef;frozen cell;gamma-radiation sensitivity