본 연구는 병원성 Escherichia coli O157:H7 균주에 의한 식중독을 미연에 예방하고자 우육에 본 균주를 오염, 동결시켜 전자선에 의한 살균효과를 조사하였다. $37^{circ}C$에서는 배양 16시간째에 최대균수를 나타내었고 $4^{circ}C$에서는 균주의 증식이 거의 없었다. E. coli O157:H7 균주는 대수기나 정지기 모두가 $0^{circ}C$ (chilled)와 $-18^{circ}C$ (frozen)에서 배양시 약 $10^{7};CFU/mL$의 균수를 나타내었고 $-18^{circ}C$에서는 $20^{circ}C$ 보다 균주의 사멸율이 높았다. 동결육에 오염된 E. coli O157:H7 균주의 방사선 감수성은 $D_{(10)}$ 값이 0.45 kGy, 불활성화계수가 $3{sim}5;kGy$에서 $6.67{sim}11.11$로 각각 나타났다. 본 결과로서 전자선 조사는 동결육에 오염된 E. coli O157:H7 균주의 제거방법으로 매우 효과가 있었다.
Treatment with electron beam irradiation was investigated for the elimination of Escherichia coli O157:H7 which has been linked to outbreaks of foodborne illness on undercooked and raw meat. Before treatment, the maximum populations were observed at 16 hr when E. coli O157:H7 was incubated in TSB at $37^{circ}C$. Incubation at $4^{circ}C$ did not influence survival and growth of the strain. The numbers of E. coli O157:H7 were present about $10^{7};CFU/mL$ in the log $(6;hr;at;37^{circ}C)$ and stationary phase $(16;hr;at;37^{circ}C)$ of cells, respectively. Freezing $(24;hr;at;-18^{circ})$ had a more marked lethal effect. The $D_{10}$ value at $-18^{circ}C$ of E. coli O157:H7 contaminated in frozen beef was 0.45 kGy, and inactivation factor were $6.67{sim}11.11$ at the radiation doses of $3{sim}5;kGy$. Therefore, electron beam irradiation was an effective method to eleminate of E. coli O157:H7.
