Gamma-Radiation Sensitivity of Pathogenic Bacteria in Beef

우육에 오염시킨 병원세균의 방사선 감수성

The gamma-radiation sensitivity of eight kinds of pathogenic bacteria related to beef was investigated in frozen cells $(-18^{\circ}C)$ with 0.1 M phosphate buffer and inoculated cells in beef. In frozen cells, D10 values of pathogenic bacteria related to beef were $0.07{\sim}0.69$ kGy, and inactivation factors were $2.90{\sim}42.86$ at the radiation doses of $2{\sim}3$ kGy. Beef was inoculated with Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Enterobacter aerogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Listeria monocytogenes, and Aeromonas hydrophila. Inoculated beef samples were packaged in air and irradiated at 0.005 to 3.0 kGy. Ninety percent of the viable pathogenic bacteria in beef was eliminated by doses of $0.1{\sim}0.61$ kGy at room temperature, and the inactivation factors were $3.28{\sim}30.0$ kGy at the radiation doses of $2{\sim}3$ kGy. Therefore, irradiation is considered to be an effective method to control pathogenic bacteria in beef.

병원세균 8종에 대하여 동결균체 및 우육접종에 의한 살균효과를 조사한 결과, 동결세포균체에서는 공시균주들의 $D_{10}$값은 $0.14{\sim}0.69\;kGy$ 나타났으며 그 중 Pseudomonas aeruginosa가 0.77 kGy, Aeromonas hydrophila와 Escherichia coli는 0.14 kGy로 방사선 감수성이 가장 높았다. 불활성화 계수는 $2{\sim}3$ kGy 조사시 $2.90{\sim}42.86$으로 나타났다. 한편 우육접종시에는 $D_{10}$값이 $0.1{\sim}0.61\;kGy$로 A. hydrophila가 0.1 kGy로 방사선 감수성이 가장 높았으며 V. parahaemolyticus가 0.61로서 가장 낮게 나타났다. 또한 이들 미생물의 완전살균을 위해서는 1.17 kGy에서 7.32 kGy 범위의 감마선 조사선량이 요구되며 불활성화 계수는 $2{\sim}3$ kGy 조사로 $3{\sim}30$ log cycles 이상 감소시킬 수 있어 감마선 조사는 육류매개 병원세균을 제어하기 위한 매우 효과적인 방법이다.