INACTIVATION OF SHEWANELLA-PUTREFACIENS BY GAMMA-IRRADIATION OF RED MEAT AND POULTRY

The resistance of Shewanella putrefaciens ATCC 8071, 8072, and 8073 to gamma radiation was determined in the presence and absence of air on mechanically deboned chicken meat (MDCM). The presence or absence of a ir (oxygen) did not significantly influence resistance to gamma radiat ion at 5C, and it was very sensitive with a D-10 value of 0.11 +/- 0.0 02 kilogray (kGy) on MDCM. A high percentage of cells surviving irradi ation were shown by impedance measurements to have suffered injury. Th e bacteria were significantly more resistant to gamma radiation at tem peratures below the freezing point. At a dose of 0.8 kGy lowering the temperature of irradiation by 10 degrees increased the survival of thi s food spoilage organism by a 1.66 log(10). The type of meat (hamburge r, ground beef round, ground pork, and ground turkey breast) did not s ignificantly alter resistance of S. putrefaciens to gamma radiation un der identical conditions (D-10 value = 0.18 +/- 0.01 kGy). The minimum radiation dose currently approved for poultry in the USA, 1.5 kGy, sh ould eliminate S. putrefaciens from meats.