HEAT INACTIVATION OF ESCHERICHIA-COLI O157-H7 IN TURKEY MEAT AS AFFECTED BY SODIUM-CHLORIDE, SODIUM LACTATE, POLYPHOSPHATE, AND FAT-CONTENT

The purpose of this research was to determine the survival of Escheric hia coli O157:H7 when heated in ground turkey containing various addit ives and fat levels. D values and z values were determined for low (3% )- and high (11%)- fat ground turkey with or without one of three addi tives: 8% NaCl, 4% sodium lactate, or a mixture of 8% NaCl, 4% sodium lactate, and 0.5% polyphosphate. Products inoculated with E, coli O157 :H7 strain 204P were mixed, aseptically placed into thermal-death-time (TDT) tubes which were sealed and heated at 52, 55, 57 and 60 degrees C. Survival was determined by enumeration on phenol red sorbitol agar , and D values were calculated by two methods. Mean D-52 values ranged from 46.8 to 104.8 min; mean D-55 values ranged from 7.7 to 27.2 min; mean D-57 values ranged from 2.7 to 13.0 min; and mean D-60 values ra nged from 0.7 to 4.8 min. The greatest survival, as evidenced by highe r (P < 0.001) D values, occurred in turkey containing the mixture of a dditives. The z values ranged from 6.09 to 4.08 degrees C, and higher z values were obtained in turkey meat containing the additive mixture versus other turkey additive formulations. The additives evaluated enh anced survival of E. coli O157:H7 in cooked turkey meat as compared to turkey meat with no additives. In contrast to earlier reports, added fat did not enhance survival (P > 0.05). Product formulation should be a critical consideration when safe cooking processes are developed fo r ready-to-eat turkey products.