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 Escherichia coli O157:H7 when heated in ground turkey containing various additives 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 additives: 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 D52 values ranged from 46.8 to 104.8 min; mean D55 values ranged from 7.7 to 27.2 min; mean D57 values ranged from 2.7 to 13.0 min; and mean D60 values ranged from 0.7 to 4.8 min. The greatest survival, as evidenced by higher (P 0.001) D values, occurred in turkey containing the mixture of additives. 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 enhanced 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 for ready-to-eat turkey products