We investigated the heat resistance of an eight-strain cocktail of Salmonella serovars in chicken supplemented with transcinnamaldehyde (0 to 1.0%, wt/wt) and carvacrol (0 to 1.0%, wt/wt). Inoculated meat was packaged in bags that were completely immersed in a circulating water bath and held at 55 to 71°C for predetermined lengths of time. The recovery medium was tryptic soy agar supplemented with 0.6% yeast extract and 1% sodium pyruvate. D-values in chicken, determined by linear regression, were 17.45, 2.89, 0.75, and 0.29 min at 55, 60, 65, and 71°C, respectively (z = 9.02°C). Using a survival model for nonlinear survival curves, D-values in chicken ranged from 13.52 min (D1, major population) and 51.99 min (D2, heat-resistant subpopulation) at 55°C to 0.15 min (D1) and 1.49 min (D2) at 71°C. When the Salmonella cocktail was in chicken supplemented with 0.1 to 1.0% transcinnamaldehyde or carvacrol, D-values calculated by both approaches were consistently less at all temperatures. This observation suggests that the addition of natural antimicrobials to chicken renders Salmonella serovars more sensitive to the lethal effect of heat. Thermal death times from this study will be beneficial to the food industry in designing hazard analysis and critical control point plans to effectively eliminate Salmonella contamination in chicken products used in this study.
STUDIES ON ISOTHERMAL CRYSTALLIZATION KINETICS OF POLYVINYL ALCOHOL