Validating Thermal Lethality to Salmonella enterica in Chicken Blood by Simulated Commercial Rendering

Abstract

The U.S. rendering industry produces materials for use in further processed animal foods and feeds and is required to scientifically validate food safety hazard control. This study aimed to provide lethality validation for Salmonella enterica during simulated commercial rendering of whole chicken blood. Chicken blood was inoculated with a blend of multiple serovars of the pathogen (S. Heidelberg, Typhimurium, Senftenberg) and subjected to heating at 82.2, 87.8, or 93.3 °C; surviving cells were enumerated incrementally up to 5.0 min. Survivor data were modeled using the GInaFiT 1.7 freeware package. D-values and t7D (time to a 7.0 log10-cycle inactivation) values were generated from best-fit model parameters. Predictive modeling analysis revealed that the survival curves of Salmonella possessed log-linear components but also possessed shoulder and/or tail components. Mean D-values declined from 0.61 to 0.12 min as heating temperature was raised from 82.2 to 93.3 °F, respectively, differing by heating temperature (p = 0.023). t7D values differed significantly by heating temperature (p = 0.001), as was also the case for shoulder length (SL) (p = <0.0001), where, at lower temperatures, a shoulder was observed versus heating at 93.3 °F. These data aid scientific validation of Salmonella enterica inactivation during thermal rendering of poultry blood for use in further processed animal foods.