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.

Lethality Validation for Human Pathogenic Salmonella enterica on Chicken Feathers and Blood during Simulated Commercial Low-Temperature Dry Rendering

“…The resulting calculated t 7 D values at 60, 70, and 80 °C were therefore 18.38, 5.03, and 2.79 min. This relationship between temperature and Salmonella D -values was also reported by Wong de la Rosa et al [ 10 ] and applied to higher processing temperatures for chicken blood. For both chicken feathers and blood, the relationship between temperature and shoulder parameters was determined to be linear and decrease with an increase in temperature.…”

“…To that end, D-values were again calculated using the Geeraerd model-provided shoulder length (SL) by re-arranging the calculation for the t4D as indicated above (Section 3.3). Our team previously used it to describe the lethality of S. Senftenberg in chicken blood heated at higher processing temperatures (82-93 • C) [10]. In the current study, the calculated t 4D periods for 60, 70, and 80 • C using the Geeraerd model were 14.60 ± 0.46, 5.40 ± 0.70, and 3.37 ± 0.20 min, respectively.…”

“…Our team previously used it to describe the lethality of S . Senftenberg in chicken blood heated at higher processing temperatures (82–93 °C) [ 10 ]. In the current study, the calculated t 4 D periods for 60, 70, and 80 °C using the Geeraerd model were 14.60 ± 0.46, 5.40 ± 0.70, and 3.37 ± 0.20 min, respectively.…”

“…In the current study, the calculated t 4 D periods for 60, 70, and 80 °C using the Geeraerd model were 14.60 ± 0.46, 5.40 ± 0.70, and 3.37 ± 0.20 min, respectively. The value of a single D when the microbial populations are in log-linear decline (i.e., not in the shoulder phase) can be calculated as the difference of the t 4 D minus the corresponding S L and divided by 4.0 [ 10 ]. The calculated D -values for S .…”

“…Pandey et al [ 9 ] reported that, during Salmonella Typhimurium inactivation in ground poultry carcasses, Salmonella could survive up to 120 min at a low rendering temperature (70 °C), wherein the pathogen was inoculated but not continuously agitated in the carcass material. Wong de la Rosa et al [ 10 ], however, reported a similar trend where D -values of Salmonella Senftenberg 775W inoculated in whole chicken blood decreased from 0.61 to 0.12 min with an increase in processing temperature from 82.2 to 93.3 °C, with an eventual loss of detection by plating at higher temperatures. Similarly, Ramirez-Hernandez et al [ 11 ] reported that the D -value decreased from 2.18 to 0.20 min as the temperature increased from 60 to 95 °C for low-fat beef rendered products and from 0.28 to 0.20 min for 50% fat beef offal.…”