Thermal death time model for Salmonella spp. in ground chicken supplemented with olive polyphenol extract and pomegranate powder

Heat is a widely used and effective method of eliminating pathogens in formulated chicken. This study was conducted to assess the interactive effects of olive polyphenol extract (OPE) and pomegranate powder (POM) (each at 0.4–2% w/w) on the heat resistance of an eight-strain mixture of Salmonella serotypes in ground chicken, as insufficient cooking time and temperature are important factors that can lead to foodborne illness. Ground chicken was inoculated and heated in a water bath for predetermined times at temperatures of 55.0, 56.5, 58.7, 61.0, and 62.5 °C. After heating, the remaining microbial population was recovered using Tryptic Soy Agar enriched with 1% sodium pyruvate and 0.6% yeast extract. The experimental data was fitted to the Baranyi model using the DMFit curve fitting software to compute decimal reduction times (D-values). The D-values were converted to natural logarithms and analyzed mathematically using second order response surface regression to generate a regression model for temperature, OPE, and POM. Without antimicrobials, the observed D-value at 55 °C in chicken was 24.3 min; temperatures of 56.5, 58.7, 61.0, and 62.5 °C decreased D-values by 63.7, 74.5, 87.0, and 98.3%, respectively. The maximum synergistic effect of the OPE and POM interaction making the pathogen less resistant to heat was observed when chicken was supplemented with both additives at a concentration of 1%. D-values at 55.0 and 62.5 °C decreased by 76.5% (0.96 min, no additive versus 0.16 min, 1% OPE and 1% POM) and 83.3% (90.96 min, control versus 0.16 min, both OPE and POM at 1% level), respectively. These findings indicate that D-values in ground chicken can be estimated using the thermal death time predictive model for any combination of temperature and food-safe pomegranate and olive powders. Increased sensitivity of Salmonella to heat has the potential to improve safety in cooked chicken. •Observed D-values of Salmonella in chicken decreased as the temperature increased.•Olive polyphenol extract or pomegranate powder in chicken decreased D-values of Salmonella.•The observed D-values were very close to the model estimated D-values.•Increased sensitivity of Salmonella to heat has the potential to improve safety in cooked chicken.