Effects and interactions of gallic acid, eugenol and temperature on thermal inactivation of Salmonella spp. in ground chicken.

The combined effects of heating temperature (55 to 65°C), gallic acid (0 to 2.0%), and eugenol (0 to 2.0%) on thermal inactivation of Salmonella in ground chicken were assessed. Thermal death times were determined in bags submerged in a heated water bath maintained at various set temperatures, following a central composite design. The recovery medium was tryptic soy agar supplemented with 0.6% yeast extract and 1% sodium pyruvate. D-values were analyzed by second-order response surface regression for temperature, gallic acid, and eugenol. The observed D-values for chicken with no gallic acid or eugenol at 55, 57.5, 60, 62.5, and 65°C were 21.85, 5.43, 2.83, 0.58, and 0.26min, respectively. A second-order polynomial model developed to inactivate Salmonella was found to be significant (p<0.0001) with a R2=0.95 and a no significant lack of fit (p>0.1073). Efficacy of the additives in increasing the sensitivity of the pathogen to heat was concentration dependent. The model developed in this study can be used by processors to design appropriate thermal process to inactivate Salmonella in chicken products used in the study and thereby, ensuring an adequate degree of protection against risks associated with the pathogen.