April 19, 2002David A. Bernier
Department of Food Science Advisor: Dr. Donald Schaffner
M.S. Seminar
Influence of Cooking Parameters on Internal Temperature
in Commercially Processed Chicken.
The current USDA-FSIS processing regulations require that cooked, ready to eat (RTE) poultry products comply with a performance standard showing a quantifiable microbiological pathogen reduction. A 7-D (10 million fold) reduction in Salmonella population must be obtained through a validated thermal process or by achieving an internal temperature of 71.1˚C (160˚F) if a food is to be considered RTE. No official post-processing technique exists for time-temperature validation of the delivered thermal process in poultry. It is therefore the processors responsibility to provide data to prove that the production methodologies used do actually eliminate pathogens. Mathematical models have been used previously to optimize thermal processing of many products. This methodology might allow processors to validate thermal processing based on easily measured oven settings, rather than relying on more labor-intensive temperature measurements on finished products. The main objective of this project was to quantify the relationship between the oven operating variables and the finished product temperature.
Air convection oven operating variables included oven temperature, wet bulb temperature, fan speed and cook time. Internal temperatures were collected for a boneless, skinless chicken thigh product (selected for its consistent size and weight). Data collected over a seventeen-month period from operation of a commercial air convection oven was analyzed using a polynomial stepwise regression to correlate oven operating parameters with finished product temperature. This large commercially obtained dataset includes 2548 individual observations of final product temperature. The results of the analysis yielded a regression equation that included four separate predictor variables. The variables Cooking Time (p < .0001) and Oven Temperature (p < .0001) accounted for most of the temperature variability. Poor overall goodness of fit for the regression model indicates that other, as yet unidentified variables may also influence final product temperature.
Further work with additional variables and alternate products may increase the goodness of fit and lead to better prediction useful for optimization of thermal processes in RTE poultry.
References:
Kachigan, S.K.Multivariate Statistical Analysis: A Conceptual Approach, Radius Press, New York, New York, 1991.
Murphy, R.Y., E.R. Johnson, L.K. Duncan, M.D. Davis, M.G. Johnson and J.A. Marcy. 2001. Thermal Inactivation of Salmonella spp. and Listeria innocua in the Chicken Breast Patties Processed in a Pilot-Scale Air-Convection Oven. J. Food Sci. 66(5): 734-741.
U.S. Dept. of Agriculture, Food Safety and Inspection Service. 1999. Performance standard for the Production of Certain Meat and Poultry Products. Fed. Regist. 64(3): 732-749.
Veeramuthu, G.J., J.F. Price, C.E. Davis, A.M. Booren and D.M. Smith. 1997. Thermal Inactivation of Escherichia coli O157:H7, Salmonella senfterberg, and Enzymes with Potential as Time-Temperature Indicators in Ground Turkey Thigh Meat. J. Food Prot. 61(2): 171-175.