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Abstract
Outbreaks of disease caused by Escherichia coli O157:H7 associated with the consumption of undercooked ground beef patties have raised interest in improving the cooking process. The inability to accurately measure temperature, using temperature probes and the complex nature of the beef patty structure makes end point temperature prediction difficult. X-ray computer aided tomography (CAT) scanning was used to characterize the internal structure of ground beef patties. Images captured by the CAT scanner showed the porous structure of the patty. Air pores were randomly distributed, as were lipid and muscle tissues after cooking. A crust layer was visualized on the cooked surfaces of the beef patty. Cross sectional images illustrated an inconsistent thickness across the patty, indicating that constant contact with the grill was not maintained. Locations of thermal probes inserted into the patty were verified using the x-ray CAT scanning. Temperatures corresponding to verified locations demonstrated temperature differences across the thickness of the patty. Finite element modeling using digital images illustrated the effect that a non-homogenous structure has on conductive heating. Homogeneous model images resulted in uniform heating, while images of ground beef patties with pores, crust, and an inconsistent cooking surface resulted in a heating pattern that is disrupted. The cook time was delayed by increasing patty thickness, crust development, and porosity. X-ray CAT scanning and FEM modeling demonstrated the effect of internal structure on conductive heat transfer in ground beef patties.