Evaluation of 54° and 60°C Holding Temperatures on Aerobic Plate Counts and Coliform Determinations of Control and Post Cooking Contaminated Beef Roast

Fabricated beef roasts were cooked to an internal temperature of 60°C and the surface inoculated with a suspension of Escherichia coli at a level of lo⁶ cells/cm². Roasts were then stored in a warming oven at 54° and 60°C for 1, 2, 6, and 12 hr. Under these conditions the destruction of this strain of E. coli is quite rapid (less than 6 hr) at the 60°C holding temperature. The holding temperatures do allow the growth of thermoduric organisms naturally present in the product to initiate exponential growth after 6 hr at 54°C. The higher holding temperature reduced the rate of multiplication of the thermoduric organisms.