Subtopic: Cold point location in conduction vs convection heated cans
Question Statement:
In a cylindrical can undergoing retort thermal sterilization, the 'cold point' (slowest heating zone) for a conduction-heating viscous food (like cream style corn) is situated at:
Options:
(A) The geometric center of the can
(B) One-fifth of the height above the bottom along the vertical axis
(C) The top lid periphery
(D) The side wall of the can
Answer Key:
A
Step-by-Step Solution & Explanation
In pure conduction heating, heat penetrates uniformly from all external boundaries, making the geometric center the slowest heating point. In convection heating, liquid buoyant currents shift the cold point to roughly 1/3 to 1/5 from the bottom.