In this work, sterilization of a canned liquid food (carrot-orange soup) in a metal can lying horizontally and heated at 121 degreesC from all sides is simulated for a 3-D geometry. Transient temperature, flow pattern, and shapes of the slowest heating zone (SHZ) during natural convection heating of canned liquid foods are predicted. The partial differential equations describing the conservation of mass, momentum and energy conservation are solved numerically using a commercial computational fluid dynamics (CFD) software (PHOENICS), which is based on a finite-volume method of analysis. The simulation shows the influence of natural convection on the liquid-flow pattern and on the movement of the SHZ. The action of natural convection forces the SHZ to migrate towards the bottom of the can as expected. The SHZ eventually stays in a region that is about 20-25% of the can height from the bottom. The secondary flow Formation and its effect on the shape of the SHZ are evident. The results of this work are compared with those for vertical can. It shows faster heating in the vertical can, which is expected due to the enhancement of natural convection caused by its longer height.