Thermal sterilization of canned food in a 3-D pouch using computational fluid dynamics

Sterilization of food in cans has been well studied both experimentally and theoretically, but little or no work has been done on sterilization of foo d in pouches. The food pouches have only been recently introduced to the ma rket. In this study, transient temperature, velocity profiles and the shape of the slowest heating zone (SHZ) have been established. for a uniformly h eated three-dimensional pouch containing carrot orange soup, using saturate d steam at 121 degreesC. The computational fluid dynamics (CFD) code PHOENI CS was used for this purpose. The liquid food used in the simulation has te mperature-dependent viscosity and density. From the simulations, the maximu m axial velocity of the soup was found to be 10(-2) - 10(-4) mm s(-1), whic h was due to the small height of the pouch and high viscosity of the soup. The SHZ was found to migrate into a region within 30-40% of the pouch heigh t above the bottom and at a distance approximately 20-30% of the pouch leng th from its widest end. The experimental measurements were conducted at Hei nz Watties Australasia based in New Zealand. The measured temperature at di fferent locations in the pouch was compared with that predicted. Both resul ts were found to be in good agreement. The results of a simulation done for the same pouch geometry and material considering pure conduction mechanism were also presented for the purpose of comparison. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.