Transient temperature and velocity profiles during thermal processes of egg shell bodies filled with a viscous liquid have been studied. Sodium carboxy-methyl cellulose suspension was used as a model system, having well known properties similar to eggwhite. The partial differential equations governing natural convection motion of fluid in a three-dimensional geometry were solved with the commercial computational fluid dynamics package Fluent. A Boussinesq approximation was used to account for the buoyancy force driving the convective motion of the fluid. Simulated temperature profiles were compared with experimentally observed data and were found to be in good agreement. It was observed that natural convection tends to force the slowest heating zone towards the bottom of the egg. Considering the flow properties of the major egg components (albumen and yolk), a similar phenomenon is expected during pasteurization of intact eggs. The effect of the presence of sphere-shaped yolk was also investigated. (C) 2003 Elsevier Ltd. All rights reserved.