An in-shell egg pasteurization process (10) includes, in a temperature raising stage (16), raising the temperature of albumen of an in-shell egg predominantly by means of microwave radiation to a temperature between 57° C. and 60° C., the albumen temperature being raised at a rate which reduces at least once over time. Simultaneously, in the temperature raising stage (16), the temperature of an external surface of the egg is raised predominantly by means of external heat radiation or conduction to a temperature of between 57° C. and 70° C., or alternatively or in addition the egg surface temperature is allowed to rise to a temperature of between 57° C. and 70° C. as a result of the microwave radiation by inhibiting heat loss from the egg. Said temperatures are then maintained by means of microwave radiation and external heat radiation or conduction for at least some time.