Abstract: Sterilizing apparatus and a method including a stepped transition heat exchange bank is used to raise the temperature of an incoming fluent food product before introducing the fluent food product to a sterilizing chamber in which the fluent food product is discharged in the form of a free-falling film; sterilizing steam is injected into the sterilizing chamber, all of which is absorbed by the fluent food product; from the sterilizing chamber, the food product with absorbed steam is passed to a vacuum chamber where part of the water in the fluent food product flashes to steam again and is removed for subsequent processing through heat exchangers and recirculation back to a steam generator upstream of the sterilizing chamber. The food product from the vacuum chamber is passed to a stepped heat exchange bank before passing to storage or packaging facilities.