bioburden that are sensitive to the pre selected temperature have been killed by using the process of the invention one can select a temperature sufficiently low to protect the product but sufficiently high to kill the target bioburden for example many spices can be safely heated at 170 u00b0 f 76 67 u00b0 c to treat for salmonella which is killed at 160 u00b0 f 71 11 u00b0 c following the dwell period the product is cooled and dried cooling is carried out in accordance with conventional methods for example the chamber may be flushed with multiple inert gas washes via the inert gas ejection system 8 nitrogen heated to the chamber target temperature may be added to the chamber until the pressure is at or above atmospheric pressure the vacuum pump 9 is turned on and the pressure is reduced to the minimum pressure attainable in the system this nitrogen pulse followed by re evacuation is repeated until the produce temperature stops falling product temperature decreases as subsequent washes remove water from the product load as the water evaporates the load cools maintaining the heating jackets 3 on the chamber 2 at the elevated temperature ensures that condensation does not occur and that steam removal occurs as efficiently as possible at this time air is introduced into the chamber and the process is complete according to another embodiment the process begins with an initial evacuation steam to a pressure p1a lower than the final target pressure is introduced the steam flows or is pulsed at this pressure until the product temperature is.