Patent ID: 8663556

Claim:
A method for sterilizing powder or grain, comprising: applying heat and pressure in which powder or grain is supplied into a heated gas flow pipe kept under heated and pressurized conditions, and the powder or grain is transferred while coming into direct contact with a heated condensable gas in the heated gas flow pipe for 0.008 to 2 seconds; sterilizing with instantaneous reduced pressure the powder or grain, wherein the heated condensable gas and the powder or grain are instantaneously released into a space having a pressure lower than that in the heated gas flow pipe, water contained in microorganisms adhering to the powder or grain is boiled rapidly, and tissues of the microorganisms are destroyed, cooling the heated condensable gas and the powder or grain by a non-condensable gas supplied from a cooling unit; and separating the cooled powder or grain from the heated condensable gas and the non-condensable gas, wherein in the step of sterilizing, the heated condensable gas and the powder or grain is passed through a pressure reducing unit provided downstream of the heated gas flow pipe to perform a pressure reduction process, and the pressure reduction process is achieved within 0.00001 to 0.1 second.