AT A FILLING RATE AT WHICH STERILIZING TIME BECOMES CONSTANT WITHOUT DEPENDING ON AN AMOUNT OF HEAD SPACE GAS IN A GRAPH SHOWING RELATIONSHIP BETWEEN THE STERILIZING TIME AND THE AMOUNT OF HEAD SPACE GAS IN WHICH THE VERTICAL AXIS REPRESENTS THE STERILIZING TIME AND THE HORIZONTAL AXIS REPRESENTS THE AMOUNT OF THE HEAD SPACE GAS, A LIQUID FOOD IS FILLED IN A FLEXIBLE POUCH AND, AFTER THE POUCH IS SEALED, THE POUCH IN UNRESTRAINED CONDITION IS SUBJECTED TO RECIPROCATING STERILIZATION.