Patent GB-993757-A (GB)
Title: A method of treating material to reduce the count of organic life therein
IPC: A23L5/30
Filed: 1962-12-11
Abstract: In treating a mass of material having porosity for the passage of gas therethrough in a closed chamber with a gas to reduce the count of organic life in the material, the gas is given a pulsating movement in the chamber by repeatedly changing the overall gaseous pressure in the chamber between higher and lower effective treating pressures. The repeated changing of the overall gaseous pressure may be effected continuously by alternately pumping gas into and out of the chamber, by the movement of a plunger in and out of the chamber, or by operation of an inflatable balloon or metal bellows.  Two gas pumps giving an irregular cycle having a greater amplitude than the cycle of each may be operated for a short time at the beginning of a treatment period.  Materials specifically mentioned; tobacco, spices such as ground red pepper or paprika, cocoa, flour, rice, grains, starch, dehydrated vegetables, seeds, nuts and nut meats, raisins, prunes and apricots.  According to an example ground red pepper is packed in a 300 pound drum, 22 inches in diameter and 36 inches high, lined with two layers of polyethylene film impervious to propylene oxide; the drum so packed is placed alone in a chamber of dimensions 6 x 3,5 X 13 feet.  The chamber with a wall temperature of 110 DEG F., is sealed and evacuated to a vacuum of 29 inches of mercury and into the evacuated chamber there is introduced 40 pounds of propylene oxide gas, thereby reducing the negative pressure to 14 inches.  Gas is introduced and removed so as to change the pressure in 10-minute regular cycles for three hours, between the limits of 14 and 16 inches of mercury; the chamber is then evacuated to a pressure of 29 inches of mercury, flushed with air and opened.  Samples were taken at the top, middle and bottom of the drum for counting the surviving bacteria, yeasts and moulds per gram.  In a control experiment the pressure in the chamber is kept static over the three hour treatment period.  In other examples, the negative pressure was changed (2) in 30-minute regular cycles between the limits of 12 and 23 inches of mercury, (3) in 7-minute cycles involving departures of 1 to 2 inches from 14 inches of mercury and (4) to give 13 cycles per hour involving pressure changes between 9 and 11 inches of mercury.ALSO:In treating a mass of material having perosity for the passage of gas there-through in a closed chamber with a gas to reduce the count of organic life in the material, the gas is given a pulsating movement in the chamber by repeatedly changing the overall gaseous pressure in the chamber between higher and lower effective treating pressure. The repeated changing of the overall gaseous pressure may be effected continuously by alternately pumping gas into and out of the chamber, by the movement of a plunger in and out of the chamber, or by operation of an inflatable balloon or metal bellows.  Two gas pumps giving an irregular cycle having a greater amplitude than the cycle of each may be operated for a short time at the beginning of a treatment period.  Materials specifically mentioned: tobacco, spices such as ground red pepper or paprika, cocoa, flour, rice, grains, starch, dehydrated vegetables, seeds, nuts and nut meats, raisins, prunes and apricots.  According to an example ground red pepper is packed in a 300 pound drum, 22 inches in diameter and 36 inches high, lined with two layers of polyethylene film impervious to propylene oxide; the drum so packed is placed alone in a chamber of dimensions 6 x 3.5 x 13 feet.  The chamber with a wall temperature of 110 DEG F., is sealed and evacuated to a vacuum of 29 inches of mercury and into the evactuated chamber there is introduced 40 pounds of propylene oxide gas, hereby reducing the negative pressure to 14 inches.  Gas is introduced and removed so as to change the pressure in 10-minute regular cycles for three hours, between the limits of 14 and 16 inches of mercury; the chamber is then evacuated to a pressure of 29 inches of mercury, flushed with air and opened.  Samples were taken at the top, middle and bottom of the drum for counting the surviving bacteria, yeasts and moulds per gram.  In a control experiment the pressure in the chamber is kept static over the three hour treatment period.  In other examples, the negative pressure was changed (2) in 30-minute regular cycles between the limits of 12 and 23 inches of mercury, (3) in 7-minute cycles involving departures of 1 to 2 inches from 14 inches of mercury and (4) to give 13 cycles per hour involving pressure changes between 9 and 11 inches of mercury.