Treatment to reduce microorganisms with carbon dioxide by multiple pressure oscillations

Abstract

Apparatus and methods to non-thermally treat goods for human consumption with carbon dioxide. Apparatus and methods rely on multiple pressure changes of carbon dioxide to affect one of three processes. A first process rapidly freezes and thaws water on the surface of the goods in rapid succession multiple times to detrimentally affect pathogens. A second process raises the pressure and temperature of carbon dioxide to supercritical conditions to detrimentally affect the lipids in the membranes of pathogens. A third process adjusts the pressure to form a dense carbon dioxide liquid with a low pH that may also detrimentally affect pathogens. All processes may be repeated or performed in succession, or in any order. Optionally, thereafter, the goods may be stored at low temperature in substantially 100% carbon dioxide for further pathogen reduction.

1 . Apparatus, comprising:
 (a) a housing defining a cylindrical chamber with a first end and an opposite, second end;   (b) a first piston and a second piston disposed in a sealing manner at the opposite ends of the chamber, wherein the first piston and the second piston are driven towards one another to pressurize contents within the chamber to a first, high pressure and withdrawn to depressurize contents within the chamber to a second, lower pressure; and   (c) a mixer disposed within the housing to mix any contents within the chamber.   
     
     
         2 . The apparatus of  claim 1 , wherein the mixer has a piston-like member disposed in the housing, wherein the piston-like member is in a sealing disposition with the inner surface of the chamber. 
     
     
         3 . The apparatus of  claim 1 , wherein the mixer has a piston-like member disposed in the housing, and the piston-like member has an opening for the passage of goods from one end of the chamber towards the other. 
     
     
         4 . The apparatus of  claim 1 , further comprising an ultrasonic generator that transmits ultrasonic energy to the mixer to separate microorganisms from goods being processed within the chamber. 
     
     
         5 . The apparatus of  claim 1 , wherein the first and the second pistons are driven by the introduction and withdrawal of a liquid compatible with goods edible for human consumption. 
     
     
         6 . The apparatus of  claim 1 , wherein the mixer is configured to rotate and reciprocate in relation to the chamber length. 
     
     
         7 . The apparatus of  claim 1 , further comprising a first and a second end cap disposed at opposite ends of the housing to form a first chamber and a second chamber, wherein the chambers receive a fluid to drive the first piston and the second piston. 
     
     
         8 . The apparatus of  claim 1 , further comprising a first positive displacement pump to introduce goods to be treated within the chamber. 
     
     
         9 . The apparatus of  claim 1 , further comprising a second positive displacement pump to remove goods from within the chamber. 
     
     
         10 . An apparatus for the treatment of goods, comprising:
 a cylinder having two ends opposite to each other;   a first end cap disposed at a first end of the cylinder;   a second end cap disposed on a second and opposite end of the cylinder; and   a first piston configured to reciprocate within the cylinder between the two end caps, wherein the reciprocation of the first piston reduces and increases a space between the first piston and the second end cap.   
     
     
         11 . The apparatus of  claim 10 , wherein the piston is caused to reciprocate by the introduction of and withdrawal of a fluid into a space between the first piston and the first end cap. 
     
     
         12 . The apparatus of  claim 11 , further comprising a second piston disposed to reciprocate within the cylinder between the two end caps, wherein the second piston is disposed between the first end cap and the second end cap, and the second piston is caused to reciprocate by the introduction of and withdrawal of a fluid into a space between the second piston and the second end cap. 
     
     
         13 . The apparatus of  claim 10 , further comprising a shaft traversing the first end cap and the first piston, wherein the shaft includes a mixer at one end thereof, wherein the mixer is located within the space between the first piston and the second end cap. 
     
     
         14 . The apparatus of  claim 13 , further comprising a second piston, wherein the mixer is located in a space between the first piston and the second piston. 
     
     
         15 . The apparatus of  claim 13 , further comprising a conduit in the shaft, and perforations to allow introduction of an agent into the space between the first piston and the second piston. 
     
     
         16 . The apparatus of  claim 13 , further comprising a third piston member attached to an end of the shaft, wherein the piston member includes an opening to allow the passage of goods. 
     
     
         17 . The apparatus of  claim 10 , further comprising water, carbon dioxide, or a combination, and beef in the space between the first piston and the second end cap. 
     
     
         18 . The apparatus of  claim 10 , further comprising an acid and beef in the space between the first piston and the second end cap. 
     
     
         19 . The apparatus of  claim 10 , further comprising a conduit to empty contents from the space between the first piston and the second end cap. 
     
     
         20 . The apparatus of  claim 10 , further comprising a conduit connected to the space between the first piston and the second end cap, wherein the first piston is configured to remove goods from the space by movement of the first piston toward the conduit. 
     
     
         21 . The apparatus of  claim 10 , further comprising a conduit connected to the space between the first piston and the second end cap, wherein the first piston is configured to remove fluid from the space by movement of the first piston toward the conduit. 
     
     
         22 . The apparatus of  claim 10 , further comprising a conduit connected to the space between the first piston and the second end cap, and a second piston disposed to reciprocate within the cylinder between the two end caps, wherein the first piston and the second piston are configured to remove fluid or goods from the space by movement of the first piston and second piston toward the conduit. 
     
     
         23 . The apparatus of  claim 22 , wherein the conduit is between the first and second pistons. 
     
     
         24 . Apparatus, comprising:
 (a) a housing defining a cylindrical chamber with a first end and an opposite, second end and at least one connection between the chamber and a valve;   (b) a first piston and a second piston disposed in a sealing manner at the opposite ends of the chamber, wherein the first piston and the second piston are driven towards one another to pressurize contents within the chamber to a first, high pressure and withdrawn to depressurize contents within the chamber to a second, lower pressure; and   (c) the first piston, the second piston, or both first and second pistons are arranged to pressurize the chamber contents so as to cause the contents to be transferred via the connection to a valve through the connection.