Cem Corporation

Edwin D Neas

Terry S Floyd

Zairani Zakaria

Wyatt P Hargett

Michael K Handley

Dennis Palmer Manchester

Kevin S Marchitto

Stephen T Flock

A process for rapidly sterilizing biological media, such as broths and gels used as incubation or growth media to test the presence of microorganisms, such as bacteria, includes applying microwave radiation to such an aqueous biological medium contained in a microwave transmissive pressure retaining container, such as a capped cylinder made of polytetrafluoroethylene, which cap is preferably equipped with ports, by directing the microwave radiation through the container and onto the medium in such amount that the pressure in the container and the temperature of the medium are raised above ambient pressure and temperature, and maintaining such raised pressure and temperature for a time sufficient to sterilize the medium. In a preferred operation the microwave heating at elevated pressure and temperature takes place for about five minutes, the pressure during that time is 30 to 50 psig, the microwave heating of the medium takes place in a radiation confining chamber of a microwave apparatus, a plurality of containers for the biological medium is present in such chamber, the containers are kept in motion by an oscillating turntable, and the pressure in at least one container is monitored and the application of microwave radiation is controlled in response to that pressure. In a broader process aspect the contained material is heated but not necessarily sterilized. Also within the invention is the apparatus utilized in the described process.

Process and apparatus for controlled microwave heating under pressure

A microwave heating system which is especially useful for rapidly, uniformly and positively sterlizing biological media, such as broths and gels used as incubation or growth media for bacteria, includes a source of microwave radiation, a microwave chamber, a container or a plurality of containers in the chamber, and a mixer for mixing the contents of the container or containers during heating. The mixer is at least partially external to the container and is capable of operating when the container is positively sealed to prevent contamination of the contents, and the mixer is preferably a combination of an external magnet and a mixing element which is at least in part of magnetic material and is moved by changes in the magnetic field set up by the magnet, as the container and contained mixing element are moved with respect to the magnet, as on an oscillating turntable. Other systems for mixing the material in the container are also within the invention, although they are not as satisfactory as that previously described, and such other systems include mechanical systems, such as solenoid activated cores or extensions thereof for pushing vertically against a turntable and thereby moving it out of its normal horizontal plane, cams for accomplishing the same purpose, devices for causing the containers to swing, in pendulum-like motion, as they are rotated, and ultrasonic devices. The apparatus may be used for various other heating operations and even for mixings, without heatings.

Microwave heating system

A process for rapidly sterilizing biological media, such as broths and gels used as incubation or growth media to test the presence of microorganisms, such as bacteria, includes applying microwave radiation to such an aqueous biological medium contained in a microwave transmissive pressure retaining container, such as a capped cylinder made of polytetrafluoroethylene, which cap is preferably equipped with ports, by directing the microwave radiation responsive to container pressure through the container and onto the medium in such amount that the pressure in the container and the temperature of the medium are raised above ambient pressure and temperature, and maintaining such raised pressure and temperature for a short time, usually less than ten minutes, which is sufficient to sterilize the medium. In a preferred operation the microwave heating at elevated pressure and temperature takes place for about five minutes, the microwave heating of the medium takes place in a radiation confining chamber of a microwave apparatus, a plurality of containers for the biological medium is present in such chamber, which are kept in motion by an oscillating turntable, the pressure is controlled and monitored, and after sterilization is complete the medium is controllably cooled and is poured out into an incubating container, such as a Petri dish, or into a plurality of such containers.

Process for rapid sterilization of biological media

A rapid, microwave-based Kjeldahl digestion method wherein microwave energy is applied to an acid/sample mixture at the beginning of, and thereafter during the digestion. After the application of microwave energy is discontinued, the digestate is diluted by pulsed addition of water, followed by continuous addition of water. Dilution in this manner prevents a sudden surge in gas evolution, and eliminates the need for an intervening cooling step, thereby reducing processing time. Also provided is a method for fat separation from a fat-containing protein sample during the digestion.

Microwave-based Kjeldahl method

A microwave-based apparatus for rapid digestion of a sampel by a Kjeldahl method is provided which includes a reaction vessel surrounded by an insulator in the form of, for example, a cup. The reaction vessel is disposed in the internal chamber of a microwave system, which includes a wall having an aperture. A connector tube is slidably disposed in the aperture, wherein one end of the tube is connected to the mouth of the reaction vessel, and the other end is connected to a suction device external to the chamber. A biasing element is provided outside the chamber to assist in joining the slidable connector tube to the mouth of the vessel, yet enabling removal of the vessel from the chamber without detachment of the biasing element.

Digestion apparatus useful for a kjeldahl method

A microwave-based apparatus useful for rapid digestion is provided. The apparatus includes a hollow tubular body having an end sealingly joined to a reaction vessel disposed within a microwave system. The end of the tubular body has grooves for the flow of air through the sealed tubular body/reaction vessel joint. A scrubber removes digestion off gases. Also provided is a rapid, microwave-based, Kjeldahl digestion method.

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Charlotte, NC, United States of America

Edwin D Neas