Abstract:
An improved heat exchange system and methodology, and an improved material treatment system and methodology, based on that heat exchange system, for providing improved pasteurized and sterilized packaged food products is disclosed. Improved pasteurized and sterilized packaged food products produced thereby are also disclosed.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to heat exchange generally and more particularly to sterilization of food products using highly efficient heat exchangers.  
         BACKGROUND OF THE INVENTION  
         [0002]    The following U.S. Pat. Nos. of the applicant are related to the subject matter of the present invention: 6,158,504; 5,928,699, 5,670,198 and 5,768,472.  
         SUMMARY OF THE INVENTION  
         [0003]    The present invention seeks to provide an improved heat exchanger and improved pasteurized and sterilized food products realized by use of the improved heat exchanger.  
           [0004]    There is thus provided, in accordance with a preferred embodiment of the present inventions a vacuum heat exchange system including:  
           [0005]    a container partially filled with a liquid and maintained under a vacuum;  
           [0006]    a first heat exchanger disposed in the liquid in the container, the first heat exchanger receiving, a first fluid material, heating the liquid and thereby cooling the first fluid material; and  
           [0007]    a second heat exchanger disposed outside of the liquid in the container, the second heat exchanger receiving a second fluid material and being heated by vapors of the liquid, thereby heating the second fluid material,  
           [0008]    at least one of the first and second heat exchangers including an agitator for agitating, the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0009]    Preferably, the first heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Alternatively, the second heat exchanger includes an agitator for agitating the second fluid material passing therethrough to enhance heat exchange generally throughout the second fluid material. Additionally or alternatively, both of the first and second heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0010]    In accordance with a preferred embodiment of the present invention, at least one of the first and second heat exchangers includes a scraped surface heat exchanger.  
           [0011]    Additionally, the vacuum heat exchange system also includes an electroheater for heating the first fluid material prior to receipt thereof by the first heat exchanger. Alternatively, the vacuum heat exchange system also includes an electroheater for receiving the second fluid material from the second heat exchanger.  
           [0012]    In accordance with a preferred embodiment of the present invention, the first and second fluid materials are the same material at different temperatures and the vacuum heat exchange system also includes an electroheater for heating the first fluid material prior to receipt thereof by the first heat exchanger and the first fluid material is received by the electroheater from the second heat exchanger.  
           [0013]    There is also provided, in accordance with a preferred embodiment of the present invention, a material treatment system including:  
           [0014]    an electroheater operative to rapidly heat a first fluid material; and  
           [0015]    a vacuum heat exchange subsystem operative to rapidly cool the first fluid material following electroheating thereof, the vacuum heat exchange subsystem including:  
           [0016]    a container partially filled with a liquid and maintained under a vacuum;  
           [0017]    a first heat exchanger disposed in the liquid in the container, the first heat exchanger receiving the first fluid material, heating the liquid and thereby cooling the first fluid material; and  
           [0018]    a second heat exchanger disposed outside of the liquid in the container, the second heat exchanger receiving a second fluid material and being heated by vapors of the liquid, thereby heating the second fluid material,  
           [0019]    at least one of the first and second heat exchangers including an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0020]    Preferably, the first heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Alternatively, the second heat exchanger includes an agitator for agitating the second fluid material passing therethrough to enhance heat exchange generally throughout the second fluid material Additionally or alternatively, both of the first and second heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0021]    In accordance with a preferred embodiment of the present invention, at least one of the first and second heat exchangers includes a scraped surface heat exchanger.  
           [0022]    In another preferred embodiment of the present invention the electroheater supplies the first fluid material to a holding tank, prior to receipt of the first fluid material by the first heat exchanger. Alternatively or additionally, the electroheater receives the second fluid material from the second heat exchanger.  
           [0023]    In accordance with still another preferred embodiment of the present invention, the first and second fluid materials are the same material at different temperatures and the electroheater heats the first fluid material prior to receipt thereof by the first heat exchanger and the first fluid material is received by the electroheater from the second heat exchanger.  
           [0024]    There is additionally provided, in accordance with a preferred embodiment of the present invention, a material treatment system including:  
           [0025]    electroheater operative to rapidly heat a first fluid material;  
           [0026]    a first vacuum heat exchange subsystem operative to rapidly cool the first fluid material following electroheating thereof, the first vacuum heat exchange subsystem including:  
           [0027]    a container partially filled with a liquid and maintained under a vacuum;  
           [0028]    a first heat exchanger disposed in the liquid in the container, the first heat exchanger receiving the first fluid material, heating the liquid and thereby cooling the first fluid material; and  
           [0029]    a second heat exchanger disposed outside of the liquid in the container, the second heat exchanger receiving a second fluid material and being heated by vapors of the liquid, thereby heating the second fluid material,  
           [0030]    at least one of the first and second heat exchangers including an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material; and  
           [0031]    a second vacuum heat exchange subsystem operative to preheat the first fluid material prior to electroheating thereof, the second vacuum heat exchange subsystem including:  
           [0032]    a container partially filled with a liquid and maintained under a vacuum;  
           [0033]    a third heat exchanger disposed in the liquid in the container, the third heat exchanger receiving a third fluid material, heating the liquid and thereby cooling the third fluid material; and  
           [0034]    a fourth heat exchanger disposed outside of the liquid in the container, the fourth heat exchanger receiving the first fluid material and being heated by vapors of the liquid, thereby heating the first fluid material,  
           [0035]    at least one of the third and fourth heat exchangers including an agitator for agitating, the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0036]    Preferably, the first heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Alternatively, the second heat exchanger includes an agitator for agitating the second fluid material passing therethrough to enhance heat exchange generally throughout the second fluid material. Additionally or alternatively, both of the first and second heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0037]    In accordance with a preferred embodiment of the present invention, the third heat exchanger includes an agitator for agitating the third fluid material passing therethrough to enhance heat exchange generally throughout the third fluid material. Alternatively, the fourth heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Additionally or alternatively, both of the third and fourth heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0038]    In accordance with a preferred embodiment of the present invention, at least one of the first and second heat exchangers includes a scraped surface heat exchanger. Additionally or alternatively, at least one of the third and fourth heat exchangers includes a scraped surface heat exchanger.  
           [0039]    In another preferred embodiment of the present invention, the electroheater supplies the first fluid material to a holding tank, prior to receipt of the first fluid material by the first heat exchanger.  
           [0040]    There is further provided, in accordance with a preferred embodiment of the present invention, a packaged food product characterized in:  
           [0041]    having a viscosity exceeding approximately 5,000 centipoise;  
           [0042]    being sterilized; and  
           [0043]    being aseptically packaged.  
           [0044]    Preferably, the packaged food product has a pH exceeding approximately 4.5.  
           [0045]    There is yet further provided, in accordance with a preferred embodiment of the present invention, a packaged humus food product characterized in:  
           [0046]    being sterilized; and  
           [0047]    being aseptically packaged.  
           [0048]    There is still further provided, in accordance with a preferred embodiment of the present invention, a packaged egg food product characterized in:  
           [0049]    being sterilized; and  
           [0050]    being aseptically packaged.  
           [0051]    There is additionally provided, in accordance with a preferred embodiment of the present invention, a packaged egg food product characterized in:  
           [0052]    being sterilized; and  
           [0053]    being aseptically filled and sealed following sterilization and cooling thereof.  
           [0054]    Preferably, the packaged egg food product is coagulated.  
           [0055]    There is further provided, in accordance with a preferred embodiment of the present invention, a packaged egg food product characterized in:  
           [0056]    being pasteurized to at least 75 degrees Centigrade;  
           [0057]    being aseptically filled and sealed following pasteurization and cooling thereof; and  
           [0058]    being liquid.  
           [0059]    There is also provided, in accordance with a preferred embodiment of the present invention, a vacuum heat exchange method including:  
           [0060]    partially filling a container maintained under a vacuum with a liquid;  
           [0061]    receiving a first fluid material in a first heat exchanger disposed in the liquid in the container, heating the liquid and thereby cooling the first fluid material; and  
           [0062]    receiving a second fluid material in a second heat exchanger disposed outside of the liquid in the container, heating the second heat exchanger by vapors of the liquid, thereby heating the second fluid material,  
           [0063]    where at least one of the first and second heat exchangers includes an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0064]    Preferably, the first heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Alternatively, the second heat exchanger includes an agitator for agitating the second fluid material passing therethrough to enhance heat exchange generally throughout the second fluid material. Additionally or alternatively, both of the first and second heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0065]    In accordance with a preferred embodiment of the present invention, at least one of the first and second heat exchangers includes a scraped surface heat exchanger.  
           [0066]    In another preferred embodiment of the present invention, the vacuum heat exchange method also includes heating the first fluid material in an electroheater prior to receipt thereof by the first heat exchanger. Additionally or alternatively, the vacuum heat exchange method also includes receiving the second fluid material into an electroheater from the second heat exchanger.  
           [0067]    In yet another preferred embodiment of the present invention, the first and second fluid materials are the same material at different temperatures and the vacuum heat exchange method also includes:  
           [0068]    receiving the first fluid material from the second heat exchanger; and  
           [0069]    heating the first fluid material using an electroheater prior to receipt thereof by the first heat exchanger.  
           [0070]    There is further provided, in accordance with a preferred embodiment of the present invention, a material treatment method including:  
           [0071]    rapidly heating a first fluid material using an electroheater; and  
           [0072]    rapidly cooling the first fluid material following electroheating thereof by:  
           [0073]    partially filling a container maintained under a vacuum with a liquid;  
           [0074]    receiving, the first fluid material in a first heat exchanger disposed in the liquid in the container, heating the liquid and thereby cooling the first fluid material; and  
           [0075]    receiving a second fluid material in a second heat exchanger disposed outside of the liquid in the container, heating the second heat exchanger by vapors of the liquid, thereby heating the second fluid material,  
           [0076]    where at least one of the first and second heat exchangers includes an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0077]    Preferably, the first heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Alternatively, the second heat exchanger includes an agitator for agitating the second fluid material passing therethrough to enhance heat exchange generally throughout the second fluid material. Additionally or alternatively, both of the first and second heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0078]    In accordance with a preferred embodiment of the present invention, at least one of the first and second heat exchangers includes a scraped surface heat exchanger.  
           [0079]    In another preferred embodiment of the present invention, the vacuum heat exchange method also includes supplying the first fluid material to a holding tank from the electroheater prior to receiving the first fluid material in the first heat exchanger. Additionally or alternatively, the vacuum heat exchange method also includes receiving the second fluid material into the electroheater from the second heat exchanger.  
           [0080]    In still another preferred embodiment of the present invention, the first and second fluid materials are the same material at different temperatures and the vacuum heat exchange method also includes:  
           [0081]    receiving the first fluid material by the electroheater from the second heat exchanger; and  
           [0082]    heating the first fluid material in the electroheater prior to receipt thereof by the first heat exchanger.  
           [0083]    There is yet further provided, in accordance with a preferred embodiment of the present invention, a material treatment method including:  
           [0084]    rapidly heating a first fluid material using an electroheater; and  
           [0085]    rapidly cooling the first fluid material following electroheating thereof by:  
           [0086]    partially filling a container maintained under a vacuum with a liquid;  
           [0087]    receiving a first fluid material in a first heat exchanger disposed in the liquid in the container, heating the liquid and thereby cooling the first fluid material; and  
           [0088]    receiving a second fluid material in a second heat exchanger disposed outside of the liquid in the container, heating the second heat exchanger by vapors of the liquid, thereby heating the second fluid material,  
           [0089]    where at least one of the first and second heat exchangers includes an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material; and  
           [0090]    preheating the first fluid material prior to electroheating thereof by:  
           [0091]    partially filling a container maintained under a vacuum with a liquid;  
           [0092]    receiving a third fluid material in a third heat exchanger disposed in the liquid in the container, heating the liquid and thereby cooling the third fluid material; and  
           [0093]    receiving the first fluid material in a fourth heat exchanger disposed outside of the liquid in the container, heating the fourth heat exchanger by vapors of the liquid, thereby heating the first fluid material,  
           [0094]    where at least one of the third and fourth heat exchangers includes an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0095]    Preferably, the first heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material. Alternatively, the second heat exchanger includes an agitator for agitating the second fluid material passing therethrough to enhance heat exchange generally throughout the second fluid material. Additionally or alternatively, both of the first and second heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0096]    In accordance with a preferred embodiment of the present invention, the third heat exchanger includes an agitator for agitating the third fluid material passing therethrough to enhance heat exchange generally throughout the third fluid material. Alternatively, the fourth heat exchanger includes an agitator for agitating the first fluid material passing therethrough to enhance heat exchange generally throughout the first fluid material Additionally or alternatively, both of the third and fourth heat exchangers include an agitator for agitating the fluid material passing therethrough to enhance heat exchange generally throughout the fluid material.  
           [0097]    Preferably, at least one of the first and second heat exchangers includes a scraped surface heat exchanger. Additionally or alternatively, at least one of the third and fourth heat exchangers includes a scraped surface heat exchanger.  
           [0098]    In another preferred embodiment of the present invention, the material treatment method includes supplying the first fluid material to a holding tank from the electroheater prior to receiving, the first fluid material in the first heat exchanger.  
           [0099]    There is additionally provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged food product including:  
           [0100]    producing a food product having a viscosity exceeding approximately 5,000 centipoise;  
           [0101]    sterilizing the food product; and  
           [0102]    aseptically packaging the food product.  
           [0103]    Preferably, the packaged food product has a pH exceeding approximately 4.5.  
           [0104]    There is further provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged humus food product including:  
           [0105]    sterilizing the humus food product; and  
           [0106]    aseptically packaging the humus food product.  
           [0107]    There is still further provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged egg food product including:  
           [0108]    sterilizing the egg food product; and  
           [0109]    aseptically packaging the egg food product.  
           [0110]    There is yet further provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged egg food product including:  
           [0111]    sterilizing the egg food product;  
           [0112]    cooling the egg food product; and  
           [0113]    aseptically filling and sealing the egg food product in a package.  
           [0114]    Preferably, the egg food product is coagulated.  
           [0115]    There is additionally provided, in accordance with a preferred embodiment of the present invention, a method of preparing a packaged liquid egg food product including:  
           [0116]    pasteurizing the liquid egg food product to at least 75 degrees Centigrade;  
           [0117]    cooling the liquid egg food product; and  
           [0118]    aseptically filling and sealing the liquid egg food product in a package.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0119]    The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:  
         [0120]    [0120]FIG. 1A is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with a preferred embodiment of the present invention;  
         [0121]    [0121]FIG. 1B is a sectional illustration of a portion of an agitator operative in accordance with a preferred embodiment of the present invention;  
         [0122]    [0122]FIG. 2 is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with another preferred embodiment of the present invention;  
         [0123]    [0123]FIG. 3 is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with still another preferred embodiment of the present invention;  
         [0124]    [0124]FIG. 4 is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with a preferred embodiment of the present invention;  
         [0125]    [0125]FIG. 5 is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with another preferred embodiment of the present invention;  
         [0126]    [0126]FIG. 6 is a temperature-time graph illustrating aspects of operation of embodiments of the present invention;  
         [0127]    [0127]FIG. 7 is a simplified illustration of an electroheating system useful with highly viscous materials and products containing particles; and  
         [0128]    [0128]FIG. 8 is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with yet another preferred embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0129]    Reference is now made to FIGS. 1A and 1B, which are simplified sectional illustrations of a vacuum heat exchange system constructed and operative in accordance with a preferred embodiment of the present invention As seen in FIG. 1A, the vacuum heat exchange system preferably includes a thermally insulated enclosure  100 , the interior of which communicates with the ambient atmosphere via a vacuum pump  102 , which preferably maintains the interior of enclosure  100  at subatmospheric pressure, typically about 29″ of mercury.  
         [0130]    Enclosure  100  is partially filled with a cooling liquid  104 , preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure  100 . A heated fluid material  106 , such as a heated food product which has undergone electroheating, is preferably supplied to a conduit  108  which extends through the liquid  104 . As the heated fluid material  106  passes through the conduit  108 , in thermal contact with the walls thereof, it becomes cooled by evaporating the liquid  104 . The cooled fluid material then flows from the conduit  108 .  
         [0131]    In accordance with a preferred embodiment of the present invention, an agitator  110 , typically in the form of an elongate shaft  112 , having outwardly extending vanes  114 , is disposed in conduit  108 , and rotated therein about an axis  116 , as by a motor  118 , to provide enhanced uniformity of thermal contact between the heated fluid material  106  and the walls of the conduit  108 . A preferred type of conduit  108  and agitator  110  are together known as a scraped surface heat exchanger.  
         [0132]    In accordance with a preferred embodiment of the present invention a cooling liquid  120 , preferably water, is caused to pass through a conduit  122 , preferably a coil, which extends through enclosure  100 , above the level of the cooling liquid  104 . The temperature of the cooling liquid  120  is preferably sufficiently low as to cause vapors of the cooling, liquid  104  to condense upon contact with the outer walls of conduit  122  and to fall downward into cooling liquid  104 , as drops  124 .  
         [0133]    Reference is now made to FIG. 2, which is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with another preferred embodiment of the present invention. As seen in FIG. 2, the vacuum heat exchange system preferably includes a thermally insulated enclosure  200 , the interior of which communicates with the ambient atmosphere via a vacuum pump  202 , which preferably maintains the interior of enclosure  200  at subatmospheric pressure, typically about 29″ of mercury.  
         [0134]    Enclosure  200  is partially filled with a cooling liquid  204 , preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure  200 . A heated liquid  206 , such as heated water, is preferably supplied to a conduit  208 , preferably a coil, which extends through the liquid  204 . As the heated liquid  206  passes through the conduit  208 , in thermal contact with the walls thereof, it heats the liquid  204 , generating heated vapor  214 .  
         [0135]    In accordance with a preferred embodiment of the present invention, a cool fluid material  210  is caused to pass through a conduit  212 , which extends through enclosure  200 , above the level of the cooling liquid  204 . As the cool fluid material  210  passes through the conduit  212 , in thermal contact with the walls thereof, it becomes heated by the heated vapor  214  from liquid  204 . The heated fluid material then flows from the conduit  212 .  
         [0136]    In accordance with a preferred embodiment of the present invention, an agitator  220 , typically in the form of an elongate shaft  222 , having outwardly extending vanes  224 , is disposed in conduit  212 , and rotated therein about an axis  226 , as by a motor  228 , to provide enhanced uniformity of thermal contact between the cool fluid material  210  and the walls of the conduit  212 . A preferred type of conduit  212  and agitator  220  are together known as a scraped surface heat exchanger.  
         [0137]    Reference is now made to FIG. 3, which is a simplified sectional illustration of a vacuum heat exchange system constructed and operative in accordance with still another preferred embodiment of the present invention. As seen in FIG. 3, the vacuum heat exchange system preferably includes a thermally insulated enclosure  300 , the interior of which communicates with the ambient atmosphere via a vacuum pump  302 , which preferably maintains the interior of enclosure  300  at subatmospheric pressure, typically about 29″ of mercury.  
         [0138]    Enclosure  300  is partially filled with a cooling liquid  304 , preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure  300 . A heated fluid material  306 , such as a heated food product which has undergone electroheating, is preferably supplied to a conduit  308 , which extends through the liquid  304 . As the heated fluid material  306  passes through the conduit  308 , in thermal contact with the walls thereof, it becomes cooled by evaporating the liquid  304 , thereby heating the liquid  304 , generating heated vapor  309 . The cooled fluid material then flows from the conduit  308 .  
         [0139]    In accordance with a preferred embodiment of the present invention, an agitator  310 , typically in the form of an elongate shaft  312 , having outwardly extending vanes  314 , is disposed in conduit  308 , and rotated therein about an axis  316 , as by a motor  318 , to provide enhanced uniformity of thermal contact between the heated fluid material  306  and the walls of the conduit  308 . A preferred type of conduit  308  and agitator  310  are together known as a scraped surface heat exchanger.  
         [0140]    In accordance with a preferred embodiment of the present invention a cool fluid material  320 , such as a food product which is to be electroheated, is caused to pass through a conduit  322 , which extends through enclosure  300 , above the level of the cooling liquid  304 . The temperature of the cool fluid material  320  is preferably sufficiently low as to cause vapors of the cooling liquid  304  to condense upon contact with the outer walls of conduit  322  and to fall downward into cooling liquid  304 , as drops  324 . As the cool fluid material  320  passes through the conduit  322 , in thermal contact with the walls thereof, it becomes heated by the heated vapor  309  from liquid  304 . The heated fluid material then flows from the conduit  322 .  
         [0141]    In accordance with a preferred embodiment of the present invention, an agitator  330 , typically in the form of an elongate shaft  332 , having outwardly extending vanes  334 , is disposed in conduit  322 , and rotated therein about an axis  336 , as by a motor  338 , to provide enhanced uniformity of thermal contact between the cool fluid material  320  and the walls of the conduit  322 . A preferred type of conduit  322  and agitator  330  are together known as a scraped surface heat exchanger.  
         [0142]    Reference is now made to FIG. 4, which is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with a preferred embodiment of the present invention. As seen in FIG. 4, the system and methodology of FIG. 4 typically comprises a preheating subsystem  400 , such as that shown in FIG. 2 and described hereinabove, which receives a fluid material, such as a food product, to be preheated and preheats it to a desired temperature, an electroheater  402 , which heats the preheated fluid material to a predetermined temperature for a predetermined time and a cooling subsystem  404 , such as that shown in FIG. 1A and described hereinabove, which receives the electroheated fluid material, typically from a holding tank  406 , cools the fluid material and supplies it to an aseptic filling mechanism  408  after it has been further cooled in conventional cooler  409 , thereby producing a packaged product having new and superior characteristics.  
         [0143]    Pre-heating, subsystem  400  preferably comprises a thermally insulated enclosure  410 , the interior of which communicates with the ambient atmosphere via a vacuum pump  412 , which preferably maintains the interior of enclosure  410  at subatmospheric pressure, typically about 29″ of mercury.  
         [0144]    Enclosure  410  is partially filled with a liquid  414 , preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure  410 . A heated liquid  416 , such as heated water, is preferably supplied to a conduit  418 , preferably a coil, which extends through the liquid  414 . As the heated liquid  416  passes through the conduit  418 , in thermal contact with the walls thereof, it heats the liquid  414 , generating heated vapor  419 .  
         [0145]    In accordance with a preferred embodiment of the present invention a cool fluid material to be preheated  420 , such as a food product, is caused to pass through a conduit  422 , which extends through enclosure  410 , above the level of the cooling liquid  414 . As the cool fluid material  420  passes through the conduit  422 , in thermal contact with the walls thereof, it becomes heated by the heated vapor  419  from liquid  414 . The heated fluid material then flows from the conduit  422 .  
         [0146]    In accordance with a preferred embodiment of the present invention, an agitator  430 , typically in the form of an elongate shaft  432 , having outwardly extending vanes  434 , is disposed in conduit  422 , and rotated therein about an axis  436 , as by a motor  438 , to provide enhanced uniformity of thermal contact between the fluid material  420  and the walls of the conduit  422 . A preferred type of conduit  422  and agitator  430  are together known as a scraped surface heat exchanger.  
         [0147]    The pre-heated output of the scraped surface heat exchanger is preferably supplied to electroheater  402 , which is operative to heat the pre-heated fluid material to an elevated temperature in a very short time. Suitable electroheaters are described in applicant&#39;s U.S. Pat. Nos. 6,304,718, 6,088,509; 5,863,580; 5,768,472; 5,636,317; 5,609,900; 5,607,613; 5,583,960; 5,415,882; 5,290,583 and 4,739,140, the disclosures of which are hereby incorporated by reference. A preferred embodiment of an electroheater is described hereinbelow with reference to FIG. 7.  
         [0148]    The heated output of electroheater  402  is preferably supplied via a holding tank  406  to cooling subsystem  404 . Cooling subsystem  404  preferably comprises a thermally insulated enclosure  440 , the interior of which communicates with the ambient atmosphere via a vacuum pump  442 , which preferably maintains the interior of enclosure  440  at subatmospheric pressure, typically about 29″ of mercury.  
         [0149]    Enclosure  440  is partially filled with a cooling liquid  444 , preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure  440 . The electroheated fluid material  446  is preferably supplied to a conduit  448 , which extends through the liquid  444 . As the electroheated fluid material  446  passes through the conduit  448 , in thermal contact with the walls thereof it becomes cooled by evaporating the liquid  444 .  
         [0150]    In accordance with a preferred embodiment of the present invention, an agitator  450 , typically in the form of an elongate shaft  452 , having outwardly extending vanes  454 , is disposed in conduit  448 , and rotated therein about an axis  456 , as by a motor  458 , to provide enhanced uniformity of thermal contact between the electroheated fluid material  446  and the walls of the conduit  448 . A preferred type of conduit  448  and agitator  450  are together known as a scraped surface heat exchanger.  
         [0151]    In accordance with a preferred embodiment of the present invention a cooling liquid  460 , preferably water, is caused to pass through a conduit  462 , preferably a coil, which extends through enclosure  440 , above the level of the cooling liquid  444 . The temperature of the cooling liquid  460  is preferably sufficiently low as to cause vapors of the cooling liquid  444  to condense upon contact with the outer walls of conduit  462  and to fall downward into cooling liquid  444 , as drops  464 .  
         [0152]    The cooled output of cooling subsystem  404  is preferably supplied to conventional cooler  409  for further cooling prior to being sent to aseptic filling mechanism  408  which produces a packaged product having enhanced shelf life and storage temperature insensitivity.  
         [0153]    Reference is now made to FIG. 5, which is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with another preferred embodiment of the present invention. As seen in FIG. 5, the system and methodology of FIG. 5 typically comprises a preheating and cooling vacuum heat exchange subsystem  500 , such as that shown in FIG. 3 and described hereinabove which receives a fluid material, such as a food product, to be preheated and preheats it to a desired temperature, an electroheater  502 , which rapidly heats the fluid material to a predetermined temperature for a predetermined time and then supplies it to a holding tank  504  and thence back to subsystem  500  for rapid cooling thereof, and an aseptic filling mechanism  506 , which receives the cold fluid material via a conventional cooler  508  and produces a packaged product having new and superior characteristics of shelf life and temperature insensitivity.  
         [0154]    As seen in FIG. 5, the vacuum heat exchange system preferably includes a thermally insulated enclosure  510 , the interior of which communicates with the ambient atmosphere via a vacuum pump  512 , which preferably maintains the interior of enclosure  510  at subatmospheric pressure, typically about 29″ of mercury.  
         [0155]    Enclosure  510  is partially filled with a cooling liquid  514 , preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure  510 .  
         [0156]    In accordance with a preferred embodiment of the present invention a fluid material  520 , such as a food product which is to be electroheated, is caused to pass through a conduit  522 , which extends through enclosure  510 , above the level of the cooling liquid  514 . The temperature of the fluid material  520  is preferably sufficiently low as to cause vapors of the cooling liquid  514  to condense upon contact with the outer walls of conduit  522  and to fall downward into cooling liquid  514 , as drops  524 . As the cool fluid material  520  passes through the conduit  522 , in thermal contact with the walls thereof, it becomes heated by the heated vapor  526  from liquid  514 . The heated fluid material then flows from the conduit  522 .  
         [0157]    In accordance with a preferred embodiment of the present invention, an agitator  530 , typically in the form of an elongate shaft  532 , having outwardly extending vanes  534 , is disposed in conduit  522 , and rotated therein about an axis  536 , as by a motor  538 , to provide enhanced uniformity of thermal contact between the fluid material  520  and the walls of the conduit  522 . A preferred type of conduit  522  and agitator  530  are together known as a scraped surface heat exchanger.  
         [0158]    The preheated output of conduit  522  is preferably supplied to electroheater  502 , which is operative to heat the pre-heated fluid material to an elevated temperature in a very short time. Suitable electroheaters are described in applicant&#39;s U.S. Pat. Nos. 6,304,718; 6,088,509; 5,863,580; 5,768,472; 5,636,317; 5,609,900; 5,607,613; 5,583,960; 5,415,882; 5,290,583 and 4,739,140, the disclosures of which are hereby incorporated by reference. A preferred embodiment of an electroheater is described hereinbelow with reference to FIG. 7.  
         [0159]    The heated output of electroheater  502  is preferably supplied via holding tank  504  and a pump  540  to a conduit  542 , which extends through the liquid  514 . As the heated fluid material passes through the conduit  542 , in thermal contact with the walls thereof, it becomes cooled by evaporating the liquid  514 .  
         [0160]    In accordance with a preferred embodiment of the present invention, an agitator  550 , typically in the form of an elongate shaft  552 , having outwardly extending vanes  554 , is disposed in conduit  542 , and rotated therein about an axis  556 , as by a motor  558 , to provide enhanced uniformity of thermal contact between the heated fluid material and the walls of the conduit  542 . A preferred type of conduit  542  and agitator  550  are together known as a scraped surface heat exchanger.  
         [0161]    Aseptic filling mechanism  506  receives the cooled fluid material from conduit  542  after it has been further cooled in conventional cooler  508  and produces a packaged product having new and superior characteristics of shelf life and temperature insensitivity.  
         [0162]    Reference is now made to FIG. 6, which is a temperature-time graph illustrating operation of the present invention for processing food products, such as humus, in accordance with preferred embodiments of the present invention, such as those shown and described hereinabove with particular reference to FIGS. 4 and 5.  
         [0163]    As seen in FIG. 6, the food product is rapidly preheated by the first heat exchanger, such as heat exchanger  400  (FIG. 4) or  500  (FIG. 5), typically from a temperature of 40 degrees C. to a temperature of 85 degrees C. in approximately 40 seconds. Thereafter, the food product is heated to about 130 degrees C. by the electroheater, such as electroheater  402  (FIG. 4) or  502  (FIG. 5), in a fraction of a second. It is then cooled to a temperature of 85 degrees C. by the vacuum heat exchanger, such as heat exchanger  404  (FIG. 4) or  500  (FIG. 5), in approximately 40 seconds, after being held for a period of time in a holding tank at 130 degrees C. It is then preferably cooled further from a temperature of 85 degrees C. to approximately 40 degrees C. or below before being aseptically packaged.  
         [0164]    It has been found by the applicant that humus which has been sterilized by rapid heating and cooling as described hereinabove is characterized by having extremely long shelf life without requiring refrigeration and by having substantial tolerance to temperature abuse.  
         [0165]    It has also been found by the applicant that liquid egg which has been pasteurized by rapid heating, typically to temperatures in the range of 75-85 degrees C., and cooling, similar to that described hereinabove, is characterized by having extremely long refrigerated shelf life and by having tolerance to temperature abuse.  
         [0166]    Reference is now made to FIG. 7, which is a simplified illustration of an electroheater which is particularly suitable for use with viscous products, such as humus. As seen in FIG. 7, a viscous product, such as humus, typically having a viscosity in the range of 20,000 centipoise is supplied at a high rate, typically in the range of 1,500 to 5,000 liters/hour through an electrically insulative conduit  700 , in the direction indicated by arrows  702 .  
         [0167]    Three conductive electrodes,  704 ,  706  and  708  are preferably arranged in spaced mutual arrangement along conduit  700 . Each electrode preferably includes a hollow disc, the interior of which communicates with the interior of conduit  700  by means of a plurality of downstreamly directed angled openings  710 . A relatively small quantity of a conductive fluid, typically 1 to 5 liters/hour per electrode, is supplied to conduit  700  from supply conduits  712 ,  714  and  716 , which output to respective electrodes  704 ,  706  and  708  and thence via openings  710  to conduit  700 . It is seen that preferably electrodes  704  and  708  are grounded, while electrode  706  receives AC current at high voltage, preferably at mains frequencies.  
         [0168]    The arrangement of FIG. 7 is preferred for electroheating of relatively viscous materials, since it generally prevents physical contact between the viscous materials and electrodes  704 ,  706  and  708 . Also, there are no obstacles to flow and no change of diameter, so the velocity is high and uniform.  
         [0169]    Reference is now made to FIG. 8, which is a simplified sectional illustration of a material treatment system and methodology constructed and operative in accordance with yet another preferred embodiment of the present invention.  
         [0170]    As seen in FIG. 8, the material treatment system and methodology of FIG. 8 employs a thermally insulated enclosure  800 , the interior of which is in communication with the ambient atmosphere via a vacuum pump  802 , which preferably maintains the interior of enclosure  800  at subatmospheric pressure, typically about 29″ of mercury.  
         [0171]    Enclosure  800  is partially filled with a cooling liquid  804 , preferably water, which boils at room temperature at the subatmospheric pressure of 29″ of mercury within enclosure  800 . A scraped surface heat exchanger  806  is disposed in enclosure  800  and includes a conduit  808 , part of which extends through the liquid  804 . Heated fluid material  810 , such as an electroheated food product, passes through the conduit  808 , in thermal contact with the walls thereof, and becomes cooled by evaporating the liquid  804 .  
         [0172]    In accordance with a preferred embodiment of the present invention, an agitator  812 , typically in the form of an elongate shaft  814 , having outwardly extending vanes  816 , is disposed in conduit  808 , and rotated therein about an axis  818 , as by a motor  820 , to provide enhanced uniformity of thermal contact between the heated fluid material  810  and the walls of the conduit  808 .  
         [0173]    Disposed inside enclosure  800  above the level of the cooling liquid  804  is a condensing coil  822 . A coolant, such as water, preferably passes through condensing coil  822 .  
         [0174]    The system of FIG. 8 also preferably comprises a reservoir  824  in fluid communication with the interior of enclosure  800 , such as by means of a flexible tube  826 . Reservoir  824  preferably contains cooling liquid  804  which can flow into the interior of enclosure  800  via flexible tube  826 . Another flexible tube  828  is preferably provided to ensure that the vacuum maintained inside enclosure  800  is also maintained inside reservoir  824 . Reservoir  824  is preferably mounted onto a vertical track (not shown) for selectable vertical positioning relative to enclosure  800 , thereby to enable ease of selection of the level of cooling liquid  804  in enclosure  800 . This level effectively controls the amount of cooling produced by the system by determining how much of the scraped surface heat exchanger  806  is disposed in the liquid  804 .  
         [0175]    It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specification and which are not in the prior art.