Abstract:
An apparatus and method for surface crust freezing of a food product utilizes a refrigeration shell enclosing a freezing chamber, the freezing chamber having a cavity shaped to substantially accommodate the shape of the exterior surface of the food product; the cavity communicating with the refrigeration shell; a transport substrate to carry the food product into the freezing chamber; a cryogen supply; and a gas circulation device in the refrigeration shell in communication with the cryogen supply to introduce a cooling flow of gas containing cryogen into the cavity so as to contact the food product along its exterior surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of the filing date of U.S. Provisional Application for Patent Ser. No. 60/404,069, filed Aug. 16, 2002. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to the slicing of ready to eat meat logs or chubs.  
       BACKGROUND  
       [0003]     Ready-to-eat (“RTE”) meat logs, or chubs, are rolls of processed meat which can be, for example, of a diameter from about 3 to about 6 inches, and up to about 72 inches in length. After the meat logs are processed, i.e., prepared, they must be sliced for market. In order to slice the meat logs in a cost effective manner, especially in consideration of the amount of material that must be sliced, it is necessary to cool and preferably freeze the surface layer of the meat log for proper and effective slicing. The cylindrical shape of the meat log makes them difficult to freeze in standard chilling tunnels and, in those situations where the crust is frozen unevenly, the slicing process is less effective and the cutting device becomes clogged with the meat material.  
         [0004]     The market for ready-to-eat (“RTE”) products offered in supermarkets is increasing, as is the need for cost-effective slicing processes.  
         [0005]     An unfrozen meat log impacted by a slicing blade is cut less effectively and less accurately than would be the case when using a surface frozen meat log. Conventional meat log cutting apparatus, upon retraction of the blade for a subsequent cut, cause portions of the product to adhere to the blade, which portions are flung about the processing area, while some of the material is retained on the blade surface during the subsequent cut. This causes increased maintenance and repair of the blade and support for the machinery, and is a less effective processing of the meat log. In machines conducting 1000 slices a minute, this could translate into a 5-15 percent loss of product.  
         [0006]     Typical meat log processing apparatus include the following: 
    1. Conveyer belts upon which the food product is conveyed to a chilling region, which chills only one side of the meat log.     2. A plurality of meat logs are loaded in bulk into a large cryogen freezer, and the cooling medium is circulated about the meat logs in order to cool them to where the meat logs are ready for slicing.    
 
         [0009]     However, these known processes take from 15 minutes to 4 hours, depending upon the equipment installed and the consistency of the composition of the meat logs. These known apparatus and methods are not cost effective, are time consuming, and consume large amounts of floor space.  
         [0010]     Other apparatus and methods of crust-freezing meat products in preparation for cutting or slicing operations are disclosed in U.S. Pat. No. 4,943,442, which is directed to a method and apparatus for forming a frozen crust on a preformed meat body by direct immersion of a pumped, meat stream in liquid nitrogen in a freezer, followed by downstream severing and patty formation; and in U.S. Pat. No. 5,352,472, which is directed to a method and apparatus for freezing the surface of loaf-shaped meat products by compressing the loaf against a refrigerated contact surface prior to slicing. These apparatus and methods involve direct contact with either a liquid or solid heat exchange medium.  
         [0011]     It would therefore be desirable to have a high gas-flow cruster apparatus and method, which uniformly freezes the exterior surface crust of the meat log and also is adapted to conform to the shape of the meat log for effective and accurate processing thereof.  
       SUMMARY  
       [0012]     An apparatus is provided for surface crust freezing of a food product comprising: a shell enclosing a freezing chamber, the freezing chamber having a cavity shaped to substantially accommodate a shape of the exterior surface of the food product; the cavity in communication with the shell; a transport substrate to carry the food product within the freezing chamber; a cryogen supply; and a gas circulation device in the shell in communication with the cryogen supply to introduce a cooling flow of gas containing cryogen into the cavity to contact the food product along its exterior surface.  
         [0013]     In one embodiment in which the food product is cylindrical in shape, the freezing chamber comprises an impingement cylinder having openings substantially across its length for communicating the cooling flow from the gas circulation device into cooling impingement jets of cryogen directed perpendicular to the surface of the food product.  
         [0014]     In another embodiment in which the food product is cylindrical in shape, the freezing chamber comprises a cylinder having an opening for communicating the cooling flow from the gas circulation device along the interior of the cavity parallel to the exterior and longitudinal axis of the food product.  
         [0015]     In another embodiment, the freezing chamber includes at least one open mesh basket adapted to accommodate the shape of the food product, the basket is carried on a drive wheel through a substantially ovaloid (that is, circular or oval) impingement chamber within the shell, the impingement chamber having impingement holes about its circumference communicating with the shell exteriorly and the freezing chamber interiorly, the basket being adapted to rotate in relation to the drive wheel such that the entire exterior of the food product is exposed to the cooling flow from the gas circulation device into the cooling impingement jets of cryogen directed through the impingement holes from the exterior of the impingement chamber substantially perpendicular to the surface of the food product. The interior of the impingement chamber is in communication with the gas circulation device to recirculate gas and cryogen to the gas circulation device.  
         [0016]     In yet another embodiment, the freezing chamber includes at least one open mesh basket adapted to accommodate the shape of the food product, the basket is carried on a drive wheel through an elongated, substantially ovaloid (that is, circular or oval) elongated shell within the shell, the elongated shell communicating with the shell exteriorly and the freezing chamber interiorly, the basket being adapted to rotate in relation to the drive wheel such that the entire exterior of the food product is exposed to the cooling flow from the gas circulation device along the interior of the elongated shell parallel to the exterior and longitudinal axis of the food product.  
         [0017]     A method of surface crust freezing of a food product is provided comprising: transporting the food product into a freezing chamber having a cavity shaped to substantially accommodate the shape of the exterior surface of the food product; and, introducing a cooling flow of gas containing cryogen into the cavity so as to contact the food product along its exterior surface.  
         [0018]     In one embodiment, the method includes communicating the cooling flow into cooling impingement jets of cryogen directed perpendicular to the surface of the food product.  
         [0019]     In another embodiment, the method includes communicating the cooling flow along the interior of the cavity parallel to the exterior and longitudinal axis of the food product. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention, and, together with the description, serve to explain the principles of the invention, but are not intended to limit the invention as encompassed the claims of the application.  
         [0021]      FIG. 1  is a perspective view of an RTE meat log inside a cylinder where impingement flow is employed.  
         [0022]      FIG. 2  is a perspective view of an RTE meat log inside a cylinder where cross flow is employed.  
         [0023]      FIG. 3  is a cross-sectional view of one embodiment of the cruster apparatus.  
         [0024]      FIG. 4  is a cross-sectional view along the longitudinal length of the embodiment of  FIG. 3  of the cruster apparatus.  
         [0025]      FIG. 5  is a cross-sectional view of another embodiment of the cruster apparatus.  
         [0026]      FIG. 6  is a cross-sectional view of a further embodiment of the cruster apparatus.  
         [0027]      FIG. 7  is a perspective view of the embodiment of  FIG. 6  of the cruster apparatus.  
         [0028]      FIG. 8  is a cross-sectional view of another embodiment of the cruster apparatus.  
         [0029]      FIG. 9  is a cross-sectional view along the longitudinal length of the embodiment of  FIG. 8  of the cruster apparatus.  
         [0030]      FIG. 10  is a cross-sectional view of yet another embodiment of the cruster apparatus.  
         [0031]      FIG. 11  is a cross-sectional view along the longitudinal length of the embodiment of  FIG. 10  of the cruster apparatus. 
     
    
     DETAILED DESCRIPTION  
       [0032]     The present apparatus and method provides for a uniform freezing (“crusting”) of the meat log to a selected depth from the meat log surface, preferably ¼ inch, which crusting is uniform throughout the surface of the meat log, in order to overcome the disadvantages of known apparatus and methods. Freezing or crusting time for apparatus and process disclosed herein is about 1½ minutes to about 2 minutes.  
         [0033]     The apparatus provides a cylindrically shaped freezing section that crusts a meat log product uniformly and much more efficiently than known chilling tunnels. In one embodiment, an impinging-type gas flow is employed which is directed uniformly along an exterior surface of the meat log, disposed within a cylindrically shaped chamber, so that the high velocity and perpendicular impingement heat transfer is effected along the entire surface of the meat log. In an alternative embodiment, a cross-flow gas flow is used, wherein the gas moves at high velocities parallel to a surface or longitudinal axis of the meat log. This embodiment produces comparable surface heat transfer coefficients to that of the impingement heat transfer embodiment.  
         [0034]     Each of the embodiments described provides for a very cold surface crust (approximately 1/4 inch deep) to be rapidly achieved by the meat log. Upon removal from the apparatus, the meat log can be sped to a high-speed slicer, wherein the crusting process permits a uniform, neat, and cost effective slicing operation.  
         [0035]     As an example, one embodiment of the apparatus and process utilizes impingement type gas flow of cryogen, such as carbon dioxide or nitrogen gas, in a straight pass-through configuration. The meat log is loaded into one end of the apparatus, and is removed with a full frozen crust at the opposite end. A plurality of screw-type conveyors may be used to convey the product through the freezing apparatus and process. This method is effective for freezing round, cylindrical shaped meat logs. As a result of the conveying process, the meat log is rotated while it is frozen, eliminating the need for a moving impingement cylinder. Since meat logs are produced in a number of various cross-sectional shapes, other embodiments of the apparatus and process accommodate these shapes. The “cryogen” discussed in this Specification may include solid or liquid carbon dioxide or nitrogen, provided by a cryogen supply and mixed with the respective cryogenic gas to form a cooling gas flow.  
         [0036]     In certain embodiments, the meat log is conveyed for crusting along a passage formed between a pair of dual hemispheres or impingement plates through which a cooling flow of a cryogen, such as carbon dioxide or nitrogen gas, is circulated to crust the meat log. In an alternative embodiment, the arrangement of the dual hemisphere impingement plates may be set off to the side, as opposed to being beneath the blower which circulates the cryogen. The conveyer in these embodiments may be a screw-type system, where the meat log has a circular cross-section. However, if the cross-section of the meat log is other than round, the conveyer may comprise belts. In yet another embodiment, the apparatus is inverted to facilitate cleaning beneath the apparatus, and between the apparatus and the underlying surface.  
         [0037]     In alternative embodiments, the blower may be opposite the slot so that gas is drawn through the cylinder. That is, the blower may be positioned at an exit of the impingement cylinder and the slot at an entrance to the impingement cylinder.  
         [0038]     In certain embodiments, a “rotary type” meat log crusting apparatus may be employed, again utilizing impingement type gas flow. The meat logs may be loaded and discharged at one port, for example by being placed in a stainless steel mesh basket, and being conveyed between two cylinders. One complete rotation will result in all surfaces of the product being frozen. Centrifugal fans mounted to the sidewall of the freezer provide the high-pressure cryogen gas to the impingement cylinders.  
         [0039]     Another “rotary type” apparatus embodiment utilizes cross-flow type gas movement. The meat log is conveyed along a similar path as described above. However, without using impingement cylinders, the total space required for freezing is significantly reduced. As in the above embodiment, the meat logs are conveyed in mesh baskets and centrifugal fans provide the necessary gas flows. The cryogen gas is forced along the surface of the meat log and is circulated back into the fans, as the process continues.  
         [0040]     Food freezing apparatus and methods are disclosed in U.S. Pat. Nos. 4,803,851; 6,263,680; and 6,434,950; and in U.S. Published Patent Application No. 2001/0025495, all assigned to The BOC Group. These patents and application are incorporated by reference herein, as if fully written below.  
         [0041]     For a more complete understanding of the apparatus and process, reference may be had to FIGS.  1  to  11  shown in connection with the description of various the embodiments.  
         [0042]     The flow patterns of the various embodiments of the cruster apparatus are generally described in  FIGS. 1 and 2 . The cylinders  12  and  16  are used for exemplary purposes to illustrate the flow patterns used to freeze the surface layers of the RTE meat logs in the various embodiments of the apparatus and process. In  FIG. 1  the surface layer of an RTE meat log  13  is frozen to a specified depth with impingement flow of a cooling flow. For example, the cylinder  12  is provided with holes  14  up and down its length, and the holes  14  provide for communication between the interior cavity  37  and exterior of the cylinder  12 . Therefore, when the cooling flow is directed toward the cylinder  12 , it is focused by the holes  14  into various cooling jets  15 . Inside the cylinder  12 , the cooling jets  15  are perpendicular to the exterior of the RTE meat log  13 . As the cooling jets  15  impinge the exterior of the RTE meat log  13 , the cooling jets  15  absorb heat, and subsequently freeze the surface layer of the RTE meat log  13 . The impingement flow as described hereinabove is used in the first, second, third, and fourth embodiments described hereinafter, to freeze the surface layer of the RTE meat logs.  
         [0043]     In  FIG. 2 , the surface layer of an RTE meat log  17  is frozen to a specified depth with cross flow of a cooling flow  18 . For example, the cylinder  16  is provided with a slot  19 , and the slot  19  allows for communication between the interior cavity  37  and exterior of the cylinder  16 . Therefore, when the cooling flow  18  is directed toward the cylinder  16 , it enters the slot  19 , and moves at a high velocity parallel to the exterior of and along the longitudinal axis of the RTE meat logs  17 . As the cooling flow  18  is applied to the exterior of the RTE meat log  17 , the cooling flow  18  absorbs heat, and subsequently freezes the surface layer of the RTE meat log  17 . The cross flow as described hereinabove is used in the fifth embodiment of the apparatus and process to freeze the surface layer of the RTE meat logs.  
         [0044]     As shown in  FIGS. 3 and 4 , the first embodiment of the cruster using impingement flow is generally indicated by the numeral  20 . The impingement cruster  20  includes a refrigeration shell  21  having a ceiling  22 , a floor  23 , and side walls  24  and  25 . The refrigeration shell  21  has an entrance  26  and exit  27 , and functions as a tunnel freezer for freezing the surface layer of the RTE meat log  30 .  
         [0045]     Extending through the ceiling  22  is a motor shaft  31  attached to a motor  32 . The motor  32  is located on the exterior surface of the ceiling  22 , and is provided with an electrical supply (not shown). The motor  32  drives a blower assembly  33 , and the blower assembly  33  includes an impeller  34  and a volute  35 . The blower assembly  33  is attached to an impingement shell  40  using a shroud  36 , and is used to circulate and re-circulate gas around the impingement shell  40 .  
         [0046]     The impingement shell  40  is formed from hemispherical impingement plates  41  and  42 , and is supported in the interior of the refrigeration shell  21  using support legs  38  and  39 . As shown in  FIG. 3 , the impingement shell  40  is cylindrically shaped to accommodate the cylindrical shape of the RTE meat log  30 . That is, the hemispherical impingement plates  41  and  42  effectively envelop the cylindrical shape of the RTE meat log  30 . However, the impingement shell  40  can be adapted to accommodate RTE meat logs having different shapes.  
         [0047]     As shown in  FIG. 4 , the impingement shell  40  extends through the longitudinal length of the refrigeration shell  21 . Furthermore, as shown in  FIG. 3 , a conveyer system  44  consisting of two rotating screws  45  and  46  is provided on the interior cavity  37  of the impingement shell  40 . The rotating screws  45  and  46  support the RTE meat log  30  inside the impingement shell  40 , and are used to convey the RTE meat log  30  along the longitudinal lengths of the refrigeration shell  21  and impingement shell  40 . Furthermore, as the rotating screws  45  and  46  move the RTE meat log  30  through the impingement shell  40 , the rotating screws  45  and  46  simultaneously rotate the RTE meat log  30 .  
         [0048]     The rotation of the RTE meat log  30  allows a cooling flow  47  supplied by the blower assembly  33  to be applied uniformly to the exterior of the RTE meat log  30 . For example, the impingement shell  40  is provided with holes (or apertures)  48 , and these holes  48  allow the cooling flow  47  to enter, and be spread throughout the interior cavity  37  of impingement shell  40 .  
         [0049]     The cooling jet pattern  50  created by cooling flow  47  inside the impingement shell  40  is shown in  FIG. 3 . Various cooling jets are formed as the cooling flow  47  passes through the holes  48 . The cooling flow  47  may comprise a cryogenic gas (CO or N 2 ), and the heat of the RTE meat log  30  is absorbed when the cooling flow  47  impinges the exterior of the RTE meat log  30 . As such, the uniform application of the cooling jet pattern  50  to the exterior of the RTE meat log  30  uniformly freezes the surface layer of the RTE meat log  30  to a selected depth. In practice, the RTE meat log  30  is loaded onto the conveyer system  44  and into the impingement shell  40  at the entrance  26  of the refrigeration shell  21 , and is subsequently removed from the exit  27  with a frozen surface layer.  
         [0050]     After the cooling jet pattern  50  is applied to the exterior of the RTE meat log  30 , the reflected gas flow  51  is drawn by the impeller  34  into the blower assembly  33 , and is subsequently re-circulated. For example, the impeller draws the reflected gas flow  51  into the shroud  36 . The shroud  36  communicates with the interior cavity  37  of the impingement shell  40 , and encloses an opening therein. After entering the shroud  36 , the impeller  34  draws the reflected gas flow  51  through the volute  35 . The volute  35  acts as the entrance to the impeller  34 . After entering the impeller  34 , the reflected gas flow  51  is mixed with the above-discussed cryogen, and subsequently re-circulated as the cooling flow  47 .  
         [0051]     Attached to the exterior of the impingement shell  40  are vibrators  56  and  57 . The vibrators  56  and  57  can be pneumatically or mechanically actuated, and are used to prevent snow and ice from building up inside the holes provided in the impingement shell  40 . The frequency and time intervals of the vibrations provided by the vibrators  56  and  57  are dependent on the process conditions, including the moisture content of the RTE meat log  30 , the humidity of the ambient air in and outside the refrigeration shell  21 , and the temperature on the interior of the refrigeration shell  21 .  
         [0052]     As shown in  FIG. 5 , the second embodiment of the cruster apparatus using impingement flow is generally indicated by the numeral  60 . The impingement cruster  60  includes a refrigeration shell  61  having a ceiling  62 , a floor  63 , and side walls  64  and  65 . Like refrigeration shell  21 , the refrigeration shell  61  functions as a tunnel freezer for freezing the surface layer of an RTE meat log  30  is frozen. However, unlike the refrigeration shell  21 , the motor shaft  31  extends through the floor  63 . The motor shaft  31  is attached to a motor  32 , and the motor  32  is located on the exterior surface of the floor  63 . As such, the legs  66  and  67  support the refrigeration shell  61 , and provided clearance for the motor  32 .  
         [0053]     Like the impingement cruster  20 , the motor  32  in the impingement cruster  60  drives the blower assembly  33 , and the blower assembly  33  is used to circulate and re-circulate gas around the impingement shell  40 . However, in the impingement cruster  60  and refrigeration shell  61 , the blower assembly  33  is inverted. For example, a support plate  68  is provided inside the refrigeration shell  61 . The support plate  68  extends between the side walls  64  and  65 , and carries the support legs (not shown) supporting the impingement shell  40 . Consequently, the volute  35  is provided below the support plate  68 , the shroud  36  is provided above the support plate  68 , and a opening (not shown) in the support plate allows the volute  35  and shroud  36  to communicate.  
         [0054]     Other than the different configuration, the impingement cruster  60  operates like the impingement cruster  20 . That is, as the RTE meat log  30  is conveyed and rotated by the conveyer system, the cooling flow supplied by the blower assembly  33  enters the impingement shell  40 , and a cooling jet pattern is applied uniformly to the exterior of the RTE meat log  30 . The uniform application of the cooling jet pattern to the exterior of the RTE meat log  30  uniformly freezes the surface layer of the RTE meat log  30  to a selected depth. After the cooling jet pattern impinges the exterior of the RTE meat log  30 , the reflected gas flow is drawn by the impeller  34  through the shroud  36  into the volute  25 , and is subsequently re-circulated by the blower assembly  33 .  
         [0055]     As shown in  FIGS. 6 and 7 , the third embodiment of the cruster apparatus using impingement flow is generally indicated by the numeral  70 . The impingement cruster  70  includes a refrigeration shell  71  having a ceiling  72 , a floor  73 , and side walls  74  and  75 . Like refrigeration shells  21  and  61 , the refrigeration shell  71  functions as a tunnel freezer for freezing the surface layer of an RTE meat log  30 . Furthermore, like the refrigeration shell  21 , but unlike the refrigeration shell  61 , the motor shaft  31  extends through the ceiling  72 . The motor shaft  31  is attached to a motor  32 , and the motor  32  is located on the exterior surface of the ceiling  72 .  
         [0056]     Like the impingement crusters  20  and  60 , the motor  32  in the impingement cruster  70  drives the blower assembly  33 , and the blower assembly  33  is used to circulate and re-circulate gas around the impingement shell  40 . However, in the impingement cruster  70  and refrigeration shell  71 , a low pressure plenum  76  and shroud  77  are used. For example, the impingement shell  40  is attached to the low pressure plenum  76  using brackets  78 . The shroud  77  provides for communication between the interior cavity  37  of the impingement shell  40  and the low pressure plenum  76 .  
         [0057]     When operating, the cooling flow supplied by the blower assembly  33  enters the impingement shell  40  through holes  48  to create cooling jet pattern  50 . The uniform application of the cooling jet pattern  50  the exterior of the RTE meat log  30  uniformly freezes the surface layer of the RTE meat log  30  to a selected depth. Furthermore, after the cooling jet pattern  50  is applied to the exterior of the RTE meat log  30 , the reflected gas flow is drawn by the impeller  34  into the lower pressure plenum  76  through the shroud  77 , and is subsequently re-circulated by the blower assembly  33 .  
         [0058]     As shown in  FIGS. 8 and 9 , the fourth embodiment of the cruster apparatus using impingement flow is generally indicated by the numeral  100 . The impingement cruster  100  includes a cube-shaped refrigeration shell  101  having a ceiling  102 , a floor  103  and side walls  104 ,  105 ,  106  and  107 . The impingement cruster  100  is supported by pedestals  108  and  109  attached to the exterior surface of the floor  103 .  
         [0059]     Extending through the side wall  107  are motor shafts  112  and  113  attached to motors  114  and  115 . The motors  114  and  115  are located on the exterior surface of the side wall  107 , and are provided with an electrical supply (not shown). The motors  114  and  115  are used to rotate blowers  116  and  117  attached to the motor shafts  112  and  113 . As will be discussed hereinbelow, the blowers  116  and  117  are used to circulate and re-circulate gas around the interior of the refrigeration shell  101 .  
         [0060]     Supported on the interior of the refrigeration shell  101  is a cup-shaped impinger  118 . The cup-shaped impinger  118  is partially formed from concentric impingement cylinders  120  and  121 . As shown in  FIG. 9 , the impingement cylinder  120  has a larger diameter than impingement cylinder  121 . Furthermore, the impingement cylinder  120  also has a longer length than the impingement cylinder  121 .  
         [0061]     To form the cup shape of the cup-shaped impinger  118 , the space between the impingement cylinders  120  and  121  is enclosed using a ring-shaped plate  124 , and circular-shaped plates  125  and  126 . For example, the ring-shaped plate  124  is joined to the diameters of the impingement cylinders  120  and  121 , and encloses one end of the cup-shaped impinger  118 . Furthermore, to enclose the other end of the cup-impinger  118 , the circular-shaped plate  125  is joined around the circumference of the impingement cylinder  120  and the circular-shaped plate  126  is joined around the circumference of the impingement cylinder  121 . As such, the impingement cylinders  120  and  121 , along with the ring-shaped plate  124  and the circular plates  125  and  126  form the cup-shaped impinger  118 . Like the above-referenced impingement shell  40 , the cup-shaped impinger  118  is provided with holes  128 . The holes  128  extend through the impingement cylinders  120  and  121 , and allow for communication between the interior of the refrigeration shell  101  and the interior of the impinger  118 .  
         [0062]     Supported on the interior of the cup-shaped impinger  118  is a drive wheel  131 . The drive wheel  131  supports a plurality of conveying baskets  132  at various positions around the circumference of the cup-shaped impinger  118 . The conveying baskets  132  are hinged to the drive wheel  131 , and, like the baskets of a ferris wheel, the orientation of the conveying baskets  132  adjusts with respect to the drive wheel  131  as the drive wheel  131  rotates. The conveying baskets  132  are composed of wire mesh, and, as shown in  FIG. 9 , extend through the interior of the cup-shaped impinger  118 .  
         [0063]     Carried by each of the conveying baskets  132  are RTE meat logs  133 . The individual conveying baskets  132  are adapted to accommodate the shape of the RTE meat logs  133 . Consequently, as the drive wheel  131  rotates, the conveying baskets  132  and RTE meat logs  133  are rotated within the interior of the cup-shaped impinger  131 . As will be discussed hereinbelow, the rotation of the drive wheel allows the surface layer of the RTE meat logs  133  to be frozen.  
         [0064]     As the drive wheel rotates inside the cup-shaped impinger  118 , cooling flows  134  and  135  are provided by the blowers  116  and  117 . The cooling flows  134  and  135  circulate around the interior of the refrigeration shell  101  and the exterior of the cup-shaped impinger  118 , and ultimately enter the interior of the cup-shaped impinger  118  through holes  128 . As the cooling flows  134  and  135  enter the holes  128  various cooling jets (not shown) are formed. The cooling jets ultimately impinge the exterior of the RTE meat log  133 . The cooling flows  134  and  135  consist of a cryogenic gas (CO or N 2 ), and the heat from the RTE meat logs  133  is absorbed when cooling jets formed from the cooling flows  134  and  135  are applied to the exterior of the RTE meat logs  133 .  
         [0065]     An inlet  136  and an outlet (not shown) are provided near the bottom of the refrigeration shell  101 , and a conveyer system  138  extends therethrough. The inlet  136  allows RTE meat logs  133  to be loaded and the outlet allows RTE meat logs  133  to be unloaded via the conveyer system  138  into the conveying baskets  132 . As such, the conveying system effectively allows the individual RTE meat logs  133  to be loaded and subsequently unloaded from the conveying baskets  132  as the drive wheel  131  rotates between various positions.  
         [0066]     In practice, each of the RTE meat logs  133  is loaded into the conveyor baskets  132  via the conveyor system  138  at the inlet  136 . The rotation of the drive wheel  131 , enables each of the RTE meat logs  133  to complete at least one rotation around the interior of the cup-shaped impinger  118 . During the rotation of the RTE logs  133  around the interior of the cup-shaped impinger  118 , the uniform application of the cooling flows  134  and  135  to the exterior of the RTE meat logs  133  uniformly freezes the surface layer of the RTE meat logs  133  to a selected depth. After at least one rotation around the interior of the cup-shaped impinger  118 , each of the RTE meat logs  133  is unloaded from the conveying baskets  132  at the outlet.  
         [0067]     As described hereinabove, the cooling jets formed from the cooling flows  134  and 135 freeze the surface layer of the RTE meat logs  133 . However, after the cooling jets impinge the exterior of the RTE meat logs  133 , the reflected gas flows  140  and  141  are drawn from the interior of the cup-shaped impinger  118  through the holes  142  and  143  and into the blowers  116  and  117 . The holes  142  and  143  are provided in the circular-shaped plate  125 , and allow the reflected gas flows  140  and  141  to enter the blowers  116  and  117  to be re-circulated as cooling flows  134  and  135 .  
         [0068]     As shown in  FIGS. 10 and 11 , the fifth embodiment of the cruster apparatus using cross flow is generally indicated by the numeral  200 . The cruster  200  includes a box-shaped refrigeration shell  201  having a ceiling  202 , a floor  203  and side walls  204 ,  205 ,  206  and  207 . The cruster  200  is supported by pedestals  208  and  209  attached to exterior surface of the floor  203 .  
         [0069]     Extending through the side wall  207  are motor shafts  212 ,  213 , and  214  attached to motors  216 ,  217 , and  218 . The motors  216 ,  217 , and  218  are located on the exterior surface of the side wall  207 , and are provided with an electrical supply (not shown). The motors  216 ,  217 , and  218  are used to rotate blowers  220 ,  221 , and  222  attached to the motor shafts  212 ,  213 , and  214 . As will be discussed hereinbelow, the blowers  220 ,  221 , and  222  are used to circulate and re-circulate gas around the interior of the refrigeration shell  101 .  
         [0070]     Supported on the interior of the refrigeration shell  201  is an oval-shaped plate  225  with holes  226 ,  227 , and  228 . Extending from the perimeter of the oval-shaped plate  225  is an elongated shell  230  having an oval cross-section. Furthermore, provided adjacent the blowers  220 ,  221 , and  222  is an oval-shaped baffle  231 .  
         [0071]     Supported on the interior of the refrigeration shell  201  is a drive wheel  241 . The drive wheel  241  supports a plurality of conveying baskets  242  at various positions. The conveying baskets  242  are hinged to the drive wheel  241 , and, like the baskets of a ferris wheel, the orientation of the conveying baskets  242  adjusts with respect to the drive wheel  241  as the drive wheel  241  rotates. The conveying baskets  242  are composed of wire mesh, and, as shown in  FIGS. 10 and 11 , are encapsulated inside the elongated shell  230  along with the drive wheel  241 .  
         [0072]     Carried by each of the conveying baskets  242  are RTE meat logs  243 . The individual conveying baskets  242  are adapted to accommodate the shape of the RTE meat logs  243 . Like the conveying baskets  132 , the conveying baskets  242  are composed of wire mesh. As will be discussed hereinbelow, as the drive wheel  241  rotates, the conveying baskets  132  and RTE meat logs  243  are rotated within the interior of the elongated shell  230 , and the rotation of the drive wheel  241  allows the surface layer of the RTE meat logs  243  to be frozen.  
         [0073]     As the drive wheel rotates inside the elongated shell  230 , a cooling flow  244  is provided by the blowers  220 ,  221 , and  222 . The cooling flow  244  circulates around the inside of the elongated shell  230 . For example, the oval-shaped baffle  231  causes the cooling flow  244  to be directed outwardly from the blowers  220 ,  221 , and  222  toward the conveying baskets  242  and RTE meat logs  243 . However, the elongated shell  230  captures the cooling flow  244 , and ensures that the cooling flow is adequately applied to the RTE meat logs  243 . The cooling flow  244  is a cross flow which moves at a high velocity parallel to the exterior along the longitudinal axis of the RTE meat logs  243 . As shown in  FIG. 10 , parts of the cooling flow  244  are disposed adjacent the conveying baskets  242  and RTE meat logs  243 . The cooling flow  244  consists of a cryogenic gas (CO or N 2 ), and the heat from the RTE meat logs  243  is absorbed when the cooling flow  244  is applied to the exterior of the RTE meat logs  243 . Overall, the heat transfer coefficients of the cooling flow  244  is comparable to the heat transfer coefficients of the cooling jets formed from the cooling flows  134  and  135  when using impingement flow.  
         [0074]     An inlet  246  and an outlet (not shown) are provided near the bottom of the refrigeration shell  201 , and a conveyer system  248  extends therethrough. The inlet  246  allows RTE meat logs  243  to be loaded and the outlet allows RTE meat logs  243  to be unloaded via the conveyer system  248  into the conveying baskets  242 . As such, the conveying system effectively allows the individual RTE meat logs  243  to be loaded and subsequently unloaded from the conveying baskets  242  as the drive wheel rotates between various positions.  
         [0075]     In practice, each of the RTE meat logs  243  are loaded into the conveyor baskets  242  via the conveyor system  248  at the inlet  246 . The rotation of the drive wheel  241 , enables each of the RTE meat logs  243  complete at least one rotation around the inside of the elongated shell  230 . During the rotation of the RTE logs  243  around the inside of the elongated shell  230 , the uniform application of the cooling flow  244  to the exterior of the RTE meat logs  243  uniformly freezes the surface layer of the RTE meat logs  243  to a selected depth. After at least one rotation around the inside of the elongated shell  230 , each of the RTE meat logs  243  are unloaded from the conveying baskets  242  at the outlet.  
         [0076]     As described hereinabove, the cooling flow  244  freezes the surface layer of the RTE meat logs  243 . However, after the cooling flow  244  is applied to the exterior of the RTE meat logs  243 , the remaining gas flows  250  and  251  flow around the outside of the elongated shell  230  and into the blowers  220 ,  221 , and  222 . The holes  226 ,  227 , and  228  allow the remaining gas flows  250  and  251  to pass into the blowers  220 ,  221 , and  222 , and be re-circulated as cooling flow  244 .  
         [0077]     Each of the embodiments of the cruster apparatus act to rapidly freeze the surface layer of the RTE meat logs to approximately 0.25 inch deep. Upon removal from the various embodiments, the RTE meat logs can be transferred to a cutting blade to be sliced. The frozen surface layer of the RTE meat logs allows for a uniform, neat, and cost-effective slicing operation as described hereinabove.  
         [0078]     All dimensions and parameters discussed with respect to all the embodiments are by way of example and not limitation. It will be appreciated that other sizes and shapes of the apparatus and its component parts may be employed. Although the invention has been described in detail through the above detailed description and the preceding examples, these examples are for the purpose of illustration only and it is understood that variations and modifications can be made by one skilled in the art without departing from the spirit and the scope of the invention. It should be understood that the embodiments described above are not only in the alternative, but can be combined.