Abstract:
To shorten a long aging time required for meat processing and reducing the viable cell count of a carcass before being cooked, an electric stimulus is imparted by applying an AC voltage via from electrode needles to at least the neck and legs of the meat carcass. The AC voltage is turned on for a time Ton and then turned off for a time Toff, and the application of the voltage is repeated a predetermined number of cycles. The Ton period is not longer than the Toff period, although the first Ton period can be longer than the Toff period. The voltage is not higher than 100V, and the frequency is not higher than the commercial frequency (maximum, 60 Hz). The aging effect is improved by stimulating the entire meat carcass electrically from at most three points.

Description:
[0001]    This is a continuation of both International Application PCT/JP 2005/017582 having an international filing date of 26 Sep. 2005 and International Application PCT/JP2006/317611 having an international filing date of 06 Sep. 2006, which claims priority to PCT/JP 2005/017582. The disclosures of both International applications, in their entirety, including the drawings, claims, and the specifications thereof, are incorporated herein by reference. 
       BACKGROUND 
       [0002]    Conventionally, it is typical to stun poultry with an electrical shock, then thereafter bleed, scald, defeather, eviscerate, cool, and age at low temperatures for extended periods. In the conventional method, the carcass is usually scolded to make the removal of feathers easier. Next, the carcass is defeathered, and then eviscerated. As there is a fear that the carcass becomes deteriorated during succeeding elongated processing scheme, its temperature at this point is reduced to about 4.4° C., typically by chilling the carcass in an ice or cold water bath. The chilled carcass is then aged at this low temperature for an extended period, for example, on the order of about 4 to 12 hours, to provide the required degree of tenderness and organoleptic quality. 
         [0003]    After the low temperature aging process, the carcass is drained and cooked. However, the time required to age the carcass from the evisceration to cooking is about 4 hours to half a day in the case of poultry carcass, and 7 to 10 days or more in the case of large carcasses, such as those of pigs and cows. Such an extended aging period may cause a great problem from the hygiene and operation viewpoint. 
         [0004]    According to the method for processing poultry disclosed in U.S. Pat. No. 4,675,947, a live poultry bird is slaughtered without applying electrical energy, the resulting carcass is scalded, then the carcass is held in a warm, humid atmosphere at a temperature approximately equal to the normal temperature of the live bird before defeathering, and then the carcass is eviscerated. During while the carcass is held in the warm, humid atmosphere, intermittent electrical stimulation is applied to the carcass for a period sufficient to render the poultry meat tender upon subsequent cooking without the need for an extended, low temperature aging period. This method eliminates the low temperature aging, which requires an extended period, and a solution containing phosphate salts and sodium chloride is introduced to the carcass or component parts thereof to further improve tenderness. 
         [0005]    However, it is ideal to evade deposition of phosphate salts and sodium chloride in natural food. Thus, there remains a need to greatly reduce the time period required for the aging of carcasses in comparison with conventional processing apparatuses and methods. There also remains a need to reduce viable cell count on the carcasses before cooking. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention relates to carcass processing apparatus and method, in particular, for shortening the time required to aging carcasses and sterilizing the carcasses, and more specifically to shortening of the aging time by applying current from before rigor mortis sets in but during while the rigor mortis is occurring to reduce viable cell count. 
         [0007]    One aspect of the present invention is a carcass processing apparatus. The apparatus includes a carcass transfer device for transferring eviscerated carcass in a state before vigor mortis sets in but during while the vigor mortis is occurring, and a voltage applying device for applying electrical stimulation to a carcass transferred in the state before vigor mortis sets in but during while the vigor mortis is occurring. The voltage is alternating voltage and the electrical stimulation includes a plurality of periods of voltage applications and periods between the voltage applications. Each of the period of the voltage applications, the period between the voltage applications, the period from a first voltage application set-in to a last voltage application cutoff, and amplitude and frequency of the alternating voltage, are adjustable. 
         [0008]    The voltage applying device can include an inverter with an electric power source to supply alternating voltage of 100V or lower. Alternatively, the voltage applying device supplies electric power of commercial frequency reduced in voltage to 100V or lower. The voltage applying device can supply alternating voltage of a frequency lower than that of commercial electric power. The period of voltage application can be shorter than the period between the voltage applications. 
         [0009]    The voltage applying device includes electrode needles configured to stick through the skin of the carcass and apply electrical stimulation to the carcass. The voltage applying device can include a primary feeder wire configured to supply high-frequency current and a magnetic core with a secondary winding that is movable along the primary feeder wire without contacting the primary feeder wire. The secondary winding produces voltage when the magnetic core with the secondary winding moves along the primary feeder wire without contacting the primary feeder wire, to provide noncontact transmission of electric power. 
         [0010]    The magnetic core can have a recess or groove. The primary feeder wire can have a plurality of spaced waveform shapes that extend in a horizontal plane such that when the magnetic core with the secondary winding is moved horizontally, part of the waveform shaped primary feeder wire is received in the recess or groove to induce voltage in the secondary winding by the high-frequency current passing through the primary feeder wire, while the primary feeder wire outside the recess or groove does not induce voltage in the secondary winding. 
         [0011]    A plurality of carcass transfer devices can be provided. The transfer devices can be moved along an endless route. The apparatus can further include a carcass engaging section, a needle-sticking and wing-holddown section, a voltage applying section, and a carcass discharging section provided along the endless route. The primary feeder wire need only be provided in the voltage applying section. 
         [0012]    The apparatus can further include a guide shaft fixed to the transfer device. The voltage applying device can be attached to the transfer device. The voltage applying device can include a carcass hanger having electrode needles configured to stick into the feet or leg of the carcass, and a slider having electrode needles configured to stick into the breast part of the carcass. The slider can be vertically movably supported relative to the transfer device and guided by the guide shaft. The slider is movable up to allow the electrode needles of the slider to stick into the carcass until tips of the electrode needles reach a hollow of the carcass produced by evisceration of the carcass. The slider is movable down so that the tips of electrode needles is between the bottom of the hollow and a lower end of the carcass before voltage is applied to the carcass via the electrode needles of the carcass hanger and the slider. 
         [0013]    The slider can include a ball plunger comprising a ball and a spring for biasing the ball. The guide shaft can be provided with a groove for receiving the ball such that the ball engages the groove to restrict the movement of the slider at a height position with which the tips of electrode needles is between the bottom of the hollow and the lower end of the carcass. 
         [0014]    Another aspect of the present invention is a method of processing a carcass. The method can include the steps of eviscerating the carcass, applying a first electrical stimulation to the carcass in a state before vigor mortis sets in but during while the vigor mortis is occurring, chilling the carcass to lower the temperature thereof, and applying a second electrical stimulation to the carcass following the chilling step. The first and second electrical stimulations include a plurality of periods of voltage applications and a period between the voltage applications, the voltage being alternating voltage. Each period of the voltage applications, the period between the voltage applications, the period from a first voltage application set-in to a last voltage application cutoff, and amplitude and frequency of the alternating voltage, are adjustable. 
         [0015]    At least one of the first or second electrical stimulation applying step includes a first sub step of applying electrically stimulating voltage for a first time interval, a second substep of waiting for a second time interval, in which no voltage is applied, after the first time interval ends, and a third substep of repeating the first and second substeps. The first time interval is shorter than the second time interval. 
         [0016]    Alternatively, at least one of the first or second electrical stimulation applying step includes a first substep of applying electrically stimulating voltage for a first time interval, a second substep of waiting for a second time interval, in which no voltage is applied, after the first time interval ends, a third substep of applying electrically stimulating voltage for a third time interval, a fourth substep of waiting for the second time interval, in which no voltage is applied, after the third time interval ends, and a fifth substep of repeating the third and fourth substeps. The first time interval can be longer than the second time interval and the third time interval. The second time interval is longer than the third time interval. 
         [0017]    At least one of the first or second electrical stimulation applying step includes a sixth substep of applying electrically stimulating voltage for a fourth time interval, a seventh substep of waiting for a fifth time interval, in which no voltage is applied, after the fourth time interval ends, and an eighth substep of repeating the sixth and seventh substeps. The fourth time interval is shorter than the fifth time interval. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0018]      FIG. 1  is a flowchart of a conventional carcass processing. 
           [0019]      FIGS. 2A and 2B  are examples of voltage apply cycle for applying electrical stimulation to the carcass, and  FIG. 2C  is an example of voltage waveform. 
           [0020]      FIG. 3  is a front view of an embodiment of the carcass processing apparatus. 
           [0021]      FIG. 4  is a right-side elevational view of the carcass processing apparatus of  FIG. 3 . 
           [0022]      FIG. 5  is a side elevational view showing a state the carcass is electrically stimulated in the apparatus of  FIG. 3 . 
           [0023]      FIG. 6  is an operation flowchart of the carcass processing apparatus. 
           [0024]      FIG. 7  is a histogram showing aging effect of the carcass processed with the conventional method. 
           [0025]      FIG. 8  is a plan view of another embodiment of the processing apparatus. 
           [0026]      FIG. 9  is a perspective view of the carcass carrier of the apparatus of  FIG. 8 . 
           [0027]      FIG. 10  is a side elevation of the carcass carrier of the apparatus of  FIG. 8 . 
           [0028]      FIGS. 11A and 11B  are respectively a section view along the line  11 A- 11 A and  11 B- 11 B of  FIG. 8 . 
           [0029]      FIG. 12  is a section view of the slider. 
           [0030]      FIG. 13  is a schematic representation showing the mechanism of sticking/withdrawing the carcass with electrode needles by shifting the slider provided with the needles in the needle-sticking and wing-holddown section. 
           [0031]      FIG. 14  is a graph comparing the amount of inosinic acid in the carcass after the carcass is applied with electrical stimulation and then deboned according to the present invention and that according to the conventional method. 
           [0032]      FIG. 15  is a table showing results of improvement in meat quality according to the invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0033]    Preferred embodiments of the present invention will now be detailed with reference to the accompanying drawings. It is intended, however, that unless particularly specified, dimensions, materials, relative positions and so forth of the constituent parts in the embodiments shall be interpreted as illustrative only not as limitative of the scope of the present invention. 
         [0034]    Before explaining the various embodiments according to the present invention, a conventional carcass processing will be explained in reference to  FIG. 1 , which shows a flowchart of a conventional carcass processing. According to the conventional carcass processing, the carcass, after being stunned with an electrical shock, bled, scalded, and defeathered, is eviscerated at an evisceration step S 40 . The eviscerated carcass is suspended in a transfer conveyor line at a suspension transition step S 41   a  in a state before rigor mortis sets-in but during while the rigor mortis is occurring. Then, at an electrical stimulation applying step S 41   b , viable bacteria count adhered to the carcass is reduced by applying electrical stimulation for a few minutes, which stimulation promotes biochemical change in the muscle tissue of the carcass. Then, at a chilling step S 42   a , the carcass reduced in viable cell count is subjected to low temperature processing. Then, at a thigh removing step S 42   b , the thighs of the carcass is removed. Then, at an aging step S 43 , the carcass is aged in an aging room. The time required to age the carcass is about 4 hours to a half day. Lastly, at a dissection step S 44 , the carcass is dissected and breast meat is obtained. 
         [0035]    According to a first carcass processing method according to the present invention, the conventional processing step mentioned above in  FIG. 1  can be used, but the voltage waveform is changed in the electrical stimulation applying step S 41   b , by which the time required to age the carcass is shortened to about 2 hours (from about 4 hours to a half day of the conventional processing method) while attaining the same result as that of the conventional method. The first carcass processing method includes a transfer step of transferring the carcass subjected to the evisceration step S 40 , which carcass is in a state before rigor mortis sets-in but during while the rigor mortis is occurring, and a stimulation applying step of applying electrically stimulating voltage having a plurality of voltage apply cycles of different duration applied to the carcass in a state before rigor mortis sets-in but during while the rigor mortis is occurring with a voltage applying device via carcass holding members by ON-OFF operation of the voltage apply device. The electrical stimulation is applied by ON-OFF operation of alternating voltage with durations of ‘ON’ and ‘OFF.’ The period from the first ‘ON’ to the end of the last ‘ON,’ and the value of voltage and its frequency are determined and varied to optimize the effect of the electrical stimulation. Specifically, an alternating voltage of 100V or lower can be applied at a frequency lower than the commercial frequency (maximum 60 Hz), with the ‘ON’ duration shorter than the ‘OFF’ duration. 
         [0036]      FIG. 2A  is an example of voltage applying cycle at the electrical stimulation applying step S 41   b . The electrically stimulating voltage applying operation includes a first step, a second step, and a third step. The first step of applying electrically stimulating voltage continues for a time interval of X followed by an interruption of voltage application for a time interval of Y. Then, in the subsequent second step, application of electrically stimulating voltage continues for a time interval of Z followed by an interruption of voltage application for a time interval of Y. In the third step, the electrically stimulating voltage application and the interruption thereof being the same as in the second step are repeated. The feature of this electrically stimulating voltage application mode is that the voltage application duration X is longer than that of Y and Z. 
         [0037]      FIG. 2B  is another example of voltage applying cycle. Here, a time interval Ton of the electrically stimulating voltage application and a time interval Toff of the interruption thereof are different from each other. This ON-OFF operation is repeated. The electrically stimulating voltage application period means a time period from the first voltage ‘ON’ to the last voltage ‘OFF’, as shown in  FIG. 2B .  FIG. 2C  is an example of the voltage waveform applied during the time interval Ton in  FIG. 2A  or  FIG. 2B . In this embodiment, Ton, Toff, alternating voltage (100V or lower), and alternating frequency (commercial frequency or lower, maximum 60 Hz), can be determined and varied to optimize the effect of the electrical stimulation. 
         [0038]    According to a second carcass processing method according to the present invention, a second electrical stimulation applying step is further provided after the chilling step (low temperature cooling step) S 42   a  before the thigh removing step S 42   b . That is, this method includes the evisceration step, the first electrical stimulation applying step (such as in the first method) of applying electrical shock to the carcass in a state before rigor mortis sets-in but during while the rigor mortis is occurring, a low temperature chilling step, and a second electrical stimulation applying step (similar to the first electrical stimulation applying step) of applying electrical shock to the carcass following the chilling step. The mode of electrically stimulating voltage application in each of the electrical stimulation applying steps can be determined and varied to optimize the effect of the electrical stimulation. 
         [0039]      FIG. 3  is a front view of a first embodiment of the carcass processing apparatus according to the present invention that can be used to carry out the methods described above. The apparatus includes a transfer conveyor  10 , a voltage applying section  20 , and an electrical control section  18 . The transfer conveyor  10  includes a transfer mechanism  11 , which includes a frame work  10   a , a horizontally circular guide rail  12  located in the upper part of the frame work  10   a , a transfer chain  15  for transferring a plurality of roller carriers (not shown in  FIG. 3 ) attached thereto to be guided by the guide rail  12 , a drive sprocket wheel  14   a , a driven sprocket wheel  14   b , and a driving geared motor  13 , and a plurality of shackles  16  each for clamping the feet  25   a  of the carcass  25 , the shackles being attached detachably to each of hooks  15   a  attached to the transfer chain  15 . 
         [0040]      FIG. 4  is a right-side elevation of the carcass processing apparatus of  FIG. 3 . The transfer conveyor  10  constitutes a round route of an outward route  27   a  and a return route  27   b  via the transfer chain  15  looped over the drive sprocket  14   a  and driven sprocket  14   b  in the upper center part of the frame work  10   a . The voltage applying section below the transfer conveyor  10  includes electrode rails  1 ,  2 ,  3  and grounding electrodes  22 , each of which is located right below the outward route  27   a  and return route  27   b  respectively. Each of the grounding electrodes  22  includes two electric wires running parallel to each other and supported on a grounding electrode supporter  22   a . Alternating voltage of 100V or lower is supplied to the electrode rails  1 ,  2 , and  3  from a commercial electric source or a variable frequency electric source of an inverter. In this case, in the voltage waveform shown in  FIG. 2C  uses frequency C that is a commercial frequency or lower (maximum 60 Hz), and voltage E is 100V or lower. 
         [0041]    The electrode rails  3  just below the outward route  27   a  and return route  27   b  are located such that width W 2  between the electrode rails  3  is a little wider than width W 1  between the hooks  15   a  attached to the endless chain  15  so that when the carcass  25  is hanging from the hook  15   a  with its feet held in the shackle  16  while the shaft part of the shackle  16  contacts the electrode rail  3  positively with a contact pressure. The grounding electrode  22  is supported on the grounding electrode support  22   a  such that width W 3  between the two electric wire of the grounding electrode is a little smaller than the diameter of the neck  25   b  of the carcass  25  so that the electric wires can pinch the neck  25   b  when the feet  25   a  of the carcass  25  are held in and the carcass  25  hanging from the shackle  16 . Thus, electrically stimulating voltage can be applied to the carcass  25  without fail via the electrode rail  3 , the shackle  16 , the feet  25   a  of the carcass  25 , the neck  25   b  of the carcass  25 , and the grounding electrode  22 . 
         [0042]      FIG. 5  is a side elevation viewed from the outward route  27   a  showing a state in which the carcass  25  is electrically stimulated. A needle  51  for sticking the breast of the carcass  25  is supported by a metal supporter  52 . The metal supporter  52  is pushed to contact the electrode rail  2  positively, with the pressure pushed by the carcass when the carcass is stuck with the electrode needle  51 , toward the electrode rail  2 . Predetermined stimulating voltage is applied to the carcass  25  via the electrode rail  2 . A needle  53  for sticking the root part of the neck  25   b  is attached to an end part of a metal bar  54  that is swingably supported by a bearing  56 , which is supported by a metal supporter  57 . By moving down a grip  55  provided at other end part of the metal bar  54 , the electrode needle  53  sticks into the carcass and the metal supporter  57  contacts the electrode rail  1  positively with a pressure. Predetermined stimulating voltage is applied to the carcass  25  via the electrode rail  1 . The metal supporters  52  and  57  are connected with an insulating plate  58 . Each mode of electrically stimulating voltage applied to each of the electrode rails  1 ,  2 , and  3  is determined to optimize the effect of the electrical stimulation. 
         [0043]    When performing electrical stimulation, usually the transfer conveyor  10  is stopped in a state where a plurality of carcasses are hanging from the conveyor, and ON-OFF of voltage application is controlled by the electrical control section  18 . With the present apparartus, electrically stimulating operation of large number of carcasses is made possible, and the apparatus can be effectively utilized to compose an automatic processing line. 
         [0044]      FIG. 6  is an operation flowchart of the carcass processing apparatus. The operation process will be explained using a stimulation voltage application mode shown in  FIG. 2A  as an example. First, the power source is switched on at step S 30 . Then whether operation of the transfer conveyor  10  is interrupted or not is judged at step S 31 . When the transfer conveyor  10  is being interrupted, the voltage application of the first step through the third step shown in  FIG. 2A  is performed as shown in  FIG. 6  from step S 32  through step S 36  to end the voltage application, or as shown by a step  37  in  FIG. 6 , a step or steps is selected from among the first to third steps of  FIG. 2A , and voltage application is performed for a desired period for the selected step or steps. When the transfer conveyor  10  is operating, a cycle of application of voltage of 100V, 50 Hz for 1 second and interruption for succeeding 1 second, for example, is repeated while the transfer conveyor is operating. This repetition of cycle can be started with a start button (e.g., switch) and stopped with a stop button (e.g., switch). The transfer conveyor  10  is operated continuously at normal speed of 1.52 m/min., for example, by switching ON with the start button and switching OFF with the stop button. The electric control section  18  is provided with a section to set electrically stimulating voltage application mode and controls voltage applying in accordance with the determined mode. 
         [0045]    Referring to  FIGS. 8-13 , a second embodiment of the processing apparatus according to the present invention will be explained. Referring to  FIG. 8 , which is a plan view of the second embodiment of the processing apparatus, a plurality of carcass transferring bodies  61  are provided to be transferred along a transfer rail  60  forming a circulation route. There are provided along the circulating route of the transfer rail  60  a carcass engaging section  67  where the carcass is engaged to the carcass transferring bodies  61 , a needle-sticking and wing-holddown section  68  where needles for applying voltage to the carcass are stuck into the carcass, a voltage applying section  65  where electrically stimulating voltage is applied to the carcass, and a carcass discharge section  66  where the carcass that has been electrically stimulated is discharged. 
         [0046]    Each of the carcass transferring bodies  61  is provided with a pick-up coil  62  includes a magnetic core and a secondary winding. In the voltage applying section  65 , alternating current of commercial frequency is converted to high-frequency alternating current by an AC/HF converter  64  attached to the carcass carrier  61 , and the high-frequency current is conducted to a primary feeder wire (hereafter referred to as litz wire)  63 . By the passage of the high-frequency current through the litz wire  63 , voltage is induced in the secondary winding of the magnetic core of the pick-up coil  62 , and electric power is transmitted from the litz wire  63  to the pick-up coil  62  without contacting with each other. 
         [0047]    The litz wire  63  is formed into a shape of so-called alternating rectangular wave as shown in  FIG. 9  and supported by a litz wire supporter provided to a side wall. When a part of the litz wire passes through the airspace of the pick-up coil  62 , stimulation voltage application is ‘ON’, i.e., the passage time interval is Ton, and when a part of the litz wire passes outside of the airspace of the pick-up coil  62 , stimulation voltage application is ‘OFF’, i.e., the passage time interval is Toff. The wave shape of the litz wire can be determined arbitrary as desired. Since Ton and Toff can be switched by the wave shape of the litz wire  63 , the litz wire can be always energized so that the switching of power source becomes unnecessary. Thus, continuous energizing (not batch control) of energizing of the litz wire is allowed, resulting in efficient energizing control. Further, the litz wire  63  does not exists in the carcass discharge section  66  and carcass engaging section  67 , where manual work is needed, safety is secured for workers in the discharge section  66  and engaging section  67 . 
         [0048]    Referring to  FIGS. 9 and 10 , which show perspective and side elevation views of the carcass carrier  61 , the carcass carrier  61  has a wheel  71  that engages the transfer rail  60  so that the carcass carrier  61  can move along the transfer rail  60 . The high-frequency current conducted from the litz wire  63  through noncontact transmission of electric power to a HF/AC converter  73  is converted to alternating voltage by the converter  73 , and distributed to electrode needles  74  and electrode needles  77  via an electric wire  76  and frame elements and a carcass hanger of the carcass carrier  61  to apply electrical stimulation to the carcass  81 . The carcass  81  is stuck at its feet or legs with the electrode needles  74  provided at an end of the carcass hanger to be fixed thereto so that the carcass hangs from the carcass hanger with its breast part supported on a shoulder support plate  75 . A slider  78  moves up by a shaft  79  to allow the electrode needles  77  provided with the slider  88  to stick into the breast part of the carcass  81 . This way, the electrode needles  74 ,  77  are stuck into the carcass, penetrating the skin  81   a  of the carcass as can be seen in the areas indicated by circles A and B of  FIG. 10 . Electrical stimulation can be applied at low voltage to the carcass via the electrode needles  74  and  77 . 
         [0049]      FIG. 11A and 11B  are respectively a section view along the line  11 A- 11 A and  11 B- 11 B of  FIG. 8 . As shown in  FIG. 11A , the pick-up coil  62  is shaped to have the general shape of a letter E in its cross section, i.e., to have a pair of outer magnetic cores  62   a ,  62   b  and a central magnetic core  62   c  so that a pair of airspace  62   d ,  62   e  are formed between the outer cores  62   a ,  62   b  and central core  62   c . The litz wires  63  are supported by litz wire supporters  70  fixed to a side wall  69  respectively such that, when the pick-up coil  62  fixed to the carcass carrier  61  travels along the transfer rail  60 , a part of each litz wire  63  is received in each of the airspaces  62   d  and  62   e  without contacting the walls of the airspaces. When high-frequency alternating current is fed to the litz wires  63 , a magnetic field of time varying direction of field line and field intensity is generated in the pick-up core  62 , and voltage is induced in the secondary windings  62   f  when a part of the litz wire  63  is in the airspace  62   d  or  62   e  of the pick-up coil  62  as shown in  FIG. 11A . When the litz wire  63  is not in the airspace  62   d  or  62   e  of the pick-up coil  62  as shown in  FIG. 11B , a magnetic field in the pick-up core  62  is not generated even if the high-frequency is passing through the litz wire  63 ; the litz wire  63  and the pick-up coil  62  are electrically interrupted. 
         [0050]      FIG. 12  is a section view of the slider  78 . The slider  78  can be moved up and down along the shaft  79 . The vertical position of the slider  78 , when the electrode needles  77  provided to the slider  78  sticks into the breast part of the carcass  81 , can be determined by the engagement of a ball of a plunger  90  including the ball and the spring, with a groove  93  provided to the shaft  79 . The slider  78  is movable up and down by guiding a guide member  92  attached to the slider  78  along a guide groove  91  in which the guide member  92  is received, as explained hereunder referring to  FIG. 13 . 
         [0051]      FIG. 13  is a schematic representation showing the mechanism of sticking/withdrawing the carcass with the electrode needles  77  by the vertically shifting of the slider by guiding the slider via the guide groove  91  in the needle-sticking and wing-holddown section  68 . The carcass  81  is hooked at its feet to the electrode needles  74  of the carcass hanger of the carcass carrier  61 , so that the carcass becomes fixed to the carcass hanger with its breast part supported on the shoulder support plate  75  of the carcass carrier  61  in the carcass engaging section  67 . The carcass carrier  61  is transferred along the transfer rail  60  to the needle-sticking and wing-holddown section  68 . 
         [0052]    In the needle-sticking and wing-holddown section  68 , the guide member  92  of the slider  78  provided with the electrode needles  77  enters the guide groove  91 . The guide groove  91  is formed to have a lowest groove  91  a continuing to a highest groove  91   b , which continues to an intermediate height groove  91   c  running in a height position between the highest groove  91   b  and lowest groove  91   a  as can be seen in  FIG. 13 . When the guide member  92  attached to the carcass carrier  61  travels along the lowest groove  91   a , the tips of the electrode needles  77  are below the carcass  81 . When the guide member  92  moves up along the guide groove  91  toward the highest groove  91   b  as the carcass carrier  61  travels along the transfer rail  60 , the electrode needles  77  stick into the carcass penetrating the skin  81   a  of the carcass  81 . When the guide member reaches the highest groove  91   b , the tips of the electrode needles  77  has run into the hollow  81   b  produced by the evisceration of the carcass  81 . The electrode needles  77  moves down as the guide member  91  moves down toward the intermediate height groove  91   c  as the carcass carrier  61  travels. When the guide member  92  is traveling in the intermediate height groove  91   c , the tips of the electrode needles  77  is between the bottom of the hollow  81   b  and lower extremity of the carcass  81 . 
         [0053]    By allowing the electrode needles  77  to penetrate the carcass  81  until the tips of the electrode needles  77  run into the hollow  81   b  of the eviscerated carcass  81  and then to be drawn back until the tips are between the bottom of the hollow  81   b  and lower end of the carcass in this way, the electrode needles  77  can be stuck into the carcass  81  through the flabby skin  81   a  of the carcass positively. By allowing the electrode needles to penetrate the skin  81   a  of the carcass  81 , electrical stimulation can be applied to the carcass  81  at low voltage. 
         [0054]    By forming the guide groove  91  such that the height position of the slider  78  when the guide member  92  is in the intermediate height groove  91   c  coincides with the height position of the slider  78  when the ball of the ball plunger  90  engages with the groove  93  of the shaft  79 , the slider  78  can be retained at the height position with which the electrode needles  77  attached to the slider  78  is stuck into the carcass  81 , so it is enough to provide the guide groove  91  in the needle-sticking and wing-holddown section  68 , and the guide groove  91  need not be provided in the voltage applying section  65 . 
         [0055]    Aging effect by electrical stimulation is different depending on the voltage, frequency, and cycle pattern of applied voltage. Effects of aging was compared by changing voltage, frequency, and cycle pattern for stimulating at frequencies lower than 60 Hz and voltages equal to or lower than 100V. A cycle pattern shown in  FIG. 2B  was used with Ton different from Toff. In some examples, Ton was set equal to Toff. 
         [0056]    A first setting (100V, 60 Hz, 2 minutes of electrical stimulation period) was compared with a second setting (20V, 60 Hz, 2 min. of electrical stimulation period). With the first setting, scorching, and discoloration occurred on the test piece. With the second setting of 20V, scorching and discoloration were scarcely observed. The aging effect was irrelevant to the voltage (i.e., no correlation between the aging effect and these voltages) and almost the same in the two cases. Consequently, a lower stimulating voltage is preferred. 
         [0057]    Then, a third setting (20V, 5 Hz, 1 second of Ton, 2 seconds of Toff, 3 minutes of stimulation period) was compared with a fourth setting (20V, 60 Hz, 1 second of Ton, 2 seconds of Toff, 3 minutes of stimulation period). The aging effect was better with the third setting. Consequently, a lower frequency is preferred. 
         [0058]    Further, the third setting (20V, 5 Hz, 1 second of Ton, 2 seconds of Toff, 3 minutes of stimulation period) was compared with a fifth setting (20V, 5 Hz, 1 second of Ton, 1 second of Toff, 3 minutes of stimulation period). The aging effect was better with the third setting. Consequently, it is preferred to set the Toff period longer than the Ton period. A longer Toff period, one that provides a sufficient time for relaxation of the muscle of the test piece, improves the aging effect. 
         [0059]      FIG. 7  is a histogram showing the aging effect (general viable cell count) of the carcass processed with a conventional method. Breast meat was subjected to the following aging operations:
       (a): electrical stimulation aging (electrical stimulation +2 hours aging, breast meat of cock and hen mixed), the test breast meat was subjected to electrical stimulation of 100V, 50 Hz was applied for 5 minutes.   (b): usual aging (conventional 4 hours low temperature aging), the test breast meat was aged for 4 hours in a aging room of 2° C. after passing through a chiller.   (c): usual article (not aged, breast meat of cock and hen mixed), processed in a conventional processing line.         
         [0063]    From  FIG. 7 , it is recognized that in the case of process (a), general viable cell count is reduced conspicuously with aging hours reduced by 2 hours. According to the test result of example mentioned above, it is proved that the aging effect can be further improved. Further, the test result of the example also showed that the meat quality was improved as follows. Decomposition of ATP (adenosine triphosphate) by enzyme is promoted by applying electrical stimulation to the carcass after vigor mortis sets in. Therefore, the quality of meat after deboning can be improved by applying electrical stimulation to the carcass, i.e., the maximum value of inosininic acid, which is nucleic acid related substance, and a flavor-enhancing ingredient can be rapidly produced. 
         [0064]      FIG. 14  is a graph comparing the amount of inosinic acid in the carcass after the carcass is applied with electrical stimulation and then deboned according to the present disclosure and that in the case of reference example of the conventional method. The content of inosinic acid was 8.6 μmol/g in the test example according to the present invention, whereas 5.4 μmol/g in the case of the reference example of conventional processing. 
         [0065]    Further, tenderizing and increase in water absorbing property of the tissue can be achieved by applying electrical stimulation to the carcass after vigor mortis sets in. Raw flesh is subjected to physical treating such as massaging, tumbling, and tenderizing when seasoning and soaking to allow pickling liquor to soak into the meat and obtain processed meat products. By utilizing the effect of electrical stimulation, the ionic mass increased in permeability by electrical stimulation soaks its way into the muscle fiber and increases the water holding property, so that such physical treatment can be omitted. Meat products processed by the method as mentioned above will have high meat juice retentivity when cooled, thus reducing the cooking loss. Further, by applying electrical stimulation to the carcass after rigor mortis sets in and refrigerating the carcass in a state chemical and physical properties are retained, a delicious taste is improved and productive efficiency can be increased while keeping the quality of the meat from the hygienic standpoint. 
         [0066]    The improvement in meat quantity concerning water holding property, flavor, and hardness of the meat was measured, and the result is illustrated in  FIG. 15  together with measuring method as follows:
       Hardness: Shear strength of a piece of meat cut in a prescribed shape after heated for a prescribed time period was measured. Shear strength of the meat subjected to electrical stimulation according to the invention was lower by about 30% than that of usual meat, which means that the meat processed according to the invention was tender than usual meat.   Water holding property: Dripped water amount was measured. Water retention of the meat subjected to electrical stimulation according to the invention was higher by about 10% than that of conventionally treated meat.   Flavor or delicious taste: Amounts of nucleic acid related substance was measured using high-performance liquid chromatography. Amounts of inosinic acid, one of nucleic acid related substance, was larger in the meat subjected to electrical stimulation according to the invention than in the conventionally treated meat.       
 
         [0070]    Further, when deboning the carcass after electrical stimulation is applied, elongated aging time of the carcass in a chilled state in the conventional processing causes the muscle fiber and the connective tissue in muscle to become fragile, and fine splits of meat remain on the bone when performing mechanical deboning. Consequently, the yield of meat is reduced and the external appearance is deteriorated. According to the present processing according to the present invention, since deboning can be performed without delay after the application of electrical stimulation, the yields of meat increases in comparison with the conventional method. 
         [0071]    The present invention is applicable to a poultry carcass processing apparatus and method, and also applicable to the processing of carcasses livestock including pigs, cows, and so on. 
         [0072]    The present invention can reduce the aging time period required in the conventional carcass processing. Further, viable cell count adhered to carcasses before cooking can be reduced. Specifically, the processing time periods can be reduced by the reduction in aging time periods, which contributes significantly to control microbe growth. By applying the present invention, labor-saving automated process can be instituted, first-in first-out system and stable temperature control can be realized by composing a continuous processing apparatus. 
         [0073]    While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the present invention. All modifications and equivalents attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention accordingly is to be defined as set forth in the appended claims.