Patent Publication Number: US-7588486-B2

Title: Microwave poultry processing device and method

Description:
RELATED APPLICATION 
   This application is a continuation-in-part and claims priority to U.S. patent application Ser. No. 11/184,939, filed Jul. 19, 2005 now U.S. Pat. No. 7,241,212, which claims priority to U.S. patent application Ser. No. 11/026,932, filed Dec. 31, 2004, which claims priority to U.S. Provisional Patent Application Ser. No. 60/533,489 filed Dec. 31, 2003. The aforementioned applications are incorporated by reference herein. 

   FIELD OF THE INVENTION 
   The device and method disclosed herein relates generally to poultry processing, and in particular to a device and method utilizing radio frequencies, specifically microwaves, for killing bacteria on poultry during the processing of the poultry. The disclosed device and method also may be used to aid in depilliating poultry by loosening the feathers on poultry prior to another processing step for removing the feathers. 
   BACKGROUND OF THE INVENTION 
   The control of bacterial contamination is an important issue during the processing of poultry for human consumption. Cross-contamination of bacteria from one bird to another may be exacerbated by the mass processing of poultry and the use of automated production equipment. Operations such as chilling poultry carcasses in a chiller bath provide avenues for cross contamination through the use of a tank of chilled water that is reused to chill many poultry carcasses. Feather removal processing steps may also introduce bacteria onto the poultry from fecal matter originating in the poultry carcass&#39; lower intestine. Secondary contamination sources, such as manual processing steps, may also create risks of bacteria contamination of poultry from handlers. 
   Current methods of removing bacteria from chickens may utilize chemical treatments to kill the bacteria. For example, the water in chiller baths used to lower the temperature of poultry during processing, may also be treated with chlorine, sodium hypochlorite or other chemical treatments known in the art to kill the bacteria. Multiple washing steps may also be used to reduce bacterial contamination during processing by washing the poultry carcasses after each processing step. 
   An example of control techniques for bacterial contamination, U.S. Pat. No. 6,547,659 to Adachi et al., describes the use of multiple rinsing steps during processing, and a sterilizing step where poultry carcasses are sterilized during chilling in the chilled bath. Sterilization in the chiller bath may include chlorine solutions, or other chemical solutions added to the bath to kill any bacteria present. 
   It is recognized that killing or preventing bacterial contamination at an early stage of processing is preferred. The current methods of decontaminating the poultry carcasses are insufficient in that they are usually dependent on water-bourne chemicals or simple washing to remove bacteria. Such washing or chemical bath methods are undesirable because the wash solution may become contaminated with bacteria when used to process multiple poultry carcasses, and thus may exacerbate the problem the methods were designed to resolve. These washing steps also occur later in the processing process, after processing has opened the bird and exposed the meat of the poultry to the bacterial contamination. 
   The poultry processing device and method described in this application provide for decontamination from bacteria at a very early stage in the processing, before the poultry has been killed or cut open in any way. Further, the microwaves used to decontaminate the poultry may reach all areas of the carcass without the limitations of a water-borne treatment, which may not come in contact with all areas of the carcass. The poultry processing device described herein is non-invasive and can be utilized on live poultry without causing pain or damage to the animal. 
   The removal of feathers from poultry is also an important part of poultry processing. Various methods for loosening the feathers prior to plucking have been developed, to provide for more complete feather removal. One known method to loosen feathers is to submerge the poultry carcass in hot water to scald the poultry carcass, thereby causing the feather follicles in the skin of the carcass to open, thus loosening the feathers in the follicles. This method has a number of disadvantages, such as poor feather removal unless scald bath temperature is uniform, discoloration of the carcass if the temperature of the scald bath is too high, and contamination of internal organs with water if the poultry is still alive. Once loosened, feathers may be dislodged by force, such as hand or machine plucking, or with jets of compressed air. 
   The processing device and method described herein provide for the loosening of feathers by exposure of the chicken carcass to radio frequency electromagnetic radiation, without the problems caused by the existing methods of loosening feathers. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention is illustrated using the following figures along with the detailed description of the invention. 
       FIG. 1  is a perspective view of an embodiment of the inventive device. 
       FIG. 2  is a cross sectional view taken along line  2 - 2  of  FIG. 1 ; and 
       FIG. 3  is a cross section view, according to an embodiment, of a roller belt assembly for conveyance of the poultry. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The microwave poultry processing device and method described herein relates to a new device and method for reducing and killing bacteria in poultry during processing. The device further relates to an improved method and process for depilliating poultry carcasses. 
   Referring generally now to  FIG. 1 , an embodiment of the poultry processing device  100  is presented. In this particular embodiment, microwave radio frequency signals are transmitted along field guiding structures, e.g. structure  101 , which limit the signal transmission range. Exposure of the bacteria on and within the poultry to specific radio frequencies over a period of time will effectively kill a significant amount of the bacteria. In at least one embodiment, the field guiding structure  101  is a metallic cylinder or tube. The tube may be either fully or partially closed. In yet another embodiment, the field guiding structure  101  includes a plurality of parallel guiding plates (not shown). In at least one embodiment, field guiding structure  101  is constructed from a highly conductive metal. It may be necessary to curve the sides of field guiding structure  101 , dependent upon the parameters of the power generation, exposure time, and the like discussed below. In one embodiment, field guiding structure  101  is either coated with an easily cleaned surface or provided with a shield that can be removed for cleaning. 
   Integrated with the field guiding structure  101  is a shackle line  103 . In particular, shackle line  103  is positioned such that movement along shackle line  103  transports shackled poultry through field guiding structure  101  at a predetermined rate. Cross-referencing for a moment  FIG. 1  with  FIG. 2 , animals (poultry) are suspended upside down by any of a number of retaining or shackling devices  105  well known in the art, and are conveyed along shackle line  103  with their bodies passing through field guiding structure  101 . 
   A radio frequency coupling trough  107 , through which RF (radio frequency) signals can be coupled into field guiding structure  101 , may use antennas, apertures, probes, wires, or other methods commonly practiced in the art of microwave RF design for concentrating an RF signal or RF field, and reducing power requirements. A plurality of troughs  107  are positioned longitudinally along the length of field guiding structure  101 , as shown in  FIG. 1 . In at least one embodiment, troughs  107  are mounted through apertures in one or more parallel guiding plates. These troughs  107  are connected to a source  109  of the RF signals through guiding structures that are known as waveguides, of which waveguide  111  is exemplary. In yet another embodiment, other well known structures available for guiding electromagnetic waves at the frequencies described below may be used. It may be beneficial to place a cylindrical resonator (not shown) within the field guiding structure  101  prior to passing a radio frequency along structure  101 , to decrease the required operational power. Further, a single radio frequency transmitter  108  ( FIG. 2 ) may be used in conjunction with a microwave power splitter (not shown) to convey power through a given trough  107 . An overhead conveying system  113 , which includes shackle line  103 , is grounded to field guiding structure  101  to prevent electrical arcing which would result in undesired heating of the conveying system  113 . 
   The RF power may be supplied by a klystron, magnetron, or similar device (not shown) consistent with the peak power rating, pulse repetition frequency, duty cycle and RF frequency required by incapacitator  100 . A frequency range of from between 5 (gigahertz) GHz to 40 GHz can operatively kill bacteria on the fowl and loosen the feathers of the fowl, depending on power density. In at least one embodiment, the RF frequency is approximately 16 GHz, which is typical of Ku band microwave applications. The peak power rating is in the range of 10 kilowatts (kW) to 100 kW. In one embodiment, the optimum peak power rating is 60 kW, with an average power in the range of 20 W to 200 W, preferably 100 W. It is understood that power ratings may differ depending on the usable configuration of the RF power supply. Typically, the pulse frequency will be approximately 8400 Hz (+/−) 2500 Hz, with a pulse duration of approximately 0.20 microseconds. This is commensurate with a duty cycle of approximately 0.2%. 
   Magnetron tubes consistent with the above specifications are commercially available and are manufactured, for example, by CPI Wireless Solutions of Beverly, MA. An exposure energy density of between 150 milliwatts (mW) seconds per square centimeter and 350 mW seconds per square centimeter is sufficient to substantially reduce common bacteria present on the animals at a power density of 45 mW per square centimeter. The exposure time at this power level is in the range of 2 to 30 seconds, but will eradicate common bacteria from the animal carcass in approximately 2 to 10 seconds. 
   In one embodiment of the inventive method, the following parameters are specified: a radio frequency from between approximately 5 GHz and approximately 40 GHz, with an average power density from between approximately 10 mW per square centimeter and approximately 100 mW per square centimeter, produced and concentrated within and/or around a field guiding structure, such as field guiding structure  101 . An animal&#39;s, e.g. poultry, complete body is then exposed to the radio frequency by placing the animal&#39;s body adjacent to or within field guiding structure  101  for a period of time from between approximately 3 seconds and approximately 30 seconds. In at least one embodiment, the radio frequency is produced from a magnetron operable within the Ku band. In a second embodiment, the body of the standing, shackled and/or conveyed animal is exposed from above or from the sides with similar effects. In those cases in which repeated exposure is desired, the waveguides, e.g. waveguide  111 , can be split to provide RF at multiple points along field guiding structure  101 , or multiple magnetrons can be used in series to provide RF exposure at multiple points along field guiding structure  101 . 
   In another embodiment, as shown in  FIG. 3 , the same method or process of exposing the animal&#39;s body to RF is used while the animals are standing or resting on a surface, such as a conveyor  115 , with the RF signals transmitted generally downward towards the head or from the side towards the body and head. Conveyor  115  may be a roller belt assembly or other conveyor system well known in the art. 
   The device described herein is also useful for aiding in the depilliating of poultry during processing. The device aids in the poultry-depilliating process by causing the follicles in the skin of the poultry to open up, thus loosening the attachment between the feathers and the carcass. Once the feathers have been loosened in the follicles, some may become disconnected from the poultry. However, most feathers will remain loosely attached to the carcass. To complete the depiliation process, the carcass is processed according to any of the well-known methods of removing feathers such as by hand, by machine plucking, or by exposure to jets of compressed air, among others. 
   Methods of removing feathers known in the art will be more efficient and take less time to remove the same amount of feathers from a carcass that has been processed according to the invention described herein. The quality of the poultry carcass will be improved, as a higher percentage of feathers will be removed with less labor. The improved depilliating process will make the complete carcass processing method more efficient, less wasteful, and increase the quality of the final product. 
   An exposure energy density of between 150 milliwatts (mW) seconds per square centimeter and 350 mW seconds per square centimeter is sufficient to substantially loosen the feathers present on the poultry carcass at a power density of 45 mW per square centimeter. The exposure time at this power level is in the range of 2 to 30 seconds, but will loosen the feathers attached to the animal carcass in approximately 2 to 10 seconds. 
   It will be apparent to those skilled in the art that various modifications and variations can be made in the system and method of the present invention without departing from the spirit or scope of the invention. The present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.