Abstract:
Animal products are processed through multiple successive immersions in sanitizing solutions at different successive temperatures within controlled environments including at fluid pressures different from ambient pressure to reduce resident microbial contaminants in preparation for packaging within encapsulating material prior to retail distribution.

Description:
RELATED CASES  
       [0001]    This application is a division of application Ser. No. 10/140,735 entitled “Food Processing Method and Apparatus”, filed May 7, 2002 by M. Terry, which is a continuation-in-part of pending application Ser. No. 09/713,526 entitled “Fish, Poultry, Meat Processing Method and Apparatus”, filed on Nov. 13, 2000 by M. Terry, and the subject matter of this application is related to the subject matter of U.S. Pat. No. 5,711,980 issued on Jan. 27, 1998 to M. Terry, and to the subject matter of U.S. Pat. No. 6,050,391 issued on Apr. 18, 2000 to M. Terry, which subjects matter are incorporated herein by this reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to equipment and processes for processing and packaging fresh fish or poultry or meat to retard deterioration and promote extended shelf life.  
         BACKGROUND OF THE INVENTION  
         [0003]    Fish, poultry and meat products are commonly processed from catch or slaughter to market distribution in cold or frozen condition to retard the rate of decay of the product attributable to microorganisms present in the product. Extended shelf lives for such products commonly result from maintaining the products in frozen conditions during final processing, packaging, distribution and display. However, for such products that are not conducive to processing, packaging, distribution or display in frozen condition, icing down or otherwise refrigerating such products to cool, non-frozen condition is an alternative procedure that attains some extension of shelf life though not as extensively as in frozen condition. However, frozen product once thawed and non-frozen product commonly deteriorate rapidly out of an iced or refrigerated environment, attributable to microorganisms present on the surface of the product as well as within the product that remain present from initial processing and that are capable of rapid proliferation at elevated temperatures. In contrast to fresh produce that may be harvested in the field or orchard or vineyard and that is inherently immune from deterioration at the moment of harvest, fleshy products of fish, poultry and meat are notoriously more prone to rapid deterioration from the moment of catch or slaughter.  
         SUMMARY OF THE INVENTION  
         [0004]    In accordance with the present invention, fish, poultry and meat products are initially processed through a series of diverse environments including ambient vacuum and pressure conditions applied to processing fluids that tend to cycle the respiration rates of the product and significantly diminish the internal and surface concentrations of pathogens which affect decay of the product at elevated temperatures. The resultant product exhibits extended shelf life, even after freezing and thawing, and appealing marketability for enhanced product sales with reduced losses over longer processing, distribution and retailing intervals. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is a pictorial diagram of successive environments for processing product in accordance with the present invention; and  
         [0006]    [0006]FIG. 2 is a flow chart illustrating the process of the present invention;  
         [0007]    [0007]FIG. 3 is a perspective view of a composite sheet material that is suitable for wrapping the processed product to selectively control the aspiration rate thereof;  
         [0008]    [0008]FIG. 4 is a pictorial front view of a succession of pressure vessels in which controlled environments are established for processing product in accordance with another embodiment of the present invention;  
         [0009]    [0009]FIGS. 5 a - 5   b  comprise a flow chart illustrating another embodiment of the process of the present invention;  
         [0010]    [0010]FIG. 6 is a partial top view of a fluid circulating mechanism for the pressure vessels illustrated in FIG. 4; and  
         [0011]    [0011]FIG. 7 is a pictorial illustration of a valve for the pressure vessels of FIG. 4. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]    Referring now to FIGS. 1 and 2, there are shown pictorial diagrams of a product processing line and process containing several environments through which product  13  is processed according to the present invention, as illustrated in the flow chart of FIG. 2. Specifically, three successive environments  9 , 10 , 11  are assembled to receive fish, poultry or meat products  13  previously cleaned, scaled, filleted, or otherwise prepared or dressed from the initial natural state following catch or slaughter of the host animal. The first environment  9  includes a tank  15  containing a sanitizing solution of water and an anti-microbial agent such as peroxyacetic acid as a colorless, odorless, tasteless composition (commercially available as TSUNAMI 100) which is cooled to approximately 32°-35° F. and is circulated in the tank  15  at a concentration of about 85 parts per million parts water. The surrounding ambient conditions within environment  9  include air temperature at about 33°35° F. with relative humidity of about 98%. Product  13  is initially immersed  16  in the aqueous solution within tank  15  for about 1-3 minutes to effectively thermally shock the product, which is believed to elevate the cell respiration rate and prepare the product for the next processing environment. The dwell time of approximately 3 minutes ensures substantial reductions in surface bacterial concentrations at logarithmic rates per unit time of immersion, as is commonly known in the food processing industry. Products  13  of larger unit volumes greater than a cut size of about 10 pounds may require additional immersion time to accomplish comparable shock elevation of cell respiration rates and reductions in surface bacterial concentrations.  
         [0013]    The product thus ‘shocked’ to a state of elevated cell respiration is then transferred  17  to the second environment  10  for immersion in a tank  19  containing an aqueous solution similar to the solution contained in tank  15  and that is circulating at a temperature of about 70°-105° F. The surrounding ambient conditions within environment  10  include air temperature at about 60°-95° F. with relative humidity of about 98%. It is believed that exposure of the product  13  to this sudden increase in temperature while at an elevated cell respiration rate expands the cell matrix and cell structure (vacuole) of the product analogous to opening up the pores of the product, and this facilitates increased penetration of the anti-microbial liquid agent into the cell matrix and cell structure (vacuole). This facilitates more thorough penetration of the product by the anti-microbial liquid agent in tank  19  which is thus rendered more effective in destroying pathogens within the cell matrix of the product  13 . The product  13  remains immersed in tank  19  for about 3-7 minutes (dependent in part upon cut size and batch size) to affect substantial reductions in both the internal pathogens and any remaining surface bacteria, at rates of diminishing concentrations that vary logarithmically with time, in a manner that is commonly known in the food processing industry.  
         [0014]    The product  13  thus elevated in temperature and exhibiting enhanced absorption of the anti-microbial liquid agent in tank  19  is then transferred  21  to the third environment  11  for immersion in tank  23  containing an aqueous solution similar to the solution contained in tank  15  and that is circulating at a temperature of about 32°-35° F. The surrounding ambient conditions within environment  11  include air temperature of about 33°-35° F. with relative humidity of about 98%. This sudden decrease in temperature lowers the cell respiration rate of the product  13  to near dormancy state and promotes expulsion of absorbed liquids. The product  13  remains immersed in the tank  23  for approximately 5-10 minutes (dependent in part upon cut size and batch size) to ensure maximum expulsion of absorbed liquid and to effect substantial reductions in remaining bacterial concentrations at logarithmic rates per unit time, in a manner that is commonly known in the food processing industry.  
         [0015]    The product is then removed from the environment  11  and is transported  25  either to quick-freezing environment  24 , or directly  28  to packaging facilities  26  within a cooled environment operating at a temperature of about 33° to 35° F. The product  13  thus transported (either via quick-freezing facility  24 , or directly) to the packaging facilities  26  thus remains in dormant (or frozen) state with substantially reduced levels of pathogens that can adversely affect the deterioration of the product  13  thus processed according to the present invention.  
         [0016]    Referring still to FIG. 1, the temperature and humidity and air purity conditions within the environments  9 ,  10 ,  11 ,  26  are carefully controlled in response to the air conditioning equipment that is shown assembled above each environment. Specifically, cooling coils  31  are disposed with respect to modular blower or fan units  33  that may be assembled in modular arrays with respect to each environment  9 ,  10 ,  11  and packaging facility  26  to transfer cooled air from about the coils  31  through fine HEPA filters  35  to the respective environments. Specifically, the HEPA filters  35  are selected to restrict passage therethrough of particles and contaminants not greater than about  0 . 3 μ dimension, which therefore effectively filters out most, if not all, bacterial and pathogenic airborne contaminants. Such filters may also be assembled in modular arrays of about 2 foot by 4 foot panels for convenient cleaning and other servicing. Additionally, permeable curtains  37  such as overlapping vertical-hanging flexible strips of polyvinyl chloride (PVC) plastic material are disposed between environment  9 ,  10 ,  11  to facilitate maintaining temperature differentials in the adjacent environments  9 ,  10  and  10 ,  11 .  
         [0017]    The product  13  is transported between environments by conveyor mechanisms  39  which retrieve product  13  from the immersion tank  15 ,  19 ,  23  in one environment for transport to the next environment. And, within each immersion tank  15 ,  19 ,  23 , the product  13  is kept moving through the immersion liquid composition by submerged conveyor mechanisms  41 . In this way, dwell times of product  13  within each tank  15 ,  19 ,  23  may be controlled by the rate of movement of the submerged conveyor mechanism from an entry location for incoming product  13  to an exit location for outgoing product  13 . And, the volumetric capacity of the tanks  15 ,  19 ,  23  may be sized proportionally to the dwell time of product  13  in each tank. Alternatively, the rate of product  13  entering environment  9  may be limited by the capacity of tank  23  that requires the longest product dwell time. In this way, continuous processing of product  13  may be accomplished without backup of product  13  into the slowest processing environment.  
         [0018]    Where desirable, product  13  emerging  25  from the last processing environment  11  may be quick frozen in conventional manner within the freeze processing environment  24  for transfer to the final packaging phase in environment  26 . Alternatively, product  13  emerging from the last processing environment  11  may be transferred  25  directly to the final packaging phase where frozen product is not desirable. The packaging environment  26  is also maintained at about 33° F. and relative humidity of about 98% via the cooling coils  31  and blower or fan modules  33  and HEPA filters  35 , in the manner as previously described. In this environment, frozen product  13  transferred from the quick freeze environment  24  has only brief exposure time to non-freezing environment and has no opportunity to thaw while being wrapped and sealed or otherwise encapsulated  30  for retail distribution  32  under sustained freezing temperatures during transport and storage. Alternatively, product  13  transferred from environment  11  remains in non-frozen but dormant state during the brief interval while being wrapped and sealed or otherwise encapsulated  30  for retail distribution  32  under sustained near-freezing temperature during transport and storage.  
         [0019]    Referring now to FIG. 3, there is shown a composite flexible sheet material  44  that is applied to product  13  following processing thereof as previously described in accordance with the present invention. The composite sheet material  44  is formed as bonded layers of polyethylene film  45  over polypropylene film  47 . This composite sheet material  44  is preferred as a sealing wrap about product  13  in frozen or dormant state for transportation and storage at the respective requisite temperatures during retail distribution because of the desirable gas permeability of such composite sheet material. Specifically, it has been discovered that such composite sheet material  44  transfers oxygen and carbon dioxide, among other gases, in a manner that retains an internal modified atmosphere of typically more than about 13% oxygen and less than about 5.5% carbon dioxide. The transmission rate of gases through the composite sheet material  44  may be altered by varying the thicknesses of the films  45 ,  47  that comprise the sheet material  44 . Specifically, it has been determined that, for a thickness of the polypropylene film  45  of about 1.0-3.0 mils, and a thickness of the polyethylene film  47  of about 0.5-3.0 mils, the composite sheet material is capable of transferring about 0.01-50 microliters of oxygen per hour at freezing or near-freezing temperatures (dependent upon headspace analysis determinations of the respiration rates of the individual products  13  and their associates cuts). Such permeability with respect to oxygen is believed to benefit the product  13  wrapped and sealed in such composite sheet material because of the resultant reductions in excess oxygen available to accelerate the known KREBS cycle (i.e., the breakdown of carbon compounds generated during the decaying process limits or retards the decaying process). As the KREBS cycle, or decay cycle, is a resultant of carbolic actions taking place on and within the product  13  to generate carbon compounds, the modified environment in which the product  13  is sealed is significantly altered, in that, the amount of bacteria/pathogens/particulates in the modified atmosphere is significantly less, and the ability to break down the complex carbon compounds via excess oxygen in the sealed environment is significantly reduced.  
         [0020]    Referring now to FIG. 4, there is shown an arrangement of pressure vessels  51  and associated product conveyors for processing product  13  in accordance with another embodiment of the present invention, as illustrated in the flow chart of FIG. 5.  
         [0021]    Specifically, a product in-feed conveyor  53  may extend from an initial product loading area to a conveyor work station  55  where product  13  is initially parcelized, sorted, or otherwise initially prepared  50  for processing through the succession of controlled environments established within the pressure vessels  51 . The product  13  may be transported between vessels  51   a, b, c  via conveyors  57   a, b , and then transported to final packaging  59  via conveyor  61 . Some or all of the conveyors  53 ,  55 ,  57   a, b  may be configured and may operate as described in the aforecited U.S. Pat. No. 6,050,391.  
         [0022]    A conveyor  55 ,  57   a, b  delivers product  13  into a hopper  63  that is disposed above a valve  65  at the top of each vessel. Each such valve  65 , as illustrated in FIG. 7, may be a gate or slide valve, or the like, that is conducive to selectively passing parcelized or unit-sized product  13  from the hopper  63  into the vessel  51   a, b, c . Similar valves  66  are disposed at the base of each vessel  51   a, b, c . Each such valve  65 ,  66  may be hydraulically activated in synchronism with process requirements, as later described in detail herein.  
         [0023]    Each of the vessels  51   a, b, c  is spherically shaped and sealed between the valves  65 ,  66  in the closed condition to sustain internal pressures up to about 1500 pounds per square inch, or vacuum levels to about 0.1 Torr during batch processing therein of product  13  loaded into the vessel through hopper  63  and valve  65 . Processing sanitizing fluid such as liquid TSUNAMI, as previously described herein, is also introduced into a vessel  51   a, b, c  at a selected temperature for processing product  13  in a manner as described in detail later herein.  
         [0024]    Referred now to FIG. 6, there is shown a partial top view of mixing apparatus  67  for each vessel that is disposed approximately diametrically through the vessel  51  to deliver and retrieve processing fluids in the vessel. Specifically, a shaft  69  includes two separated, axially-aligned lumens  71 , 73  that serve as inlet  73  and outlet  71  ports for processing fluids. The inlet lumen  73  includes a plurality of jets  75  disposed along substantially the diametric length of the portion of the lumen within a vessel  51   a, b, c , and the outlet lumen  71  similarly includes a plurality of ports  77  disposed along substantially the diametric length of the portion of the lumen within the vessel. The set of jets  75  and the set of ports  77  are angularly displaced about the shaft  67 , for example, by about 90° to promote an extended period of mixing of inlet liquid in the region near the shaft  67  prior to evacuating liquid from about the shaft as the shaft  67  rotates about its elongated axis. The shaft  67  is disposed to rotate within fluid-tight seals  79 , and is rotatably supported by sets of bearing  81 ,  83  and  85 ,  87  near opposite ends of the shaft  67 . Fluid couplings to the separated lumens  71 ,  73  are formed via apertures  89 ,  91  that are disposed near opposite ends of the shaft  67 , and that communicate with respective fluid channels  93 ,  95  which surround the shaft  67  within fluid-tight seals. In this way, product  13  that is immersed in liquid for processing within a vessel  51   a, b, c , is agitated and kept moving in response to liquid circulated under pressure in through jets  75  and out through ports  77 .  
         [0025]    In operation, as illustrated in the flow chart of FIG. 5, product  13  that is initially delivered for processing in accordance with the present invention enters along conveyor  53  for delivery to the work station  55  at which preliminary processing such as unit sizing and washing and spacing along the conveyor, and the like, are performed. As valve  65  opens at the top of an initial processing vessel  51   a , product  13  is transported via conveyor  55  for delivery through the hopper  63  and valve  65  into the vessel  51   a , with valve  66  at the bottom of the vessel closed. When sufficient product  13  is delivered to the vessel  51   a , valve  65  closes to confine  52  the product within the vessel  51   a  and a processing fluid such as a mixture of water and TSUNAMI at a temperature of about 33-35° F. is introduced  54  into the vessel and section is applied. The internal pressure is then reduced to about 0.1 Torr. This initial processing of product  13  causes an increased reverse osmotic effect of the solution which prepares the cellular matrix which has been partially contracted to effect the “kill” step to follow. During such processing within a vessel  51   a , the processing liquid is circulated into and out of the vessel via the inlet and outlet lumens  71 , 73  in the rotating shaft  67  to replenish the supply of active ingredients or to agitate and circulate product within the vessel.  
         [0026]    After an interval of about  3  minutes of such initial processing in vessel  51   a , the internal pressure is normalized and the valve  66  at the bottom of the vessel is opened to release the volume of liquid and product  13  onto the next conveyor  57   a  for transport  56  to the next or intermediate stage of processing in vessel  51   b . A contracted cellular matrix state in the product  13  is thus achieved and maintained while passing to the next phase of the process. The liquid drains through a porous conveying surface into a sump for collection, filtering, heating or cooling (dependent upon the incumbent thermal exchange) and refurbishment of active ingredients prior to being resupplied to the vessel  51   a  during processing therein of a subsequent batch of product  13 .  
         [0027]    In similar manner as previously described with reference to loading product  13  into vessel  51   a , the product  13  that is transported from vessel  51   a  to vessel  51   b  via conveyor  57   a  is loaded through hopper  63  and open valve  65 , with valve  66  closed. After a sufficient quantity of product  13  is loaded into the vessel  51   b , the valve  65  is closed to confine  58  the product  13  within the vessel  516 , and processing fluid such as described previously is introduced into the vessel  60  at elevated temperature of about 70-105° F. The internal pressure is then elevated to about 29 Torr (1500 psi) for an interval of about 3-5 minutes, during which time processing liquid is circulated in the manner as previously described herein via the dual-lumen rotating shaft  67 . This intermediate processing in vessel  51   b  causes an expansion of the cellular matrix and an increased osmotic effect allowing for an increased rate of penetration of sanitizing solution to the cellular walls and into the interior portions of the cells. At the end of the processing interval, the internal pressure in vessel  51   b  is normalized to ambient pressure, and the valve  66  at the bottom of the vessel  51   b  is opened to release the volume of processing liquid and product  13  onto the next conveyor  57   b . An expanded cellular matrix state in the product  13  is thus achieved and maintained while passing  62  to the next phase of the process. Liquid is separated from the product  13 , in the manner as previously described herein, by the conveyor  57   b  that transfers the product  13  to vessel  51   c  for final processing therein prior to packaging operations at work station  59 .  
         [0028]    In similar manner, as previously described herein, the product  13  is transported via conveyor  57   b  from vessel  51   b  to vessel  51   c  for loading therein through hopper  63  and open valve  65 , with valve  66  closed. After a sufficient quantity of product is loaded into the vessel  51   c , the valve  65  is closed to confine  64  the product  13  within the vessel  51   c , and processing fluid such as previously described is introduced into the vessel  68  at reduced temperature of about 33-35° F. The internal pressure is then reduced to about 0.1 Torr for an interval of about 3-5 minutes, during which time processing liquid is circulated in the manner as previously described herein via the dual-lumen rotating shaft  67 .  
         [0029]    This final processing in vessel  51   c  (prior to packaging operations  59 ) causes a contraction of the cellular matrix and an expulsion of undesirable fluids from the tissue, as well as creating a ‘dormancy” state of cellular respiration in preparation for final packaging. At the end of the processing interval, the internal pressure is normalized to ambient pressure, and the valve  66  at the bottom of vessel  51   c  is opened to release the volume of processing liquid and product  13  onto conveyor  61 . A less-than-beginning cellular matrix state in the product  13  is thus achieved and maintained while passing to the next phase of the process. Liquid is separated from the product  13 , in the manner as previously described herein, by the conveyor  61  that transfers  70  the processed product  13  to the packaging operations  72 . The cellular matrix begins to expand to its initial state (e.g., at the beginning of the process) from the near-dormant respiration rate that was achieved through the previous processing, and this automatically dries the exterior of the product  13  and reduces the growth of pathogens which breed in oxygen and moisture.  
         [0030]    At each transition of product  13  with respect to processing vessels  51   a, b, c , the ambient conditions of temperature and relative humidity about the product  13  on a conveyor  53 ,  55 ,  57   a, b ,  61  may be controlled within control zones  56 ,  62 ,  70  that are bounded by moving air curtains, or flexible strips forming boundary walls, or the like. In an initial one of such control zones incorporating the work station  55  the temperature and humidity conditions are preferably set at about 33-35° F. and about 98% RH in the “shock” phase. In a subsequent control zone incorporating the conveyor  57   a , the temperature and humidity conditions are preferably set at about 70 105° F. and about 98% RH in the phase of cellular matrix expansion and absorption of fluids. In the control zone incorporating the conveyor  57   b , the temperature and humidity conditions are preferably set at about 31-35° F. and about 98% RH in the phase of contracted cellular matrix and dormancy cellular respiration and, in the control zone incorporating conveyor  61 , the temperature and humidity conditions are preferably set at about 1° C. and 98% RH to maintain the dormancy cellular respiration state through packaging.  
         [0031]    This succession of control zones (typically, at ambient pressure) along the course of processing stages has the effect of maintaining the desired cellular matrix state and cellular respiration rate at the respective elevated or near dormancy state. All ambient air circulating around product through the stage of processing is filtered for excluding particulate contaminants greater than about 0.12μ inches from the ambient air in the environment within which the product is transported and encapsulated. This modified environment significantly reduces the possibility of cross contamination and environmental contamination from “outside” pathogens.  
         [0032]    Equipment for filtration, and cooling and heating of the control zones and the processing liquids, as well as for pressurizing vessels and processing liquids and hydraulic fluids, may all be housed remotely from the processing of product  13  through the assembly of vessels  51   a, b, c , and be piped and ducted thereto in order to preserve sanitary conditions in the ambient environment and to avoid contaminants from machine-oriented sources.  
         [0033]    Therefore, animal products processed in accordance with the present invention exhibit much slower growth of bacteria and a retardation of the KREBS cycle. The apparatus and processes of the present invention thus greatly reduce pathogenic contaminants that contribute to the deterioration of animal products prepared for retail distribution, and thereby significantly increase retail shelf life and sanitary packaging of such products.