Abstract:
A system and method are described that provide a way to package food products. More specifically, a method of packaging food is described that provides an alternative to packaging food products with carbon monoxide. Instead, oxygen can be used during packaging in an attempt to preserve food product quality and color.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/791,680, filed Apr. 12, 2006, which is herein incorporated by this reference in its entirety. 
     
    
     FIELD  
       [0002]     The present invention generally relates to modified atmosphere packages and methods of making the same for storing food. More specifically, embodiments of the present invention provide a way to package and store food without using substantial amounts of carbon monoxide to achieve a desirable color of the food product.  
       BACKGROUND  
       [0003]     Containers have long been employed to store and transfer perishable food prior to presenting the food at a market for subsequent purchase. After perishable foods, such as meats, fruits, and vegetables, are harvested, they are placed into containers to preserve those foods for as long as possible. Maximizing the time in which the food remains preserved in the containers increases the profitability of all entities in the distribution chain by minimizing the amount of spoilage.  
         [0004]     The environment around which the food is preserved is a critical factor in the preservation process. Not only is maintaining an adequate temperature important, but the molecular and chemical content of the gases surrounding the food is significant as well. By providing an appropriate gas content to the environment surrounding the food, the food can be better preserved when maintained at the proper temperature or even when it is exposed to variations in temperature. This gives the food producer some assurance that after the food leaves its control, the food will be in an acceptable condition when it reaches the consumer.  
         [0005]     Modified atmosphere packaging (MAP) systems for one type of food, raw meats, have typically exposed these raw meats to extremely low levels of oxygen. Packaging systems that previously provided extremely low levels of oxygen were generally preferred because it was believed that the fresh quality of meat could be preserved longer under anaerobic conditions instead of under aerobic conditions. It has long been held that maintaining low levels of oxygen minimized the growth and multiplication of aerobic bacteria. An example of a modified atmosphere environment adhering to these previous standards was a mixture of gases consisting of about 30 percent carbon dioxide and 70 percent nitrogen. Most low oxygen systems attempted to provide an atmosphere for the raw meat of less than 500 ppm oxygen quickly so as to prevent or inhibit excessive metmyoglobin (brown) formation otherwise full “bloom” to oxymyoglobin (red) following storage was not thought possible.  
         [0006]     The meat using this low oxygen system takes on a less desirable purple-red color, which few consumers would associate with freshness. The deoxymyoglobin (purple-red color) is generally unacceptable to most consumers. This purple-red color, however, quickly blooms to a bright red color generally associated with freshness when the package is opened to oxygenate the fresh meat by exposure to air. The package is typically opened immediately prior to display of the fresh meat to consumers so as to induce blooming of the meat before display to the consumers.  
         [0007]     Another method commonly used to enhance the display of fresh meat to consumers is to use carbon monoxide along with a mixture of other gases such as carbon dioxide and nitrogen to surround the meat prior to packaging. The package is then heat-sealed. Generally, the low-oxygen mix has been thought to extend the shelf life of the meat by up to fifteen days from the normal five days.  
         [0008]     However, carbon monoxide also makes meat appear fresher than it actually is by reacting with the meat pigment myoglobin to create carboxymyoglobin, a bright red pigment that potentially masks the natural ageing of meats. The Food and Drug Administration (FDA) has approved the practice of adding carbon monoxide to meat as safe for use. Under current US regulations, processors do not have to indicate on the label that their meat products have been treated with carbon monoxide.  
         [0009]     Conversely, a seemingly divergent US department of agriculture regulation prohibits the introduction of ingredients in fresh meat that function to conceal damage or inferiority, or give the appearance that the product is of better or greater value than it actually is. Also, the European Union prohibits food companies from using carbon monoxide with meat and tuna products because such a practice has the ability to maintain a fresh color well beyond the microbial shelf life of the meat, thus masking spoilage. Other countries that have banned the use of carbon monoxide with tuna include, Japan, Canada, and Singapore. The consensus is that the public should have the right to know if carbon monoxide is being used during the preparation of a product they are going to consume.  
         [0010]     Since the future regulations of the use of carbon monoxide are currently unknown, strictly relying on carbon monoxide to make meat appear fresher might be unwise. However, using carbon monoxide to process and package a meat product thereby making it appear to be fresh may provide increased sales and revenues to meat producers and processors alike. Thus, there exists a need for a product and method of making such a product that provides a fresh appearance to consumers without the use of substantial amounts of carbon monoxide.  
       SUMMARY  
       [0011]     It is thus one aspect of certain embodiments of the present invention to provide a product and a method of producing such a product that does not require the use of carbon monoxide in order to appear desirable to consumers. The method uses a combination of gas(es) and holding times and temperatures that can create an end product that overcomes some of the shortcomings of the products mentioned above.  
         [0012]     Products made without requiring the use of carbon monoxide to enhance the desirability and methods and systems for producing such products are provided. Although well suited for use in bovine production, advantages offered by the present invention may be realized in the production and packaging of meat products from all age classes of bovine, porcine, and ovine animals. Additionally, embodiments of the present invention may be suitably applied to fish and crustacean products.  
         [0013]     In accordance with embodiments of the present invention, a method of producing a modified atmosphere package is provided. The method comprises placing a cut of raw meat within a first package and then backfilling the first package with a mixture of gases. The gas mixture comprises from about 65% to about 100% volume oxygen with the balance, if any, comprising at least one other gas. Examples of other gases used may include, but are not limited to, carbon dioxide, nitrogen, argon, and/or other noble gases. Additionally, trace amounts of carbon monoxide may also be used as a part of the mixture of gases. Holding the gas mixture around the meat at a predetermined temperature for a predetermined amount of time.  
         [0014]     As used herein, a “gas mixture” or “gases” is understood to mean one or more gas. For example, a suitable gas mixture may comprise pure or almost pure oxygen. There may be trace amounts of other gases included in the gas mixture, or the gas mixture may be pure oxygen. Additionally, a suitable gas mixture may comprise several gases like oxygen, carbon dioxide, argon, and carbon monoxide in various amounts.  
         [0015]     In accordance with an alternative embodiment of the present invention, a method of preparing a modified atmosphere package is provided that comprises supplying a package, a first layer having at least a portion being substantially permeable to oxygen and a second layer being substantially impermeable to oxygen. Placing a retail cut of raw meat within the package and placing the first layer on the package. Supplying a mixture of gases around the meat within the package and the first layer. The gas mixture comprises from about 65% to about 100% volume oxygen with the balance, if any, comprising at least one other gas. Holding the gas mixture around the meat at a predetermined temperature for a predetermined amount of time. Then sealing the first layer to the package and the second layer to at least one of the package and the first layer.  
         [0016]     In accordance with at least one embodiment of the present invention, a method of preparing a modified atmosphere package is provided that comprises placing a piece of meat within a first package. Thereafter, backfilling the first package with at least one gas. The at least one gas comprises from about 65% to about 100% volume oxygen with the balance, if any, comprising at least one other different gas. Then, holding the gas around the meat at a predetermined temperature for a predetermined amount of time. Suitable holding temperatures can range between about 30° F. and about 60° F. Additionally, suitable holding times can range from about 1 hour to about 36 hours.  
         [0017]     In accordance with further embodiments of the present invention, a modified atmosphere package is provided. The modified atmosphere package comprises a first package. The first package comprises a non-barrier portion substantially permeable to oxygen. The first package is configured and sized to enclose a retail cut of raw meat and create a pocket of a mixture of gases around the meat. The gas mixture comprises from about 65% to about 100% volume oxygen with the balance, if any, comprising at least one other gas.  
         [0018]     In accordance with still other embodiments of the present invention, a modified atmosphere package is provided. The modified atmosphere package comprises a first layer and a second layer of packaging. The first layer of packaging is configured and sized to enclose a retail cut of raw meat. The first layer of packaging has a mixture of gases comprising from about 65% to about 100% volume oxygen with the balance, if any, comprising at least one other gas. The first layer has at least a portion being substantially permeable to oxygen. The second layer is substantially impermeable to oxygen and is configured and sized to enclose the meat and the first layer of packaging.  
         [0019]     Additionally, in accordance with particular embodiments of the present invention, prior to, or after, being placed in one or both of the packages, the meat product may be treated with competitive bacteria. These competitive bacteria, known as euhygienic bacteria, can be non-pathogenic and/or non-spoilage bacteria. They may competitively inhibit and/or exclude the growth of pathogenic and spoilage bacteria. The use of euhygienic bacteria in the present invention generates little, if any, appreciable malodors or discolorations of food products. In one embodiment of the present invention, euhygienic bacteria are preferably facultative, sacrophilic, gram-positive bacteria, and more preferably, bacteria of the genus  Lactobacillus. By inoculating the meat (prior to or after the surrounding the meat with a packing material) with friendly bacteria, the shelf life of the meat may be greatly increased without compromising the quality of the meat or the safety of the consumer. The bacteria can be incorporated at various stages during the production process. For instance, the packages can be treated with the bacteria prior to use. Alternatively, the bacteria can be added to the meat just before being packaged.  
         [0020]     In this regard, incorporated by reference in its entirety is U.S. Pat. No. 5,374,433 to Bowling et al. Moreover, incorporated herein by reference is U.S. patent application Ser. No. 10/955,541 to Potter et al., to support claims directed to first reducing undesired bacteria carried into a facility on the hide/hair of animals.  
         [0021]     Another embodiment of the present invention is directed to a method of packaging a food product by creating an environment for red meat products such that the red color of the meat products is prolonged, thus appearing to a consumer to have fresh meat characteristics. Yet another embodiment of the present invention is directed to a system for packaging a meat product in accordance with the method as set forth herein.  
         [0022]     These and other advantages will be apparent from the disclosure of the invention(s) contained herein. The above-described embodiments and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth above or described in detail below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]      FIG. 1  is an isometric view depicting a meat product in packaging in accordance with embodiments of the present invention;  
         [0024]      FIG. 2  is a cross-sectional view of a modified atmosphere package including a piece of meat therein in accordance with embodiments of the present invention;  
         [0025]      FIG. 3  is a cross-sectional view of an alternate configuration of a modified atmosphere package including a piece of meat therein in accordance with embodiments of the present invention;  
         [0026]      FIG. 4  is a cross-sectional view of another configuration of a modified atmosphere package including a piece of meat therein in accordance with embodiments of the present invention;  
         [0027]      FIG. 5  is a flow chart depicting a method of packaging a meat product in accordance with embodiments of the present invention; and  
         [0028]      FIG. 6  is a flow chart depicting an alternative method of packaging a meat product in accordance with embodiments of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0029]     Referring initially to  FIGS. 1-4  a modified atmosphere package  10  will be described in accordance with at least some embodiments of the present invention. The modified atmosphere package  10  is typically used to encase or surround a piece of meat  11  or multiple pieces of meat  11 . The modified atmosphere package  10  includes a tray  12 , an inner package or layer  22 , and an outer package or layer  24 . The term “package” or “container” as used herein, shall be construed as any device or material capable of holding meat including, but not being limited to, a carton, casing, parcel, holder, tray, flat, bed, film, envelope, and the like. Typically, at least a portion of the inner package or layer  22  is permeable to oxygen. The inner package or layer  22  is included as a part of the tray  16  which may also be permeable to oxygen, although this is not required. The permeability of the layer  22  may be such that it allows gases to pass therethrough with relative ease. For instance, a permeable material allows the equalization of gas pressure on both side of the material, whereas an impermeable will restrict gas flow to the point where a pressure gradient may be created. In accordance with certain embodiments of the present invention, an impermeable layer of material may be such that it restricts up to 99% of gas to pass through over the course of a week or more.  
         [0030]     In an alternative embodiment, a single package may be used in lieu of two packages. More specifically, the piece of meat may be placed within a single package or on a tray and surrounded by a single layer, then the meat may be surrounded with the gas mixture as will be described more fully herein.  
         [0031]     Exemplary polymers which may be used to form the tray  16  include polystyrene foam, cellulose pulp, polyethylene, polypropylene, or any other known plastic or container material. In one embodiment, a polymeric sheet is used to form the tray  16  and is substantially composed of polystyrene foam with a thickness ranging from about 100-300 mils. Generally, a polystyrene foam tray  12  is used because of its consumer acceptance.  
         [0032]     The inner package or layer  22  may comprise a film wrapping or cover also comprised of a polymeric material, such as, but not being limited to, a polyolefin or polyvinylchloride, which is substantially permeable to oxygen. The material used to form the cover or first layer  22  preferably contains additives, which allow the material to cling itself to tray  12 . The first layer  22  may have an oxygen permeability greater than about 100 cubic centimeters per 100 square inches in 24 hours.  
         [0033]     In a more preferred embodiment, the first layer  22  preferably has rate of permeability greater than about 7000 cubic centimeters per 100 square inches in 24 hours and, most preferably, the material has a rate of oxygen permeability greater than about 10,000 cubic centimeters per 100 square inches in 24 hours. In U.S. Patent Publication No. 2003/0054072 to Merriman et al., which is herein incorporated by this reference in its entirety, a modified atmosphere package having a tray and permeable and semi-permeable layers is described.  
         [0034]     The tray  12  is generally rectangular in configuration and includes a continuous sidewall  14 , a bottom wall  16 , and a continuous rim or flange  18 . The continuous sidewall  14  encompasses the bottom wall  16 . The continuous rim  18  encompasses an upper edge of the continuous sidewall  14  and projects generally laterally outward therefrom. It is contemplated that tray  12  may be of a different shape than depicted in  FIGS. 1-4 . A food item such as a retail cut of raw meat  11  is located in a rectangular compartment defined by the bottom wall  16  and continuous sidewall  14 . The meat may have been derived from any type of animal, including, but not being limited to, beef, pork, veal, lamb, venison, fish, crustacean, or any other suitable meat product.  
         [0035]     The tray  12  may be manually or automatically wrapped with the cover or first layer  22 . The first layer  22  is wrapped over the retail cut of meat  11  and about both the sidewall  14  and bottom wall  16 , and, due to the clinging characteristic inherent in the first layer  22 , these overlapping free ends cling to one another to hold the cover  22  in place. If desired, the over-wrapped tray  12 , i.e., the first layer  22 , may be run over a hot plate to thermally fuse the free ends of the first layer  22  to the rim  18  of the tray  12 , thereby preventing or inhibiting these free ends from potentially unraveling.  
         [0036]     Once the meat  11  is covered with the first layer  22 , the cavity  26  between the first layer  22  and the meat  11  is backfilled with a gas. Typically the gas is a gas mixture that comprises between about 65% and 100% oxygen with the balance, if any, comprising at least one other gas. Generally the balance is carbon dioxide. For example, if the gas mixture backfilled into the cavity  26  comprises to 65% oxygen then the balance may be 35% carbon dioxide. Additionally, other gases may constitute a part of the balance including nitrogen, argon, or other noble gases. Once the gas has been backfilled into the cavity  26 , it is held for a predetermined amount of time at a predetermined temperature. Suitable temperatures may range between 30° F. and 60° F. If the temperature gets too low, then the oxygen may not be able to bind and a desirable red appearance may not be achieved. On the other hand, if the temperature is too high, then bacterial growth may begin and ruin the meat prematurely. For this reason, suitable holding temperatures may range between about 30° F. and 60° F. Furthermore, the gas is held in cavity  26  for a predetermined amount of time. For example, the gas may be held there for 1 to 36 hours with a preferable amount of time being between 18 and 24 hours. Essentially, the gas needs to be maintained around the meat  11  for a suitable enough amount of time to allow the oxygen to bind with the blood located on the surface of the meat  11 . A suitable bind time and temperature is determined by the final color displayed by the meat where typically red meat is a more desirable color as compared to purple or brown meat.  
         [0037]     Once the first layer  22  has been held for a suitable amount of time, then the second layer  24  is placed over the top of the first layer  22 . The second layer  24  may be sized to encapsulate the first layer  22  and the meat  11 . Once the second layer  24  is in place, it may be a vacuum packed by typical vacuum packaging machines known in the art. For example, U.S. Patent Publication 2004/0144063 to Countz, which is herein incorporated by this reference in its entirety, discloses a positive pressure packaging system that is used to seal meat products within an open package.  
         [0038]     Although the use of nitrogen in the balance of the gas mixture may be used, preferably no nitrogen is used. Additionally, the abundant oxygen may also preclude bacteria from thriving.  
         [0039]     Referring now to  FIG. 5 , a method of packaging a piece of meat or multiple pieces of meat will be described in accordance with at least some embodiments of the present invention. Initially, the meat product is produced (step  204 ). As noted above, suitable meat products for use with embodiments of the present invention may include beef, pork, fish, and other types of meat. Once the meat is produced, it is inserted into a first container (step  208 ). Of course the first product may be set onto a tray  12  and covered with a first layer  22  as described above. Alternatively, the meat is place into a first layer comprising a bag, thus no tray  12  is necessary. Once the meat is within the first layer, the layer is backfilled with gas such that the gas surrounds the meat (step  212 ). As noted above, a suitable gas mixture may include between about 65% and about 100% oxygen with the balance usually consisting of carbon dioxide. At this point, the meat  11  may also be treated with euhygienic bacteria that will be described in further detail below. Once the meat has been surrounded with the gas mixture in step  212 , a holding temperature is determined (step  216 ). Then depending upon the determined holding temperature, a suitable holding time may be determined (step  220 ). Each of the holding time and holding temperature may be dependent upon each other, for example the holding time may be determined first and the holding temperature may be determined based on the holding time. Of course, the holding time and temperature may be determined simultaneously depending upon the desired output.  
         [0040]     Once the holding time and temperature has been determined, the meat product  11  and the first container  22  are held for that determined time at the determined temperature (step  224 ). During this time the meat  11  may be subjected to a colorimeter test (step  228 ). The colorimeter test may be used to ensure quality and to further ensure that similar colors of meat  11  are produced. If, based on either the colorimeter test or the determined time and temperature, the meat  11  is ready for packaging and freezing, as determined in step  232 , then the product and the first container are inserted into a second container (step  236 ). However, if the meat  11  is not ready for packaging (i.e., the meat  11  has not been held for the determined amount of time at the determined temperature and/or the meat  11  has not developed to have a suitable color as determined by the colorimeter test in step  228 ), then the method returns to step  228  in order to determine when the meat is at a suitable color. Additionally, the meat may be held for longer than the determined amount of time if it has not yet met the colorimeter test requirements.  
         [0041]     Once the product has been held for a suitable amount of time and a desired color has been achieved, the meat  11 , along with the first container, is placed into a second container as noted above in step  236 . Thereafter, the second container is vacuum-sealed according to known methods (step  240 ).  
         [0042]     Advantages offered by embodiments of the present invention include the fact that the meat and/or containers of the meat can be treated with euhygienic bacteria. In an effort to preclude harmful bacteria from spoiling and ruining the meat produced according to embodiments of the present invention, an effective amount of euhygienic bacteria can be incorporated in the meat. Methods of preserving food products by inoculation with an effective amount of euhygienic non-pathogenic, non-spoilage bacteria are described in several U.S. patents including: U.S. Pat. No. 6,569,474 to Clayton et al. entitled, “System for preserving food products”, U.S. Pat. No. 6,287,610 to Bowling et al. entitled, “Method for increasing the tenderness of a meat product”, U.S. Pat. No. 6,039,984 to Bowling et al. entitled, “Method for treating a food processing facility”, and U.S. Pat. No. 5,869,113 to Clayton et al. entitled “Method for preserved food products and food products made thereby”, all of which are incorporated herein by this reference in their entirety.  
         [0043]     Furthermore, products that are packaged according to at least some embodiments of the present invention may have been de-haired according to methods disclosed in U.S. patent application Ser. No. 10/955,541 to Potter et al. This may further help to preclude bacteria from spoiling the meat after it has been packaged, thus freshness may extended for the end products.  
         [0044]     Referring now to  FIG. 6 a  method of packaging a piece of meat using a single package will be described in accordance with at least some embodiments of the present invention. Initially, steps  204 - 232  are performed in a similar manner to that described with reference to  FIG. 5  (step  304 ). Once the product has achieved a suitable color, the product is removed from the first container (step  308 ). A suitable color may be defined as the exact color that is desired for display of the product. Alternatively, a suitable color may be a color that is slightly different from the desired display color, but there is a chance that the color of the product will continue to change until it achieves the desired display color.  
         [0045]     After the product is removed it can be inserted into a second container (step  312 ). The second container may be the final presentation container or may simply be an intermediate container used to transport the meat to its destination. Typically, the second container is substantially impermeable to oxygen and other gases such that once the product is completely surrounded by the second container, no additional gases can access the product through the second container. Thereafter, the second container is sealed with the product inside, thereby creating a product suitable for shipping and/or presentation to an end customer.  
         [0046]     The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, sub combinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and\or reducing cost of implementation.  
         [0047]     The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.  
         [0048]     Moreover though the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.