Abstract:
The present invention is directed to a dual-ovenable food packaging, a method for packaging food and a method for cooking food. 
     A dual-ovenable food packaging in accordance with the present invention may comprise: (a) a heat-resistant tray; (b) a non-venting plastic film overwrap, and (c) a food items. 
     A method for packaging food may comprise the steps: (a) disposing a food item in a heat-resistant tray; (b) overwrapping the tray and food item with a non-venting plastic film overwrap; and (c) vacuum sealing the non-venting plastic film overwrap around the heat-resistant tray and food item. 
     A method for cooking a food item may comprise the steps: (a) disposing a food item in a heat-resistant tray; (b) overwrapping the tray and food item with a plastic film; (c) vacuum sealing the plastic film around the heat-resistant tray and food item to create a sealed packaging; and (d) heating the sealed packaging with a heating device.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to a package or container for foods and, more particularly, to a food packaging suitable for cooking of frozen or chilled foods either in a conventional radiant-heat oven or in a microwave oven. 
       BACKGROUND OF THE INVENTION 
       [0002]    In the food service industry, it is known to package food in containers or packaging adapted for the cooking of the food by heating in either a microwave oven or in a conventional radiant heat oven. Packaging that can withstand exposure to the heating and/or cooking environment of a selected type of oven is said to be “ovenable” with respect to that type of oven. To be ovenable with respect to a microwave oven, the packaging should not, for example, include materials such as metals that reflect microwaves to cause arcing or otherwise damage the oven&#39;s microwave generation. To be ovenable with respect to a conventional oven, the packaging should, for example, be able in use to withstand high ambient temperatures for extended periods of time. Packaging that is ovenable with respect to a microwave oven and a conventional oven is “dual-ovenable.” 
         [0003]    It has been customary to package food in a container comprising a heat-resistant, molded plastic tray in which the food is contained. The container is then enclosed by a plastic layer sealed around the rim of the tray or by a removable, semi-rigid, pre-formed dome lid. Often the plastic layer or dome lid is comprised of a translucent plastic to provide for the visual display of the product in supermarkets. However such plastics often lack sufficient thermal resistance for use into a microwave or conventional oven and must be removed prior to cooking. 
         [0004]    Current packaged meals use one of two cooking technologies to cook a food item. The first technology is conventional convection cooking where heated air surrounds the food. While convection cooking generally produces a cooked product which is evenly cooked and retains its moisture content, such results generally take considerable amounts of time to achieve. 
         [0005]    The second technology is steaming where water or other liquid, such as a chicken, beef or vegetable broth, is heated and converted to steam having a temperature sufficient to cook the food. Products which are steamed may also retain their moisture content and may be cooked faster than a conventional oven. However, such cooking mechanisms require that the steaming container be vented so as to maintain pressure equilibrium with respect to the atmosphere to avoid explosive ruptures of the container due to the increase of pressure inside. 
         [0006]    As such, cooking in either a conventional oven or microwave generally occurs in an open environment at atmospheric pressure. Such a cooking environment contributes to the dehydration of the food product as evaporated liquids are allowed to escape. In the case of steaming, it also prevents the use of pressure cooking to raise the boiling point of the steaming liquid past its atmospheric boiling point. 
         [0007]    Additionally, the extended cooking times for traditional conventional or steam cooking for raw food products tend to have an adverse affect on food product flavor, texture, and appearance. To reduce cook times, food items are commonly pre-cooked and require only reheating prior to consumption. However, these multiple cooking and reheating steps can also have adverse affects on the nutritional value, flavor, texture and appearance of the product. 
         [0008]    Therefore, it would be desirable to provide a dual-ovenable food packaging which may be used to cook foods at an elevated pressure, thereby reducing cook times and retaining the moisture content, nutritional value, flavor, texture and appearance of the food. 
       SUMMARY OF THE INVENTION 
       [0009]    Accordingly, the present invention is directed to a dual-ovenable food packaging and method for its use. 
         [0010]    In an embodiment of the invention, a dual-ovenable food packaging may comprise: (a) a heat-resistant tray; (b) a non-venting plastic film overwrap, and (c) one ore more food items. 
         [0011]    In a further embodiment of the invention, a method for packaging food may comprise the steps: (a) disposing one or more food items in a heat-resistant tray; (b) overwrapping the tray and food items with a non-venting plastic film; and (c) vacuum sealing the non-venting plastic film around the heat-resistant tray and food items. 
         [0012]    In a further embodiment of the invention, a method for cooking food may comprise the steps: (a) disposing one or more food items in a heat-resistant tray; (b) overwrapping the tray and food items with a non-venting plastic film; (c) vacuum sealing the non-venting plastic film around the heat-resistant tray and food items to create a sealed packaging; and (d) heating the sealed packaging with a heating device. 
         [0013]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The numerous objects and advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: 
           [0015]      FIG. 1  depicts an axonometric view of a food packaging in accordance with an embodiment of the present invention; 
           [0016]      FIG. 2  depicts a cross-sectional view of a food packaging in accordance with an embodiment of the present invention, wherein a food product is in an uncooked state; 
           [0017]      FIG. 3  depicts a cross-sectional view of a food packaging in accordance with an embodiment of the present invention, wherein a food product has been heated; 
           [0018]      FIG. 4  depicts a cross-sectional view of a food packaging in accordance with an embodiment of the present invention, wherein a food product is in an uncooked state; 
           [0019]      FIG. 5  depicts a cross-sectional view of a food packaging in accordance with an embodiment of the present invention, wherein a food product has been heated; 
           [0020]      FIG. 6  depicts an axonometric view of a food packaging in accordance with an embodiment of the present invention; 
           [0021]      FIG. 7  depicts a food packaging in accordance with an embodiment of the present invention, wherein the food packaging is to be heated in a microwave or conventional radiant-heat oven. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The following discussion is presented to enable a person skilled in the art to make and use the present teachings. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the present teachings. Thus, the present teachings are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the present teachings. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of the present teachings. 
         [0023]    Reference will now be made, in detail, to presently preferred embodiments of the invention. Additional details of the invention are provided in the examples illustrated in the accompanying drawings. 
         [0024]    Referring to  FIG. 1 , an axonometric view of a food packaging  100  in accordance with an embodiment of the present invention is disclosed. One or more food items  101  may be disposed within a heat-resistant plastic tray  102 . The food items  101  may be raw or pre-cooked and may be selected from the group comprising: proteins (e.g. fish, shrimp, poultry, beef and pork), starches (e.g. potatoes, pastas and rice), and vegetables (e.g. corn, beans, broccoli, and carrots). The food packaging  100  may be a single-serve composition comprising multiple food item  101  types packaged as a complete meal or a multi-serve composition comprising only one food item  101  type. 
         [0025]    The food items  101  may be sealed within the plastic tray  102  by a non-venting plastic overwrap  103 . In an embodiment of the invention, the film overwrap  103  may have a bag-like structure where the food items  101  and plastic tray  102  may be completely enclosed by and sealed within the film overwrap  103 . In a further embodiment of the invention, the film overwrap  103  may comprise a flat sheet of film which is placed over and heat sealed to the rim  104  of the plastic tray  102 . 
         [0026]    A non-venting film overwrap  103 , in accordance with the invention may comprise a nylon blend having selected physical properties such that it may maintain a closed cooking environment in both microwave and radiant-heat cooking environments. In order to be non-venting, a film overwrap  103  must be capable of maintaining an internal cooking environment within the packaging  100  that remains separated from the ambient environment during the cooking process. 
         [0027]    In various embodiments of the invention, the non-venting film overwrap  103  may have one or more of the following properties:
       Heat deflection temperature (66 psi): at least 400° F.   Heat deflection temperature (264 psi): at least 160° F.   Melting point: at least 420° F.   Elongation fail percentage: 150-170%       
 
       Such film overwraps may include those produced by the KNF Corporation. 
       [0032]    Such properties may enable the film overwrap  103  to expand to a certain degree under heating while maintaining its structural integrity and avoiding rupture. This allows the food packaging  100  to maintain the sealed, non-venting environment in which the temperature and pressure can be increased during the cooking process. Such capabilities may provide for the pressure cooking of the food items  101 . Because water&#39;s boiling point increases as the surrounding air pressure increases, the pressure built up inside the food packaging allows the liquid in the packaging to rise to a temperature higher than 212° F. before boiling. Most commercial pressure cookers have an internal pressure setting of 15 psi (the standard determined by the USDA). At this pressure water boils at 257° F. The various embodiments of the invention may permit pressures of up to and in excess of this USDA standard. These higher temperatures cause the food items  101  to cook faster thereby reducing cooking times and resulting in a cooked product having increased moisture content and reduced thermal degradation. 
         [0033]    In further embodiments of the invention, the amount of pressure and/or steam generated within the packaging  100  can be controlled by varying the thickness of the film overwrap  103 , the free water content of the food items  101  and/or the residual air permitted to remain with in the packaging  100  following a vacuum sealing process. The ability to adjust these variables allows for the specification of the cooking environment such that it is particularly suited to a given type of food item  101 . 
         [0034]    Referring to  FIG. 2 , a cross-sectional view of a food packaging  200  in accordance with an embodiment of the invention is disclosed. One or more food items  201  may be disposed within a heat-resistant plastic tray  202 . The food items  201  may be vacuum-sealed within the plastic tray  202  by a non-venting plastic overwrap  203 . The film overwrap  203  may comprise a cook-in-bag which is vacuum-sealed over the food items  201  and plastic tray  202 . 
         [0035]    Referring to  FIG. 3 , a cross-sectional view of a food packaging  300  in accordance with an embodiment of the invention is disclosed, wherein the food packaging  300  is subjected to cooking temperatures. One or more food items  301  may be disposed within a heat-resistant plastic tray  302 . The food items  301  may be vacuum-sealed within the plastic tray  302  by a non-venting plastic film overwrap  303 . The film overwrap  303  may comprise a cook-in-bag which is vacuum-sealed over the food items  301  and the plastic tray  302 . Due the non-venting, vacuum-sealed environment maintained within the food packaging  300 , applied heat from a cooking device will necessarily result in an increase in pressure. The elastic and heat resistant properties of the film overwrap  303  allow for a slight expansive deformation  304  so as to avoid rupture while maintaining the packaging&#39;s pressurized state. Additionally, a portion of the free water contained in the food items may be converted to steam  305 . As the pressure within the packaging  300  is elevated due to heating, the steam  305  may become superheated allowing for additional heat-transfer capabilities resulting in faster cooking. 
         [0036]    Referring to  FIG. 4 , a cross-sectional view of a food packaging  400  in accordance with an embodiment of the invention is disclosed. One or more food items  401  may be disposed within a heat-resistant plastic tray  402 . The food items  401  may be vacuum-sealed within the plastic tray  402  by a non-venting plastic overwrap  403 . The film overwrap  403  may comprise a flat sheet which is vacuum-sealed over the food items  401  and heat sealed to the rim  404  of the plastic tray  402 . 
         [0037]    Referring to  FIG. 5 , a cross-sectional view of a food packaging  500  in accordance with an embodiment of the invention is disclosed, wherein the food packaging  500  is subjected to cooking temperatures. One or more food items  501  may be disposed within a heat-resistant plastic tray  502 . The food items  501  may be vacuum-sealed within the plastic tray  502  by a non-venting plastic overwrap  503 . The film overwrap  503  may comprise a flat sheet which is vacuum-sealed over the food items  501  and heat sealed to the rim  504  of the plastic tray  502 . In order to maintain a non-venting cooking environment, the heat seal must be of sufficient strength so as to prevent the film overwrap  503  from separating from the tray rim  504  when subjected to increasing internal pressures during cooking. 
         [0038]    Referring to  FIG. 6 , an axonometric view of a food packaging  600  in accordance with an embodiment of the present invention is disclosed. One or more distinct food items  601  may be disposed within a heat-resistant plastic tray  602 . The heat-resistant plastic tray may further comprise a plurality of partitions  603  which serve to separate the food items  601  into individual portions. The food items  601  may be vacuum-sealed within the plastic tray  602  by a non-venting plastic overwrap  604 . In the depicted embodiment of the invention, the film overwrap  604  may comprise a flat sheet which is vacuum-sealed over distinct food items  601  and heat sealed to the rim  605  and partitions  603  of the plastic tray  602 . Such a configuration may allow for the free water content of the food items  601  and/or the residual air retained within the packaging  600  following vacuum sealing to be separately established for each distinct food item  601 . The ability to adjust these variables allows for the specification of multiple optimal pressure cooking environments such that each is particularly suited to a given type of food item  601 . 
         [0039]    In further embodiments, the non-venting film overwrap  604  may be disposed only over certain portions (e.g.  601   a ,  601   b ) while other portions (e.g.  601   c ,  601   d ) may be left exposed to the ambient environment or enclosed by a conventional venting film overwrap. Such a configuration would permit certain food items  601   c ,  601   d  which may cook better in an open environment (e.g. breads) to also be included in the packaging. 
         [0040]    Referring to  FIG. 7 , a dual-ovenable food packaging in accordance with an embodiment of the present invention is disclosed. The food packaging  701  may be disposed within a microwave oven  702  or a conventional radiant-heat oven  703  for cooking. 
         [0041]    It is believed that the present invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.