Consumers often prefer to cook food in a microwave oven rather than conventional ovens because of the reduced cooking time required to heat foods in a microwave oven. Consumers also want to be provided with the opportunity to cook pre- packaged food products in the package in which they were purchased without the hassle of transferring the food from one container to the next.

Unfortunately, foods cooked in a microwave oven tend to be tough and/or dry in texture and consistency, rather than tender and moist. When liquid is added to the food in an attempt to retain moisture, the food can become soggy and undesirable. In addition, microwave ovens do not evenly distribute heat to the product being cooked. This results in a cooked food product that may be very hot in one area, but cold in another area. Because of these problems, many people consider microwave cooking to be problematic and generally undesirable.

One method for improving the texture and consistency of food cooked in a microwave oven is to use steam generated by the heated food product to assist in cooking the food. Cooking with steam not only provides moisture for the food being cooked, but also results in more consistent heating throughout the food product.

In order to steam cook a food product in a microwave oven, the steam must be retained within a cooking container; accordingly, the container must be at least partially sealed. When a sealed container is used to heat a food product contained therein, pressure rapidly builds as steam is generated from the heated food product. As heating continues, this pressure will continue to escalate until the container's seal is broken, thereby relieving the pressure.

This relief often comes in the form of an explosion forcing an opening of the container and resulting in food being ejected therefrom. Not only does such an explosion create a mess, but it also undermines the attempt to use steam to cook the food product because the explosion causes a rapid release of the collected steam from the no longer sealed cooking environment.

The release of pressure can be controlled, for example, by providing vents along the edge of the base of the container, which is thereafter married to a covering. These vents create a weakened portion in the seal between the container's covering and its base.

When the sealed cooking environment attains a pressure creating a risk of explosion, the weakened portions in the seal allow for a controlled pressure release at the vents. The seal between the container's covering and its base is broken at the point where the pressure release occurs, creating a tab which may be grasped or otherwise used to pull the covering from the base, breaking the remainder of the seal such that consumption of the food product may occur. An example of such a venting configuration is described in commonly assigned U. S. Patent No. 6,559, 431, which is incorporated in its entirety herein by reference.

Although this type of venting configuration is effective for steam cooking a food product in a microwave oven, it specifically requires vents to be molded along the edge of the base of the container being used. Additionally, this type of venting configuration can not be used in containers which lack a substantially rigid base, for example, cooking bags cannot be provided with this type of venting configuration.

It is therefore the paramount object of the present invention to provide a microwave cooking container with a venting patch for steam cooking a food product contained therein, wherein the container may be any microwave cooking container having a sealed cooking environment.

This and other objects and advantages of the present invention will become apparent upon a reading of the following description.

DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a microwave cooking container with a venting patch made in accordance with the present invention; Figure la is an enlarged perspective view of the venting patch of Figure 1; Figure 2a is a perspective view of an alternative microwave cooking container with a venting patch made in accordance with the present invention and having a single compartment; Figure 2b is a perspective view of an alternative microwave cooking container with two venting patches made in accordance with the present invention and having two compartments; Figure 2c is a perspective view of an alternative microwave cooking container with three venting patches made in accordance with the present invention and having three compartments; and Figure 3 is a perspective view of an alternative microwave cooking container with a venting patch made in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 is a perspective view of a preferred microwave cooking container 10 made in accordance with the present invention for steam cooking a food product contained therein. The container 10 is constructed from a material, such as polypropylene, that is transparent to radiant energy, such as energy from a microwave oven, and generally includes at least one compartment 22 for retaining food product and an opening 19 for receiving food product. The container 10 depicted in Figure 1 further includes one or more apertures 14 to facilitate venting and a venting patch 12, which is of a sufficient size to cover the small apertures 14 in the container 10 and is sealed to the container using, for example, a heat seal or a food grade adhesive.

The preferred container 10 has a sealed cooking environment. Specifically, after food product has been delivered to the compartment 22, the opening 19 is sealed, thereby substantially fixing the volume of the container 10. The manner in which the opening 19 is sealed depends on the type of container 10 being used. For example, as shown in Figure 1, the container 10 could be a cooking bag having an opening 19 at the top end, in which case the opening 19 could be sealed using a heat seal or food grade adhesive. For another example, referring to Figure 2a, the container 10a could be a cooking tray having a base 24a with at least one compartment 22a for holding food product and a covering 26a for sealing the opening 19a to the compartment 22a. The covering 26a depicted in Figure 2a is a substantially rigid snap-on lid, which includes an angled flange 28a for securing it to the base 24a. Alternatively, the covering 26a could be flexible film which is sealed to the base 24a of the tray using, for example, a heat seal. Again, it is contemplated that any container having a sealed cooking environment could be used without departing from the spirit and scope of the present invention.

As previously mentioned, the container may include more than one compartment.

Referring now to Figures 2b and 2c, when the container 110a, 210a includes a plurality of compartments 122a, 123a, 222a, 223a, 221a, it is preferred that each compartment 122a, 123a, 222a, 223a, 221a have a sealed cooking environment and an associated venting patch 112a, 113a, 212a, 213a, 21 la for controlled venting of each individual compartment.

The various containers 10, 10a, 110a, 210a, lOb of the present invention each use the steam generated by the heated food product to assist in cooking the food taking advantage of the ideal gas law, a distillation of several kinetic theories including Boyle's Law and Gay-Lussac's Law. More specifically, such containers take advantage of the proportional relationship between pressure and temperature when volume and number of

gas molecules remain constant. This proportional relationship can be expressed as a mathematical equation, (P2/Pl) = (T 2/Ti), where Pl is the initial pressure, P2 is the final pressure, Tl is the initial temperature, and T2 is the final temperature. Accordingly, any increase in pressure will result in a proportional increase in temperature that would not occur at ambient pressures. For example, if the pressure was to increase 1.2 fold (e. g., <BR> <BR> from 1 to 1.2 atmospheres), the temperature would also increase 1.2 fold (e. g. , from 275 K to 330 K, which is an increase from 35°F to 134°F).

Referring again to Figure 1, the venting patch 12 is designed to maintain the fixed volume of the sealed container 10 until the pressure from the steam generated during heating increases to a point that it causes the seal of the venting patch 12 to break, thereby exposing one or more apertures 14. Because the volume of the container 10 remains constant until venting occurs, the pressure within the container 10 increases as the moisture from the food product in the compartment creates steam as it approaches its boiling point. The heightened pressure resulting from the presence of the trapped steam causes the temperature within the container 10 to increase above a temperature able to be achieved at ambient pressures. Steam cooking using the container 10 of the present invention thus results in more consistent heating throughout the food product, faster preparation time, and an end product with desirable texture and consistency.

It is preferred that the container 10 and venting patch 12 be designed such that venting preferentially occurs through the aperture 14. Although it is not necessary, it is preferred that, when the venting patch 12 is sealed to the container 10, a steam pocket 18 is created therebetween, the steam pocket 18 being in fluid communication with the interior of the bag 5 via the aperture 14. The preferred steam pocket 18 comprises at least one steam guide 62 and an associated pair of steam horns 72,73. Referring now to Figure la, the steam guide 62 is a substantially V-shaped portion of the pocket with tip of the"V" ending before the edge of the venting patch 12 seal. The steam horns 72,73 are positioned on either side of the steam guide 62. Each steam horn 72,73 is also a portion of the pocket along the seal of the opening 19 ending before the edge of the seal. It is preferred that each steam horn 72,73 have a curved shape that is angled toward the tip of the guide 62.

As mentioned above, when the food product in the container 10 is prepared for consumption, the moisture from the food product creates steam as it approaches its boiling point. The steam generated causes the pressure within the container 10 to increase. As the pressure continues to build, the steam travels through the aperture 14 into the pocket 18.

The guide 62 directs the steam and pressure to its tip. Likewise, the steam horns 72,73, which are angled inward toward the tip of the guide 62, direct the steam and pressure

toward the tip of the guide 62. Thus, the pressure is heavily concentrated at the tip of the guide 62, causing the venting to occur at this preferential location.

Because different foods have different textures and moisture contents, the same pressure is not ideal for cooking all types of foods. With this in mind, it is contemplated and preferred that the container 10 be capable of customization, thereby creating an optimal cooking environment for the type of food product contained therein.

In this regard, the angle of the pair of steam horns 72,74 of the pocket 18 may be varied such that their tips terminate at points of various distances from the tip of an associated guide 62, thus allowing the concentration of pressure to be directed over various widths along the venting patch 12 seal. By changing the width of the concentration of pressure, different internal pressures can be achieved and the length of cooking time occurring prior to venting can be controlled. Alternatively, the cooking environment may be controlled by varying the degree of adhesive power of the seal thereof. In this regard, it is generally preferred that the adhesive power of the seal of the venting patch 12 is not as great as the adhesive power of the seal of the opening 19.

Turning now to Figure 3, the cooking environment can also be controlled by altering the surface area of the seal between the venting patch 12b and the container lOb.

For example, as shown in Figure 3, the venting patch 12b can be constructed from a strip of material folded over the sealed opening 19b of container before being sealed thereto.

Of course, it is contemplated that steam patches having a variety of shapes could be used without departing from the spirit and scope of the present invention.

It will be obvious to those skilled in the art that other modifications may be made to the invention described herein without departing from the spirit and scope of the present invention.