Package making – Methods – With contents treating
Reexamination Certificate
1998-12-23
2002-06-25
Gerrity, Stephen F. (Department: 3721)
Package making
Methods
With contents treating
C053S427000
Reexamination Certificate
active
06408598
ABSTRACT:
BACKGROUND OF THE INVENTION
It is common practice in packaging many goods, including food items and particularly, meat products, to use a substantially rigid tray and a flexible, polymeric upper lid. During the packaging process, the product is placed in the tray. The lidding material is fed from a roll across the tray, covers the product, and typically is sealed to the tray edges to form the finished package. However, relatively bulky or awkwardly shaped products which extend above the upper flange of a conventional packaging tray, i.e., high profile products, are not readily accommodated by such a packaging operation.
High profile meat products are regularly packaged in supermarkets in an in-store overwrap process. By such process, the high profile product is placed in a tray, a polymeric film is stretched around the product and tray, and then the overwrapped tray is pressed onto a heated plate to weld together the pleats and folds of the film at the underside of the tray. The resultant package, an upper film tensioned across the uppermost portions of the high profile product and extending, under tension, to the outer edges of the tray, is readily recognized by consumers. Yet, the preparation of such packages on an individual basis has long been recognized to be inefficient and expensive. Instead, it is preferable to butcher and package such meat products at a central processing facility which benefits from economies of scale, and then ship the packaged meat to individual supermarkets or other retail outlets. It is believed that the central processing of meat can also lead to a higher quality, more sanitary product with a longer shelf-life than meat which is butchered and packaged in individual supermarkets.
One method for providing centrally packaged high profile meat products has been vacuum skin packaging (VSP). In a typical vacuum skin packaging process, the product is placed on a support member, a thermoformable film is extended over product and support member, the film is drawn upwardly into a cavity above the product and heated to its softening temperature, the space between the upwardly drawn film and the product and support member is evacuated and the heated film is released onto the product, thermoforming itself to the product and welding to the remaining upper surface area of the support member.
Vacuum skin packaging is an excellent packaging process for a variety of products.
However, there are some drawbacks to vacuum skin packaging high profile products. First, it can be difficult to provide an upper VSP film which is capable of being sufficiently drawn to accommodate an irregularly shaped high profile product without undue thinning and potential breakage in the crevices of the product or without unsightly folds and pleats in the film where it welds to the support member. Second, even a perfectly vacuum skin packaged high profile product can present an unusual and, therefore, less preferred appearance to consumers who are accustomed to the appearance of in-store overwrapped packages.
The concerns with packaging a high profile product are exacerbated when the product is one, as is the case for many meat products, which must be packaged under certain environmental conditions. For example, for some meat products it is desirable to package and distribute the meat in a low oxygen environment and then expose the meat to a high oxygen environment immediately prior to presentation for sale. For such meat products a substantially gas-impermeable lidding film which peelably delaminates (i.e., delaminates upon peeling) to expose a gas-permeable film, thereby causing a change in the environmental conditions within the package is often employed.
As is discussed above, historically, large sub-primal cuts of meat have been butchered and packaged in each supermarket. Fresh red meat presents a particular challenge to the concept of centralized processing and packaging due to its oxygen-sensitivity. Such oxygen-sensitivity is manifested in the shelf-life and appearance (color) of a packaged meat product. For example, while a low-oxygen packaging environment generally increases the shelf-life of a packaged meat product (relative to meat products packaged in an environment having a higher oxygen content), red meat has a tendency to assume a dark red color when packaged in the absence of oxygen or in an environment having a very low oxygen concentration, i.e., below about 5% oxygen. Unfortunately, such a dark red color is undesirable to most consumers, and marketing efforts to teach the consumer about the acceptability of the dark red color have been largely ineffective. When meat is exposed to a sufficiently high concentration of oxygen, e.g., as found in air, it assumes a bright red color which most consumers associate with freshness. After 1 to 3 days of such exposure, however, meat assumes a brown color which, like. the dark red color, is undesirable to most consumers (and indicates that the meat is beginning to spoil).
Thus, in order to effectively butcher and package meat products in a central facility for distribution to retail outlets, the meat would desirably be packaged, shipped, and stored in a low-oxygen environment for extended shelf-life, and then displayed for consumer sale in a relatively high-oxygen environment such that the meat is caused to “bloom” into a red color just before being placed in a retail display case. While in the retail display case, the meat product is desirably contained in a package which protects it from microbial and other contamination. In order to attain the maximum economic benefit from centralized packaging, the package in which the meat product is displayed for consumer sale is the same package in which the meat product is initially packaged and shipped from the central processing facility.
Accordingly, there is a need in the art for a package and process for centrally packaging high profile products which provides a conventional package appearance and which may be employed for environment-sensitive products.
SUMMARY OF THE INVENTION
Such need is met by a packaging process which includes the steps of providing a support member which includes a product support surface and a periphery, providing an upper film which includes a sealant layer, the sealant layer being sealable to the support member, orienting the film to an orientation ratio of from about 9.0:1 to about 16.0:1, positioning a product on the product support surface of the support member such that at least a portion of the product extends upwardly above the level of the periphery, extending the upper film above the support member and product, the sealant layer being immediately above and adjacent to the support member and the product, drawing the upper film into a concavity by differential pressure, maintaining the concave shape of the upper film while heating the film, removing gases from the space between the upper film and the support member and product, introducing a desirable gas into the space, releasing the upper film such that it shrinks toward the product and the support member, the desirable gas being retained within the space precluding close contact of the film with the lowermost portions of the product, and sealing the upper film to the periphery of the support member, wherein at least the step of heating the film shrinks the film, thereby tensioning it onto and across the underlying product.
This need is also met by providing a package which includes a support member which includes a product support surface and a periphery, a product contained on the product support surface, at least a portion of the product extending upwardly above the level of the periphery, an oriented upper film tensioned across and at least partially heat shrunk onto the uppermost portions of the product and sealed to the periphery of the support member, and a desired gas trapped between the support member and the upper film.
DEFINITIONS
As used herein, the term “film” refers to a thermoplastic material, generally in sheet or web form, having one or more layers formed from polymeric or other ma
Cryovac Inc.
Gerrity Stephen F.
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