U.S. patent application number 11/077477 was filed with the patent office on 2005-09-15 for vacuum skin packaging.
Invention is credited to Kane, James P. JR., Libert, Timothy A., Moore, Shanna La'Vonne, Visioli, Donna Lynn.
Application Number | 20050199524 11/077477 |
Document ID | / |
Family ID | 34963163 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050199524 |
Kind Code |
A1 |
Visioli, Donna Lynn ; et
al. |
September 15, 2005 |
Vacuum skin packaging
Abstract
Disclosed are packages and methods for packaging perishable
foods such as meat, fish, poultry, vegetables or other food
products. The packaging comprises a vacuum skin package comprising
a film having specific package gas permeability requirements and a
framing element within which the packaged goods are held.
Inventors: |
Visioli, Donna Lynn; (Lower
Gwynedd, PA) ; Kane, James P. JR.; (Wilmington,
DE) ; Libert, Timothy A.; (Hockessin, DE) ;
Moore, Shanna La'Vonne; (Hockessin, DE) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY
LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1128
4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
34963163 |
Appl. No.: |
11/077477 |
Filed: |
March 10, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60552268 |
Mar 11, 2004 |
|
|
|
Current U.S.
Class: |
206/497 ;
206/524.1; 53/427 |
Current CPC
Class: |
B65B 31/00 20130101;
B65B 25/062 20130101; B65B 25/067 20130101; B65B 25/064
20130101 |
Class at
Publication: |
206/497 ;
053/427; 206/524.1 |
International
Class: |
B65D 065/00 |
Claims
1. A vacuum skin package to contain perishable goods comprising (a)
a first flexible web of gas permeable skin wrapping plastic
material; (b) one or more rigid or semi-rigid framing elements to
surround but not contact the perishable goods; and (c) a second
flexible web of gas permeable skin wrapping plastic material;
wherein the first flexible web and the second flexible web are
sealed to each other to contain the perishable goods.
2. The package of claim 1 wherein the gas permeable plastic
materials have an OTR greater than or equal to 10,000 cc/m.sup.2/24
hr.
3. The package of claim 2 wherein the gas permeable plastic
materials comprise metallocene polyethylene.
4. The package of claim 2 wherein the gas permeable plastic
materials comprise ethylene/acid copolymers at least partially
neutralized with at least one cation, modified with at least one
organic acid, or both.
5. The package of claim 2 wherein the one or more framing elements
are interposed between the first flexible web and the second
flexible web such that the one or more framing elements are in
contact with the inside face of the first flexible web and in
contact with the inside face of the second flexible web to surround
but not contact the perishable goods; and the first flexible web
and the second flexible web are sealed to each other to contain the
one or more framing elements and the perishable goods.
6. The package of claim 2 wherein the one or more framing elements
are in contact with the outside face of the first flexible web and
optionally in contact with the outside face of the second flexible
web to surround but not contact the perishable goods; and the first
flexible web and the second flexible web are sealed to each other
to contain the perishable goods.
7. A method of packaging goods comprising (a) placing perishable
goods on a first flexible web of gas permeable skin wrapping
plastic material in contact with the inside face of the first
flexible web; (b) placing one or more rigid or semi-rigid framing
elements in contact with the inside face of the first flexible web
to surround but not contact the perishable goods; (c) placing a
second flexible web of gas permeable skin wrapping plastic material
over the perishable goods and the one or more framing elements such
that the inside face of the second flexible web is in contact with
the perishable goods, the one or more rigid or semi-rigid framing
elements and the inside face of the first flexible web; and (d)
sealing the first flexible web and the second flexible web to each
other to contain the one or more framing elements and the
perishable goods.
8. A method of packaging goods comprising (a) placing perishable
goods on a first flexible web of gas permeable skin wrapping
plastic material in contact with the inside face of the first
flexible web; (b) placing a second flexible web of gas permeable
skin wrapping plastic material over the perishable goods such that
the inside face of the second flexible web is in contact with the
perishable goods, and the inside face of the first flexible web;
(c) placing one or more rigid or semi-rigid framing elements in
contact with the outside face of the first flexible web and
optionally in contact with the outside face of the second flexible
web to surround but not contact the perishable goods; and (d)
sealing the first flexible web and the second flexible web to each
other to contain the perishable goods.
Description
[0001] This application claims the benefits of U.S. Provisional
Application 60/552,268, filed Mar. 11, 2004, the entire disclosure
of which is incorporated herein by reference.
[0002] The invention relates to packaging, to packaging for
containing meat, fish, poultry, vegetables or other food products,
and to method for packaging goods using this improved
packaging.
BACKGROUND OF THE INVENTION
[0003] Perishable goods are subject to exposure to and
contamination by microbial organisms such as bacteria, molds and
the like by contact with airborne organisms or by contact with
organisms on surfaces. The contamination can result in accelerated
spoilage, toxin formation and other harmful effects. Thus it is
desirable to protect the goods from contact with microbial
organisms. Packaging such perishable goods in gas impermeable
materials such as foil, paperboard and oxygen barrier films can
provide a barrier to microbial contamination.
[0004] However, an anaerobic organism such as Clostridium botulinum
produces a potent toxin that is the causative agent of botulism, an
extremely virulent, dangerous, food poisoning. Since C. botulinum
is an anaerobe, gas impermeable materials such as foil, paperboard
and oxygen barrier films may not be suitable to package goods
highly susceptible to botulin toxin formation. Spores of C.
botulinum are heat resistant; it is impossible to kill the spores
by merely heating the food. It is necessary to provide a package
that allows oxygen to contact the surface of perishable goods to
minimize the growth of C. botulinum. Thus, packages for fresh fish
must provide a physical barrier to microbial and other
contamination, yet provide for oxygen permeability.
[0005] C. botulinum contamination is particularly problematic in
fresh fish. Traditionally, fresh fish has been sold in ice-chilled
containers open to the atmosphere to minimize the growth of C.
botulinum and consequent toxin formation. Such sales methods
previously have been limited to relatively small geographic areas
near the bodies of water where the fish were caught. For broader
distribution, fish has traditionally been frozen.
[0006] With modern distribution methods, the desire of consumers in
inland regions to consume fresh rather than frozen fish has
increased. However, packaging of fresh fish to minimize the dangers
of botulism is difficult. C. botulinum growth and toxin formation
can occur as a result of time/temperature abuse during processing,
storage, and distribution. Potentially hazardous conditions can
occur in as little as two hours at temperatures >70.degree. F.,
11 hours at 50-70.degree. F., two days at 42-50.degree. F., and 7
days at 37.9-41.degree. F.
[0007] Typical vacuum packaging inhibits the growth of common
spoilage organisms, but does so under conditions that exclude
oxygen and therefore does not inhibit the growth of C. botulinum.
Therefore, vacuum packaging under conditions that exclude oxygen
increases the likelihood that botulin toxin may be produced is
unacceptable to consumers.
[0008] In packaging meat, fish, poultry, vegetables or other food
products, it is also desirable to provide for relatively long shelf
life of the packaged goods in a package that does not affect the
appearance or keeping qualities of the packaged goods, is
relatively simple and inexpensive to manufacture, yet sufficiently
robust to protect the packaged goods from damage.
[0009] Vacuum skin packaging is a common method of packaging many
goods where goods are tightly packaged within a wrapping material
and where substantially all of the atmospheric air is excluded.
Often the goods are placed in a tray or on a board background to
increase the rigidity of the package to allow for better
merchandising. In some cases, such as frozen fish, the packaged
goods themselves are sufficiently rigid that additional rigid
packaging elements are not needed.
[0010] Packaging has also been known to include certain gases to
enhance the keeping qualities and the shelf life of the contents.
Typically these packages are made from a plastic material that
provides at least a partial barrier to the ingress of unwanted
gases. The plastic material may be such that it allows gases that
may be generated within the package to escape. Other known plastic
materials allow certain gases to permeate to enhance the keeping
qualities of the packaged goods. See, e.g., U.S. Pat. Nos.
4,685,274; 4,840,271; 5,025,611; 5,103,618 and 5,115,624. However,
the packages disclosed therein can retain only a limited volume of
the gas in the headspace.
[0011] Some products, such as fresh fish, must be packaged in a
film with specific gas permeability properties to ensure food
safety to prevent the growth of anaerobic bacteria. In the case of
fresh fish, use of a backing, such as a board, base or tray, is not
acceptable because the backing blocks the oxygen from contacting
the fish.
[0012] U.S. Food and Drug Administration (FDA) guidance defines
that packaging with "OTR greater than or equal to 10,000
cc/m.sup.2/24 hr can be regarded as oxygen permeable". Such an OTR
is unattainable with typical foam trays used in packaging
foodstuffs such as fresh meats.
[0013] The FDA guidelines also note that "use of an oxygen
permeable package will not compensate for the restriction to oxygen
exchange created by practices such as packing . . . in deep
containers from which the air is expressed." If FDA guidelines
regarding oxygen permeability are not met, a Hazard Analysis of
Critical Control Points (HACCP) plan, a quality assurance protocol
widely used in the food industry, must be established. Temperature
monitoring is required and time/temperature indicators (TTI's) must
be provided on shipping containers. While temperature controls and
monitoring can be accomplished during the distribution chain, it is
impractical to do so after the packaged fresh fish has been sold to
the consumer. The combinations of time and temperature that could
provide hazardous levels of botulin toxin could easily occur during
post-sale consumer handling of the packaged fresh fish.
[0014] It is therefore desirable to develop a vacuum skin package
that has specific gas permeability and a framing element within
which the packaged goods are held thereby providing sufficient
rigidity to the package but does not contact the contents (i.e. the
packaged goods). The goods are in contact only with the gas
permeable film, which allows for adequate oxygen to contact the
surface of the goods. Packages can be made with gas impermeable
materials if oxygen is available in the headspace of the package to
inhibit growth of anaerobic organisms. However, it is difficult to
provide sufficient oxygen in the headspace of such a package to
provide extended protection against growth of anaerobes.
SUMMARY OF THE INVENTION
[0015] The invention includes a vacuum skin package that can
contain perishable goods in which the package comprises or is
produced from (a) a first flexible web of gas permeable skin
wrapping plastic material; (b) one or more rigid or semi-rigid
framing elements to surround but not contact the perishable goods;
and (c) a second flexible web of gas permeable skin wrapping
plastic material wherein the first flexible web and the second
flexible web are sealed to each other to contain the perishable
goods. The packages can comprise or be produced from a gas
permeable plastic materials having an oxygen transmission rate
(OTR) greater than or equal to 10,000 cc/m.sup.2/24 hr.
[0016] The invention also include a method of packaging goods
comprising (a) placing perishable goods on a first flexible web of
gas permeable skin wrapping plastic material in contact with the
inside face of the first flexible web; (b) placing one or more
rigid or semi-rigid framing elements in contact with the inside
face of the first flexible web to surround but not contact the
perishable goods; (c) placing a second flexible web of gas
permeable skin wrapping plastic material over the perishable goods
and one or more framing elements such that the inside face of the
second flexible web is in contact with the perishable goods, the
one or more rigid or semi-rigid framing elements and the inside
face of the first flexible web; and (d) sealing the first flexible
web and the second flexible web to each other to contain the one or
more framing elements and the perishable goods.
[0017] Alternatively, the method can comprise (a) placing
perishable goods on a first flexible web of gas permeable skin
wrapping plastic material in contact with the inside face of the
first flexible web; (b) placing a second flexible web of gas
permeable skin wrapping plastic material over the perishable goods
such that the inside face of the second flexible web is in contact
with the perishable goods, and the inside face of the first
flexible web; (c) placing one or more rigid or semi-rigid framing
elements in contact with the outside face of the first flexible web
and optionally in contact with the outside face of the second
flexible web to surround but not contact the perishable goods; and
(d) sealing the first flexible web and the second flexible web to
each other to contain the perishable goods.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The term micron (.mu.) equals to {fraction (1/1000)} of a
millimeter (mm). A micron is sometimes referred to as micrometer
(.mu.m). The term mil equals to {fraction (1/1000)} of an inch or
to 25.4 microns.
[0019] The phrase "inside face" refers to the face of a film or
packaging web that is in contact with the packaged goods and is
contained within the package after it is formed. The inside face of
the packaging web serves as both the food-contact face and the
sealant face, because portions of the surface of that face are in
contact with the food and other portions of the surface of that
face are in the area where seals are made.
[0020] The phrase "outside face" refers to the face of a film or
packaging web that is not in contact with the packaged goods and
provides the exterior surface of the package after it is
formed.
[0021] The perishable goods can be meat, fish, poultry, fresh
vegetables, or combinations of two or more thereof although other
types of goods such as other foodstuffs can be packaged if
desired.
[0022] The packaging webs can be prepared from films of
thermoplastic compositions with OTR preferably greater than or
equal to 10,000 cc/m.sup.2/24 hr.
[0023] OTR of films are dependent on the thickness of the film and
the inherent permeability of its composition. Permeability is
dependent on such factors as temperature, relative humidity and
pressure of the gas impinging on the film. Typically OTR is
calculated using standard conditions normalized to 23.degree. C.,
50% relative humidity and 1 atmosphere.
[0024] For good appearance of the package for retail display, it
may also be desirable to use films that are not stretched by the
weight of the packaged goods (i.e. resists creep).
[0025] In a first embodiment of this aspect of the invention, the
one or more framing elements are interposed between the first
flexible web and the second flexible web such that the one or more
framing elements are in contact with the inside face of the first
flexible web and in contact with the inside face of the second
flexible web to surround but not contact the perishable goods; and
the first flexible web and the second flexible web are sealed to
each other to contain the one or more framing elements and the
perishable goods.
[0026] In a second embodiment of this aspect of the invention, the
one or more framing elements are in contact with the outside face
of the first flexible web and optionally in contact with the
outside face of the second flexible web to surround but not contact
the perishable goods; and the first flexible web and the second
flexible web are sealed to each other to contain the perishable
goods.
[0027] Films suitable for the packaging webs can comprise
metallocene polyethylene (mPE) (especially grades with densities
less than 0.91 g/cc, and more especially grades with densities less
than 0.89 g/cc,), which have high OTR.
[0028] The metallocene polyethylene (mPE) employed in the present
invention can be any such polyethylene as generally known in the
art provided the oxygen permeability is sufficiently high to afford
the requisite permeability necessary for the packaging web. More
specifically, the metallocene polyethylene should have a density
less than 0.91 g/cc, preferably less than 0.89 g/cc, at which
densities the normalized OTR.sub.n at 23.degree. C. and 50%
relative humidity will be greater than about 12,400
cc-mil/m.sup.2.day.atm, preferably greater than about 20,000
cc-mil/m.sup.2.day.atm. These mPEs can optionally be blended with
other low crystalline polyolefin or amorphous polyethylenes (such
as low density polyethylene, LDPE; linear low density polyethylene,
LLDPE; other mPE and the like) provided the blend retains
significantly high permeability. The composition may further
comprise ethylene copolymers such as ethylene/vinyl acetate
copolymers or ethylene/alkyl (meth)acrylate copolymers for improved
processing. Also, the composition may further comprise
ethylene/acid copolymers at least partially neutralized with
inorganic cations (i.e. ionomers).
[0029] For example, a 2-mil thick film of mPE with a density of
less than 0.89 g/cc and OTR.sub.n) greater than about 20,000
cc-mil/m.sup.2.day.atm will have an OTR of 10,000 cc-mil/m.sup.2/24
h.
[0030] Compositions comprising ethylene copolymers at least
partially neutralized with cations (ionomers) and modified with
organic acids are also suitable for preparing films having high
oxygen permeability. These compositions are described in greater
detail in PCT Patent Application Publication WO03/089240,
incorporated herein by reference. This publication also describes
multi-layer films having high oxygen permeability, particularly
multi-layer films comprising at least one layer of modified ionomer
and at least one layer of mPE.
[0031] An ethylene copolymer is a polymer that can comprise repeat
units derived from about 5 to about 50%, or about 10 to about 19%,
or 12 to 15%, by weight (wt %) of a polar monomer such as acrylic
acid, alkyl acrylic acid, or alkyl acrylate, or combinations of two
or more thereof, based on the total weight of the ethylene
copolymer. The alkyl group may contain up to about 20 carbon atoms
such as methyl, ethyl, butyl, isobutyl, pentyl, hexyl, and
combinations of two or more thereof.
[0032] An ethylene copolymer may comprise up to 35 wt % of an
optional comonomer such as carbon monoxide, sulfur dioxide,
acrylonitrile; maleic anhydride, maleic acid diesters,
(meth)acrylic acid, maleic acid, maleic acid monoesters, itaconic
acid, fumaric acid, fumaric acid monoester, a salt of these acids,
glycidyl acrylate, glycidyl methacrylate, and glycidyl vinyl ether,
and combinations of two or more thereof.
[0033] The acid moiety of an ethylene copolymer may be neutralized
with a cation to produce an ionomer. The neutralization, for
example, can range from about 0.1 to about 100, or about 10 to
about 90, or about 20 to about 80, or about 20 to about 40 percent,
based on the total carboxylic acid content, with a metallic ion.
The metallic ions can be monovalent, divalent, trivalent,
multivalent, or combinations of two or more thereof.
[0034] The ionomer can also be a blend of an ionomer having a
greater than 20% neutralization and, for example, an ethylene
(meth)acrylic acid copolymer to achieve the desired degree of
neutralization.
[0035] Examples of ethylene copolymers include, but are not limited
to, ethylene/methyl acrylate (EMA), ethylene/ethyl acrylate (EEA),
ethyl acrylate (EA), ethylene/butyl acrylate (EBA),
ethylene/isobutyl acrylate/methacrylic acid, ethylene/methyl
acrylate/maleic anhydride, ethylene/butyl acrylate/glycidyl
methacrylate (EBAGMA) and ethylene/butyl acrylate/carbon monoxide
(EBACO), and butylacrylate (BA).
[0036] Examples of commercially available ethylene copolymers
include those available from E. I. du Pont de Nemours and Company
(DuPont), Wilmington, Del., carrying the trademarks of Surlyn.RTM.,
Nucrel.RTM., Appeel.RTM., Bynel.RTM., and Elvaloy.RTM., and
Elvax.RTM.
[0037] The making of the film, multi-layer film, and corresponding
film structures can be by any such method as practiced in the art.
As such, the film and film structures can be typically cast,
extruded, co-extruded and the like including orientation (either
axially or biaxially) by various methodologies (e.g., blown film,
bubble techniques, mechanical stretching or the like, or
lamination). Various additives as generally practiced in the art
can be present in the respective film layers including the presence
of tie layers and the like, provided their presence does not
substantially alter the properties of the permeable film or film
structure. Such additives can comprise antioxidants and thermal
stabilizers, ultraviolet (UV) light stabilizers, pigments and dyes,
fillers, anti-slip agents, plasticizers, other processing aids, and
the like.
[0038] The packages comprise two gas permeable film webs. The two
film webs are typically two individual sheets of film. The webs may
consist of identical compositions and appearance. Alternatively,
one web may be different than the other web. For example, one web
may be clear, allowing visualization of the packaged goods and the
other may be opaque and/or colored to provide a background. One or
both of the webs may also be printed with designs, logos,
alphanumeric text and/or the like to provide a pleasing appearance
for the package and/or to provide information to the consumer. One
skilled in the art can appreciate that a single web of film may be
folded onto itself to provide two overlying webs, or a tube of film
may be formed such that two overlying portions of the tube provide
the equivalent of two webs of film.
[0039] Packages can be prepared from two webs of gas permeable
packaging film. After placing the contents of the package between
the film webs and applying a vacuum, the package is formed by
adhering, preferably by heat sealing, the perimeters of the two
webs to each other. The heat sealed perimeter of the package can be
achieved by superimposing the first and second webs of polymeric
film and then heat sealing each directly to the other or heat
sealing them indirectly through the use of an intervening third
polymeric film, again as generally known and practiced in the
art.
[0040] The rigid or semi-rigid framing elements may be prepared
from paperboard or thermoplastic compositions, such as
polyester.
[0041] The framing elements are sized so that they surround the
goods to be packaged, but do not contact the goods. For example,
but not limitation, the framing elements may define a packaging
area from about 10 to about 30 cm in length and from about 10 to
about 30 cm in width, in which the goods to be packaged are placed.
Although generally described herein in terms of rectangular areas,
other shapes may be envisioned.
[0042] The framing elements may be shaped, embossed, textured and
the like to provide a pleasing appearance for the package. The
framing elements may also be printed with designs, logos,
alphanumeric text and/or the like to provide a pleasing appearance
for the package and/or to provide information to the consumer.
[0043] One embodiment of the framing element comprises a generally
flat, single piece of paperboard or thermoplastic composition
formed so that it provides a shaped perimeter margin with a
concentric opening therein. This embodiment can contact the
flexible packaging web in a generally coplanar manner, and
resembles a mat used in picture framing. The shaped perimeter may
be, for example, rectangular. The corners of the perimeter may be
square or rounded off. The concentric opening may be of similar
shape of smaller dimensions to provide a margin of equal dimension
around the shape of the framing element. Alternatively, the opening
may be of different shape than the perimeter shape to provide a
margin that has different dimensions depending on the orientation
of the opening relative to the perimeter. Shapes other than
rectangular may be used for the perimeter and/or concentric
opening. The thickness of this embodiment of the framing element
may be from about 0.5 mm to about 3 mm. The dimensions of the
margin may be from about 1 cm to about 3 cm, or greater, depending
on the shapes and sizes envisioned for the perimeter and the
concentric opening.
[0044] An alternative embodiment of the framing element comprises
one or more generally flat strips of paperboard or thermoplastic
composition shaped so that they form portions of a shaped perimeter
margin. The strips of this embodiment will contact the flexible
packaging web in a generally coplanar manner. For example, two
strips with a space between them may be used to define two sides of
a rectangle (e.g. the sides along the longer dimension of the
rectangle), with the distance of the space between the strips
providing the dimension of the other two sides (e.g. the sides
along the shorter dimension of the rectangle). Alternatively, the
strips may define other portions of the perimeter of the packaging
area. For example, a strip may form a portion of a shaped perimeter
comprising a corner and portions of two adjacent sides. A strip may
form a portion of a shaped perimeter comprising a side, two corners
and portions of two adjacent sides. The strips may also be formed
so that they provide shapes other than rectangular. For example,
the strips may be shaped as arcs, providing curved shapes. The
strips may be from about 1 cm to about 3 cm wide, or greater,
depending on the shapes and sizes envisioned for the packaging
area.
[0045] An alternative embodiment of the framing element comprises a
strip of paperboard or thermoplastic composition formed so that it
defines a packaging area that is generally coplanar with the
packaging web but also has a significant dimension in a direction
perpendicular to the plane of the packaging web to define a
packaging volume.
[0046] As disclosed above, the framing elements can be located or
placed between the two flexible packaging webs to define a
packaging area and are sealed within the package. Packages
according to this embodiment can be prepared by (a) placing
perishable goods on a first flexible web of gas permeable skin
wrapping plastic material in contact with the inside face of the
first flexible web; (b) placing one or more rigid or semi-rigid
framing elements in contact with the inside face of the first
flexible web to surround but not contact the perishable goods; (c)
placing a second flexible web of gas permeable skin wrapping
plastic material over the perishable goods and the one or more
framing elements such that the inside face of the second flexible
web is in contact with the perishable goods, the one or more rigid
or semi-rigid framing elements and the inside face of the first
flexible web; and (d) sealing the first flexible web and the second
flexible web to each other to contain the one or more framing
elements and the perishable goods.
[0047] The steps (a) and (b) can be conducted so that (a) occurs
before (b), (b) occurs before (a), or simultaneously.
[0048] In a second embodiment of the package of this invention, the
framing elements are located or placed in contact with the outside
face of one or both of the packaging webs and are on the outside of
the package.
[0049] An example of this second embodiment comprises a package
wherein the framing element comprising a generally flat, single
piece of paperboard or thermoplastic composition having a shaped
perimeter margin with a concentric opening therein is adhered to
the outside face of one of the gas permeable webs. The framing
element may be adhered by means including, for example, hot-melt
adhesive or heat sealing.
[0050] Alternatively, the framing element comprises a generally
flat, single piece of paperboard or thermoplastic composition that
can be folded around the gas permeable packaging webs to provide a
shaped perimeter with an opening. In this example, a portion of the
framing element is adhered to the outside face of the first
packaging web and a second portion of the framing element is
adhered to the outside face of the second packaging web.
[0051] Packages according to this embodiment can be prepared by (a)
placing perishable goods on a first flexible web of gas permeable
skin wrapping plastic material in contact with the inside face of
the first flexible web; (b) placing a second flexible web of gas
permeable skin wrapping plastic material over the perishable goods
such that the inside face of the second flexible web is in contact
with the perishable goods, and the inside face of the first
flexible web; (c) placing one or more rigid or semi-rigid framing
elements in contact with the outside face of the first flexible web
and optionally in contact with the outside face of the second
flexible web to surround but not contact the perishable goods; and
(d) sealing the first flexible web and the second flexible web to
each other to contain the perishable goods.
[0052] Because the framing element is outside the package, step (c)
relating to placing the framing elements may occur prior to step
(a), prior to step (b) prior to step (d), or after step (d); or
simultaneously with one of steps (a) or (b).
* * * * *