Note: Descriptions are shown in the official language in which they were submitted.
2 1 78254
.
BACKGROUND OF ~F INV~NTION
The present invention relates generally to packages for fresh
red meat. Particularly, this invention is directed to the
5 packaging of f ood products such that the packaged product may be
maintained in one condition under certain circumstances and then
converted to another condition. Specifically, packages in
accordance with the present invention provide for distribution of
a packaged product in a low oxygen environment and for introduction
10 of oxygen to the product surface at a supermarket or other retail
outlet. Such introduction of oxygen is achieved either by
permeation of oxygen through a film in contact with the product
~urface or through an exchange of atmospheric oxygen with a low
oxygen gaseous atmosphere contained around the product.
While a wide variety of food products can be packaged in
accordance with the teachings of this invention, it is particularly
advantageous in connection with the packaging of fresh red meat
such that the meat may be transported in a low oxygen atmosphere,
that is, preferably 0.596 2 or less, most preferably 0.0596 l or
20 less, and then caused to bloom when it reaches a supermarket by
exposure to oxygen.
Historically, large sub-primal cuts of meat have been
butchered and packaged in each supermarket. This, however, can be
inefficient and result in certain undesirable additional costs.
25 For example, all cuts from a large sub-primal must be sold at once.
Instead it would be preferable to permit the meat to be butchered
2 ~ 78254
and packaged at a central facility which benefits from economies of
scale and thereafter shipped to individual supermarkets such as is
done, for example, with many poultry products.
In the past, the goal of central fresh red meat pror~ ;ng has
5 not been achievable because most consumers prefer to buy meat which
is reddened in color as a result of ~oDuLe to oxygen. However,
the meat maintains its reddened color for approximately one to
three days and, thereafter, turns a brown color which is
undesirable to most consumers.
Therefore, if the meat was butchered and packaged in a gas
permeable (hereinafter "permeable") film, as is typical at retail,
at a central location and then shipped to another location for
eventual sale, in all ~ikf~l ih~od~ by the time the package reached
the retail outlet the meat would have undergone the transformation
15 to the brown color and would be effectively l~n~ hle. Conversely,
if the meat was butchered and packaged at a central location in a
gas-impermeable (hereinafter "impermeable") film, either under
vacuum or with vacuum and a low oxygen gas f lush, and then shipped
to another location for eventual sale, the meat would reach the
20 retail outlet having a purple color which is typical of meat prior
to exposure to oxygen. Heretofore, marketing efforts to teach the
consumer about the harmlessness of the purple color have proved to
be difficult. And, if the gas imp~L --hl~ film was a ~ t of
a conventional package having a tray which is overwrapped or lidded
25 with a film and which contains a low oxygen atmosphere, the
impermeable f ilm would have to be removed and replaced with a
-
2 t 78254
.
permeable film in order to allow for bloom of the meat to a bright
red color prior to display for the consumer, negating to a large
extent the benefits of a central processing facility.
A variety of packages have been developed in an effort to
5 provide a means for transporting meat in a low oxygen environment
and for quickly and easily introducing oxygen to the meat at the
retail outlet immediately prior to display to the consumer.
One approach to solving this problem has involved the
development of peelable f ilms . That is, f ilms have been developed
10 which readily delaminate into p~ -hl e and impermeable portions.
Such a film is sealed to a support member, such as a tray, which
contains the meat product, thereby forming a gas imperme~ble
package for distribution. At the retail outlet, the gas
impermeable portions are peeled from the film leaving a permeable
15 film sealed to the tray and, therefore, a gas permeable package
which allows the meat to bloom to bright red because of the
exchange with atmospheric oxygen.
The peelable film may extend over the contained product and be
sealed to the periphery of the tray as a lid or it may be heated
2~ and draped over the product under vacuum to form to a vacuum skin
package. However, for both types of packages the principal
drawback is the relatively low gas trAnC~ ion rate of the
permeable film portion after removal of the; - --hle portion.
That is, although the permeable portion of the peelable film has a
25 much higher gas tr~n~ ion rate than that of the entire f ilm
prior to ~ela~i~atio~, 5,000 to 25,000 cc/2'/2~ hrs./~t2. I~t 73'F
2 1 78254
as compared to 0 to 50 cc/m2/24 hrs./atm. at 73F prior to
delamination, it is still too low to effect bloom of the packaged
meat in a low oxygen gaseous atmosphere in a short period of time,
except in areas of intimate permeable film to meat contact.
Most of the other approaches to achieving the goal of central
fresh red meat processing have involved the development of a
variety of dual web packages of the type having a permeable film
covering the meat product and an; --hle film, which is removed
at the retail outlet, covering the permeable film wherein the
permeable film and the impermeable film are separate, discreet
films .
Examples of these types of packages include dual overwrap
packages wherein a permeable film is wrapped around the meat and
its support member and an impermeable film is wrapped about the
permeable film; dual lid packages which include a permeable lid and
an impermeable lid sealed to the periphery of the support member;
and packages with a head space which allows for the introduction of
a treating gas, typically nitrogen, carbon dioxide or some mixture
of the two, between a permeable film adjacent to the meat product
and an impermeable upper web. But, as is the case with the
peelable films discussed above, each of these dual web packages are
limited in their effectiveness by the p~ -h;~ity of the p~ -hle
film. Typical gas transmission rates for commercially viable gas
permeable films are 5,000 to 25,000 cc/m'/24 hrs./atm. at 73F which
is too low to effect rapid red meat bloom by exchange of the low
oxygen gases out and the atmospheric oxygen in.
2 1 78254
.
A further package developed to allow for central fresh red
meat processing includes a gas impermeable upper lid with a valve
defined in the lid. The package may include a treating gas between
the packaged meat and the upper lid during distribution which is
5 withdrawn through the valve and replaced with an oxygen-rich gas.
Although a rapid bloom is possible with this system, it has the
disadvantages of requiring trained operators at the retail outlet
and relatively expensive equipment to exchange each package thus
negating the cost savings of a central processing facility. The
10 presence of the valve has the further disadvantage of creating a
package appearance which is different from that which CUI~ rS are
accustomed to seeing for meat packaging. Further, a gas space
between the meat product and the impermeable film is required to
maintain a bloomed color which yields an underf illed package
15 appearance.
Yet another package developed to allow for central fresh red
meat processing provides for an excellent exchange of gases and
rapid introduction of oxygen in which an upper imperme2ble web
covers a lower permeable web which includes unsealed areas in the
20 seal of the permeable web to the tray. However, the intermittent
sealed and nonsealed areas are formed by an altered sealing head
which comprises a series of sealing "fingers" rather than a
conventional, continuous sealing surface.
Thus, it is an ob ject of the present invention to provide a
25 package which allows for central processing of fresh red meat with
mini~l processing requi~ed at re~ail.
2 1 7~254
It is yet another object of the present invention to provide
a package which is similar in appearance to that which cu~ rS
are accustomed to seeing for meat packaging.
It is a further object of the present invention to provide a
5 package which allows for rapid bloom of fresh red meat.
It is yet another object of the present invention to provide
a package which may be assembled, filled and sealed at a central
processing facility on conventional equipment.
SUM~A~Y OF T~ INVF~TION
These as well as other objects are achieved by providing a
package for a product which includes a product, an inner support
member having a cavity for receiving the product and a peripheral
15 flange, an outer support member having a cavity for receiving the
inner support member and a peripheral flange, a permeable film
sealed to the flange of the inner support member forming a first
sealed area and sealed to the flange of the outer support member
forming a second sealed area for enclosing the product, open
20 ~h~nnf~ defined by the inner support member providing for a free
f low of gases between the cavity of the inner support member and
the cavity of the outer support member, an i ~nr~ hle f ilm
enclosing the permeable film, and open r-h;lnn~ defined by the
permeable film, such that the removal of the i~r ~~hle film
25 allows for a free flow of gases between the external environment
and the packaged product via the open ~h~nn~ def ined by the
2 1 78254
permeable film and the channels defined by the inner support
member .
Such objects are also achieved by providing a package for a
product which includes a product, an inner support member having a
5 cavity formed by a base and side walls for receiving product and a
peripheral flange, the side walls of the inner support member
having a plurality of perforations defined therein, an outer
support member having a cavity for receiving the inner support
member and a peripheral flange, a permeable film sealed to the
10 upper flange of the inner support member forming a first sealed
area and sealed to the flange of the outer support member forming
a second sealed area for enclosing the product, an impermeable film
enclosing the permeable film, and open ~-h~nn~l c defined by the
permeable film, such that the removal of the impermeable film
15 allows for a free flow of gases between the external environment
and the packaged product via the open ~-hAnn~lR and the perforations
def ined within the inner support member .
RRTRl;' DRS-'RTP'I'ION OF THE nRAWTNGS
A detailed description of preferred embodiments of the
invention follows, with reference to the accompanying drawings,
wherein:
Fig. 1 is a perspective view of a package in accordance with
25 the present invention;
Fig. 2 is a cross-section of the package of Fig. 1;
2 1 78254
Fig. 3 is a cross-section of another ~mho-lir-mt of the packaqe
of the present invention:
Fig. 4 is a cross-section of yet another omho~lir L of the
package of the present invention;
Fig. 5 is a partial cross-section of a still further
t of the package of the present invention;
Fig. 6 is a partial cross-section of another ~ t of the
package of the present invention:
Fig. 7 is a partial cross-section of yet another ` ';- t of
the package of the present invention:
Fig. 8 is an enlarged sectional perspective view of the
package of Fig. 7 during removal of the imr~ -~hle film
Fig. 9 is a partial cross-section of a still further
embodiment of the package of the present invention; and
Fig. 10 is a partial cross-section of another embodiment of
the package of the present invention.
DETATrrn DES~RTPTION OF TT~r pRr~rRRFn EMr~oDIMr~NTs
The present invention is directed to a tray-type package for
meat and other perishable goods which includes an outer support
member or tray, an inner support memher or tray nested in the outer
tray, a permeable film sealed to both the inner tray and the outer
tray and an impermeable film enclosing the p~ --hlf~ film. The
package most preferably includes a low oxygen gaseous atmosphere,
such as a nitrogen/carbon dioxide mix. Perforations defined within
2 1 78254
the permeable f ilm between its seal to the inner tray and its seal
to the outer tray and perforations defined within the tray walls of
the inner tray act together to form open rh~nnPl ~ for the rapid
release of the low oxygen atmosphere and introduction of oxygen to
s the packaged product upon removal of the impermeable film at retail
while essentially precluding contamination of the packaged product.
Looking specifically to the figures of the drawing, Figure 1
shows a package 10 in accordance with the present invention. An
outer support member or tray 12 includes a base 14 and side walls
16 which define a cavity 18. A flange 20 extends outwardly from
the upper periphery of the side walls and includes an outer flange
portion 22 and an inner flange portion 24 separated by a depression
26. Inner support member or tray 28 includes a base 30 and side
walls 32 defining a cavity 34 for receiving a product 36. An upper
15 flange 38 extends outwardly about the upper periphery of the side
walls .
As is better seen in the cross-sectional view of Figure 2,
inner tray 28 is received by and contained within cavity 18 of
outer tray 12. Preferably, ridges 40 are formed in the base of the
20 inner tray, such that a major portion of the bott~ ~ surface of
inner tray base 30 is maintained at least slightly above the
uppermost surface of outer tray base 14.
As may also be seen from Figure 2, the inner tray is
nP~-P~s~rily smaller than the outer tray. It is also preferred that
25 the inner tray has a height from the bottommost surface of its base
~o the ~ sur~ace of its f~ange which is less than that of
. 2178254
the outer tray and which, when the inner tray is nested in the
outer tray, allows for the respective flanges of the two trays to
be substantially coplanar. Thus, permeable film 42 may be sealed
to both flanges while maintaining a substantially flat
configuration. However, it is also within the scope of the present
invention to provide the flange of the inner tray either below or
above the level of the outer tray f lange .
Regardless of the relative levels of the two flanges,
permeable film 42 is sealed to the flange 38 of the inner tray
forming an inner seal 44 and to the inner portion 24 of flange 20
of the outer tray forming an outer seal 46. T ,- --hle film 48 is
sealed to the outer portion 22 of outer tray flange 20 only.
Perforations 50 are defined within permeable film 42 between
inner seal 44 and outer seal 46. Perforations 52 are defined
within side walls 32 and, less preferably, base 30 of inner tray
28. Thus, upon removal of the ;r~r- --hle film, open ~-hAnnPlc are
defined between the external c~ Are and the packaged product
allowing for a rapid introduction of oxygen and a correspon~l; nAjl y
rapid blooming of a packaged meat product.
The present inventive package has the unusual advantage of
allowing for a free flow of gases to and from a packaged product
while essentially precluding contamination of the product. After
removal of the impermeable film, any contaminants entering the
package through perforations 50 deîined within the p~ --hle film
are trapped at the lower portion of the package at base 14 or
between base 14 and base 30 and away from the packaged product.
2 t 78254
Thus, it is preferred that ridges 40 are defined within base 30 to
provide ample space for receipt of any contaminates and it is
preferred that perforations are not included in base 30 of the
inner tray.
llowever, for applications where a space is not desired between
the two bases, ridges may be omitted as is shown in Figure 3. For
such embodiment package 60 includes outer tray 62 having a base 64.
Inner tray 66 includes base 68 which rests directly on the upper
surface of outer tray base 64. Similarly, where contamination is
unlikely or of less concern, perforations may be defined in an
inner tray base which includes ridges to allow for a f low of gases
to and from the bottom side of the packaged product. Such a
construction may also be preferred as a means to allow any emitted
blood or other liquid, known as purge, to be drained away from the
lS meat product for a neater appearance when a ~ r is viewing the
package through the permeable f ilm as is shown in Figure 4 .
Package 70 includes outer tray 72 having a base 74. Inner tray 76
includes a base 78 with ridges 80 and perforations 81 defined
therein. A soaker pad 82 is preferably included between the inner
tray base 78 and outer tray base 74.
A further alternative P~hoA;r--~t is the provision of a single
flange rather than a dual flange for the outer tray. Such may be
employed when a precise means is available for sealing the
permeable film to an inner portion of the single flange and for
subsequently sealing the i - -hl e f ilm to an outer portion of
ingle il6gge ~ di~closed i= ~pe=di~ U.S. Seri-il No.
21 78254
.
That is, the primary reason a dual flange is preferred
for use on the outer tray of the present invention is that it
facilities the automated sealing of two separate webs to the
flange. In the embodiment of Figure 6 package 90 includes outer
tray 92 with flange 94. Inner tray 96 includes flange 98.
Permeable film 100 is sealed to flange 98 and to the inner
periphery of flange 94. Impermeable film 102 is sealed to the
outer periphery of flange 94 outboard of the seal between the
permeable film and the flange.
A second circumstance under which a single flange may be
employed on the outer tray of the present inventive package is when
an adequate, peelable seal may be made between the i ~J~L --hle film
and the permeable film. Rather than sealing the illl~ L - hle film
directly to the outer tray, it is possible, with the proper
selection of film c~ Ants, to form a seal directly to the
permeable film which may be peeled away without disturbing the seal
between the permeable film and the outer tray flange. Such a tray
is set forth in Figure 5. P~ckage 110 ;nAl~ e-A outer tray 112
having flange 114. Inner tray 116 includes flange 118. Permeable
film 120 is sealed to flange 118 and flange 114. T --hle film
122 is sealed to permeable film 120 and may be peeled away without
disrupting the seal between permeable film 120 and flange 114.
As a further variation, a single film which is capable of
delaminating into a po -hle web and an imr~ --hle web may be
partially perforated therethrough, with complete perforations being
formed through the permeable port on, at the appropriate location,
~t 78254
.
as is disclosed in copending U.S. Serial No. . Such a film
may be sealed at the permeable 3ide thereof to the two f langes .
When the impermeable portion is ~ ;n~ted and removed,
perforations formed in the permeable web between the seals with the
inner tray and outer tray flanges form open channels which act with
perforations in the inner tray to allow for a rapid gas exchange.
Yet a further alternative embodiment of the present invention
employs a tray disclosed in copending U.S. Serial No. , which
is a dual f lange tray having grooves def ined in the inner portion
of the dual flange. Looking specifically to Figure 7, the outer
tray 161 of package 160 has a cavity 162 and an upper flange 164
which includes inner flange portion 166 and outer flange portion
168 separated by depression 170. As above, depression 170 allows
for trimming of any film sealed to the inner flange portion 166 and
provides a clear delineation between the sealing area for an inner
permeable film and an outer impermeable film.
In the present omho~;- t, inner flange portion 166 includes
grooves 172 defined therein and spaced about the perimeter of the
flange. As can be seen from the drawing of Figure 8, a top
; _ --hle film 174 is sealed to the support member at outer
flange portion 168. Preferably, a peelable seal is formed between
the ;~r~ --hle film 174 and outer flange portion 168 such that the
outer i~.~eL --hle film may be readily removed from the package at
retail .
Figure 8 is an enlarged sectional view of the upper flange 164
of package 160 upon removal of impermeable film 174. Permeable
13
2 1 78254
film 176 is sealed to the support member at inner flange portion
166. However, ~rooves 172 defined in inner flange portion 166
provide for open channels between the tray cavity 162 and
depression 170. When impermeable film 174 is sealed to outer
flange portion 168, depression 170 is enclosed, as is shown in
Figure 7. However, upon removal of film 174, depression 170 and
grooves 172 def ine open ~-hAnn~l c into tray cavity 162 . Inner tray
180 includes side walls 182 having perforations 184 defined there.
Thus, removal of film 174 allows for a rapid release of the low
oxygen atmosphere and introduction of oxygen to the packaged
product via the open channels def ined by grooves 172 and
perforations 184. Therefore, by the present embodiment it is not
necessary to perforate the permeable film during the packaging
process .
As yet a further alternative embodiment the inner tray may
include grooves defined in its single flange such that perforations
within the tray side walls are not needed. Such embodiment is
illustrated in the cross-sectional view of Figure 9 in which
package 200 includes outer tray 202 and inner tray 204. Grooves
206 defined in the flange 208 of inner tray 204 eliminate the need
for perforations in side walls 210. In combination with
perforations 212 defined in permeable film 214, such grooves allow
for a release of any contained low oxygen gaseous c~ re and
for a rapid introduction of oxygen to the packaged meat product
216, as is shown, upon removal of an upper i -hle film.
When used in conjunction with the dual flanged tray having
14
~ 2 1 7825~
grooves in the inner flange portion, discussed above, perforations
in both the tray side walls and the film, between the two trays,
are 2voided as is shown in the cross-sectional view of Figure 10.
For that ~ t, package 220 includes outer tray 222 with dual
flange 224 having an outer portion 226, an inner portion 228 and
depression 230 therebetween. Inner flange portion 228 includes
grooves 232. Inner tray 234 has a single flange 236 with grooves
238 defined therein. Upon removal of an upper impermeable film
grooves 232 and grooves 238 provide an open channel between the
external atmosphere and the packaged meat product 240, as is shown.
Regardless of the package configuration employed, it is
preferred that the inner tray of the present inventive package is
a solid rigid polymer such as, for example, polyester, polystyrene,
high density polyethylene, or polyvinyl chloride, laminated with a
sealant layer. Foamed polymers are less preferred because of
possible outg~c~;n~ of oxygen and other residual gases into the low
oxygen c~ re of the package. However, foamed trays which
include barrier sealant films laminated to both surfaces thereof
are also within the scope of the present invention.
The outer tray must act as a barrier but may be a rigid solid
polymer, a barrier sealant coated polymer, a barrier sealant coated
foamed polymer, or a barrier sealant coated pulp or paperboard
tray. If foamed, the outer tray only requires a barrier film on
the inner surface in order to prevent outgassing of residual gases
into the package.
The permeable f ilm or web of the present invention is an
2 t 78254
oxygen permeable or non-barrier film or skin which may be a
formable or stretchable material. Typical polymeric materials for
the present permeable film may include any material which may be
securely sealed and bonded to the support member, such as
5 polyethylene or any of a variety of ethylene copolymers including,
for example, ethylene vinyl acetate, ethylene acrylate copolymers,
ethylene acrylic acid copolymers including metal neutralized salts
thereof, and ethylene alpha-olefin copolymers. Such ethylene
alpha-olef ins may be heterogeneous or ht j "~US in nature . That
10 is, ethylene alpha-olefins which have been formed by conventional
Zeigler-Natta catalysis and are heterogeneous in nature, such as
linear low density polyethylene (LLDPE), are within the scope of
the present invention as well as such copolymers which are formed
by single site catalysis, such as any of a variety of forms of
15 metallocene catalyst technology, and are homogeneous in nature are
also within the scope of the present invention. A preferred
permeable film for use in accordance with the present invention is
a symmetrical, five layer oriented film having the ~ u~;LuLe:
EVA / LLDPE / EVA / LLDPE / EVA
20 although a wide variety of permeable films may be employed.
The impermeable film or web of the present invention may be
any suitable barrier layer, film or laminate which is substantially
impermeable to gas such as oxygen so that a fresh meat product
contained in a vacuum or other low oxygen ai -- re pocct~qc-t~c an
25 t~nh lnt-t~c~ shelf life over a package without the barrier layer.
Suitable polymeric materials having gas barrier properties for use
16
~ 21 78254
in the present invention include ethylene vinyl alcohol copolymers,
vinylidene chloride copolymers (PVDC) such as vinylidene chloride
vinyl chloride or vinylidene chloride methyl acrylate. Laminates
of a sealable film and a barrier structure which includes a barrier
5 layer and a tough, non-forming material such as a biaxially
oriented nylon or biaxially oriented polyester are especially
preferred for use as the impermeable lidding of the present
inventive packages. A preferred impermeable web has the structure:
biax nylon / PVDC // EVA / LLDPE / seal
lO wherein the double slashes (//) indicate adhesive lamination of the
two webs, although a variety of laminates and multilayer films may
be employed as the impermeable web of the present invention.
Generally, the films or webs which may be employed in
accordance with the present invention may be monolayer or
15 multilayer. Nultilayer films may be employed when all of the
properties required of the f ilm cannot be achieved by a single
polymeric component or a blend of polymers in a single layer. For
example, an impermeable film to be sealed to a tray in all
l;kf-l;h~lod will comprise a multilayer film because several
20 properties are needed including peelable sealability, oxygen
barrier and impact properties, and outer abuse properties. Thus,
the film employed will most likely contain three layers at a
minimum: a seal layer, a barrier layer and an outer abuse layer.
Further internal layers such as adhesive layers and bulk layers may
25 also be included. Laminates of sealable films and nonforming
materials such as biaxially oriented polyester or biaxially
17
2178254
oriented nylon are also within the scope of the present invention
and are widaly recognized as superior lidstocks for tray-type
packages .
The foregoing description of preferred ' ~ ts of the
5 invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form disclosed, and modifications and
variations are possible in light of the above t~ch; ngs or may be
acquired from practice of the invention. The ~ ;r--~ts were
1~ chosen and described in order to explain the principles of the
invention and its practical application to enable one skilled in
the art to utilize the invention in various ~ ; r S and with
various modif ications as are suited to the particular use
contemplated. It is intended that the scope of the invention be
15 def ined by the claims ~rp-~n~led hereto, and their e~uivalents .
