U.S. patent number 3,764,057 [Application Number 05/280,172] was granted by the patent office on 1973-10-09 for high strength open bottom packaging tray.
This patent grant is currently assigned to Diamond International Corporation. Invention is credited to Kenneth D. Bixler, Richard F. Reifers.
United States Patent |
3,764,057 |
Reifers , et al. |
October 9, 1973 |
HIGH STRENGTH OPEN BOTTOM PACKAGING TRAY
Abstract
A tray of molded pulp or the like is provided for the packaging
of meat, poultry or fish in conjunction with an overwrap
transparent film. The tray bottom is formed of a plurality of
inverted V or U-shaped ribs joining or intersecting in two
directions and defining open windows therebetween, the height of
each inverted V-shaped rib being on the order of several times the
thickness of the remainder of the tray, the side and end walls
having double sloped portions, and the total volume of the inverted
V-shaped ribs being approximately equal to the volume of a bottom
of an imperforate bottom tray of the same size.
Inventors: |
Reifers; Richard F. (New York,
NY), Bixler; Kenneth D. (New York, NY) |
Assignee: |
Diamond International
Corporation (New York, NY)
|
Family
ID: |
23071988 |
Appl.
No.: |
05/280,172 |
Filed: |
August 14, 1972 |
Current U.S.
Class: |
229/407;
217/26 |
Current CPC
Class: |
B65D
1/34 (20130101); Y02W 90/10 (20150501); Y02A
40/90 (20180101); Y02W 90/13 (20150501); Y02A
40/961 (20180101) |
Current International
Class: |
B65D
1/34 (20060101); B65d 001/00 (); B65d 065/00 () |
Field of
Search: |
;229/2.5,29M,29F
;217/26,30 ;206/45.33 ;99/174 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Moorhead; Davis T.
Claims
What is claimed is:
1. In a generally rectangular molded tray for the packaging of
fresh meat, fish or poultry in conjunction with a transparent
overwrap film heat-sealed thereabout, said tray comprising upwardly
and outwardly inclined side walls defining the rectangular
configuration; a generally rounded corner between each adjacent
side wall; and a peripheral lip extending outwardly from said side
walls and defining the periphery of said tray, the improvement
comprising:
means for providing improved oxygen breathing through the bottom of
the tray and for providing visibility through the bottom of the
tray and for supporting the meat, fish or poultry at the bottom of
said tray while maintaining a high humidity thereabout
substantially without the formation of liquid pools, and also for
protecting meat freshness and improving meat quality maintenance,
said breathing and support means comprising a plurality of strong,
substantially solid ribs having an inverted V-shaped cross-section
with rounded apices, some of said ribs extending in one direction,
and other of said ribs extending in a different direction, said
ribs meeting and defining therebetween a plurality of open windows,
said ribs having a section modulus in combination with said side
walls such that the total strength is substantially equal to the
beam strength of a tray of the same material of equal weight with a
flat, imperforate bottom;
and means to resist sidewall deformation from the inward pressure
of wrapping film and to increase rigidity and strength at the
location where said inverted V-shaped ribs join said side walls,
said means comprising a curved portion in each of said side walls
thereby defining in such side walls a straight upper portion, a
curved center portion and a straight bottom portion, said bottom
portion having a height equal to the height of said inverted
V-shaped ribs.
2. A tray in accordance with claim 1 molded of wood pulp.
3. A tray in accordance with claim 2 wherein said side walls are of
bowed construction.
4. A tray in accordance with claim 2 wherein said ribs have a
height about five times the thickness of said side walls.
5. A tray in accordance with claim 2 wherein said ribs have an
included V-angle of about 10.degree. .
6. A tray in accordance with claim 1 wherein said ribs extend
parallel and perpendicular to said side walls and thereby meet at
right angles to form rectangular open windows.
7. A tray in accordance with claim 1 wherein the bottom portion of
said side walls are inclined at an angle of about 5.degree. from
the vertical.
Description
FIELD OF THE INVENTION
The present invention relates to an open bottom food container and,
more particularly, to a food container for use for the packaging of
fresh meat, poultry and fish in conjunction with a transparent
overwrap film, and where the bottom wall is replaced with a
plurality of open windows defined by structural beams; and the
resultant high strength package so produced.
BACKGROUND
Molded wood or paper pulp food trays have served the food packaging
industry well for many years for the packaging of meat, fish and
poultry. Such trays have the advantage, besides low price and low
cost to the consumer, of being clean, sturdy and safe; of being
biodegradable so as to minimize the solids pollution problem; of
being capable of assimilating the free liquid juices which exude
from meat, fish and poultry; of being air and vapor permeable so as
to maintain color and freshness of meat and permit passage of
liquid vapors. Nevertheless, in spite of the many advantages of
such molded wood pulp trays, certain locals have effectively
outlawed their usage by the requirement that a very high percentage
of the food packaged therein be visible to the consumer and since
wood pulp is normally opaque, such trays have not met this legal
requirement.
Consequently, in such locals the only packaging trays utilizable in
view of such laws are clear plastic trays. These clear plastic
trays have many defects, some shared with foam plastic trays,
including reduced strength, increased usage cost because of
downgrading of meat, fabrication of non-biodegradable material;
such trays have sharp edges which tend to cut the packaging film
and/or hands, as well as the meat packaged therein. These trays
collect liquid exudants in puddles from the meat, fish and poultry
packaged therein, thereby not only causing discoloration of the
packaged product, but also serving as a bacterial breeding ground
and further serving to opacify the package itself and provide
distortion in the remaining transparent areas thereby contributing
to the very problem which such trays were designed to overcome;
blood that goes under the tray acts to release the sealed film
causing soiled hands, soiled check-out counters, leaking packages,
etc. In addition, the conventional plastic trays, being formed of
non-breathable material, inhibit oxygen migration to the meat at
the bottom of the tray; this causes further discoloration of the
meat and it is well known that meat in plastic trays deteriorates
on the bottom first.
Another defect of the clear plastic trays involves their
transmission of light along the plane of the tray walls, i.e. a
light pipe or fiber optic effect; this causes further discoloration
of the bottom of the meat. Light has a negative effect on meat
quality causing discoloration more quickly than meat which is
maintained more in the dark but under otherwise similar conditions.
Because of the light pipe effect meat packaged in clear plastic has
its bottom exposed to light constantly even when the tray rests on
an opaque object such as the bottom of the meat cooler on an
underlying package or between two packages.
SUMMARY
It is, accordingly, an object of the present invention to overcome
the defects of the prior art.
It is another object of the present invention to provide a molded,
nestable tray, preferably of molded wood pulp or the like, for the
packaging of meat, fish and poultry which, in spite of being made
of generally opaque or translucent material, provides a superior
quality of visibility of the packaged product.
It is another object of the present invention to provide for the
clean, safe and effective packaging of meats, fish and poultry.
It is another object of the present invention to provide a meat
tray which, although being primarily open on the bottom, is
sufficiently strong so as to facilitate the handling of meat which
tends to be floppy.
It is another object of the present invention to provide a meat
packaging tray which is not only effective but which is
inexpensive.
It is another object of the present invention to provide a meat
packaging tray which provides up to about 90% visibility of the
meat packaged, by providing minimized effective support contact of
the meat packaged in the bottom of the tray.
It is another object of the present invention to provide a meat
packaging tray having improved fresh meat quality maintenance and
superior visibility which are properties enhanced by the absence of
visibility distorting and breathability inhibiting accumulations of
free liquids, the tray tending to inhibit the exuding of juices by
the meat but accepting any liquid which is exuded, in a controlled
manner.
It is a major object of the present invention to provide a high
visibility meat tray having an open multiple window bottom which
has increased, rather than decreased, strength even when
overwrapped with stretchable, transparent plastic film which acts
to compress and sometimes collapse a conventional tray; and which
also has high beam strength.
It is another object of the present invention to provide a meat
packaging tray which provides visibility by providing a minimum
surface contact of the meat.
It is another object of the present invention to provide for
improved meat storage by providing a packaging tray in which the
bottom side of the meat is subjected to increased oxygen
transmission and in which the bottom of the meat is not subject to
rapid deterioration as in imperforate plastic trays.
It is another object of the present invention to provide a
packaging tray in which the bottom side of the meat is subjected to
improved oxygen availability to best maintain freshness and
color.
It is another object of the present invention to maintain the
packaged meat in a moist but not wet condition.
It is another object of the present invention to eliminate meat
contact with a non-breathing tray structure and provide an oxygen
permeable, see-thru structure that keeps meat from touching the
film windows on the bottom of the tray.
It is another object of the present invention to obviate the
necessity of utilizing clear plastic food trays which often provide
poor, distorted visibility, clear polystyrene plastic not being
oxygen permeable and thus tending to discolor the meat, and which
also transmit light to the bottom of the tray because of fiber
optic effect thereby adding to the discoloration problem, the clear
plastic also collecting exuded liquid in pools thereby adding to
visibility distortion and forming bacterial breeding grounds, and
causing nutrient loss.
These and other objects and the nature and advantages of the
instant invention will be more apparent from the following
description:
Meat packaging trays have evolved substantially over the years. The
earlier trays had essentially straight side walls and a flat
peripheral lip, and these served the trade successfully for many
years. However, as the nature of transparent plastic wrap film
changed and non-elastic and non-shrink cellophane was replaced with
more elastic thermoplastic or stretch overwrap films, the tray in
accordance with Reifers U.S. Pat. No. 3,185,371 was developed
improving the tray performance. In more recent years there has been
a strong consumer desire for greater visibility of fresh meat
packaged in trays.
One of the earlier attempts to provide visibility through the
bottom wall of the tray involved simply providing one or more
relatively large openings in the bottom of the tray. However, this
was found to weaken the tray and was not a successful approach to
the problem. The next attempt was to utilize a raised lip about the
periphery of the opening(s) in the bottom wall of the tray, the
function of the upwardly extending lip being to hold the meat
upwardly, to trap juices, and to stiffen and reinforce the
structure. However, this approach was not successful as the meat
tended to sag through the large opening(s) and the structure was
still too weak.
A recent approach, corresponding to the invention of the Bixler
application Ser. No. 53,545 now U.S. Pat. No. 3,698,623 uses a
plurality of meeting or intersecting, inverted V or U-cross-section
shaped ribs extending across the bottom of the tray. This
construction provides maximum visibility with minimum meat contact,
and the inverted V-shaped ribs provide for a reinforced structure.
The construction exemplified in the Bixler application is, in many
respects, a successful approach to the problem, and the present
invention constitutes an improvement on this basic
construction.
In particular, the embodiments illustrated in the Bixler
application still suffer, under certain conditions, from some
weakness, these weaknesses being manifested when a tray containing
meat, fish or poultry is tightly overwrapped with transparent
stretch film which strongly squeezes the tray side walls inwardly
distorting them and causing failure where ribs only are the single
support to side walls. Thus, in certain environments it is found
that the embodiments illustrated in the Bixler application need to
be strengthened, particularly where the V-ribs are joined to the
side walls of the tray. Thus, the smaller trays in accordance with
the embodiments shown in the Bixler application may fail at this
location because of the compressive force of the film alone whereas
the larger size trays fail more easily here because of the
compressive force of the film and because of greatly reduced beam
strength in relation to the increased strength that is actually
needed in the longer side walls.
Improved strength was provided in the larger size trays by the
utilization of an improved force transfer distribution or
transition zone shown in copending application Ser. No. 246,600.
While this construction provides the preferred form in the larger
size trays, in the smaller trays, to the contrary, the transition
zone provided in the exemplified constructions of such copending
application cover too great an area and thereby reduce the
visibility to a greater degree than desirable. In addition, the
great beam strength provided by such a transition zone is not
necessary in the smaller trays because their smaller width and
length provides a reduced beam length.
The present invention provides an improved structure in the
smallest sized trays by the utilization of an improved transition
zone at the location where the ribs of inverted V cross-section
meet the side and end walls of the tray. This is accomplished by
providing double sloped end and side walls which provide good side
wall cave-in resistance, adequate beam strength, and maximized
visibility.
As with the trays exemplified in the copending applications, there
may be substantial variability in the size and shape of the ribs.
In general, the height of the ribs is dependent on the size of the
window openings therebetween, so that the smaller the opening and
the greater the number of ribs for any given tray bottom area, the
smaller the ribs need be in height, both for sufficient strength
and for packaged product maintenance. In this latter regard, the
packaged meat should be kept off the overwrap film on the bottom of
the tray. In general, many small ribs tend to reduce visibility so
that the preferred minimum rib height should be on the order of
about 1/4inches with openings therebetween of about 13/16 inch by
13/16 inch at the bottom of the inverted V-shaped ribs.
In general, it will be understood that the higher the ribs, the
greater will be the strength. Greater rib strength is also
provided, when the tray is molded of wood pulp, by the use of a
narrow U or V-angle. In general, the total volume of the ribs
forming the bottom of the tray and defining the open windows
therebetween, is about 90-100 percent of the volume and weight of
the same area of a bottom of a conventional tray of the same size,
such as that shown in the Reifers U.S. Pat. No. 3,185,371.
Fresh meat packaged in conjunction with the tray of the present
invention, when formed of molded wood pulp, stays fresh much longer
than meat packaged in the so-called clear polystyrene trays. Over
the normal holding time in the supermarket showcase, fresh meat
packaged in accordance with the present invention has better bloom
retention, flavor retention, and better blood control resulting in
substantial savings due to reductions in rewraps, less downgrading,
and less actual meat loss. Improvement also occurs in the
appearance of meat packaged in accordance with the present
invention compared with meat packaged in foam plastic trays. In
general, the tray of the present invention provides improved oxygen
transmission, moisture vapor and blood control under the meat, no
fiber optic problem like clear polystyrene trays, all resulting in
improved meat appearance with unequalled protection to meat
freshness.
The improved characteristics of the package of the present
invention are accomplished by the use of the high support beams of
inverted V-cross-section, which are themselves strong and which
meet the end and side walls along a transition zone which maintains
high side wall compression resistance. This rib connection with the
side and end walls is accomplished by the use of walls which have a
double slope. The high rib strength, when the tray is manufactured
of wood pulp, is provided by rib filling which determines the
precise configuration of the ribs; the filling, in turn, is
determined by the rib V-angle, the type of material from which the
tray is formed, and the weight, height and rib thickness. These
factors are selected to optimize window visibility, strength and
nesting of the tray. In general, the included V-angle will lie in
the range of about 5.degree. to 35.degree. .
The fundamental aspects of the tray in accordance with the present
invention may be said to be: spaced beam members, the spacing being
open between such beam members to allow for viewing the tray
contents between each beam of relatively solid material. The
section modulus of the beams is such that in combination with the
end and side walls, the total strength equals or exceeds the beam
strength of a tray of the same material of equal or slightly more
weight with a flat, solid bottom.
For a better understanding of the invention, a possible embodiment
thereof will now be described with reference to the attached
drawing, it being understood that such embodiment is intended as
merely exemplary and in no way limitative.
BRIEF DESCRIPTION OF DRAWING
FIG. 1 is a top plan view of an embodiment of a tray in accordance
with the present invention;
FIG. 2 is a bottom plan view of the tray of FIG. 1;
FIG. 3 is a front elevation of the tray of FIGS. 1 and 2; and
FIG. 4 is a section taken along line 4--4 of FIG. 1.
DETAILED DESCRIPTION OF EMBODIMENT
Noting the drawing, it will be seen that a tray 10 is provided for
the packaging of meat, fish or poultry in association with an
overwrap film of transparent plastic material such as shrink or
stretch plastic film, or heat-sealable cellophane. The tray 10 has
four upwardly and outwardly inclined walls 16 and these are
preferably bowed as described in Reifers U.S. Pat. No. 3,185,371.
The adjacent side walls merge at rounded corners 12, and such side
walls terminate at their upper end in a downwardly and outwardly
extending peripheral lip 14; while any conventional peripheral lip
may be used, the preferred lip corresponds to the special lip
disclosed in copending application Ser. No. 246,600.
Instead of a flat bottom as is conventional, the tray 10 is
provided with a plurality of ribs 20 which extend between the
bottoms of the side walls 16. As is illustrated, the ribs 20
preferably extend in two different directions at right angles and
are uniformly spaced to define therebetween windows of a more or
less rectangular configuration. Of course, it will be understood
that there may be provided variations in the configuration,
spacing, height and arrangement of the ribs and of the windows,
e.g. the ribs may intersect or meet at different angles so as to
provide brick-work, diamond shaped, etc. window patterns.
As best seen in FIG. 4, the ribs 20 form a cross-section and
inverted V-shape with their apices forming the meat supporting
surface, and it is clear from inspection that the V-apex of each
rib is well rounded unlike the sharp ribs which might be present in
hard plastic that might cut or otherwise damage the meat. In this
illustrated embodiment the V ribs vary in cross-section along their
length, i.e. they undulate, from a minimum included angle -- midway
between each intersection -- of about 10.degree. or less, to a
maximum included angle -- adjacent each intersection -- on the
order of about 30.degree. included V-angle. Such ribs are about
5/16 inches high and the open windows therebetween are about 11/16
inches square. At the bottom of each rib 20 there is provided a
slight horizontal flange portion 22 which is of a minimum width
midway between each rib intersection, and of maximum width adjacent
each rib intersection; for purposes of illustration the flanges 22
are shown in the drawing to be of larger size than in actual
practice.
A major feature of the present invention constitutes the shape of
the side walls 16 as best shown in FIGS. 3 and 4. While in the past
it has been conventional to provide a side wall of a single
curvature, it has now been found in accordance with the present
invention that in order to maximize strength and visibility in a
small tray of the size shown, that it is necessary to provide a
double sloped wall. Thus, the upper part of each wall 16 has an
upper straight portion 15, an intermediate curved portion 17 and a
lower straight portion 18. The curved portion 17, in the preferred
embodiment, has a radius of curvature of 0.187 inch. Also, in the
preferred embodiment, the upper portion 15 of the walls 16 is
inclined from the vertical at an angle of 17.degree.. On the other
hand, the lower vertical portion 18 is inclined at the same angle
or substantially the same angle as the inverted V-shaped ribs 20
and, accordingly, has a steep angle of only about 5.degree. from
the vertical.
While the tray of the present invention is preferably molded of
conventional wood or paper pulp stock which may be formed or
preformed from a water slurry, it will be understood that other
materials may be used; the ribs may be made of harder paper stock,
or such ribs may be specially pressed or other wise treated. In a
preferred embodiment, the wood pulp stock comprises about 3 percent
ureaformaldehyde wet strength resin or about 11/2 percent
melamine-formaldehyde wet strength resin (both FDA approved) and,
furthermore, has a large capacity to accept free liquids which have
exuded from the "problem cuts" or "heavy bleeders," as they are
known in the art; in this embodiment the bottom of the tray ribs
may be specially treated with an inert, impervious water-resistant
substance, e.g. wax or plastic such as polyethylene, while the
upper portions of the ribs will accept this free liquid and expand
to provide a softened cushion for the meat. If desired, the rib
tops may also be coated with the impervious substance, leaving the
side rib surfaces and its center free to accept excess free
liquids.
As illustrated, the lip 14 is provided with a special shape which
is particularly useful when used in combination with the special
wood pulp stock having free liquid accepting capacity. The
peripheral lip 14 has an outwardly extending horizontal terminal
portion 141 and an upper domed portion 142. When overwrapped with a
heat-sealable film the film contacts the lip at both location 141
and location 142 and thereby forms a double seal or gasket. With
the "problem cuts" of beef, namely the 10-15 percent of the meat
packaged which bleeds profusely, the special accepting furnish in
conjunction with the double sealing provided by the lip 14,
prevents the travel of free liquid by capillary action between the
film and the lip from the inside to the outside of the tray where
it would cause the plastic heat seal of the plastic film to open
thereby effecting leakage and unwrapping of the package, besides
providing an unsightly appearance.
The special lip 14 also has mechanical advantages even without the
special accepting furnish. Thus the lip 14 is provided with greater
material mass which provides additional cave-in resistance against
the tension exerted by the stretched overwrapped film. In addition,
the horizontal portion 141, being at a height considerably lower
than the top 142 of the lip 14, absorbs inwardly directed forces in
a manner that stresses the side wall 16 less because the resultant
lever arm is lower, e.g. 30-35 percent lower. Additional vector
analysis shows that the net effect in inward deflection resulting
from inward force is reduced and there is 12 percent less bending
moment.
If desired, the tray of the present invention may be formed of
other, equivalent materials, the structural advantages of the tray
deriving from its geometry. For example, the tray may be formed of
plastic foam, such as structural cellular polystyrene foam
comprising on the order of 70 percent void space, or porous
polyolefin material or other open cell plastic, or a biodegradable
plastic such as biodegradable foam polystyrene. If formed of
materials having different strength characteristics, various
changes in the configuration may be necessary and depending on the
material, certain advantages may be absent.
It will be understood that visibility through the bottom of the
tray to the bottom surface of the meat is very great, on the order
of at least 80 percent, and that there is a minimum surface contact
of the meat on the soft rounded apices of the inverted V's.
The tray of the present invention has many advantages, a number of
which have been delineated above. In brief, however, it may be
noted:
a. Visibility -- Both sides of the meat, fish or poultry may be
viewed, providing up to 90 percent view of contents with at least
80 percent of the bottom of the contents being visible. This
actually results in improved visibility when compared to clear
plastic trays some of which introduce an added layer of thick
plastic sheet in each window area and do not control juices which
distort, mislead, and impair vision where they exist.
b. Strength -- Added beam of structural members across bottom adds
stiffening. Tray easily resists all types of normal handling: (1)
The tray has sufficient strength to resist handling during
wrapping; compression of film on the inward side wall is the main
force which tends to cause side wall deformation or collapse, but
the present tray resists such deformation or collapse. (2) The tray
resists damage from handling in the store and by consumer at home;
insufficient beam strength of package for weight of contents may
tend to deform or break some packages when lifted, but the tray of
the present invention tends to resist such deformation or
breakage.
c. Breathability -- For meat freshness and bloom protection, the
open meat suspending structure promotes oxygen transfer as does the
absence of free liquid pools which in other packages clog the pores
of the overwrap film. This maintains better meat color and provides
for maintenance of meat bloom and quality over the extended period
for store sale to home storage. In addition, no anaerobic bacteria,
such as slime bacteria or botulism, are possible with the high
oxygen transmission provided.
d. Juice Control -- The ribbed tray suspends the entire bottom of
the meat in a moisture saturated atmosphere, desirable for meat
quality preservation. Only a small amount of liquid exudes from the
meat and a portion of this water evaporates to provide this
moisture laden atmosphere; the remaining portion of exuded liquid
is controlled by the pulp. This controlled acceptance of free
liquids enhances appearance, maintains near perfect visibility and
prolongs the freshness and bloom of the meat. The actual contact of
the meat with the tray is less than any tray structure ever known
in commercial use. This minimal contact of the meat with the tray
together with the maintenance of the moisture saturated atmosphere
inhibits the exuding of liquids and insures that the meat retains
its moist surface and juicy character but without forming puddles
or pools of liquid.
e. Nestability -- Trays nest closely for economical storage and
shipping. The bottom itself determines the stacking interval and
gives good denesting as well as prevention of jammed trays. The
inverted V-shaped ribs are preferably indented in the bottom to
match or complement the upper part of the rib shape thereby
reducing the stacking interval with consequent reduced storage and
shipping costs without a sacrifice in strength. The uniform rib
support of the stacked tray bottoms allows ram stacking under
pressure to reduce the stacking height of the trays. In addition to
the obvious advantages of space saving provided, such ram stacking
also aids denesting, since each tray tends to separate, due to the
internal compressive spring back produced by pressure stacking of a
natrually resilient material.
f. Refrigeration -- Beam bottom construction holds meats suspended,
providing improved circulation of moisture saturated air for
oxygenation of the meat.
Contrary to the so-called clear polystyrene tray, the construction
of the present invention with its open windows serves to
effectively control the free flowing of bloody liquid.
Just one drop of blood in the polystyrene tray creates an immediate
problem in the specific window area because of distortion of
remaining visibility, and additionally exposes the meat surface to
a pool of bloody liquid that provides a broth for bacterial action,
often causing slime buildup and causing shorter shelf life in the
store and in the home refrigerator. By way of contrast, the trays
of the present invention with the multiple open window features
maintain the advantages of control of exuding liquid, primarily by
maintaining a saturated atmosphere about the meat but also by
controlled acceptance while at the same time taking advantage of
this control to maintain excellent visibility in the windows that
are breathable, maintaining great effectiveness of the transparent
film over the entire surface of the package, protecting it to the
maximum freshness and minimum bacterial action.
The trays of the present invention also have no problem of cutting
film like the clear plastic trays because the film is protected by
the soft edges of the pulp tray. The meat contained in the clear
polystyrene tray is exposed to bacteria and other contamination
when the film has been cut by the sharp edges of the polystyrene
tray. After extended storage the meat in the clear polystyrene
trays nearly always discolors on the bottom first because of the
destructive effects of the non-breathing, light transmitting, clear
styrene material. On the other hand, the trays of the present
invention work to protect the meat freshness so perfectly that the
bottom of the meat most always retains its meat freshness longer
than the top of the meat under conditions of extended storage.
It will be understood that the invention is not limited to the
embodiment disclosed which is offered illustratively and that
modifications may be made without departing from the invention.
* * * * *