Note: Descriptions are shown in the official language in which they were submitted.
_CKGROUND OF THE INVENTION ~L259025
This invention relate~ generally to vacuum meat stuffing and
relates more particularly ~o vacuum packaging of a molded meat product in
a thermoplastic bag suited for cook-in use.
In vacuum meat pressing, a portion of a moldable raw meat, such
as sectioned ham, is pressed while under vacuum into a cookiug mold
having a generally cylindrical shape, then cooked while in the mold, and
thereafter packaged as a pre-cooked compacted meat product. Alternative-
ly, the raw meat may be pressed into a can or fibrous casing. Conven-
tioDally, a vacuum meat press refers to a meat press that operates inside
a vacuum chamber. In operation, first a moldable raw meat portion is
placed inside a stuffing horn within the vacuum chamber, then the chamber
is closed and a vacuum drawn, and then a plunger pushes the moldable raw
meat through the stuffing horn into a cooking mold initially placed over
the discharge end of the stuffing horn. As the mold is filled by advance-
ment of the plunger, the mold retracts from the stuffing horn along a ~~
guide that exerts selected resistance to retraction of the mold, such as
by a pneumatic cylinder, to yield a selected extent of compaction in the
pressed raw meat. The vacuum chamber is then opened, and the filled mold
removed for cooking. Cooking is done usually by immersion in hot water or
steam typically at 155-170F for 3-5 hours.
Representatively, such a vacuum meat press is commercially
available from Belam B.V. of Uden, Holland. The Belam vacuum meat press
has the feature that as the vacuum is drawn, a holding period is allowed
to elapse sufficient to deaerate the raw meat before pressing to elimi-
nate residual air pockets within the meat and thereby to produce a solid,
cavity free product.
; L~59~Z5
It is the aim of the preseDt invention to provide an improvement
in vac~um meat stuffing wbereby, concurrent witb vacuum stuffing, a raw
meat portion is vacuum packaged in a shrink bag suitable for cook-iD and
shipment of a molded, pre-cooked meat product; Advantageously, such a
pre-packaged ~ood prod~ct is shipped and marketed, while remaining in
its cook-in packaging. A problem in conventional vacuum pacXaging of
molded meat products in thermoplastic bags is incomplete vacuumizing due
to entrapped residual air.
The term "cook-in'l as pertains to packaging is intended to refer
to packaging material structurally capable of withstanding exposure to
cook-in time-temperature conditions while containing a food product. The
packaging material properly characterized as cook-in will maintain seal
integrity and will be delamination resistant under such conditions. The
packaging material will also be heat shrinkable under these conditions so
as to form a neatly fitting package and preferably should have a tendency
to~ard product adhesion to minimize "cook-out" or collection of fluids
between the surface of the food product and the interior surface of the
bag.
Of general interest concerning the present invention is the
disclosure of U.S. Patent No. 4,285,980 for "Method For Preparing Molded
Poultry Product" issued August 25, lg81 to Lewis, directed to molding and
precooking a poultry product using a mold and a flexible bag within the
mold into which poultry meat is flowed followed by closing the bag and
cooking the molded poultry by heating the mold.
Of general intèrest is the disclosure of U.S. Patent 2,779,681
for '`Method Of Preparing And Packaging Meat" issued January 29, 1957 to
Sell, directed to packaging meat in the ready-to-eat condition by vacuum
~ackagiDg meat pieces in a sbrinkable bag, then shrinking tbe bag to press
the ~eat pieces contained therein, and then cooking the packaged meat.
-- 2 --
f~25
Of general interest is the disclosure of United States
Patent 3,928,933 for "Method For Evacuating Packages" issued
December 30, 1974 to Burrell, directed to dual chamher vacuum
packaging in thermoplastic bags utilizing in-chamber gathering and
clipping apparatus for bag closure.
Of general interest is the disclosure of United States
Patent 4,043,011 for "Packaging ~achines" issued August 23, 1977
to Giraudi et al, directed to an in-chamber gathering and clipping
system wherein gathering arms are rotated about a hub and a clip
punch is driven to advance a clip from within the hub onto a bag
neck gathered by the gathering arms.
SUMMAR~ OF THE INVENTION
The present invention provides an improvement in vacuum
meat stuffing whereby, concurrent with vacuum stuffing, deaerated
moldable meat is compacted into a thermoplastic bag, and then the
bag is vacuum closed. Thus, in a single vacuumized operation a
moldable meat product is deaerated, stuffed, ancl vacuumed
packaged, representatively in a cook-in bag. By combining the
vacuum stuffing and vacuum packaging in a single vacuumized
operation, not only is a second vacuumizing step eliminated, but
by virtue of the meat being deaerated immediately prior to
stuffing, entrapped residual air is substantially eliminated in
the final vacuum package.
Accordingly, there is provided a method for vacuum
packaging a molded meat product, comprising: a) loading a
moldable meat product into a stuffing horn of a meat s~uffer
within a vacuum chamber; b) placing a thermoplastic bag onto said
,
~zs~s
horn, and then a cooking mold over said bay so that sald bag lines
said mold, the length of said bag being greater than the length of
said mold to define a bag neck portion; then c) vacuumizing said
chamber; and after a holding period sufficient to deaerate said
meat, then d) advancing said meat from said horn to fill the bag
lined mold; e) substan~ially removing any meat from within said
bag neck; and f) retracting said mold from said horn and closing
said bag neck by gathering and clipping; followed by g) venting
said vacuum chamber, steps c) through f) being accomplished while
the meat is under continuous vacuumization.
Additionally, there is provided apparatus for vacuum
packaging a molded meat product, comprising: a) a vacuum meat
stuffer havlng a stuffing horn; b) means ~or vacuum deaerating a
moldable meat product; c) means for advancing said meat after
deaeration and while still under vacuum from said horn into a
cooking mold lined with a thermoplastic bag having a length
greater than said mold to define a bag neck portion; d) means for
retractlng said mold from said horn; e) means for substantlally
removing any meat from said bag neck; and f) means for closing
said bag, while still under vacuum, by gathering and clipping said
bag neck.
Further details are given below with reference to the
drawings wherein:
FIGU~ES 1-3 schematically show, in side view cross-
section, the steps in operating a vacuum meat press according to
an embodiment of the invention; and
, ~ ~
'
~2~S90~
FIGURE 4 schematically shows a plan view arrangement of
another embodiment for a plural stuffing operation within a single
vacuum chamber using a vacuum pump stuffer.
4a
~..
DESCRIPTION OF THE PREFERREV EMBODIMENTS ~ ~5~025
ReferriDg specifically to the drawings, in FIG. 1, there is
shown in schematic cross-section a representative vacuum meat press
modified in accordance with the iDvention and configured in the beginning
step of an operational cycle. During an operating cycle, a raw moldable
meat portion is loaded into the pressl the press is vacuumized to deaerate
the meat, then the moldable meat is pressed into shape uDder vacuum into
a cook-in bag lined cooking mold, and while still under vacuum the ~ag is
closed by gathering and clipping. Vacuum meat ~ress 11 shown iD its
initial configuration has a portion of moldable raw meat 12, such as
sectioned and massaged raw ham, placed inside stuffing horn 13. Stuffing
horn 13 is generally a hollow elongate structure having an open discharge
end at 19 and an access port at 12a for initially placing the meat portion
into the horn. At the loading end of the horn is a pneumatically driven
plunger 14 with ram 15 closely fitting inside horn 13, the close fit
being pro~ided by sliding friction element 16 which is urged against the
inside sur~ace of horn 13 by a compressed spring internal to ram 15 (not
shown). The apparatus is situated inside a vacuum chamber 17 defined by
a machine base 22 and a hinged lid 18. Over the discharge end 19 of horn
13, there is placed first a thermoplastic bag 20, then a cooking mold 21
is placed over bag 20, so that the bag lines the cooking mold, the com-
bination beîng inserted onto the discharge end of the stuffing horn.
Carrier 23 is brought under the cooking mold, the carrier riding on a
sliding friction foot 24 and being attached to the end of a retraction
plunger 26 which is preieràbly pneumatically actuated Thus, in setting-
up the initial configuration of the apparatus 11 at the beginning of an
operating cycle, ram 15 is fully retracted as shown, and, with closure
lid 18 open, a ràw meat portion 12 is placed inside horn 13. A thermo-
l'~S9~Z5
-lastic bag 20 is placed over discharge end 19 of ~he ~orn, then a cooking
mold 21 is placed over the bag aDd carrier 23 is brought ~nder the bag
liDed mold by advancing retraction plunger 26 against the end of the
stuffing horn. After lid 18 is closed, vacuum chamber 17 is vacuumized
by a conventional vacuum source (Dot shown). Before pressing begins,
there is a brief holding period of several secoDds sufficient to deaerate
the raw meat portion. This preliminary deaeration is essential so that
there will be substantially no entrapped residual air pockets witXin the
final vacuum packaged configuration. At completion of this preparatory
deaeration, pressing action is begun. By elimination of air pockets in
the final vacuum packaged configuration, the amount of purge accumulating
inside the final package over its shelf life is minimized thereby maintain-
ing visual appeal of the packaged product.
In ~lG. 2, tbere is shown the ne~t step in the vacuum pressing
operation wherein ram 15 is driven forward to press the meat portion 12
through the discharge end 19 of stuffing horn 13 into the bag lined mold
2~ and 21. As ram 15 is driven forward to stuff the meat into the bag
lined mold, the mold on carrier 23 is forced o~f horn 13. ~IG. 2 depicts
the end of pressing and the beginning of retraction at the point where
the bag lined mold just clears horn 13. When ram 15 is driven forward to
its fully extended position at the discharge 19 of horn 13, the pressing
step is complete. Retraction plunger 26 tends to counter retraction
motion of the mold by a selected-extent, representatively exerting a
counter-force equal to about 50~ of the pressing force exerted by ram 15.
The purpose of this counter retraction force of pluDger ~6 is to achieve
a selected extent of compaction of meat portion 12 in the bag lined
cooking mold.
- 6 -
~ 2.'5~0~5 -
In FIG. 3 there is shown the fiDal step in the vacuum packagiDg
operation. Carrier 23, together with bag liDed cookiDg mold 21, is fully
retracted by retraction plunger 26 to sufficiently separate the compacted
meat from discharge 19 of horn 13 so that bag 20 may be closed. A pair
of lateral press rollers 30a,b, which are pneumatically positioned
laterally compress the neck of bag ~0. The bag neck is that portion of
the bag toward its open end that extends outside the cooking mold beyond
the pressed meat. The purpose of press rollers 30a,b is to expel any
meat trailings that may remain in the bag neck as a preliminary step to
closing the bag. Such expelling action is accomplished by the motion of
the bag lined mold during retraction on carrier 23 since the rollers are
free-wheeling and not driven. The rolling of press rollers 30a,b is
therefore caused by the retraction of carrier 23. The collapsed pinching
between rollers 30a,b pushes any meat trailings left in the bag neck
outside the bag. The purpose of this expelling action is twofold.
~irst, closing of the bag neck is facilitated as discussed below. Second,
any trailings left in the bag nèck beyond the bag neck closure would
eventually decay thereby rendering the final package unsightly to a con-
sumer. Next, the stuffed bag is closed by gathering and clipping using
an in-chamber clipper indicated generally at 35. The in-chamber clipper
is representatively of the type disclosed in U.S. Patent 47043,011 cited
above and hereby incorporated by reference. Such a clipper device oper-
ates by pivoted gathering arms closing in on the bag neck aDd collapsing
the bag neck in the gathered zone down to about the size of a clip or
staple. Then a clip is advanced from a clipper magazine so that the clip
is driven around the gathered portion of the bag neck and against a die in
one of the gathering arms to cause the clip to be collapsed around the
ga~hered portion of the bag neck thereby forming an air tight seal.
Another example of in-chamber clipping is given in U.S. Patent 3,928,938
~ LZ~9~
ci ~ above which schel~atically shows the steps in a ~at~eridg and
clipping sequence. To facilitate bag neck gathering by the in-chamber
clipper 35, a presser bar 36 and a set of preli~inary gathering arms is
provided at 37 (indicated generally) which gathers-down the bag neck over
clipper 35 so that when the gathering arms of clipper 35 gather-up, the
collapsed bag neck will be encircled. Presser Bar 36 and preliminary
gatherer 36 are pneu~latically actuated toward the end of retraction and
before actuation of clipper 35. Representatively, the bag neck portion
of bag neck 20 will be about seven inches long, i.e. the bag 20 will
extend about seven inches beyond the cooking mold 21 to allow sufficient
clearance of the fully retracted bag lined cooking n~old from the discharge
eDd 19 of horn 13 while maintaining draping of the bag neck on horn 13,
this clearance being suficient for the operation of presser rolls 30a,b
and in-chamber clipper 35. ~be presser rolls are released as the gather-
ing ar~s of the clipper are actuated. At this point with the bag being
vacuum closed, the operational cycle of the vacuum meat press is complete.
Representatively, about 2-8 cycles per minute may be accomplished in
semi-continuous operation.
~590Z5
At the conc]usion of an operating cycle closure lid ~ of
v~cuum chamber 17 is opened and the meat stuffed bag lined mold is re-
moved. At this poi~t the raw meat will be pressed aDd vacuum packaged
inside bag 20. ~he vacuum package inside its cooking mold will then be
subjected to cooking conditions, for example by immersion in hot water or
steam. Cooking is carried out typically in the 155-170F range for 3-5
bours. Preferably the bag is o~ a shrink material so that during this
cooking step the bag shrinks snuggly around the meat product contained
therein to produce a neatly packaged configuration. At the conclusion of
the cookiDg step, tbe stuffed bag is removed from the cooking mold and is
ready for shipment. Since the bag is of the cook-in type, the bag does
not significantly degrade during this cook-in step. Thus, according to
the improvementl of the invention, a moldable meat product may be pressed
and vacuum packaged in one operation with substantially no entrapped air,
then being ready for cook-in followed by dirèct shipment for end use.
This overall approach may be summarized by the term "cook-in-ship". In
addition to the bag being of a shrink material, it also includes a barrier
material to prevent oxygen permeation thereby prolonging shelf-life of
the final product. Preferably, the cook-in bag will have an interior
surface having a tendency for adhesion to meat during cook-in so that
exudation of fluids from the meat during cooking will be minlmized thereby
enhancing appel of the packaged product.
In ~IG. 4, there is shown a schematic cross-sectional plan view
of an alternative embodiment having a plurality of stu~fing horns so that
a plurality of stuffed meat vacuum packages may be obtained with a single
operating cycle. Dual vacuum stuffer 50 has vacuum chamber 56 which
contains stuffing horns 5~a,b discharging to bags 53a,b lining molds
54a,b respectively ~the molds being shown as retracted). Operation of a
cycle is as discussed above ~ith mold retractors 55a.b retracting the
_ 9 _
l.ZS~30~5
stuffed bag lined molds respectively aDd providing clearance for presser
rolls 58a,b and 58c,d, preliminar~ gatherers 59a,b and iD-chamber clippers
57a,b to operate (as described above) respectively. This embodiment
differs significantly from the foregoing embodiment also in that a vacuum
pump stufier is used to compact the raw meat into the bag lined mold,
i.e. moldable raw meat is pumped from a vacuumized (deaeration) reservoir
into and through the stuffing horn. After start up, the horn will be
coDtinuously filled with meat as meat portions are repeatedly extruded
into bag lined molds during semi-continuous operation. The deaeration
holding period at the beginning of a cycle will be sufficient to deaerate
the meat surface at the discharge end of the stuffing horn remaining
after completion of the previous cycle. Meat pump stuffers are com-
mercially available and generally function using a screw type auger to
a2vance a log of moldable meat. Representative meat pump stuffers are
available from Vemag GmbH of West Germany. This dual arrangement can be
similarly ex.ended for the desired number of simultaneous stuffings.
~ Although the present invention has been described in conjunction
with prelerred embodiments, it is to be understood that modifications and
variations may be utilized without departing from the principals and
scope of the invention, as those skilled in the art will readily under-
staDd. Accordingly, such modifications and variations may be practiced
within the scope of the following claims_~
- 10 -
