2,925,346
1
- cured meat color which is stable over a longer ‘reader
vtime than has been possible'h'e‘retofore.
’
'
In accordance with the present invention, cured meat
having a‘ desirable ?xed pink color is hermetically '
GETTERWGQEYACHUMPAQKAGES
Y
packaged in a container, and the packaged product is
" protected against the adverse-e?ect which oxygen would;
have on the cured color of the meati'product by the
I -
Robert H. Harpe?Park rarest, Ill.,faiid' Roliéi't
Kit
tle, Tonawanda, N.Y., assignors to Swift & Company,
Chicago, 11]., a corporation of Illinois
'
presence within the package of a‘v substance which acts’ '
as an oxygen “getter”,and color brightener. A “getter” '
No Drawing. Application August 12, 1957
7
Serial No. 677,767
'
U
10'
_ _
as this term has been used in connection with the vacuum
tube art is a substance which cleans gases 'such as oxygen’
6 Claims.’ (Cl. 99-—_174)
from a given'area. The “getter” may react with ‘uncomé
bined oxygen present within the area, and thereby remove
the oxygen orv the oxygen may be absorbed by the
This invention relates .to ‘the packaging ' of meat 15 “getter.” As used in this description, “getter” is intended§ '
products and more’particularly, to a method of forming
‘ to denotejthe material such as nitric oxide which com
an hermetically sealed package of meat product having
bines. with uncombined oxygen within an area such as
an improved appearance andkeeping qualities.
the ‘ interior of a package and renders , the oxygen;
Vacuum packaging of foods in ?exible transparent
innocuous.
'
wrappers has developed into ‘a highly specialized art.. 20 in the production of cured meats, theprimary?objective'
‘Advantages to be realizedfroin. suohpackagin'g“ include‘;
. "
is to convert the-natural occurring heme pigments, hemo
. an improved. retention of ‘color,- ?avor, and "other
sIObiIiIand myoglobin,‘ to'nitric oridehemoglobinand’ 1
properties};v Moreover, there is anJadvantage infmer
nitricioxide myoglobin, and to avoid thetproduction ‘of "
chandising since'products so packaged are readily visible 2, , theiundesirable grayishor brownish methemoglobinjand
to potential consumers.‘ Because ofj‘the ‘fact that‘ the ,5, metmyoglobin
'
pigments. Conventional, curing; processes;
product 'is' clearly visibleI in the package,
_ ,food
V processors’
marketing
alert for new
‘their
methods
products
by which
in ‘thistheymayproduce
:faShlOlJ' are constantly
attrac
suc'hfas those well knownin the artinvolvetheuse 'of- '
nitrate andnitrite salts and vrequire azsubstantial-rper'iod‘.
.
'ofrtime ‘before the curedcolor develops since'the pro-r ' I
tive packages which show the productpina more appetizingv
duction of the curing agent is dependent uponthe activity-2'
and favorable manner. ‘~ j Packages‘ilformed from ?exible 3.0 of certain bacteria present in the meat, g-There isidisclosed‘ ,
transparent ?lms’ may either be under’reduced pressure in US. application Serial No. 644,793,v ?led March 8,
or may contain an inert gas under a slightly positive
. 1957,"wherein the inventor-is Robert H. Harper, a
pressure 'or, substantially’ at atmospheric pressure, . Vmethod for the quick curing'of'meat. In accordance
Vacuumpackaging in a transparent, gas impermeable, " with this method, a stable cured color is developed in the
?exible wrapper is illustrated in Patent No. 2,621,129 " 35_, meat by the use of gaseous nitric oxide as the curing
to John M. Ramsbottom et al. The use of an inert gas:
agent in a much shorter periodv of time than had previ
in back?lling a ?exible, gas impermeable container?is
illustrated in Patent No. 2,623,826, to Sanford R.
Grinstead.
' ously'been considered possible. All of the meat products
which could be cured by prior art methods may also, '
"
It has now become common practice in the meatv 40
industry to merchandise table-ready meats in the form
of hermetically sealed packages containing, severallslices
of product enclosed in a’ gas impermeable wrapper.’
be cured in this manner.
f‘
r
or,
,_
.
q
-
Although ‘it is, possible to obtain, by‘ ~the~method set
'forth in. the aforementioned patent application, cured;
meat products vhaving a higher degree of'cure than;has
been'possible heretofore in a much shorter time than has‘
Typical meat products which are merchandise'din this
been possible heretofore, the problemv with respect to ' '
fashion include such cured meats as bologna, pickle and 45 stabilization of this brilliant cured color in a transparent
pimento loaf, sliced .ham, thuringer, and al'widiegvarietyv
ofother cured meat products.
package has'not, as far-'as we, are aware,'been‘ solved,
It, is7 most
V r important,
.
‘Since, oxygen ',reacts with the pigments'vwhich' give the
because the product is continuously’ onidisplay' mrthe
.transparent package, thatthe product retain anattractive
cured ‘color'to'meat, forming gray or "grayish-brown '
color and generally desirableiappearance? lniaddition,
50. desirable to, keep ‘the curedgmeat out of thepresenc‘e' -
these characteristics shouldbe'maintainedover a'reason;
vof uncombined oxygen, ‘and this-is particularly so' when ~
methemoglobin and metmyoglobintpigments, itlisl'imosti
able period of time, resulting in a product having agoodr
shelf life.
large‘ surface areasof the cured product such- as,ai'e
present inv slices ofproduct are concerned. :The method
Color is one of the more
important factors’
I
in providing an attractive product, and therefore, any
~. method by which the quality ofcolor isimproved or 55
the length 'of time, of color retention is increased is ,
disclosedrherein presents substantial advantages over the
vacuum packaging and, ‘inert gas‘_ packaging suggested ‘by
others in the art. ,
a
I I
.
Speci?cally, the method of the present invention in
volves the packaging of a-cured meatproduct within an
case of cured meat products which have a desirable pink
atmosphere. having a small amount of"available ‘nitric
color when freshly cured and a grayish orrbrownis'h ‘color 60 oxide.
In one embodiment of the method, slices of a '
ation after exposure to gaseous oxygenfor a period of
greatly to be desired.
This is particularly'so in the
' cured product such as ham or bologna, for example, are,
It is, therefore, an objectlof this invention to provide
an improved method ofpackaging meat products wherein
‘the keeping qualities and desirable color, qualities of the
product are maintained at a high'levelg
i‘ V
_
~
Another object of the'inventionis .tov provide a package
of cured meat product having a desirablecured meat color
stabilized against‘ deterioration ofusaid'colori 1;; J '_
placed inav transparent pliable, v?exible containeryand
oxygen, is removed, from thecontainer by vacuumization 65 gtolabout 29 inches Hg. The package is tl'reriiback?lledv 7“ 'v
with an amount of nitric oxide to decrease the vacuumby Y "9 '
about) inches Hg and sealed. ,A bright and ‘stable.
colored‘ product‘is produced by this method and the
, packageof meat ‘product produced hythis'method far ,
superior both‘ with respect to 'thebrilliance of thejcolo'r .. V
another object of thislinv'ention is the-provision ,70' and the stabilitly ofthe *brilliantcolor to products which
,
of a method for packaging curedmeats having a desirable?
are simply, vacuum packaged, and alsoito those which‘.
2,925,846
Y
in
,
a.
.
Table 2
aropacka'g'ed in‘ac'eor‘dance‘ with the technique’ involving
,back?lling with inert gas.
In the examples which follow, the advantages of this
invention are illustrated by=~a comparison of packages
prepared in accordance with this invention with those’
prepared by prior art methods.
Product
EXAMPLE I
Bologna, Control ______________ __'_ _______________ __
Time of Exposure
(Hrs)
0
Bologna, Test_'__
Vacuuimized packages of sliced thuring'er, ham and
-___
10
9
5
9
8
Ham, Control. __________________________________ __ '
10
4.
Ham, Test
10
10.
bologna, which had been stored for a period of time, were
opened and the slices in each package were divided into
_
' EXAMPLE In
two samples, one sample to be used as a control and
As an alternative to the use of vacuum as a means
the other to be treated in accordance with the method
for removing oxygen from the package, sliced bologna
of this invention. The control sample was placed in an 15 enveloped in an oxygen-impermeable ?lm such as Saran
envelope of a gas-impermeable, ?exible film. The pack
was subjected to the sweeping action of a stream of
age was vacuumized to 29" Hg in a vacuum chamber.
oxygen-free gaseous nitrogen. After about 30 seconds’
This vacuumization results in substantially complete re
exposure of the interior of the package to the stream of
moval of air or other gases contained in the package or
nitrogen, nitric oxide equivalent to about one inch Hg
in the pores of the product. The vacuum chamber is 20 back?ll wasintroduced. The substantially oxygen-free‘,
then connected to a source of oxygen-free nitrogen and
package containing a small amount of nitric oxide was
back?lled with an amount of nitrogen to decrease the‘
sealed and. the package was then exposed to a light source
vacuum by about 2” Hg; When the desired degree of
in a manner similar to that set forthin Example .I above.v
partial vacuum is obtained, the package is sealed.
After some six hours exposure time, there was no vap‘ Packages treated by the method of this invention are 25 parent fading in the desirable bright color of the sample.v
handled substantially in accordance with the procedure
A variation on the foregoing procedure involves vacu->
set forth for the control packages except that nitric oxide
rather than nitrogen is employed as the back?lling gas.
umizing- the package after it is swept with nitrogen and
thenpartially back?lling with a small amount equivalent
The packaged products, both controls and treated samples,
of nitric oxide before sealing. An additional alternative.
were then held'under' a source of light‘ rated at 35 foot 30 which may be employed is sweeping the package with
c-andles, which is comparable to the amount of light which
oxygen-free gaseous nitrogen containing a small amount
packages are exposed ‘to in the usual display case.
The
following table shows the color evaluation of each of the
samples after exposure of the samples to the light source
for. varying periods of time.
of nitric oxide.‘ The proper amount of nitric oxide con
taining nitrogen which should be added to the package:
is easily determinable by the disappearance of traces of
35 brown color typical of nitrogen dioxide which are present"
within the package as a result of uncombined oxygen. In
accordance with this embodiment of the procedure, thev
- point at which further sweeping with nitrogen containing
Table 1
nitric oxide may be terminated is that at which no further‘
Time of Exposure (Hrs)
40 nitrogen dioxide as evidenced by the aforementioned color
Product
0
1
2
3
4
5
is present.
6
.
It can be seen that in some cases the packages which:
9
8
7
7
7
'7
Thuringer, Test_____l
Earn, Control..-
Thurlnger, Control __________________ ._
____ 9
____ 10
8
1O
8
9
8
8
8
7
8
7
i
8
17
6
Ham, Test ______ __
____
10
10
1O
10
10
1O
10
Bologna, Control____
____ 1O
10
9
8
7
6
6
Bologna, Test ________________________ __ 10
10
9
8
8
7
7
result will be substantially at atmospheric pressure, where
as in other cases the packages will be under sub-atmos45 pheric pressure or at a slight positive pressure.
In order to clearly demonstrate that the elfect provided
by the presence of available nitric oxide within the pack
age is one of gettering and rather than merely attaining
1 Brown.
a higher degree of cured pigment, the following test was
50 conducted. Two packages, of sliced bologna having one
The color ratings set forth in this example‘ and other ex
end of the package open were'placed in a vacuum cham
amples which follow are arrived at by averaging the evalu
ber. The chamber was vacuumized and back ?lled with
ations of a panel of 5 members. A rating of 10 is as
nitric oxide. The packages were held in the nitric oxide
near a completely cured color as can be judged visually
atmosphere for about 60 seconds. One of the packages’
and is seldom given by a panel of experts acquainted with 55 was then removed from the chamber in an unsealed con
cured meats. A conventional cured bologna, for example,
dition so that it became exposed to air. This pack
will have an initial rating of 8 and, on rare occasions,
age was then vacuumized and sealed in accordance with
a rating of 9 before exposure to light. Many cured meat
conventional processing procedures. The other sample
products sold in meat markets are rated about 6, this
which remained in the vacuum chamber was vacuumized
being the minimum acceptable rating for a cured product. 60 without exposure to. oxygen and the package was then
A rating of 4 would be described as a dull gray ‘with a
sealed; A comparison of the two samples showed that the
slight pink undercast. The color rating of 5 is generally
sample which had been exposed to oxygen had very poor
considered poor, and, of course, any rating as low as 1
would be representative of a product which is repulsive.
EXAMPLE II
color retention while that which was held in the vacuum
chamber between the nitric oxide and vacuumization steps
65 showed a superior color, much better than that which
had been exposed to the air, but somewhat less attractive
than those samples containing a residual amount of nitric
Sliced ham and sliced bologna were treated substantially
oxide.
inv accordance with the method set out in Example I,
The material from which ?exible containers used in
and the treated samples were exposed to normal showcase 70 this process is made must be impervious to air and in
lighting conditions for 10 hours. After a 10-hour ex
cludes such well-known packaging materials as Saran,
posure period, the control sample had faded considerably
which is a trademark'for a co-polymer of vinyl chloride
in each case while the treated sample retained a desirable
and vinylidene chloride, Mylar, which is a trademark for
bright color. , In Table 2 which follows, the color evalu
a polymethylene terephthalate ?lm, as well as cellophane
ations of each sample are set forth‘.
75 andlaminates of these plastic ?lms with each other or with
2,925,846
,
i
6
5
said container with nitric oxide to a lower degree of par
other materials. These materials can be sealed by any
acceptable method.
'
. tial vacuum, and thereafter sealing said container to pro-
other than ?exible ?lm may be treated in accordance with
the method of this invention, since the basis of the in
vention lies in insuring that a residual amount of nitric
oxide be retained within the area containing the cured.
meat product, the amount of residual
‘
oxide.
'
-
'
4. A process of packaging cured meat products to pro
vide an attractive, bright colored product and inhibit color
degradation in said product which comprises: placing
"the product in a container, sweeping said container and
said product with gaseous nitrogen ‘to substantially re-‘
oxide being
slightly in excess ‘of that required" to reactwith any un
combined oxygen present in the area. Products‘pack 10 move oxygen from said container, adding a smallamount
aged'in metal cans, glass containers or plastic‘ lined ?bre ’ of nitric oxide to said container, and thereafter vsealing
' i said container to provide a package which is substany
tially at atmospheric pressure. '
board containers,’ for instance, can be treated by- the
r ' herein disclosed method; '
a
‘ 5. A process of packaging cured meat products to pro-,
Obviously many, modi?cations and, variations of the .
invention as hereinbefore set forth ‘may be made without 15 'vide. an attractive, bright‘ colored product and inhibit
fore only such limitations should be imposed as are indi- "
color degradation in said product which comprises: plac
ing the product in a container, subjecting the product and
cated in, the appended claims.
the container to a source of gaseous nitrogen containing
depanting from the spirit and scopethereof, and there
We claim:
'
>
'
.
1. A process of packaging cured meat products to pro
vide an attractive, . bright colored product and inhibit
‘ color degradation in said product whichicomprises; plac~
ing the product in a container, removing oxygen from the
product and container, back?lling the‘ container with a
gaseous oxide of nitrogen, and thereafter sealing said con
tainer.
vide an attractive, bright coloredproduct and‘ inhibit
color degradation in said product ‘which comprises: plac
ing the product in a container, subjecting the product
and the container to a high vacuum to remove oxygen
from said product and said container, back?lling said
container with nitric oxide to a lower degree of partial
vacuum and thereafter sealing said container while it is
subjected to said partial vacuum.
2,0
a small amount of nitric oxide, and thereafter sealing
said container to provide a package which is substantially
at atmospheric pressure. .
a
' 6. A process of packaging ‘cured meat products to pro
videa stable cured color in the meat and protect said
meat product against oxygen comprising: placing the .
product in a container, sweeping the product and con
tainer with gaseous nitrogen containing a small amount _
.
2. A process of packaging cured meat products to pro
'
3. A process of packaging cured meat products to pro- '
vide an attractive, bright colored product and inhibit
color degradation in said product which comprises: plac
ing the product in a container, sweeping said container
and product with nitrogen to substantially remove oxy
gen therefrom, subjecting said substantially oxygen-free
container and product to a partial vacuum, back?lling
‘ '
vide a package having a small amountof'available nitric
Of course, cured meat products packaged in containers
of nitric oxide to remove oxygen from said container,
and hermetically sealing said container whereby to pro
vide a small amount of residual nitric oxide within said
container.
'
-
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,017,144
2,621,129
Gironcoli ________ ._;____ Feb. 13, 1912
Ramsbottom et a1 ____ __y__ Dec. 9, 1952
2,623,826
Grinstead ___________ .._ Dec. 30, 1952
OTHER REFERENCES
“Food Industries,” September 1949, pp. 37, 38, 190
and 192, article entitled How Nitrogen Protects the
Quality of Foods.