Note: Descriptions are shown in the official language in which they were submitted.
~364~
Background of the Inventlon
Preservation of ~ood materials is a problem which con-
tinually confronts the ~ood lndustry. Food materlals, æuch
as ~lesh or fish must be preserved in a marketable state while
it ls transported ~rom the site o~ production to the market
and must remain wholesome after purchase by the consumer. Fresh
animal flesh, meat and ~lsh, for example, has a high moisture
content and is dif~icult to preserve since they provide a ready
media for growth o~ contaminating organisms. In addition to
meats, fresh vegetables, ~ruits and berries also have a high
moisture content and, as a consequence, have a very limited
shel~ life when sold in the ~resh state.
Food scientists have resorted to a variety of techniques
to extend the li~e of food products. The methods employed
.
have entailed the use o~ low temperatures, such as refrigeration
and ~reezing; packaging techniques, such as canning; heat treat-
ments, such as pasteurizing and autoclaving techniques; drying
to reduce the moisture content; and the use of preservative
materials. The art has used a variety of chemical preser-
vatlves. Hlstorlcally, sugar and salt (NaCl) have been usedto preserve food for many years. The use of sodium chloride
brlne solutions dates back many centuries. More recently, a
~ider variety o~ chemical preservative materials has been applied
by the rood scientist in an attempt to increase the use~ul li~e
of ~oods. Typical o~ these preservative materials are the
anti-bacterial and antimycotic agents, such as sorbic acid,
proprionic acid, and the sodium and potassium salts o~ proprionic
and sorbic acid. Other materials which have been used as pre~
servatives are ethoxyquin, BHA, BHT, sul~ur dioxide, acetic acid,
3 phosphoric acid and phosphate salts, gallic acid and gallic acid
esters~ and many other chemical materialæ.
.;
The preservatlves used by the prlor art have proven to
be quite useful in extending the shelf llfe of many food pro-
ducts. However, the preservatlves used by the prior art are
not uniformly effectlve for all food systems and are limited in
their ability to extend the shelf life of many food products
without the use of other preserving techniques, e.g., canning
or refrigeration techniques. Many of the prior art preserva-
tlves are also limited in their abllity to preserve food
materials without adversely effecting the appearance and/or
palatability o~ the food products.
Summary o~ the Invention
We have discovered a new method for preservin~ food
materials whlch enable us to package the materials in inexpen-
sive packaging and to store the materials under room temperature
conditions for long periods o~ time. The materials will not
support bacterial growth. The materials can be packaged by
simple, inexpensive processes and do not require expensive
canning and sterilizlng techniques to preserve them. The
materials can be packaged in the uncooked state or they may be
cooked. Many products can be preserved by the process of this
invention, including both human foods and pet foods. Materials
which are suitable for human consumption may be preserved
equally as well. Proteinaceous materials such as meats, eggs,
stews, patés, and soy protein have been successfully preserved.
Other materials which have been successfully preserved are
salads, fruits, melons, tomatoes, cherries, tomato paste and
other vegetable materials. The process of the invention has
the unique advantage of allowing many fresh meat and vegetable
materials to be preserved in a marketable state without canning for
substantlally long perloùs of tlme.
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The process of preserving foods involves treating
the food materials with an effective amount of a preservative
such as dihydroxy acetone. This preservative system is sub-
stantially complete when used as disclosed and reduces or sub-
stantially eliminates the need for preservatives of a palata-
ability reducing or physiologically undesirable character. The
preservative may typically be added to the materials in propor-
tions of about 0.5% to 15% or more by weight. A range of about
3% to 5% by weight has been found to be effective depending on
the product to be preserved and its moisture content. Preser-
vative levels both above and below these levels can be effective
depending on the conditions of storage, their moisture content
and the length of time stability is desired. Longer times and
higher temperatures generally require a greater quantity of pre-
servative than short time cool storage conditions. The preserva-
tive can be added to the materials in a variety of ways, either
by spraying a solution of the preservative, on the materials,
by immersing the materials in a solution of preservative, by
mixing, or by injecting the preservative into the food material.
The residual content of the product will consist of nutri-
; tional and therapeutic components necessary to provide a
satisfactory ration, i.e., one having the complete nutritional
and healthful properties desired. For example, the solids will
be the vitamin, mineral, protein, energy, and therapeutic
materials needed for adequate health and nutrition of the animal
for which the food product is designed.
The final product may contain additional stabilizing,
coloring and flavoring ingredients in addition to the preserva-
tive materials used in order to promote specific coloring or
flavoring effects, but such materials will not normally be of
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1~36~
the palatability reducing or degradinK type, or lf necessary,
their use will be minimal. The standard FD~C food colors,
BHA, BHT, smoke flavor, hamburger flavor, minerals and vltamins
are materials which may easily be added to the products of our
invention. It is expected that the product may also contain
additional nutritional and therapeutic materlals to improve
or lncrease the nutritional value of the final product, to render
the product nutritionally complete or therapeutically more
deslrable.
After the materials are treated by the process of this
invention, they are packaged and prepared for shipment to the
consumer. Packaging may be accomplished by simply wrapplng the
materials in a paper or polymer film wrap or tube. Polypropylene,
foil wrap and polyvinyl chloride (PVC) film wrapping materials
have proven to be satisfactory for maintaining the preserved
products in a bacteriologically stable, palatable form.
Description of the Preferred Embodiments
The process of the invention has proven to be extremely
effective in preserving high moisture food products such as
meats, fish, and poultry which have a high natural moisture-con-
tent and which also have a high level of bacterial contamination
as received. A typical example of pre~ious food products of this
type is high moisture canned stew for humans or a pet food. A
product of this type typically has a moisture content above 50%
by weight (method of Karl Fischer), ~or example, 75% by weight,
and is made from meat, fish, or poultry which may have a high
level of initial bacterial contamination prior to processing.
In addition to meat sources 7 the products, for example a
high moisture pet food, would also typically contain other
nutritious materials to provide a nutritionally balanced food
- 1036~
product. The other nutrient mater~als in addition to meat
would chlefly be proteinaceous and farinaceous food sources,
vitamins and minerals. By meat, fish, poultry, farinaceous
food sources, proteinaceous food sources, vitamins and minerals,
we mean those food nutrlent sources which are well known ln
the art and which are used in ~ood products for humans or in
animal foods. Materials ln these categories are well known
in the art and are described in references and literature well
known in the art, for example, in United States Patent Number
lo 3,119,691 or USDA H ndbook No. 8.
The following examples are selected from the many experi-
ments which have been conducted and are included to illustrate
the invention to those skilled in the art and are not intended
to limit the scope of the invention.
EXAMPLES
Example 1
A meat spread preserved from bacterial spoilage using
dihydroxy acetone was prepared from 50% browned meat, 1.8% wheat
flour, 1.4% salt and spices, 1.3% non-fat dry milk, 2.5% corn-
starch and 3.0% vegetable oil and the remalnder water and preser-
vative as follows:
Fresh ground bee~ was browned in a skillet and the fat
cooked out of the meat was removed. The remaining ingredients,
other than the browned meat, were added to a steam ~acketed
kettle with the water and dihydroxy acetone and heated until the
starch of the wheat flour and cornstarch began to gel. The
browned meat portion was then added and mixed, and the mixture
was heated to 190F. for about five minutes. Heating was then
stopped and the mixture was allowed to cool and was then packed
lnto plastic bags. Samples were prepared having no dihydroxy
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; acetone, 1.0% dihydroxy acetone, 3.0% dihydroxy acetone, and
5.0% dihydroxy acetone. The samples were stored at room tempera-
ture and examined perlodically for signs of spoilage. The
results of the storage tests are shown in Table I.
TABLE I
Meat Spread Wlth Dihydroxy Acetone
69% Moisture (Karl Fischer)
'
., .
,
~; Months Control 1.0% 3.0% 5.0%
Control - Inltlal Count 900/gm; Termlnal Count 30 x 16/gm
1.0% - Initial Count 560/gm; 7 Month Count 100 x 102/gm
3.0% - Initial Count 420/gm; 7 Month Count ~ 10/gm
5.0% Initial Count 120/gm; 7 Month Count ~ 10/gm
Example 2
` A splced corn goulash (Mexican corn) was prepared which
was preserved by dihydroxy acetone from 88% frozen shelled corn,
5.0% margarine, 0.6% salt, 0.4% chili powder, 3.0% pimentos, and
3.0% chopped green pepper as ~ollows:
The margarine was melted in a skillet and the other ingre-
dients were added to the sklllet and mixed. The dihydroxy
acetone was then added at this stage and mixed, and the mixture
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6~1
was heated in a 450F. oven ~or twenty mlnutes to an internal
temperature o~ about 190F. The mixture was then allowed to
cool to room temperature and was then packed in plastlc bags.
Samples were prepared having no addition Or preservative, 1.0%
addition, 3.0% addition and 5.0% addition. The sample~ were
stored at room temperature and were examined periodlcally for
; signs o~ spoilage. The results of the storage tests are shown
in Table II.
TABI.E II
Mexican Corn With Dihydroxy Acetone
65% Moisture (Karl Fischer)
. 9
6 -
4 1 j
3 I 1
2 ` I ~ i
. .
.
Months Control 1.0% 3.0% 5.0%
Control - Initial Count C10/gm; Terminal Count >30 x 16/gm
1.0% - Initial Count 160/gm; 7 Month Count ~10
3.0% - Initial Count 120/gm; 7 Month Count ~10
5.0% - Initial Count 170/gm; 7 Month Count 30 x 103 (mold
; count one sample)
Example 3
A breakfast roll product preserved from spoilage by using
3 dihydroxy acetone was prepared from 8.12% egg, 10.15% vegetable
oil, 4.05% sugar, 37.6% wheat flour, 1.01% baking powder, .51%
salt, and 38.6% milk as follows:
:10316~1
The flour, sugar, baking powder and salt were weighed
and mixed together. The eggs were beaten separately and mlxed
with the oil, and the milk and dry ingredients were added to
the eggs and mixed to form a batter. The chemical preservative
was then mixed into the batter and the batter was proportioned
into muffin pans and baked in a 450F. oven for thir~y minutes
to an internal temperature of about 190F. The muf~ins were
then cooled to room temperature and packed in plastic bags. The
samples were prepared having no preservative system added, 0.5%,
1.0% and 2.5% preservative system. The samples were stored at
room temperature and examined periodically for signs of spoilage.
The results of the storage tests are shown on Table III.
TABLE III
Roll With Dihydroxy Acetone
32% Moisture (Karl Fischer)
~ 2
O I
Months Control 0.5~ 1.0% 2.5%
Control - Initial Count 60/gmj Terminal Count ~ 30 x 106/gm
0.5% - Initial Count C10/gm; Terminal Count ? 30 x 106/gm
1.0% - Initial Count~ 10/gm; 7 Month Count~ 10/gm
2.5% - Initial Count ~10/gm; 7 Month Count 10 x 12/gm
(mold count one sample)
Example 4 1~4~
Mashed potato systems, preserved against bacterial spoilage
; by dihydroxy acetone were prepared from peeled potatoes by
cooking the potatoes in a steam kettle until tender, dralning,
weighing and mashing the potatoes and adding 4% margarlne, .6%
salt, .005% pepper, and 11% milk. While the additional lngre-
dients were mixed to the mashed potatoes and while the potatoes
were still hot at a temperature of about 120F., the preservatlve
chemical was added and mixed. A~ter the preservative was mixed
in with the mashed potatoes, they ~ere allowed to cool to room
temperature, for over a period of about one hour, and then packed
in plastic bags and stored at room temperature. They were
examined periodically for signs of spollage. The levels of
additlon and the results of the storage testsare shown on Table
IV.
TABLE IV
Mashed Potatoes ~ith Dlhydroxy Acetone
77% Moisture (Karl Flscher)
; 6
3 Months Control 1.0% 3.0% 5.0%
Control - Initial Count 58 x 102/gm; Termlnal Count~ 30 x 106/gm
1.0% - Inltial Count 12 x 102/gm, Terminal Count ~30 x 106/gm
3.0% - Initial Count 10 x 102/gm; Termlnal Count> 30 x 106/gm
5.0% - Inltial Count 900/gm; Terminal Count 100 x 103/gm (mold)
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It is realized that variations in these and related
factors could readily be made within the concept taught herein.
The invention is intended to be limited only by the scope of
the appended claims and the reasonably equivalent methods and
products to those def1ned thereln.
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