U.S. patent application number 10/618397 was filed with the patent office on 2004-01-15 for improvements in pasteurized eggs.
Invention is credited to Davidson, L. John, Wagner, Myron A..
Application Number | 20040009271 10/618397 |
Document ID | / |
Family ID | 27569544 |
Filed Date | 2004-01-15 |
United States Patent
Application |
20040009271 |
Kind Code |
A1 |
Davidson, L. John ; et
al. |
January 15, 2004 |
Improvements in pasteurized eggs
Abstract
There is provided a process for pasteurizing in shell chicken
eggs (2) carried in stacks (1) by placing the eggs in a heated
fluid bath (4) having a temperature of between about 128 to 145
degrees F., allowing the eggs to dwell in the heated fluid bath
until there is a log reduction of at least 4.6 of any Salmonella
bacteria within the eggs, removing the eggs from the heated liquid
bath and into a gaseous atmosphere (26), and contacting the eggs
with an antibacterial fluid (28) containing an antibacterial agent.
Preferably, the eggs are thereafter contacted with a sealant such
as wax. In the gaseous atmosphere the eggs further pasteurize to at
least a 5 logs reduction of the bacteria by way of residual heat in
the eggs. During cooling in the gaseous atmosphere, the eggs suck
the antibacterial fluid into the eggs between the inside of the
shells and the membranes and provide antibacterial barriers in the
eggs.
Inventors: |
Davidson, L. John;
(Atkinson, NH) ; Wagner, Myron A.; (Wilmington,
DE) |
Correspondence
Address: |
KENYON & KENYON
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
27569544 |
Appl. No.: |
10/618397 |
Filed: |
July 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10618397 |
Jul 10, 2003 |
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10084444 |
Feb 28, 2002 |
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10618397 |
Jul 10, 2003 |
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09954462 |
Sep 14, 2001 |
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09954462 |
Sep 14, 2001 |
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08962766 |
Nov 3, 1997 |
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5843505 |
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60271726 |
Feb 28, 2001 |
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60271746 |
Feb 28, 2001 |
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60314631 |
Aug 27, 2001 |
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60335031 |
Nov 2, 2001 |
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Current U.S.
Class: |
426/298 |
Current CPC
Class: |
A23L 15/00 20160801;
A23B 5/18 20130101; A23B 5/0052 20130101; A23B 5/14 20130101; A23B
5/10 20130101; A23L 15/30 20160801; A23B 5/12 20130101 |
Class at
Publication: |
426/298 |
International
Class: |
A23B 005/00 |
Claims
What is claimed:
1. A method of pasteurizing in-shell chicken eggs, comprising: (1)
placing the eggs in a heated fluid having a temperature of between
about 128.degree. F. and 146.degree. F.; (2) allowing the eggs to
dwell in the heated fluid until there is a log reduction of at
least 4.6 of any Salmonella bacteria within the eggs; (3) removing
the eggs from the heated fluid and into a gaseous atmosphere; and
(4) contacting the eggs with an antibacterial fluid containing an
antibacterial agent.
2. The method of claim 1, wherein the log reduction is about above
4.75.
3. The method of claim 2, where the log reduction is about 6 to 12
logs.
4. The method of claim 1, wherein the heated fluid is at different
temperatures.
5. The method of claim 4, wherein a first temperature of the heated
fluid is about 139.degree. F. to 146.degree. F., and a second
temperature of the heated fluid is about 130.degree. F. to less
than 135.degree. F. and a third temperature of the heated fluid is
about 135.degree. F. to 138.degree. F.
6. The method of claim 4, wherein the heat fluid is water and the
water is contained in an elongated tank through which the eggs
traverse from an entrance end of the tank to a middle zone of the
tank and to an exit end of the tank.
7. The method of claim 6, wherein near a bottom of the tank a
plurality of jets are dispersed through which a jet fluid is passed
from the jets into the water.
8. The method of claim 7, wherein some of the jets are arranged
transverse to a major axis of the tank and one series of the
transverse jets is spaced apart along the major axis from another
series of the transverse jets.
9. The method of claim 8, wherein the jet fluid rises vertically in
the water and to at least near a top of the water to provide a jet
fluid wall in the water near each of the spaced apart series of
jets, and between two such jet fluid walls a jet fluid walled
compartment is formed.
10. The method of claim 9, wherein there are at least two jet fluid
walled compartments along the major axis and at least two of the
compartments are maintained at different temperatures.
11. The method of claim 10, wherein the jet fluid is a gas or
liquid.
12. The method of claim 11, wherein the gas air and the liquid is
water.
13. The method of claim 10, wherein at least three compartments are
maintained at different temperatures.
14. The method of claim 13, wherein there are an entrance
compartment, a middle compartment, and an exit compartment and the
length along the major axis of the tank of the entrance compartment
is from 0.1 to 0.3 the length of the tank, the middle compartment
is from 0.3 to 0.7 the length and the exit compartment is from
about 0.1 to 0.3 the length and the temperature within the entrance
compartment is from 139.degree. F. to 146.degree. F., the middle
compartment is from 132.degree. to less than 135.degree. F. and the
exit end compartment is from 135.degree. F. to 138.degree. F.
15. The method of claim 14, wherein the length of the entrance
compartment is from about 0.1 to about 0.2, the middle compartment
is from about 0.2 to 0.6 and the exit compartment from about 0.1 to
0.2 and the respective temperatures are from about 141.degree. F.
to 143.degree. F., 133.degree. F. to 134.5.degree. F. and
136.degree. F. to 139.degree. F.
16. The method of claim 1, wherein the antibacterial agent is any
one of FDA Food Use approved bacteriacides.
17. The method of claim 16, wherein the bacteriacide is selected
from chlorine, bromine, ozone, hydrogen peroxide and quaternary
ammonia compounds.
18. The method of claim 16, wherein the antibacterial fluid is
water.
19. The method of claim 1, wherein the antibacterial fluid is
contacted with the eggs and is also contacted with mechanical
equipment handling the eggs subsequent to the eggs exiting the
heated fluid.
20. The method of claim 19, wherein the antibacterial fluid is
sprayed onto the eggs and onto the mechanical equipment and prior
to the eggs contacting the mechanical equipment.
21. The method of claim 1, wherein after contacting the eggs with
the antibacterial fluid the eggs are contacted with an egg pore
sealant.
22. The method of claim 21, wherein the pore sealant has an
antibacterial agent therein.
23. The method of claim 22, wherein the antibacterial agent is a
FDA Food Use approved bactericide.
24. The method of claim 21, where the pore sealant is selected from
food grade polymers, waxes and soluble proteins.
25. The method of claim 24, wherein the sealant is wax.
26. The method of claim 21, wherein the sealant is sprayed onto the
eggs.
27. The method of claim 21, wherein after contacting the eggs with
the sealant, an amount of sealant which remains on the eggs is at
least equal to 90% of natural egg pore sealant removed from the
eggs during the dwell of the eggs in the heated fluid.
28. The method of claim 1, wherein the eggs exit the heated fluid
with a log reduction of about at least 4.6 and while the eggs are
in the gaseous atmosphere residual heat in the eggs increases the
log reduction to at least 5.
29. The method of claim 28, wherein the eggs are in the gaseous
atmosphere for about 1.5 to 3.5 minutes.
30. A method of pasteurizing in-shell chicken eggs comprising: (1)
placing the eggs in a heated fluid having temperatures between
about 128.degree. F. and 146.degree. F. so as to heat the eggs,
said heated fluid having a first temperature of about 139.degree.
F. to 146.degree. F., a second temperature from about 130.degree.
F. to less than 135.degree. F. and a third temperature from about
135.degree. F. to 138.degree. F., and wherein the first, second,
and third temperatures of the heated fluid are maintained in
separate zones of the heated fluid; (2) allowing the eggs to pass
through the first, second, and third temperatures in a time period
which causes at least a log reduction of 4.6 of any Salmonella
bacteria within the eggs; and (3) removing the eggs from the heated
fluid to a gaseous atmosphere and allowing the eggs to cool.
31. The process of claim 30, wherein while the eggs are in the
gaseous atmosphere, the eggs are contacted with an antibacterial
fluid containing an antibacterial agent.
32. The process of claim 31, wherein after the eggs are contacted
with the antibacterial fluid, the eggs are contacted with an egg
pore sealant.
33. The process of claim 32, wherein the sealant has an
antibacterial agent therein.
34. The method of claim 30, wherein the eggs remain in the gaseous
atmosphere until the eggs reach a final log reduction of at least
about 5.
35. The method of claim 34, wherein a final log reduction is up to
about 12.
36. The method of claim 30, wherein the heated fluid is water and
the water is contained in an elongated tank through which the eggs
traverse from an entrance end of the tank to a middle zone of the
tank and to an exit end of the tank and near a bottom of the tank a
plurality of jets are dispersed through which a jet fluid is passed
from the jets into the water.
37. The method of claim 36, wherein some of the jets are arranged
transverse to a major axis of the tank.
38. The method of claim 37, wherein one series of the transverse
jets is spaced apart along a major axis from another series of
transverse jets.
39. The method of claim 38, wherein the jet fluid rises vertically
in the water and to at least near a top of the water to provide a
jet fluid wall in the water near each of the spaced apart series of
jets, and between two such jet fluid walls a jet fluid walled
compartment is formed.
40. The method of claim 39, wherein there are at least three jet
fluid walled compartments along the major axis and the three
compartments are maintained at the first, second and third
temperatures.
41. The method of claim 40, wherein the jet fluid is a gas or
liquid.
42. The method of claim 40, wherein there are an entrance
compartment, a middle compartment and an exit compartment and the
length along the major axis of the tank of the entrance compartment
is from 0.1 to 0.3 the length of the tank, the middle compartment
is from 0.3 to 0.7 the length and the exit compartment is 0.1 to
0.3 the length.
43. The method of claim 42, wherein the length of the entrance
compartment is from about 0.1 to about 0.2, the middle portion is
from about 0.2 to 0.6 and the exits from about 0.1 to 0.2 and the
respective temperatures are from about 141.degree. F. to
143.degree. F., 133.degree. F. to 135.degree. F. and 136.degree. F.
to 137.degree. F.
44. The method of claim 31, wherein the antibacterial agent is any
one of FDA Food Use approved bactericides.
45. The method of claim 31, wherein the antibacterial fluid is
contacted with the eggs and is also contacted with mechanical
equipment handling the eggs subsequent to the eggs exiting the
heated fluid.
46. The method of claim 45, wherein the eggs and mechanical
equipment are sprayed with the antibacterial fluid and the
mechanical equipment includes egg destacking equipment.
47. The method of claim 32, wherein the pore sealant has an
antibacterial agent therein.
48. The method of claim 47, wherein the antibacterial agent is a
FDA Food Use approved bactericide.
49. The method of claim 32, wherein the pore sealant is selected
from food grade polymers, waxes and soluble proteins.
50. The method of claim 49, wherein the sealant is wax.
51. The method of claim 32, wherein the sealant is sprayed onto the
eggs.
52. The method of claim 30, wherein while the eggs are in the
gaseous atmosphere residual heat in the eggs increases the log
reduction to at least 5.
53. The method of claim 52, wherein while the eggs are in the
gaseous atmosphere for about 1.5 to 3.5 minutes.
54. The method of pasteurizing in shell chicken eggs, comprising:
(1) passing the eggs through a tank containing a heated fluid at
different temperatures in separate zones of the heated fluid, said
different temperatures being from about 139.degree. F. to
146.degree. F. in a first zone, from about 130.degree. F. to less
than 135.degree. F. in a second zone and from about 135.degree. F.
to about 138.degree. F. in a third zone; and (2) removing the eggs
from the heated fluid when the eggs have reached at least about 4.6
log reduction of any Salmonella within the eggs.
55. The method of claim 54, wherein the log reduction is about
4.8.
56. The method of claim 55, wherein the log reduction is up to
12.
57. The method of claim 54, wherein the heated fluid is water and
the eggs traverse the tank from an entrance end to a middle zone of
the tank and to an exit end of the tank, and the first, second and
third temperature zones corresponds, respectively, thereto.
58. The method of claim 57, wherein near a bottom of the tank a
plurality of jets is dispersed through which a jet fluid is passed
from the jets into the water.
59. The method of claim 58, wherein some of the jets are arranged
transverse to a major axis of the tank.
60. The method of claim 59, wherein one series of the transverse
jets is spaced a part along the major axis from another series of
transverse jets.
61. The method of claim 60, wherein the jet fluid rises vertically
in the water and to at least near a top of the water to provide a
jet fluid wall in the water near each of the spaced apart series of
jets, and between two such jet fluid walls a jet fluid walled
compartment is formed.
62. The method of claim 61, wherein there are at least two walled
compartments along the major axis and the at least two walled
compartments are maintained at the different temperatures.
63. The method of claim 58, wherein the jet fluid is a gas or
liquid.
64. The method of claim 63, wherein the gas is air and the liquid
is water.
65. The method of claim 62, wherein there are an entrance
compartment, a middle compartment and an exit compartment and the
lengths along the major axis of the tank of the entrance
compartment is from 0.1 to 0.3 the length of the tank, the middle
compartment is from 0.3 to 0.7 the length and the exit compartment
is from 0.1 to 0.3 the length and the temperature within each of
the compartments corresponds to the different temperatures,
respectively.
66. The method of claim 65, wherein the length of the entrance
compartment is from about 0.1 to 0.2, the middle compartment is
from about 0.2 to 0.6 and the exit compartment is from about 0.1 to
0.2 and the respective temperatures are from about 141.degree. F.
to 142.degree. F., 133.degree. F. to less than 135.degree. F. and
136.degree. to 137.degree. F.
67. The method of claim 54, wherein after the eggs are removed from
the heated fluid, the eggs are passed into a gaseous
atmosphere.
68. The method of claim 67, wherein after the eggs pass into the
gaseous atmosphere the eggs are contacted with an antibacterial
fluid containing an antibacterial agent.
69. The method of claim 68, wherein the antibacterial agent is any
one of FDA Food Use approved bactericides.
70. The method of claim 68, wherein the antibacterial fluid is
contacted onto the eggs and is also contacted onto mechanical
equipment handling the eggs.
71. The method of claim 70, wherein the antibacterial fluid is
sprayed onto the eggs and the mechanical equipment prior to the
eggs contacting the mechanical equipment.
72. The method of claim 68, wherein after contacting the eggs with
the antibacterial fluid, the eggs are contacted with an egg pore
sealant.
73. The method of claim 73, wherein the pore sealant has an
antibacterial agent therein.
74. The method of claim 73, wherein the antibacterial agent is a
FDA Food Use approved bactericide.
75. The method of claim 72, wherein the pore sealant is selected
from food grade polymers, waxes and soluble proteins.
76. The method of claim 72, wherein the pore sealant is at least
translucent when applied to the eggs.
77. The method of claim 72, wherein the sealant is wax.
78. The method of claim 72, wherein the sealant is sprayed onto the
eggs.
79. The method of claim 72, wherein after contacting the eggs with
the sealant, the amount of sealant which remains on the eggs is at
least equal to 85% of natural egg pore sealant removed from the
eggs during the dwell of the eggs in the heated fluid.
80. The method of claim 79, wherein the amount is at least 90%.
81. The method of claim 67, wherein while the eggs are in the
gaseous atmosphere residual heat in the eggs increases the log
reduction to at least about 5.
82. The method of claim 81, wherein the eggs are in the gaseous
atmosphere for about 1.5 to 3.5 minutes.
83. A pasteurized egg having an antibacterial fluid disposed
between an egg membrane and an inside of a shell of the egg.
84. An apparatus for pasteurizing in shell chicken eggs, comprising
a support for the eggs and an application device in proximity to
the support for applying to at least partially pasteurized eggs an
antibacterial fluid.
85. A method of protecting an at least partially pasteurized egg
from rot bacteria while the egg is in a heated condition,
comprising contacting the egg with an antibacterial fluid having an
antibacterial agent therein.
86. The method of claim 85, wherein the antibacterial agent is a
FDA Food Use bactericide.
87. The method of claim 86, wherein the bactericide is a quaternary
ammonium compound.
Description
RELATED APPLICATIONS
[0001] This application claims priority to and is a continuation of
U.S. Provisional Patent Application Serial Nos. 60/271,726, filed
Feb. 28, 2001; 60/271,746, filed Feb. 28, 2001; No. 60/314,631,
filed Aug. 27, 2001 and No. 60/335,031, filed Nov. 2, 2001 and is a
continuation-in-part of U.S. Non-Provisional application Ser. No.
09/954,462, filed Sep. 14, 2001, which application in turn is a
continuation-in-part of Non-Provisional application Ser. No.
09/613,832, filed Jul. 11, 2000, now U.S. Pat. No. 6,322,833,
issued on Nov. 27, 2001, which patent is an ultimate divisional
application of U.S. Non-Provisional application Ser. No.
08/962,766, ultimately filed on Aug. 25, 1995 and now U.S. Pat. No.
5,843,505, issued on Dec. 1, 1998
BACKGROUND OF THE INVENTION
[0002] Pasteurized eggs are relatively new items of commerce in the
United States, and indeed, throughout the world. While the art has
sought for sometime to devise effective methods for pasteurizing
eggs, as described in detail in U.S. Pat. No. 5,843,505, which
patent is incorporated herein by reference and relied upon for
disclosure, until the existence of the process described and
claimed in that patent, pasteurizing of eggs had not been
successful either from a commercial point of view or a
functionality point of view. Functionality refers to a group of
properties of eggs including yoke index, Haugh units, yoke
strength, angel cake volume, sponge cake volume, foam stability,
whippability, and lysozyme properties. All of these functionalities
are well known to the art and are described in detail in the
above-noted patent and, for conciseness herein will not be
described in detail. However, for example, the angel cake volume is
sensitive to egg white protein damage. Heat damage to the protein
will increase whipping time and decrease cake volume. Foam
stability is a measure of the volume of foam of whipped egg whites.
Heat damaged white protein will provide less foam volume and
therefore is less desirable in making meringues and the like. Haugh
units also measure the foam stability of whipped egg whites and is
important in many uses of eggs for baking and cooking. Yoke index
is a measure of the yoke height versus the yoke width. When
breaking a fresh egg into a pan for frying, if the yoke index is
not proper, the yoke will look flat and unappealing in a sunny side
up fried egg. Yoke strength is a measure of the strength of the
yoke membrane to retain the yoke and is important when frying
eggs.
[0003] The above-noted U.S. Patent describes and claims processes
where eggs may be pasteurized in keeping with the relatively new
U.S. Food and Drug Administration definition of pasteurized eggs,
which includes a requirement that any Salmonella species in the egg
is reduced by an amount equal to at least 5 logs. Those processes
are also carried out such that the pasteurized eggs do not have
substantial loss of functionality, particularly in regard to the
Haugh units, as well as the yoke index and yoke strength.
[0004] As a result of the processes described and claimed in that
patent, substantial commercialization of pasteurized eggs has now
taken place.
[0005] Very basically, the processes entail heating raw eggs in a
heat transfer medium at certain temperatures within certain
parameter lines of a graft shown in that patent and for a time
sufficient that a Salmonella species which may be present in the
eggs is reduced by an amount of at least 5 logs. In one example of
that patent, the internal temperature of the yoke is brought to
133.degree. F. and maintained at that temperature by addition of
heated or cooled water to a pasteurizer until any Salmonella
bacteria in the egg is reduced by at least 5 logs. Depending upon
the particular pasteurizer, the history of the raw eggs being
pasteurized, the temperature of the raw eggs entering the
pasteurizer and their size, ambient temperatures around the
pasteurizer, as well as other factors, a total pasteurizing time of
somewhere about 64 minutes or more is required. Of course, the time
of dwell of the central portion of the yoke of the eggs being
pasteurized will be considerably less than that in accordance with
the parameter lines A and B of the graft in that patent. However,
the 64 minutes so called total processing time, including the time
required to bring the yokes to the temperatures required by that
patent for pasteurization, substantially increases the cost of
production of pasteurized eggs. It would, of course, be of a
substantial advantage to the art to considerably shorten the total
processing time required for such pasteurization.
[0006] Also, it was found that eggs, which are commercially
pasteurized according to that patent, do not have the extended
shelf life of the eggs pasteurized in the examples of that patent.
Indeed, in commercial pasteurization of the eggs, it was found that
a substantial percentage of the pasteurized eggs, even with proper
traditional storage conditions, unexpectedly had a shelf life of
only about 21 days before rot began to appear in the pasteurized
eggs. This, of course, was of concern in regard to the commercial
operation, and it was well recognized that this is a disadvantage
in the commercial process of pasteurizing eggs and that it would be
of substantial advantage to the art to considerably extend the
shelf life of the commercially pasteurized eggs.
[0007] The above-noted patent also discloses that the heat transfer
medium for pasteurizing the eggs may be heated to more than one
temperature during the pasteurizing process. However, as a
practical matter, having the heat transfer medium, e.g. water, at
different temperatures, provides advantages and more efficiency,
but requires a series of separate pasteurizing tanks, along with
the added capital costs. This also requires placing large volumes
of eggs in one tank, removing the eggs from that tank, and placing
and removing the eggs from a succeeding tank or tanks. It was
determined that using multiple tanks and the apparatus for moving
the eggs in and out of the tanks not only complicated the
pasteurizing process, but substantially increased the cost thereof.
In this latter regard, one of the hazards of pasteurizing eggs is
that if during handling eggs break in a pasteurizing tank, then for
food safety reasons, the process must be stopped, the tank drained,
well-cleaned, and replenished with hot water. It was therefore
recognized that it would be a substantial advantage to carry out
the pasteurizing process at multiple temperatures but without the
necessity of using multiple tanks. This would provide the
advantages disclosed in the aforementioned patent that multiple
temperatures of pasteurization can decrease the total time required
for pasteurization and, thus, substantially reduce the
pasteurization costs.
[0008] Further, the prior art considered it important that the eggs
be removed from the pasteurizer as soon as a 5 log reduction of any
Salmonella in the eggs is achieved. This is in order to prevent
unwanted additional pasteurization, i.e. above the 5 logs safety
requirement, which would adversely affect the functionality of the
pasteurized eggs. However, this rather rigid requirement in the
pasteurization, as it was perceived by the art, made it difficult
to precisely achieve that 5 log reduction, while at the same time
retaining the functionality of fresh raw eggs, without very careful
control of the pasteurization process, along with expensive and
extensive control devices. It would, of course, be of an advantage
to the art to pasteurize eggs without such expensive control.
SUMMARY OF THE INVENTION
[0009] In regard to the above-discussed advantage of reducing the
total pasteurization time, it was discovered that the total
pasteurization time could be reduced by certain uses of
multi-temperatures in the pasteurization process. These certain
multi-temperatures include at least three different temperatures or
temperature ranges, and especially where a first temperature(s)
encountered by the eggs is at a higher temperature(s), a second
temperature(s) encountered by the eggs is at a preferred
pasteurization temperature(s), and a third temperature(s)
encountered by the eggs is again at a higher temperature(s). More
precisely, the first temperature(s) should be between about
139.degree. F. and 146.degree. F., the second temperature(s) should
be between about 130.degree. F. and less than 135.degree. F., and
the third temperature(s) should be between about 135.degree. F. and
138.degree. F. As a subsidiary discovery in this regard, it was
found that, however, the time in which the eggs dwelled at the
three different temperatures or temperature ranges must be
different with a shorter time at the first higher temperature(s), a
longer time at the second more desired pasteurization
temperature(s), and a shorter time at the higher third
temperature(s).
[0010] As another discovery in this regard, it was found, contrary
to the understanding in the art, that the eggs need not be
pasteurized to at least a 5 logs reduction of Salmonella in the
pasteurizer, e.g., a pasteurization water bath. Prior to the
present invention, it was considered essential that the eggs reach
a 5 logs reduction in the pasteurization water bath and after the 5
logs reduction, the eggs are immediately removed from the
pasteurization bath and placed in a chilled water bath to prevent
further heating, pasteurization, and deterioration of functionality
that would be caused by further pasteurization. It has been found,
contrary thereto, that the eggs can be removed from the
pasteurization bath when reaching only about a 4.6 logs, e.g., a
4.8 logs reduction, especially about a 4.75 logs reduction, and
that residual heat in the eggs will achieve the 5 logs reduction
after the eggs are removed from the pasteurizer. When the eggs are
immediately passed into a gaseous atmosphere, e.g., air, after
removal from the pasteurizer, pasteurization will continue to occur
until the eggs reach a temperature below about 128.degree. F. Thus,
during that dwell in the gaseous atmosphere, additional
pasteurization will take place and will reach at least a 5 log
reduction.
[0011] As another important discovery, it was found that in a
conventional elongated pasteurizing tank, even though the water
therein is a single body of water, it is possible to generate
different temperature zones along a major axis of that tank such
that the temperatures noted above could be achieved. This is
because heat generated in localized zones within the tank can form
zones of different temperatures by way of vertical convection of
the water in the tank.
[0012] As another discovery in this regard, it was found that the
different temperature zones can be substantially sharpened into
distinct temperature compartments having different temperatures by
use of a plurality of series of transverse jets spaced apart along
a major axis of the tank. These jets cause a jet fluid to pass from
the bottom of the tank toward the top of the tank and provide
something of a jet fluid wall for containment of the water at the
different temperatures.
[0013] Also, it was found that after pasteurization of the eggs in
the pasteurizer, and when the eggs are in the gaseous atmosphere,
mentioned above, that the eggs should be contacted with an
antibacterial fluid containing an antibacterial agent. Thus, any
unwanted bacteria, such as rot bacteria and air borne pathogens,
which might penetrate the eggs during cooling in the gaseous
atmosphere, are substantially killed or very significantly reduced
in number by the antibacterial agent in the antibacterial fluid,
such that the eggs are will rot during long term refrigerated
storage. In deed, this is applicable to protect from rot bacteria
any at least partially pasteurized egg that is in a heated
condition, that is applying to that egg an antibacterial fluid
containing an antibactericide.
[0014] Thus, briefly stated, in one regard, the present invention
provides a method of pasteurizing in-shell chicken eggs by placing
the eggs in a heated fluid having a temperature between about
128.degree. F. and 146.degree. F. The eggs are allowed to dwell in
the heated fluid until there is a log reduction of at least 4.6 of
any Salmonella bacteria within the eggs. The eggs are removed from
the heated fluid and placed in a gaseous atmosphere. Thereafter,
the eggs are contacted with an antibacterial fluid containing an
antibacterial agent, so as to prevent rot in the eggs, as briefly
mentioned above and explained in more detail below.
[0015] More preferably, the eggs are placed in the heated fluid
where the heated fluid has a first temperature(s) of about
139.degree. F. to 146.degree. F., a second temperature(s) from
about 130.degree. F. to less than 135.degree. F., and a third
temperature(s) from about 135.degree. F. to 138.degree. F. The
first, second, and third temperatures of the heated fluid are
maintained in separate zones of the heated fluid. The eggs are
allowed to pass through the first, second, and third temperatures
in a time period which causes a log reduction of at least 4.6 and
preferably at least 4.75 of any Salmonella bacteria in the eggs.
The eggs are removed from the heated fluid and passed into the
gaseous atmosphere where the eggs are allowed to cool and further
pasteurize so as to reach a log reduction of at least 5.0.
[0016] In a preferred form of the invention, the heated fluid is
water and the water is contained in a tank, especially, an
elongated tank through which the eggs traverse from an entrance end
of the tank to a middle zone of the tank and to an exit end of the
tank. Near the bottom of the tank a plurality of jets are disposed
through which a jet fluid is passed. Some of the jets are arranged
transverse to a major axis of the tank and are spaced apart such
that the jet fluid rises vertically to at least near the top of the
tank to provide a jet fluid wall near each of the spaced apart
series of jets. This provides more sharply defined different
temperatures along the major axis of the tank, particularly for
increasing the speed and especially the precision of pasteurization
and to reduce the loss of functionally.
[0017] In a further preferred form of the invention, not only is
the antibacterial fluid contacted with the eggs after the eggs exit
the pasteurizing tank, but the antibacterial fluid is contacted
with mechanical equipment handling the eggs subsequent to the eggs
exit of the pasteurizing tank. This avoids viable amounts of
bacteria on any of the mechanical equipment from entering into the
eggs.
[0018] In another form of the invention, after the eggs have been
contacted, e.g. sprayed, with antibacterial fluid, the eggs are at
least partially coated with a sealant to prevent entrance of
bacteria into the eggs after processing.
[0019] In another form of the invention, the eggs are allowed to
dwell in the heated fluid for a time sufficient to cause at least a
6 and up to 12 logs reduction of the Salmonella bacteria. This will
produce a partially coagulated or cooked egg which is useful in the
fast-food and nursing industries, since the egg is not only highly
reduced in any possible Salmonella, but will cook much more quickly
in preparing, for example, sunny side up eggs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a diagrammatic illustration of the overall
process;
[0021] FIG. 2 is an enlarged diagrammatic view of the pasteurizer
of FIG. 1;
[0022] FIG. 3 is a diagrammatic view of an apparatus for creating
fluid jets in a pasteurizing liquid; and
[0023] FIG. 4 is an illustration of one method of contacting the
eggs with an antibacterial fluid.
DETAILED DESCRIPTION OF THE INVENTION
[0024] As noted above, there are several different aspects of the
invention, each one of which is important, but together these
aspects provide not only the important reduction in time and costs
required for pasteurizing eggs, but equally importantly
considerably extend the shelf-life of the eggs, and this latter
feature of the invention is most important. In the process
described and claimed in the above-noted patent, pasteurization was
carried out in the examples by way of a single water tank. After
each pasteurization of a plurality of eggs in the water tank, for
food safety, the tank would be drained, cleaned, re-filled with
water, and re-heated for a further pasteurization. As a result, any
bacterial contamination of water in the tank from a pasteurization
would be removed prior to further processing in a further
pasteurization. However, when the process is put into commercial
operation, with commercial size tanks involved, e.g. 3,000 to 4,000
gallons, it very costly and impractical to empty such tanks after
each pasteurization of a lot of eggs. Indeed, in a commercial
operation, for commercial viability, a series of lots of eggs must
be passed through the pasteurizing tank while the water in that
tank remains suitable for many subsequent pasteurizations.
[0025] It was discovered that the water in the commercial tanks,
even though heated to higher temperatures, nevertheless could
support growth of certain bacteria, especially rot causing
bacteria. Further, in that prior process, since the eggs were
pasteurized to a 5 log reduction of Salmonella before exiting the
pasteurizing tank, it was necessary to place the eggs, immediately
after exiting the pasteurizing tank, into a chilling water tank in
order to reduce the internal temperature of the eggs to below that
temperature where deterioration of the functionality of the eggs
would occur, generally speaking below about 128.degree. F. Here
again, the chilled water of the chilling tank, for commercial
operation, is not changed with each lot of eggs. It is essentially
reused for many pasteurizations and chillings. It was discovered
that rot bacteria proliferate in the chilling water tank. As the
eggs cooled in the chilling water tank, water from the pasteurizing
bath, containing rot bacteria, and water from the chilling bath,
containing rot bacteria, are sucked through the porous shells of
the eggs and into the eggs themselves. This is because at the
temperatures of the pasteurizer most of the natural sealant in an
eggshell is removed, i.e. the sealant which seals the pores in an
eggshell. Since the pores are open during at least part of the
pasteurization and during the chilling, those exposed pores allow
water from the pasteurizing bath and chilling bath to be sucked
into the eggs during cooling in the chilling bath. Since those
waters could contain rot bacteria, upon storage, the pasteurized
eggs were subject to considerable premature rotting.
[0026] Further, it was found that even though bactericides are
placed in the pasteurizing bath and in the chilling water, e.g.
hydrogen peroxide, so as to substantially reduce the numbers of rot
bacteria in those waters, those bacteria could not be totally
eliminated and upon long term storage, significant experiences of
rot of the pasteurized eggs occurred in about three weeks. Thus,
while the use of bactericides in the pasteurizing water and
chilling water are helpful, it does not entirely solve the
problem.
[0027] Thus, one of the broader aspects of the invention is the
discovery that the chilling bath must be eliminated in order to
avoid the probability of rot of the pasteurized eggs on long term
refrigerated storage. However, with the chilling bath eliminated,
its function of stopping further pasteurization beyond 5 logs which
would increase deterioration of the functionality of the eggs,
especially the albumen thereof, is also eliminated. The question
became how can the further deterioration of the functionally be
quickly and effectively stopped without the chilling bath.
[0028] As another discovery of the present invention, it was
determined that with the elimination of the chilling bath, the eggs
could be adequately cooled in a gaseous atmosphere, for example
ambient air, so as to stop further pasteurization and decreased
functionality. However, as a subsidiary discovery in this regard,
it was found that in order to cool the eggs in air and not exceed,
substantially, the 5 log reduction of pasteurization, the eggs must
be removed from the pasteurizer prior to reaching a 5 log
reduction, contrary to the art accepted process. More specifically,
it was found that with usual pasteurization temperatures of
somewhere in the range of 133.degree. F., the eggs could be removed
from the pasteurizer after reaching at least about 4.6 logs, and
the residual heat of the eggs while dwelling in the gaseous
atmosphere would continue the pasteurization to achieve at least a
5 log reduction. This not only eliminated the need for the
deleterious and expensive chilling bath, but in turn and just as
importantly, considerably shortened the time required for
pasteurization of the eggs in the pasteurizer, which is a decidedly
commercial advantage.
[0029] As yet a further broader discovery in this regard, it was
found that when the eggs are allowed to dwell in the gaseous
atmosphere and cool for further pasteurization as described above,
the eggs suck into the eggs the gaseous atmosphere, just as the
eggs had sucked in the chilling water of the chilling bath. While
the gaseous atmosphere could be an antibacterial atmosphere,
through the use of, for example, ozone, chlorine, bromine, or the
like, it was found that this approach is relatively expensive,
difficult to contain and unreliable for consistent results. Thus,
as a subsidiary discovery in this regard, it was found that the
gaseous atmosphere, such as air, even though somewhat contaminated
with ambient rot and/or pathogen organisms, is nevertheless
acceptable so long as when the eggs are withdrawn from the heated
fluid of the pasteurizer and into the gaseous atmosphere and while
their internal heat (temperature) is greater than the ambient
temperature, the eggs are contacted with an antibacterial fluid
containing an antibacterial agent. Thus, as the eggs begin to cool
in the gaseous atmosphere and suck into the eggs the surrounding
atmosphere, the antibacterial fluid will pass into the eggs. That
antibacterial fluid will be disposed between the inside of the
shells and the outer membranes of the eggs and, especially, in the
air pockets (sacks) at the large ends of the eggs. During
pasteurization the air pockets are considerably reduced, but upon
cooling again expand. Thus, as an egg cools, the antibacterial
fluid is pulled into the air pocket of that egg. Any rot and/or
pathogen bacteria that might be in the ambient gaseous atmosphere
will be substantially killed or rendered nonviable by the
antibacterial agent in the antibacterial fluid.
[0030] As a further broader discovery, as noted above, the loss of
the natural sealant of the eggs during pasteurizing provides an
opportunity, during post pasteurization and storage, for ambient
rot or pathogenic bacteria to enter the eggs through the porous
shells. Thus, as a further discovery, it was found that after the
antibacterial fluid is applied, it is preferable that the eggs be
at least partially coated with a sealant, for example, waxes, which
replaces the natural sealant of the eggs lost during
pasteurization. This prevents ambient bacteria from entering the
eggs during storage.
[0031] Also, as a broader discovery, it was found that the sealant,
preferably, will also contain an antibacterial agent, so that the
sealant, e.g. wax, used to replace the natural sealant of the eggs
lost during pasteurization will not only form a barrier to ambient
rot and/or pathogenic bacteria but an antibacterial barrier to that
bacteria.
[0032] As yet a further broader subsidiary discovery, it was found
that since the chilling bath must be eliminated, this created
opportunities for variations in the log reduction in the
pasteurized eggs by removing the eggs with as little as only at
least about a 4.6 log reduction from the pasteurizing bath, as
noted above. However, in addition, it was found that the eggs could
be pasteurized to a much higher log reduction, e.g., 6, 8, 9, or
even 12 log reduction. While this provides an exceptionally safe
egg, such higher log reductions do substantially increase the loss
of functionality of the eggs. The eggs are at least partially
cooked during the higher log reductions. However, it was found that
up to about a 12 log reduction still left the eggs in a
substantially fluid state, i.e. such that the eggs could be broken
and scrambled or fried in the conventional manner. However, such
eggs will be cooked in the conventional manner, e.g. scrambled or
fried, in a very short time, e.g., about one-half of the usual
cooking time. This was found to be particularly useful for
fast-food restaurants where the time of cooking is important to the
economics of preparing the eggs and the increased safety of the
eggs is important for liability purposes. It is also important for
health care facilities, e.g., nursing homes, where ingestion of
Salmonella by a patient could be disastrous.
[0033] The general overall process is diagrammatically illustrated
by FIG. 1. In that Figure, a stack 1 of eggs 2 which may contain
many dozens of eggs is moved in a direction 3 toward a pasteurizer,
e.g. a tank, generally, 4 which is shown in the example of FIG. 1
as an elongated tank having a major axis 7 and a minor axis 8. The
stack 1 of eggs 2 is moved into the pasteurizer 4 as shown by arrow
9 and passed through the pasteurizer 4 along the major access 7. In
a preferred form of the invention, described in detail below, the
pasteurizer 4 has three zones or compartments, shown in FIG. 1 as
entrance zone or compartment 11, middle zone or compartment 12, and
end zone or compartment 13, all of which is described in more
detail below. These three zones or compartments 11, 12, and 13 are
heated by a plurality respective heating means. The Figure shows
representative heaters 14, 15, and 16, although many more would
normally be used. These heaters can take various forms, e.g. hot
water heaters, gas heaters, electrical heaters, etc.
[0034] Also, within the pasteurizer 4 are jets 18, which are
disposed near the bottom 19 of pasteurizer 4. Some of the jets are
arranged transverse to major axis 7 and parallel to minor axis 8
and are spaced apart which, as explained more fully below, can form
the separate zones or compartments 11, 12, and 13.
[0035] The stack 1 exits pasteurizer 4 in end zone or compartment
13 as shown by arrow 21. In one form of the process, the stacks of
eggs are unloaded by a conventional destacker apparatus shown very
schematically as 22, in a motion shown by arrow 23, so as to place
the eggs 2 on conveyor 25. This is done in a gaseous atmosphere 26,
which can be ambient air. In one form of the process, while the
eggs are in that gaseous atmosphere and before or after being
placed on conveyor 25, they are contacted, e.g., sprayed, with an
antibacterial fluid 28 and that same antibacterial fluid 28 is
contacted, e.g., sprayed, onto the destacking apparatus 22. The
antibacterial fluid 28 is sprayed from spray device(s) 29. While
the eggs could be otherwise placed onto the eggs, e.g. immersed or
rolled or painted with the antibacterial fluid, spraying is
preferred.
[0036] As the eggs move along conveyor 25 they are cooled in the
gaseous atmosphere 26 to a temperature below which pasteurization
takes place and further deterioration of the functionality is
ceased. However, in order to further avoid rot recontamination
during storage, the eggs 1 are contacted, e.g., sprayed, with a
sealant 30 from a distribution device(s) 31. The sealant, e.g. wax,
can be applied to the eggs at a point that the eggs are either
warmer or colder than the temperature of the sealant, but there is
an advantage in applying the sealant to the eggs while the eggs are
warmer than the sealant so as to ensure an even flow of the sealant
across the entire surface of the eggshell which will seal most of
the pores in the eggshell, as described in more detail below.
[0037] After the sealant has set, the eggs are sent to a
conventional packaging machine 33 where the eggs are packaged in a
conventional manner.
[0038] The above is a summary of the overall process of the
invention, and the following will provide additional details in
connection with that overall process.
[0039] In the method of pasteurizing in-shell chicken eggs, the
eggs are placed in a heated fluid having a temperature(s) of about
128.degree. F. and 146.degree. F. At temperatures below about
128.degree. F., no substantial pasteurization takes place and at
temperatures above 146.degree. F., the decrease in functionality is
simply not acceptable. There are, however, very preferred
temperatures within that range, as described more fully below.
[0040] The heated fluid may be any desired fluid, since it is not
the fluid that is important but the heat transfer from the fluid to
the eggs. Thus, the fluid may range from steam to a fluidized solid
particulate bed to microwaves traveling through air to heat lamps
radiating through air to light beams passing through air but will
usually be water, including glycol/water solutions, water/alcohol
solutions, and the like. As a practical commercial matter, the
heated fluid will normally be water, with or without additives,
e.g. glycols, bactericides, salts, and the like, and for purposes
of clarity and conciseness in this application, the heated fluid,
when mentioned in detail, will be described as water.
[0041] The eggs are allowed to dwell in the heated fluid, e.g.
water, until there is a log reduction of at least 4.6, preferably
4.75 or 4.8, log reduction of any Salmonella bacteria within the
eggs. This causes a substantial but not complete pasteurization of
the eggs. The eggs are then removed from the heated fluid into the
gaseous atmosphere. Here, again, the particular gaseous atmosphere
is not important, since the important functions are that of further
pasteurizing and cooling the eggs. The atmosphere could be ozone or
chlorine or bromine or any of the other food use bactericides or it
could be nitrogen or oxygen, but again, for practical purposes in a
commercial operation, the gaseous atmosphere will normally be air.
While in the gaseous atmosphere, the eggs are contacted with an
antibacterial fluid containing an antibacterial agent. Also while
the eggs are in the gaseous atmosphere, the residual heat of the
eggs, for example, at temperatures around 133.degree. F., will
allow the eggs to further pasteurize while cooling to below about
128 and especially below 125.degree. F. Thus while in that gaseous
atmosphere and cooling, the log reduction of the eggs will increase
to about 5 logs or slightly above. The temperature of the eggs
exiting the pasteurizer, the time in the gaseous atmosphere, as
well as the temperature of the gaseous atmosphere, are coordinated
so as to achieve at least about a 5 log reduction.
[0042] However, as briefly noted above, for institutional food use,
where partial precooking of the eggs is desired in order to shorten
the time for complete cooking of the eggs, e.g., scrambled or sunny
side up eggs, and/or improve the safety of the eggs, the log
reduction of the eggs exiting the pasteurizer may be as high as
about 8, 9, or 12 logs. At such log reductions, some thickening of
the eggs takes place, but on the other hand and importantly, the
eggs remain fluid. Therefore, in a fast food restaurant, for
example, the eggs may be cracked onto a griddle in the usual manner
and fried, sunny side up, for immediate serving. However, since the
eggs have at least a 6 or 8 or 12 log reduction, they are extremely
safe for commercial restaurant customers or patients in a health
care institution and may be served sunny side up without any
substantial fear of an adverse result. This is especially useful in
nursing homes where any Salmonella infection could be very
dangerous to older people and the soft cooking of raw eggs is no
longer allowed by the FDA. In addition, the eggs with this higher
log reduction will cook in about one-half of the time of a fresh
egg. This is of exceeding importance to commercial restaurants,
e.g., fast food restaurants, so that they may be assured that eggs
may be served, for example, sunny side up, without adverse results,
and, in addition, the eggs can be very quickly cooked for serving.
This result is possible because the chilling bath is eliminated,
according to the present invention.
[0043] As noted above, it was also discovered that the time
required for the eggs 2 in pasteurizer 4 to achieve at least a 4.6
log reduction of Salmonella is substantially shortened when the
heated fluid in the pasteurizer is at different temperatures. This
is based on the discovery that as the eggs are heated from ambient
temperatures to above the pasteurization temperature of at least
128.degree. F., for example to 133 F, very little loss of
functionality occurs, generally directly in relation to the
time/temperature above about 128.degree. F., until a 1 log
reduction is achieved. Thereafter, the rate of deterioration of
functionality caused by heat upon the egg protein is less in a
temperature range of about 133 to 134.5.degree. F. until about a 4
log reduction is reached. Thus, at this temperature range,
something of a functionality plateau is reached. After the above
mentioned 4 logs reduction, a minimum loss of functionally will
occur during the next plateau of 4 to 4.6 logs reduction, even with
increased temperatures ranging from 135 to 138.degree. F. With the
discovery of these plateaus, it became possible to increase log
reductions through the use of the above identified temperature
ranges with minimum loss of functionally.
[0044] With this discovery, it was found that the time required for
pasteurizing eggs in a water bath could be substantially shortened
if, basically, the eggs in an entrance zone or compartment 11 are
subjected to water at a higher temperature(s) and then subjected to
a lower temperature(s) in zone or compartment 12 and then to a
higher temperature(s) in end zone or compartment 13. Since the eggs
2 in stack 1 are moving in the directions of arrows 3 and 9 and
enter the pasteurizer 4, generally, at ambient temperatures or
less, e.g. down to refrigeration temperatures (40 or 45.degree.
F.), the heat transfer from the heated fluid 34 (FIG. 1) to the
eggs 2 is much greater when the temperature differential between
the temperature of the eggs and the temperature of the heated fluid
34 is greater. This can very quickly heat the eggs up to near
pasteurization temperature without deterioration of the
functionality of the eggs because the heat transfer into the eggs
is rapid enough to avoid outer albumin damage. In that higher
temperature zone, or entrance zone or compartment 11, the eggs have
not reached the 1 log reduction plateau, as noted above. By using
that higher temperature differential between the eggs and heated
fluid, the eggs are brought to a desired pasteurization temperature
in an accelerated time. Thereafter, the eggs are passed into the
middle zone or compartment 12 where the temperature(s) of that zone
or compartment is less than that of entrance zone or compartment
11, e.g. 130.degree. F. to less than 135.degree. F. and especially
133.degree. F. less than 135.degree. F. The eggs can be heated at
that temperature for some time so as to effect higher
pasteurization without substantial reduction of functionality until
the second plateau at about 4 logs is reached. In this connection,
it was recognized that in order to provide the public with a safe
and low cost pasteurized egg, the pasteurizer water temperature
range and the time of exposure of the eggs to the water must be
related to the maximum rate of heat transfer that the eggs could
provide without damage to the albumin protein.
[0045] As noted above, according to the present invention the
chiller is eliminated, and the residual heat of the eggs is
utilized for further pasteurization of the eggs in the gaseous
atmosphere after removal from the pasteurizer. It is highly
advantageous to heat the eggs to a temperature higher than the
temperature of middle zone or compartment 12 so as to increase the
residual heat. Therefore, in the end zone or compartment 13, the
temperature is again raised to, for example, 135-138.degree. F., so
as to provide more residual heat to the eggs in the gaseous
atmosphere. The time, however, is quite short in that end zone or
compartment and even though the eggs will have exceeded the 4 log
reduction to reach the next plateau, since the time is short, very
little additional deterioration of functionality occurs.
[0046] Of course, the pasteurizer could be divided into two zones
or more then three zones as described above, but two zones are less
efficient and more then three zones becomes unnecessarily complex.
Therefore the division into three zones, i.e., the higher
temperature entrance zone, the desired pasteurizing temperature
middle zone, and the additional residual heat exit zone are the
preferred forms of a multiple temperature pasteurization of
eggs.
[0047] In this latter regard is has been found that the temperature
of the heated fluid is preferably about 139.degree. F. to
146.degree. F. as the first temperature of the heated fluid and
about 130.degree. F. to less than 135.degree. F. as the second
temperature and about 135.degree. F. to 138.degree. F. as the
third. Of course, when the heated fluid is water and the water is
contained in the elongated tank 4, through which the eggs
transverse the tank from the entrance of the tank to the middle
zone of the tank and exit from the exit zone of the tank, those
temperatures correspond to the entrance zone compartment 11, the
middle zone compartment 12 and end zone compartment 13. It should
be noted that the above mentioned patent relates processing to the
center of the yoke temperature. That temperature will be
continually changing as the eggs traverse the tank with the three
zones or compartments.
[0048] There are several ways of maintaining the temperatures of
the zones or compartments. One way is to have the heat input, and
hence temperature, of entrance heater 14, middle heater 15 and end
heater 16 different, i.e., a higher temperature in entrance heater
14, a lower temperature in middle heater 15 and, again, a higher
temperature in end heater 16. These different temperatures of the
heaters will produce, for example, three zones of different
temperatures throughout the water of the pasteurizing bath as stack
1 of the eggs 2 (and succeeding stacks) transverse along the tank 4
in the direction of major axis 7. This is because as the eggs in
the stacks transverse the tank, a natural convection from the
bottom 19 of tank 4 to the top 35 of tank 4 occurs. This creates a
form of vertical convection. Generally, the heaters of the tank
will be disposed near the bottom 19 of tank 4. Thus, the
individually controlled heaters heat the water (heated fluid 34) at
the bottom 19 of tank 4 and that water 34 contacts the eggs 2 in
each of the stacks as they serially pass through the tank and the
water rises generally vertically toward the top 35 of tank 4. This
effectively causes a circular convection motion from top to bottom
to top again, etc., in a localized zone, e.g. zones 11, 12, and 13.
The distinct temperatures of the zones are aided by a plurality of
jets 18 arranged near the bottom 19 of tank 4 through which a jet
fluid is passed from the jets into the water of the tank. This jet
fluid rises vertically in the water and is very useful in
maintaining more uniform temperatures along a vertical direction of
the tank. The jet fluid may be a gas or a liquid, such as air or
water. These jets, therefore, aid in the vertical convection of
water in a zone so as to somewhat maintain a temperature
differential between the zones.
[0049] However, that temperature differential is not a sharp
differential and somewhat graduates from one zone to the next zone.
This is not necessarily undesirable and this will produce very
satisfactory pasteurization of eggs. However, in certain
situations, it is important to pasteurize the eggs to as precise a
desired log reduction as possible and in the shortest possible
time. In that case, better control of the pasteurization to a
precise log reduction can be achieved if the zones are more
distinct. These zones can be made more distinct when some of the
jets 18 are arranged transverse to the major axis 7 and parallel to
minor axis 8. One series of transverse jets is spaced apart along
the major axis from another series of transverse jets. Since the
jet fluid passing through the jets rises vertically in the water
and to at least near the top of the water, this provides a jet
fluid wall in the water at each of the spaced apart series of jets.
These jet fluid walls form jet fluid walled compartments 11, 12,
and 13 between the jet fluid walls. By this arrangement at least
two jet fluid walled compartments along the major axis can be
maintained at fairly distinct different temperatures. In the
preferred embodiment, of course, three compartments are used for
the three different temperatures, i.e., the higher entrance
temperature, lower or middle temperature and higher exit
temperature.
[0050] The jet fluid can be simply recirculated water from the
pasteurizing tank or it can be water separately heated and passed
through the jets 18. Alternatively, the jet fluid may be air that
is separately heated and passed through the jets 18. Where the jet
fluid is the water from the pasteurizer, and is simply recirculated
through the jets, that water will be essentially at the temperature
of the particular compartment, since the heated fluid in the tank
is heated by the series of heaters, e.g., heaters 14, 15, and 16,
disposed in the tank. However, in practice, a number of heaters,
e.g., 40 to 100, may be used.
[0051] In addition, near the bottom 19 of tank 4 is normally
disposed a second series of jets through which pass a jet fluid for
perturbation of the water, as mentioned above, so as to homogenize
the temperature of the water within each compartment.
[0052] Since the stacks 1 of eggs 2, usually, pass through the
pasteurizer tank 4 at a constant speed, the time that the eggs in a
stack 1 spend at the different temperatures depends upon the length
of the compartments 11, 12, and 13 in tank 4. Those lengths can
vary, depending upon the desired log reduction of the eggs exiting
the pasteurizing tank and the temperatures within each of the three
compartments, i.e., the entrance compartment, middle compartment
and exit compartment. However, generally speaking, the length along
the major axis 7 of the tank is from about 0.1 to 0.3 the length of
the tank for the entrance compartment, from about 0.3 to 0.7 the
length of the tank for the middle compartment, and from about 0.1
to 0.3 the length of the tank for the exit compartment. Preferably,
these ratios are, respectively, 0.1 to about 0.2, 0.2 to about 0.6,
and 0.1 to about 0.2 These ratios of the length of the compartment
are particularly useful for the temperatures of the compartments
noted above, i.e., from 139.degree. F. to 146.degree. F. for the
entrance compartment, from 130.degree. F. to less than 135.degree.
F. for the middle compartment and from 135.degree. F. to
138.degree. F. for the exit compartment. Preferably however, the
length of the entrance compartment is from about 0.3 to about 0.35,
the middle compartment is from about 0.5 to 0.6 and the exit
compartment is from about 0.2 to 0.26, and the respective
temperature ranges are from about 141.degree. F. to 143.degree. F.,
132.degree. F. to less than 135.degree. F., and 136.degree. F. to
138.degree. F. The most preferred temperatures are, respectively,
142, 133, and 137 degrees F. However, these temperatures and/or the
ratios of the lengths of the compartment can vary depending upon
the log reduction of Salmonella in any eggs that is desired and, as
noted above, that log reduction can be from as little as 4.6 to
12.0 as achieved within the pasteurizing tank itself. Log
reductions will also depend on the speed of the stack of the eggs
through the pasteurizing tank.
[0053] As a general comparison of the improvement of the invention
as thus far described, in a more conventional process, where the
pasteurizing tank is at a constant temperature of, for example,
133.degree. F., the dwell time at that temperature to reach a 5 log
reduction, as required in the prior process, was close to 64
minutes and, even with ideal results, at least about 63 minutes. If
the process is carried out with only two zones or compartments,
e.g. one entrance compartment at 136.degree. F. and one compartment
at 133.degree. F., the process takes about 52 to 56 minutes.
However, with the present invention having three zones or
compartments at the most preferred temperatures, noted above, the
process can be carried out in as little as 39 to 41 minutes. Thus,
as compared with the prior process, the present process can be
carried out in considerably less time. This is a very substantial
improvement from a commercial point of view.
[0054] The antibacterial agent contained in the antibacterial fluid
28 can be any one of the FDA Food Use approved bacteriacides,
including chlorine, bromine, ozone, hydrogen peroxide and
quaternary ammonium compounds. All of these are well known and need
not be described in detail. The antibacterial fluid can be any
fluid which can contain those bacteriacides, e.g. air, nitrogen,
alcohol, etc., but preferably the antibacterial fluid is water. The
antibacterial agent used in this application and in the
applications described in more detail below, i.e., the application
of contact with equipment and the application of a sealant, all use
the antibacterial agent in the concentrations prescribed by the
FDA. For example, the specific quaternary ammonium compound
described more fully below is used in a concentration of about 100
parts per million. The eggs 2 can be contacted with the
antibacterial fluid 28 in any desired manner, but it is most
convenient that the antibacterial fluid is sprayed onto the eggs,
as shown in FIG. 1. Also, as shown in FIG. 1, the antibacterial
fluid is contacted, e.g. sprayed, onto any mechanical equipment 22,
e.g. the destacker handling the eggs, subsequent to the eggs
exiting the heated fluid. More preferably, the antibacterial fluid
is contacted (sprayed) on the mechanical equipment 22 prior to the
eggs contacting the mechanical equipment after exiting the heated
fluid of pasteurizer 4. Thus, the mechanical equipment contacting
the eggs after the eggs exit the heated fluid has been contacted
with the antibacterial fluid so that any bacteria on the mechanical
equipment is either killed or very substantially reduced by the
antibacterial fluid. Thus, since the equipment and the eggs are
sprayed with antibacterial fluid, any rot and/or pathogenic
bacteria in the gaseous atmosphere which is sucked into the egg,
especially between the membrane and the inside of the shell, will
encounter the antibacterial fluid and be either killed or reduced
to such low numbers that rot or other undesired results will not
occur within the eggs. It is preferred that the mechanical
equipment handling the eggs and the eggs are sprayed with
antibacterial fluid before the eggs reach a temperature less than
about 100.degree. F. At that temperature the eggs have cooled
sufficiently that little additional material will be sucked into
the eggs during further cooling and, thus, the antibacterial
barrier discussed below will not be substantially achieved. Also,
by that temperature, the sealant should be applied.
[0055] In this latter regard, after contacting the eggs (and
preferably the mechanical equipment) with the antibacterial fluid,
the eggs are contacted with an egg pore sealant, as briefly noted
above. Preferably that egg pore sealant has an antibacterial agent
therein and, again, the antibacterial agent is a FDA Food Use
approved bactericide such as chlorine, bromine, ozone, hydrogen
peroxide and quaternary ammonium compounds. That sealant 30 (FIG.
1) is contacted, preferably sprayed, from distribution device(s) 31
onto the eggs while the eggs are on the handling equipment, e.g.
conveyor 25.
[0056] The pore sealant can be any food grade sealant, but
preferably is food grade polymers or waxes or soluble proteins,
e.g., gelatin. For aesthetic purposes, it is preferred that the
sealant is at least transparent when applied to the eggs. Since the
usual waxes meet these requirements, wax is a preferred
sealant.
[0057] When the sealant is sprayed onto the eggs, the sealant is
preferably in a heated sealant liquid form and preferably at a
temperature above the temperature of the eggs being contacted with
the sealant so as to cause the sealant to rapidly spread along the
surfaces of the eggs.
[0058] As also briefly noted above, during pasteurization the
natural protective sealant of the eggs is substantially lost during
the pasteurization and the pores of the eggshell are open for
entrance of materials during cooling. While it is substantially
impossible to ensure that all of the opened pores on the eggshell
are closed, by careful spraying of the sealant it can be assured
that the amount of sealant which remains on the eggs after spraying
is at least equal to 50% of the natural egg pore sealant removed
from the eggs during the dwell of the eggs and the heated fluid in
pasteurization and preferably that amount is at least 70%, e.g. 85
or 90% or better.
[0059] As briefly discussed above, the present process is shortened
by taking the eggs out of the pasteurizer before a 5 log reduction
is reached, contrary the practice of the prior art. The residual
heat of the eggs causes additional pasteurization while the eggs
are in the gaseous atmosphere and that additional pasteurization
will cause the eggs to increase in the log reduction to at least 5.
The time required for the dwell of the eggs in the gaseous
atmosphere to reach that increased log reduction will depend upon
the temperature of the eggs exiting the pasteurizer, the
temperature of the gaseous atmosphere, the temperature and amount
of the antibacterial fluids sprayed onto the eggs, as well as the
size of the egg. However, generally speaking, a dwell time of about
1.5 to 3 minutes in the gaseous atmosphere will be satisfactory to
increase the log reduction from about 4.6 or 4.8 to the required 5
log reduction. That time, however, is not necessarily wasted time.
With the present invention, during that dwell time, the mechanical
handling equipment and eggs are sprayed with the antibacterial
fluid, and, in some embodiments the eggs are also at least
partially destacked from stack 1 or placed on conveyor 25 or in a
packaging machine 33, which must be done in any case in order that
the eggs may be appropriately packaged.
[0060] Thus, in the present process for pasteurizing in-shell
chicken eggs, the eggs are placed in the heated fluid with a
temperature between 128.degree. F. and 146.degree. F. and the
heated fluid has a first temperature of 139.degree. F. to
146.degree. F., and a second temperature of 130.degree. F. to less
than 135.degree. F., and a third temperature of 135.degree. F. to
138.degree. F. Those first, second and third temperatures of the
heated fluid are maintained in separate zones of the heated fluid
and the eggs pasteurize in the first, second and third temperatures
in a time period which causes at least a 4.6 or at least a 4.75 or
at least a 4.8 log reduction in any Salmonella bacterial in the
eggs. The eggs are thereafter removed from the heated fluid and
immediately passed to the gaseous atmosphere where the eggs are
allowed to cool, and the eggs will reach the required 5 log
reductions during that cooling in the gaseous atmosphere. While the
eggs are in the gaseous atmosphere, they are contacted with the
antibacterial fluid containing an antibacterial agent. Further,
preferably after the eggs are contacted with the antibacterial
fluid, the eggs are contacted with the egg pore sealant, which
preferably has an antibacterial agent.
[0061] In tests run for rot activity of eggs pasteurized according
to the most preferred process as described above, eggs have been
kept in cold storage, e.g. at a temperature of about 40.degree. F.
to 45.degree. F., for up to six months without evidence of rot in
the eggs. This is compared to approximately a maximum of 21 days
before incidents of rot occurred in eggs processed according to the
prior process, as described above. In limited but yet meaningful
long term refrigerated storage tests, eggs have remained rot-free
for up to 1 year. During such long term storage there are changes
in the eggs, in terms of functionality, as described in the
above-identified patent, but the eggs are not made un-saleable
because of incidences of rot. This is, accordingly, a very
substantial advance in the art.
[0062] FIG. 2 shows a typical pasteurizing tank 4 for carrying out
the present process and being shown in more detail. Typically, for
example, the tank might well be from 25 to 40 feet (8 to 13 meters)
long in the major axis 7 and 3 to 6 feet wide (1 to 3 Meters) in
the minor transverse axis 8 with a height of about 3 to 6 feet (1
to 3 meters). Such a tank might be divided into from 8 to 15
positions, with three positions 40, 48 and 49 being shown in FIG.
2. The Figure shows details of two and one-half positions 41. A
typical the tank may have 11 positions. While the stack 1 of eggs 2
(FIG. 1) might pass continuously through tank 4, without stopping
or interruption, this would require a much longer tank than
necessary to achieve the correct dwell times at the correct
temperatures. Therefore, normally, each stack 1 of eggs 2 will
dwell in the positions for certain lengths of time before moving to
the next position or positions. For example, each stack of eggs
might dwell in a position for 4 minutes before moving to the next
position or positions. Accordingly, if zones 11, 12, and 13 have
temperatures of, for example, 142, 133 and 137.degree. F.,
respectively, then the dwell time in zone 11 might require two and
one-half positions, 40, 41, as shown in FIG. 2 by arrows 42. The
number of positions, for example, in zone 11 will be determined by
the temperature of the eggs entering zone 11, the temperature(s) of
the zone, and the dwell time of the eggs in that zone. However,
generally speaking, it is desired that there be a substantial
differential between the temperature of the water and the eggs in
zone 11, as explained above. For example a differential of from 4
to 10.degree. F., e.g. somewhere in the range of 6.degree. F. or
so. This will provide a very fast heating of the eggs to
pasteurization temperatures, e.g., about 128.degree. F., but
without any substantial deterioration of the functionality of the
eggs. Thereafter, the eggs are moved to zone 12, for example, at
133.degree. F. and zone 12 would have a number of positions
therein, since about 133.degree. F. is the most preferred
pasteurization temperature. This will allow more thorough
pasteurization (increase in log reductions) with the least possible
loss of functionality of the eggs. Zone 13, however, might have
positions 48, 49 (FIG. 2). Those two positions are required in view
of the speed of the stacks 1 through the pasteurizer 4, as noted
above, to reach a higher temperature for residual heat of the eggs
to achieve additional pasteurization after the eggs pass from the
pasteurizer 4 to the gaseous atmosphere. However, here again, the
temperature differential in zone 13 between the eggs and the water
should not be too great, or otherwise some deterioration of the
functionally of the eggs might take place. Thus, as noted above,
the temperature of zone 13 should be about 135.degree. F. to
138.degree. F. and more preferably about 137.degree. F.
[0063] The jets 18 (see FIG. 1) can be provided by a variety of
arrangements, such as those shown in FIG. 3. In that Figure, a
conduit passes the jet fluid 46, which may be a gas or a liquid, as
explained above, into the heated fluid 34 (see FIG. 1) by way of
apertures 47 or slots 48 or a slit 49, which slit would extend
across the entire length of conduit 45.
[0064] The pressure of the jet fluid 46 within conduit 45 and
depending upon the jets involved, whether apertures 47, slots 48 or
slit 49, must be sufficient that the jet fluid rises fairly rapidly
toward the top 35 of tank 4. This not only is necessary to achieve
the homogenization of temperatures within a zone, as explained
above, but also to facilitate the formation of temperature zones
11, 12 and 13. Also, when the jets are sufficient to form the jet
fluid walls described above, those jets form more of a compartment
than a zone and the temperature differential between the
compartments is more distinct. To achieve this, as explained above,
there are a series of jets transverse to major axis 7 and parallel
to minor axis 8 of the tank so as to form thereinbetween
temperature compartments.
[0065] FIG. 4 shows an additional manner of applying the
antibacterial fluid to the eggs. As shown in that Figure, stacks 1
of eggs 2 are contained in an open carrier 50. The carrier 50 may
have, for example, three stacks across and two stacks deep on a
bottom shelf 51 and the same amount on a top shelf 52, as shown in
that Figure. Each stack 2 may have 5 or 6 flats 53, with 2 to 4
dozens of eggs on each flat. After the so loaded carrier is removed
from the pasteurizer 4, the carrier is suspended beyond and above
the pasteurizer and the eggs on the carrier are sprayed with a mist
of antibacterial fluid from a plurality of sprayers 57, four of
which are shown in the Figure, but in practice many more would be
used, e.g. 6 to 20. The mist of antibacterial fluid is at
temperature and the amount is such as to not substantially decrease
the temperature of the eggs so that the eggs can continue to
pasteurize as explained above, but the amount is sufficient to
provide substantial kill of rot bacteria while the eggs dwell in
the gaseous atmosphere, air in this case. Additional antibacterial
fluid can be applied to the eggs during subsequent processing as
explained above, e.g., during destacking or candling or other
conventional handling and packaging processes.
[0066] This will ensure that the antibacterial fluid is sucked into
the eggs and will reside between the egg membrane and the inside of
the shell. This will fully protect the eggs from entrance of viable
rot bacteria until the eggs are further protected by the
application of the egg sealant. In this regard, a preferred
bactericide is the FDA Food Use approved quaternary ammonium
compound, EPA No. 1677-43 (alkyl dimethyl benzyl ammonium
chloride). This compound is fugitive in the sense that it breaks
down to harmless compounds in a relatively short time. However, the
time is long enough for the eggs to cool and then be coated with
the eggs sealant. Thus an important feature of the invention is
that of providing a pasteurized egg having an antibacterial fluid
disposed between an egg membrane and an inside of an egg shell.
[0067] Further in this regard, an important feature of the
invention is that of providing apparatus for pasteurizing in shell
chicken eggs having a support for the eggs and an application
device in proximity to the support for applying to the eggs, which
are at least partially pasteurized, an antibacterial fluid.
[0068] The invention as described above is intended to be embraced
by the spirit and scope of the following claims.
* * * * *