(a) Field of the Invention
The present invention relates to a method of pasteurizing in-shell
eggs. More specifically in the present invention, yolk and albumen of in-shell eggs
are pasteurized separately during the process of a series of pasteurizations of
the salmonella (bacteria inhabiting in eggs with shells) by heating it to a desired
level, while various temperature measuring points are established within the egg
and according to such measuring points, the lowest temperature of the yolk and albumen
are measured through the previous pasteurization process. And having this lowest
temperature as the standard, the necessary time needed for pasteurization above
this lowest temperature is standardized, in order to have the yolk and albumen to
be pasteurized simultaneously.
(b) Description of the Related Art
There has been immense research and effort regarding the pasteurization
of salmonella-which generally inhabit inside an egg, and in particular, in the case
of the liquid egg (liquid white, liquid yolk and liquid whole egg) masses have been
produced even commercially since several decades ago. Several nations already hold
the standard regarding pasteurizing liquid egg, and its safety has also been substantiated.
The shell egg (its main ingredients being the egg shell, yolk, and
the albumen, the egg shell takes up 10~20%, the albumen takes up 55~63%, and the
yolk takes up 26~33%), an egg with an egg shell, is not simple to pasteurize due
to the complexity of its features, weight, size, form, difference in thermal conductivity
and the existence of the egg shell. Moreover, in the commercial front, immense research
and effort is attempted regarding pasteurization, and as safety having its priority
in quantity and taste serves as a top factor in food consumption of the present,
and additionally, as the nations of the global arena stress importance of the safety
of livestock from mad cow disease, foot-and-mouth disease, and so forth, there is
a demand for the research and interest in the development of shell egg pasteurization.
There are two ways in which the salmonella can be contaminated; one
being the contamination into the interior of an egg through the pore of a medium
surrounding an egg-laying facility after the egg is laid, and the other being the
contamination from the layer before the egg is laid. In the case of the former contact
contamination through the pore, it is contaminated due to the fact that generally,
eggs possess around 7,000∼17,000 pores for respiration and the salmonella can
easily pass through it. In the case of the latter, deeper parts of an egg's yolk
and albumen is contaminated due to the contamination of the layer's interior of
the body before the egg shell is formed. Both the former and latter are contaminated
into the interior of the egg, thus making pasteurization difficult. The most dangerous
sort of salmonella being the Salmonella Enteritidis(SE), an egg contaminated with
it must be pasteurized in all parts of its interior due to the fact that the Salmonella
Enteritidis(SE) contaminates the interior of an egg and deeper into the yolk and
albumen inside the egg shell through a layer's internal organs which were already
When pasteurizing through heating according to an egg's characteristics
(pH concentration, temperature of the interior, weight, size, composition, specific
gravity, form, thickness of the egg shell, difference in breed and so forth) and
the pasteurization environment (means of heating, heating medium, method of heating,
temperature of egg in the early stage and so forth), not only is an egg's temperature
different in various locations the temperature amount precedence also changes depending
on the time difference. Consequently, the complete pasteurization of the salmonella
inhabiting in the egg's interior is difficult.
When pasteurizing an egg through heating, it must be done to the level
of safeness as a food product and maintain the quality and distinctiveness of the
egg as a food in terms of the yolk and albumen's solidification. Should an egg be
pasteurized through heating at a high temperature for an extended time, it is satisfactory
in terms of safeness yet is incongruous as a food product with damages in the function
and solidification of the albumen and so forth. On the other hand, pasteurization
in a low temperature for a short period of time is satisfactory as a food yet incongruous
in the sense of safeness, and the pasteurization for a short period of time in a
high temperature will damage the egg shell and cause problems in the albumen's ripening
and solidification. Moreover, pasteurization in a low temperature for an extended
time produces low work efficiency and the gelation, in which the yolk and albumen
switch form liquid to solid and thus holds a problem in that it is not easy to pasteurize
the shell egg. The shell egg is composed of the egg shell, yolk, and albumen the
pasteurization of it is difficult due to the distinctiveness of each material, the
solidification by heat and the difference of heat conductivity, the solidification
and damage in the function of the yolk and albumen when heated, and the damage of
the egg shell and the changes in the condition of the pasteurization when a lapse
in the egg laying time affects the albumen's pH concentration.
Much research has been done on the pasteurization of the shell egg
and it was thought obvious that when pasteurizing through heating, all parts of
an egg had the same temperature, ignoring the fact that they are different, or that
the pasteurization of one part of an egg's interior (the center part of the yolk)
would sufficiently pasteurize the entire egg. For example, in US Patent No. 6,165,538,
the center of the yolk is set as the standard in determining the pasteurizing time
and temperature, and with a presumption that the pasteurization of the center of
the yolk will sufficiently pasteurize the entire egg, the pasteurizing conditions
Other methods for the treatment of whole eggs are disclosed in, e.g.,
US 6 303 176 and US 5 589 211.
However, when pasteurizing shell egg through heat, the temperatures
of the shell egg's interior are different as time goes by according to the condition
of the egg, the means of heating and the amount of heating. There are even some
instances where the central yolk part's temperature is higher, thus not pasteurizing
the yolk's exterior even if the central part of the yolk is pasteurized and the
albumen may not be pasteurized even yolk may be pasteurized. Therefore, generally
when pasteurizing with a heating medium, the temperature of the yolk and albumen
of an egg's interior will be different according to the time and measuring points.
This produces the problem of over pasteurization and under pasteurization. Moreover,
when shifting an egg in two or more heating media, the yolk and albumen's temperature
will abruptly fall. In this instance, the central part of the yolk is pasteurized
above the arranged pasteurizing temperature but exterior part of yolk breaks away
from the arranged temperature without pasteurization. In severe cases, the albumen's
temperature fall is more abrupt and while the yolk's pasteurization remains above
the arranged pasteurizing temperature, the albumen will not be pasteurized as it
has broken away from the arranged temperature.
Therefore, pasteurization of the yolk does not surely ensure the pasteurization
of the albumen nor does the pasteurization of a part of or the central part of the
yolk ensure the pasteurization of another part of the yolk or entire part of the
egg. Due to these problems, the need for pasteurization by having the lowest temperature
of the yolk and albumen as the standard in the entire pasteurizing procedure (including
the refrigerating process) is prominent.
SUMMARY OF THE INVENTION
The present invention relates to the following in the pasteurization
of shell egg with a heating medium.
After setting various temperature measuring points inside an egg's
yolk and albumen, the lowest temperature points are set among those measuring points
through the whole pasteurization procedure. The temperature of the lowest temperature
point is maintained in the required pasteurizing time above the planned pasteurizing
temperature. The yolk and albumen consequently are simultaneously pasteurized.
The present invention relates to a method in which the lowest temperature
point is the point of the lowest amount out of at least three different temperature
points of each of the yolk and albumen.
Moreover, the mentioned lowest temperature point makes extended imaginary
lines that connect the centers of the largest and the smallest sphere that circumscribe
the egg shell and the yolk to the yolk's center.
The two most closest points of the albumen from the yolk are set on
the imaginary lines and the two most closest points of the albumen from the egg
shell are set on the extended imaginary lines and the center points of the two spheres
are also set. These points are the albumen's temperature measuring points and the
point with the lowest temperature measured is selected as the lowest temperature
point. The two points of the yolk that are closest to the albumen on the imaginary
lines are set. These two points of the yolk, the two central points between the
yolk's center point and the above two points of yolk and the yolk's center point
are set as the yolk's temperature measuring points. The lowest temperature measured
from these temperature measuring points is selected as the yolk's lowest temperature
This concerns the pasteurization method of shell egg in which the
feature is that through the pasteurizing process the temperatures of the above mentioned
lowest temperature points of the yolk and albumen are measured periodically at different
times. Having these lowest temperatures as the standard, the pasteurizing temperature
and the time needed to maintain the pasteurizing temperature is determined.
BRIEF DESCRIPTION OF THE DRAWINGS
- Figure 1 is a graph that concerns the range of temperature and time for the
destruction of the salmonella according to the pasteurization level applied to the
- Figure 2 is an exemplification that illustrates the measuring the yolk and albumen's
lowest temperature standard point for that is applied to the present invention.
- Figure 3 is a graph that illustrates the temperature changes in the yolk and
albumen according to the time in the measured points after they are heated.
- Figure 4 illustrates the temperature changes in the yolk according to the time
in the measured points when they are refrigerated.
- Figure 5 is a graph that illustrates the temperature changes of the yolk according
to the time when eggs are shifted among heating mediums.
- Figure 6 is a graph that illustrates the changes in the lowest temperature of
the yolk and albumen according to the time.
- Figure 7 is a graph that illustrates the condition changes in the eggs that
have been pasteurized with the present invention, and general eggs that have not.
Reference numbers of the drawings' principal parts
DETAILED DESCRIPTION AND THE PREFERRED EMBODIMENTS
1. egg (shell egg)
In the pasteurization of an egg with a shell, the present invention
pasteurizes simultaneously the salmonella inhabiting in the yolk and albumen. Following
a prescribed method, the temperature measuring points of the yolk and albumen are
selected and having the level of pasteurization time is fulfilled. This is done
in order to prevent the occurrence of a yolk or albumen partly not being pasteurized
or the damaging of the yolk or albumen material function due to excessive pasteurization.
The changes in the means of heating or the kind or number of the heating
medium, heating method, size, weight, and form of the egg, time passed following
the laying of the egg, temperature of storage, the initial temperature of an egg
when it first enters the heating medium, and the occurrence of a washing process
does not make the temperature of the yolk and albumen fixed. Also, the means of
heating or the method, temperature or amount of the heating medium is separate from
an egg's pasteurization. This is because the pasteurization is done according to
the yolk and albumen's temperature and time it takes to maintain this temperature.
This in turn is due to the fact that through the entire pasteurization process,
the temperature and the time needed to maintain this temperature required by the
level of pasteurization must be planned by the yolk and albumen's lowest temperature.
In this detailed application, the term 'pasteurization' does not hold
the implication of the destruction of pathogenic bacteria yet the general meaning
of destroying the Salmonella Enteritidis (SE). Generally when considering the destroying
conditions of harmful microorganisms the pasteurization of the SE can ensure not
only the pasteurization of the salmonella but also other harmful germs.
The pasteurization method of a shell egg according to the present
invention is described in more detail referring to the drawings.
Figure 1 is a graph that concerns the range of temperature and time
for the destruction of the salmonella according to the pasteurization level applied
to the present invention. Figure 2 is an exemplification that illustrates the measuring
the yolk and albumen's lowest temperature standard points for that is applied to
the present invention. Figure 3 is a graph that illustrates the temperature changes
in the yolk and albumen according to the time in the measured points after they
are heated. Figure 4 illustrates the temperature changes in the yolk according to
the time in the measured points when it is refrigerated. Figure 5 is a graph that
illustrates the temperature changes of the yolk according to the time when egg is
shifted among heating mediums. Figure 6 is a graph that illustrates the changes
in the lowest temperature of the yolk and albumen according to the time. Figure
7 is a graph that illustrates the condition changes in the eggs that have been pasteurized
with the present invention, and general eggs that have not.
Figure 1 is a graph that concerns the range of temperature and time
for the destruction of the salmonella according to the pasteurization level applied
to the present invention.
As illustrated in the Figure 1, the yolk being line F3 and the range
above-thus the range between line F1 and F3. The albumen being line F7 and the range
above-thus the range between F4 and F7. This represents the required temperature
and the time needed to maintain this temperature in order to pasteurize the salmonella
inhabiting inside the yolk and albumen at a level of 5LOG to 12LOG.
The pasteurization level mentioned above has its range at a pasteurization
level of 5LOG (decreased to 1/105 from initial number) to 12LOG (decreased
to 1/1012from initial number). F1, F2, F3, F4, F5, F6 and F7 are the
thermal death time curves of the salmonella. F1 represents the time and temperature
it takes for the yolk to destroy the salmonella at the pasteurization level of 12LOG.
F2 represents the time and temperature it takes for the yolk to destroy the salmonella
at the pasteurization level of 9LOG. F3 represents the time and temperature it takes
for the yolk to destroy the salmonella at the pasteurization level of 5LOG. F4 represents
the time and temperature it takes for a pH 8 albumen to destroy the salmonella at
the pasteurization level of 12LOG. F5 represents the time and temperature it takes
for a pH 8 albumen to destroy the salmonella at the pasteurization level of 9LOG.
F6 represents the time and temperature it takes for a pH 8 albumen to destroy the
salmonella at the pasteurization level of 5LOG. F7 represents the time and temperature
it takes for a pH 9 albumen to destroy the salmonella at the pasteurization level
of 5LOG. The following is the locus according to the time (minutes; t) and temperature
- F1:log(t) = 14.43121 - 0.224889 * T
- F2:log(t) = 14.30389 - 0.2251287 * T
- F3:log(t) = 14.06163 - 0.2252666 * T
- F4:log(t) = 13.81366 - 0.2250048 * T
- F5:log(t) = 13.68152 - 0.2248754 * T
- F6:log(t) = 13.52736 - 0.2258101 * T
- F7:log(t) = 13.05205 - 0.2251104 * T
As the egg respires through the pores on its egg shell, it discharges
carbon dioxide. During this process there is nearly no change in the yolk yet the
pH concentration in the albumen increases. The salmonella's thermal resistance and
destruction rate changes according to this pH concentration. The pasteurization
of the albumen differs in the temperature and time according to the pH concentration
even at the same level of pasteurization, the lower pH concentration is the more
pasteurization time needed at the same temperature. Moreover at the same time period,
the lower pH concentration is the higher pasteurization temperature is needed.
The 7.6 to 7.9 pH concentration of an egg that has just been laid
rapidly increases to pH 9 in 1~3 days. Most commercial eggs have a pH concentration
of 8 or more. While the pH concentration of the albumen is 8.0 or more when grading,
packaging, shipping, and circulating the yolk's pH concentration does not change
greatly around 6 as it does not discharge carbon dioxide.
The present condition is that most eggs are graded, under strict quality
inspections by the country, and that consumers are likened to fresh eggs. This makes
the packaging and circulation occur shortly after the egg has been laid. Since F4,
F5, and F6 have the pasteurizing condition of the albumen's pH concentration being
8, it would be desirable. If the egg is kept in a grading and packing center or
a processing facility for an extended period of time, the pasteurization at the
level of 5LOG the albumen that has reached pH 9 can increase its range temperature
and time to F7.
If the albumen's pH concentration exceeds 9 the eggs that are below
(pasteurization of albumen above pH 9) that level are, unless not intentional, the
yolk pasteurization automatically fulfills that level of albumen pasteurization.
Thus, F7 is the true lowest (in the most weak range) pasteurization range of the
The locus (F1, F2.... F7) of Figure 1's temperature and time needed
for pasteurization at the temperature according to the pasteurization level was
obtained from experiments data using SAS Software package at a significance level
of 95% (p <0.05) on the basis of the standards commercialized in liquid eggs
in Korea and abroad, D-value(refers to decimal reduction time. This is the amount
of time that it takes at a certain temperature to kill 90% of the organisms being
studied), Z-value (the temperature change according to D-value's tenfold change)
and pasteurization theory. The pasteurization standard is this locus of the temperature
Pasteurization inspection is done by artificially injecting the SE
inside the shell eggs and following pasteurization, they are cultured in two ways,
one in LB agar, SCP, and Rambach agar at 37 degrees each for 24 hours, the other
in BPW (Buffered peptone water), SCP, and Rambach agar at 37 degrees each for 24
hours. The cultured eggs were given a positive PCR inspection.
RANGE OF TEMPERATURE FOR PASTEURIZATION
When pasteurizing a shell egg by heating with the use of a means of
heating, the heating temperature will have limitations, and the albumen and yolk
will start to solidify at around 61 ±1 °C and 65 ±1 °C respectively. In order for
the albumen to reach the planned pasteurization range of 54 °C ~59.5 °C , the egg
needs to have direct or indirect contact with a heating medium with a temperature
exceeding that in the least. at 59.5 °C or above, the albumen near the shell rapidly
increases in its solidifying rate, and in order to reduce the pasteurization process
the heating medium needs to pasteurize at a high temperature (60 °C or above) from
the beginning. Even in this situation the solidification of the albumen near the
shell, the damaging of the yolk and albumen, and the shell's breaking occur rapidly
and therefore the pasteurization temperature range is limited to 59.5 °C or below.
At this time, when pasteurizing at a low temperature the production
efficiency declines due to the long processing time. Although the problem of the
damaging of the shell is improved, the problem of gelation occurs. This situation
has a high rate of occurring when the albumen is at around 54 °C for 194 minutes
When pasteurizing the yolk at 54 °C at the level of 12LOG, the pasteurization
takes around 194 minutes and considering the time it takes for the yolk to reach
this planned temperature, it takes 194 minutes or more in the least. Thus, when
the yolk and albumen exceed 194 minutes at 54 °C or more in the least, the gelation
increases. This differs according to the condition of the egg, yet occurs at more
than 30% and therefore it is wise to set the pasteurization temperature range at
54∼59.5 °C. It is wiser to pasteurize at between 55 °C or more and 58.5 °C or
below when considering the solidification of the yolk and albumen, minimizing function
damage, gelation of the albumen, and breaking of the shell. The wisest would be
For the range of the time for pasteurization, the shortest time will
have the pasteurization level at 5LOG and the albumen's pH concentration at 9. When
both the yolk and albumen's lowest temperature reaches 59.5 °C the temperature must
be adjusted so that the lowest of three points measured according to the invention
of the yolk and albumen does not break away from this lowest temperature. The pasteurization
is complete 4.56 minutes after the yolk reaches the assigned temperature and as
for the albumen, after 0.46 minutes.
Similarly, in the case of the longest time will have the pasteurization
level at 12LOG and the albumen's pH concentration at 8. When both the yolk and albumen's
lowest temperature reaches 54 °C the temperature must be adjusted so that the lowest
of 3 points measured according to the invention of the yolk and albumen does not
break away from this lowest temperature. The pasteurization is complete 194 minutes
after the yolk reaches the assigned temperature and as for the albumen, after 46.1
The lowest temperature mentioned above is the temperature of each
hour when pasteurizing and the maintaining time for the planned temperature during
the refrigeration process is included. The pasteurization time range is one that
fulfills both the yolk and albumen; the pasteurization time being 4.56 minutes at
59.5 °C in the lowest level of 5LOG, and 194 minutes for 54°C in the highest level
of 12LOG. This is the actual time required following the reaching of the planned
Temperature and Time Range
When viewing the temperature and time range of pasteurization, the
temperature is 54~59.5 °C ,and the time in which the pasteurization of both the
yolk and albumen are fulfilled within the temperature range mentioned earlier is
4.56∼194 minutes. The time and temperature set in the range above F3 is the
pasteurization range of the yolk, and the time and temperature set in the range
above F7 is the pasteurization range of the albumen. Yet when pasteurization is
done at the farm shortly after the egg has been laid, the albumen's pasteurization
range expands to the time and temperature locus that fulfills LOG (time; minute)
=13.82085-0.2246819* (temperature; Celsius)
At this time, the time for preparation process for pasteurization,
the time it takes to reach the planned temperature, and the required time of pasteurization
including refrigeration or the time for coating process extends the whole pasteurization
processing time. This whole pasteurization processing time will differ according
to the egg condition which is the size, preservation temperature, pH concentration,
means of heating, heating medium, and method of heating.
Figure 2 is an exemplification that illustrates the measuring the
yolk and albumen's lowest temperature standard points for that are applied to the
In the pasteurization of shell eggs according to the present invention,
the core part is that the lowest temperature of an egg's interior is measured, and
in order to have this temperature reach a certain pasteurization level the time
must be maintained. Yet because of the material characteristics of the yolk and
albumen, a temperature difference occurs and in each case a temperature difference
occurs according to the points. So if the lowest temperature is not measured accurately,
a problem with an egg being only partly pasteurized occurs. Therefore, the present
invention presents the method to measure the lowest temperature according to the
The lowest temperature presented by the present invention conceives
the idea of the lowest of 3 temperatures in each of the yolk and the albumen. The
lowest temperature measuring point is not a point determined by random. When pasteurizing,
it does not matter whether the location of the egg's round region, which has the
air cell, is at the top, bottom, or horizontally. It would be wisest to have the
air cell face the top and hold the egg in a perpendicular position. In this instance,
as illustrated, after selecting the largest sphere out of the spheres circumscribing
the egg shell and yolk from the albumen, have that sphere's center as Wm and the
yolk's center as Ym. Connect Wm and Ym with a straight line and extend the line
on both sides and on the line, have the albumen's point which is closest to the
yolk as Wi. Also, have the albumen's point which is closest to the egg shell as
Wo. Suppose that the yolk's point closest to Wi is Yo and Yi is the center point
of Yo and Ym. Then, Ym, Yo, Yi and Wm, Wo, Wi are set as the standard for measuring
the lowest temperature when pasteurizing.
Additionally, having Ym as the standard, have the points that are
symmetrical to Yi and Yo on the straight line as Yii and Yoo. After selecting the
smallest sphere that circumscribes the shell and yolk, have the sphere's center
as Wmm and the yolk's center as Ym. Connect Wmm and Ym with a straight line and
extend the line on both sides. When supposing that the albumen's point closest to
the egg shell as Woo, closest to the yolk as Wii, Ym, Yoo, Yii and Wmm, Woo, Wii
are set as the standard for measuring the lowest temperature when pasteurizing.
However, the sphere mentioned above does not share any points with the air cell.
Through the pasteurizing process, the yolk and albumen become a single
or multiple lowest temperatures out of Ym, Yo, Yi and Wm, Wo, Wi respectively. Yet
in general it does not occur when a certain point of the yolk or albumen stagnates
or falls at the same temperature. The temperature after this moment in the case
of the yolk would be Ym, Yo, Yoo, Yi, Yii and in the case of the albumen would be
Wm, Wmm, Wo, Woo, Wi, Wii. Out of these, the point with the lowest temperature becomes
the single or multiple lowest temperatures.
When measuring 3 or more points as the lowest temperature, the conditions
for measuring the lowest temperature are as follows.
Have the point that corresponds to Wo as W1, and as it goes toward
the Ym direction have it go as W2, W3, W4, .... Wm, Wm+1, Wm+2, .... Wi. Have the
point that corresponds to Woo as W11, and as it goes toward the Ym direction have
it go as W22, W33, W44, ···· Wmm, Wmm+1, Wmm+2, ···· Wii. Have the point that corresponds
to Yo as Y1, and as it goes toward the Ym direction have it go as Y2, Y3, Y4 ....
Yi, Yi+1, Yi+2, ···· Ym. Have the point that corresponds to Yoo as Y11, and as it
goes toward the Ym direction have it go as Y22, Y33, Y44 .... Yii, Yii+1, Yii+2,
···· Ym. When having all of the above supposed, the lowest temperatures out of all
these points are the lowest temperatures of the yolk and albumen at that time.
Thus, the TLw and TLy below become the lowest temperatures of the
yolk and albumen and they can be the temperature of a single or multiple point.
TLw(t)=MIN T(t) (W1,W2, ... Wm,Wm+1,Wm+2, ... Wi, ... W11,W22... Wmm+1,Wmm+2...,Wii)
TLy(t)=MIN T(t)(Y1,Y2,...Yi,Yi+1,...Y11,Y22,...Yii+1, Yii+2,...Ym)
- TLw is the albumen's lowest temperature at a certain time from the beginning
to end of pasteurization.
- TLy is the yolk's lowest temperature at a certain time from the beginning to
end of pasteurization.
- MIN T(t) is the lowest temperature at t seconds.
- t would be the time, its unit being second (0 < t ≤11,640)
Through the pasteurization process which also includes the refrigeration
process, pasteurization will be done according to the planned temperature and time
at desired pasteurization level out of the lowest temperature and time set that
fulfills the conditions below. The planned pasteurization temperature of the yolk
and albumen at the point it reaches the planned temperature must not be lower than
the lowest temperature at a certain point and at a certain time of a yolk or albumen.
The yolk being line F3 and the range above, thus being the range between F1 and
F3; the albumen being line F7 and the range above, thus being the range between
F4 and F7, the pasteurization time needed must be maintained in the level the planned
Thus it must fulfill the conditions below.
- 1) Twp(tw)≤MIN
T(tw+k1)(W1,W2, ... Wm,Wm+1,Wm+2, ... Wi... W11,W22... Wmm+1,Wmm+2...,Wii)
- 2) Typ(ty)≤MIN T(ty+k2)(Y1,Y2,...Yi,Yi+1,...Y11,Y22,...Yii+1,Yii+2,...Ym)
- 3) At the ending time of pasteurization, k1-tw and k2-ty must be larger than
the required time at the planned pasteurization temperature of albumen and yolk
respectively intended by Figure 1's level of pasteurization.
(However, 0 ≤k1 ≤11,640, 0 ≤k2 ≤11,640 and k1, k2 is in
the unit of seconds.)
In the mentioned equation,
- Twp is the planned pasteurization temperature of the albumen
- tw is the time (seconds) pasteurization begins after entering the range of the
albumen's planned pasteurization temperature
- k1 is the lapse time (seconds) before the completion of pasteurization after
entering the range of the albumen's planned pasteurization temperature
- MIN T(tw+k1) is the albumen's lowest temperature at each time from after entering
the lowest temperature until the completion
- Typ is the planned pasteurization temperature of the yolk
- ty is the time (seconds) pasteurization begins after entering the range of the
yolk's planned pasteurization temperature
- k2 is the lapse time (seconds) before the completion of pasteurization after
entering the range of the yolk's planned pasteurization temperature
- MIN T(ty+k2) is the yolk's lowest temperature at each time from after entering
the lowest temperature until the completion.
As mentioned above, the pasteurization according to the present invention
must have the lowest temperature as the standard. When pasteurizing with a heating
medium to heat, shift and refrigerate, the pasteurizing results differ according
to what time and what point of temperature is the standard of pasteurization. Therefore,
the lowest temperature of each time through the pasteurization process must be the
standard, and the measuring point of that lowest temperature must be set.
Therefore, many points must be measured and the lowest temperature
out of the points must be the standard of pasteurization. It is wise to measure
at least 3 or more points of each of the yolk and the albumen and set the lowest
temperature out of them as the standard temperature for pasteurization.
The following is a detailed description of the various operations
and drawings that are applied to the invention.
When reaching the planned temperature with 1 heating medium, the temperature
of the means of heating is adjusted so that the lowest temperature of the yolk and
albumen can be maintained at or above the planned temperature for the needed time
of pasteurization. Two or more heating media of the same or different temperature
may be used when adding an additional course such as coating or to boost productivity
by continuous operations. When using two or more heating media with different temperatures,
it is wise to maintain the temperature of the following heating media or means of
heating lower than the previous heating medium or means of heating in order to minimize
the damage of the function or solidification of the yolk and albumen.
At this time, the last means of heating must be able to adjust or
maintain the temperature required by the planned temperature of the yolk and albumen
in order to fulfill the level of pasteurization time. This is done to fulfill the
needed pasteurization time in the last means of heating with the refrigerating time
was subtracted. Also, a low temperature is favorable in the prevention of function
damage for the yolk and albumen.
When pasteurizing an egg that is a shell egg, the albumen has the
possibility of its function being damaged or being solidified before the yolk reaches
the planned temperature or becomes completely pasteurized. In this instance, it
is wise to use two or more heating media or adjusting the temperature or exiting
and entering shell eggs in single heating media. At this time the albumen near the
shell rapidly loses its temperature and is effective for the prevention of solidifying,
yet it must be seen with great caution that there is no break away below the planned
Particularly, for the early reaching of the planned pasteurizing temperature,
heating medium number one which has a high temperature is used, or adding the preheating
process which narrows the temperature difference between an egg that has first contacted
a heating medium to minimize shell breakage problems (cracks), or when adding a
process such as coating, the use of two or more means of heating media is required.
Also in this instance, shifting eggs among the heating media is required, but be
ensured that no point of the egg's interior breaks away from the planned temperature
In order to minimize the albumen's function damage, it is wise for
the eggs to enter the planned temperature through the high temperature heating medium
number one and then maintaining and completing the pasteurization with a lower number
two and number three means of heating regardless the kind and number of the means
of heating and heating medium and method of heating. The pasteurization according
to the present invention ensures that the lowest temperature of the yolk and albumen
fulfills the intended level of pasteurization above the F1~F7 range by maintaining
the needed pasteurization temperature and time above the planned pasteurization
Therefore the pasteurization results differ according to what time,
what point, and what temperature is the standard in pasteurization. In severe cases
the albumen can be not pasteurized even if the yolk has been, and parts of the yolk
can be not pasteurized even if the center of the yolk is pasteurized. These problems
cannot be solved when the lowest temperature is not the standard and the lowest
temperature measuring point is not set through the entire pasteurization process.
For this, there is a need for measuring the temperature of as many
points possible to have as the pasteurization standard. It is wise to measure as
many points as possible and have the lowest temperature among them as the pasteurization
standard. At least 3 or more points of the yolk and albumen must be measured according
to Figure 2's principle and the lowest temperature among them must be the standard
temperature of the pasteurization.
If that temperature is not the lowest temperature the actual lowest
temperature point or other points could not be pasteurized. The temperatures of
the yolk and albumen are different even when the temperature of the heating medium
is fixed. The following illustrates such an instance and the temperature measuring
was done with a waterproof digital electric thermometer with an attached temperature
perception needle. The passage entered by the needle into the shell was sealed with
a silicon based adhesive.
Figure 3 illustrates the temperature change of the yolk and albumen
after heating. It is a graph that illustrates the 1 minute interval change in temperatures
of each of the yolk and albumen of a 60gram brown egg (albumen's pH concentration
8) kept in 25°C and then heated in water of 58.5°C.
The data analysis of the temperature changes of the yolk and albumen
after heating according to the exemplification research can be referred in Table
As shown in Table 1 and Figure 3, the temperatures of each point change
as time passes and it can be seen that such changes do not have a fixed sequence
of being high or low. There is an instance where as time passes, Wi, which is far
from the heating medium, is rather higher than Wm or Wo, and the yolk has a higher
temperature than the albumen. This appears to be a heat compression of the yolk
and albumen which is relevant to the effect of insulation on the transmission of
heat caused by the existence of the shell, the yolk's membrane, and the albumen's
membrane. There are instances where among points, the yolk's temperature is higher
than the albumen's temperature or the inner albumen's temperature is higher than
the outer albumen. Therefore, in order for the egg's interior to be completely pasteurized,
the pasteurization standard is the lowest temperature through the entire pasteurization
process. The lowest temperature must not be lower than the lowest temperature of
other points from the beginning to end of the pasteurization.
The example above is the instance of a fresh egg that has just been
laid a pH concentration of 8 and the center of the yolk Ym is near the geometric
center. As time passes following the egg laying, the yolk shifts near the air cell
through respiration. If the egg is kept at room temperature in the summer, after
around 2 weeks, Yoo of Figure 2 will near the air cell part of the shell. In this
instance, Ym also breaks away from the egg's geometric center and Yo rather is located
near the center. In this instance if a 60g egg that has been kept in 23~27°C room
temperature for 2 weeks after it has been laid and pasteurized through heating medium
with 58.5 °C ,after Ym has reached the planned pasteurization temperature of 54
°C, Ym's temperature is higher than Yo from 0.2°C~0.4°C. Therefore inevitably having
the temperature the yolk's center point Ym as the standard, when pasteurizing, even
if the yolk's center and Ym is pasteurized, it must be made sure that the yolk's
other points or Yo is not pasteurized.
When heat pasteurizing a shell egg that has its yolk close to the
shell, the temperature of the yolk's center becomes higher than other parts of the
yolk disregarding the heating medium, heating temperature, and heating method. As
a result, the portions that are far from the air cell may not be pasteurized even
if the yolk's central portion is pasteurized. Only the pasteurization of the points
of the lowest temperatures fulfils pasteurization of the entire egg. Therefore the
lowest temperature must be the standard of pasteurizing.
Figure 4 illustrates the yolk's temperature changes according to the
refrigeration time. It is the instance of a 60g brown egg that has been kept at
25°C room temperature and heated in water at 58.5°C. After 44.7 min has passed since
the water heating medium it is taken away from the water and at 25°C it displays
the yolk's temperature change with a 30 second gap as it refrigerates.
Should 57°C be the planned pasteurization temperature, when Ym, the
yolk's lowest temperature point, reaches the planned temperature in 28 min 30 seconds
and plans pasteurization at a 5LOG level, it would continue the 16.7 min that is
required for pasteurization. And after it contacts the heating medium the pasteurization
will be completed in 45.2 min (refrigerating process included) (In this instance,
after breaking away from the heating medium, after 1.5 min passed of the refrigerated
process is completed). Even in the refrigerated process the yolk's lowest temperature
is at 57°C for or over 1.5 min and this time must be included. And in the actual
heating medium, the heating time can be reduced to around 1.5 min.
Should the planned temperature be 57°C and the heating medium's temperature
be adjusted to maintain Yi, Yo, Ym at 57°C or near that temperature, a temperature
reversal between Ym and Yo will occur in the refrigerated process. Moreover, the
time it takes to maintain the planned temperature of 57°C will take as much as 60
seconds longer for Ym than Yo. In this instance, if the heating or the temperature
controlling method of the heating medium makes the difference in Ym and Yo's reaching
of the planned temperature 57 °C less than 60 seconds, other parts of the yolk including
Yo may not be pasteurized even if the center is.
In the above instance, if refrigerating after breaking away from the
heating medium after 44 minutes, the yolk's center (Ym) will be 57°C or above and
the time it takes to maintain will be 1.5 min. This fulfills the time needed for
pasteurization of 16.7 (44-28.5+1.5=17) min, yet when refrigerating the outer (Yo)
it takes 0.5 min at 57 or above and does not fulfill the 16.7 min. Thus the pasteurization
would be an insufficient pasteurization and therefore the time including the refrigerating
and the lowest temperature is needed. This sort of refrigerating process is essential
and the situations above will undoubtedly occur though the degree will vary. The
not pasteurized range may increase according to the setting of the planned pasteurizing
Figure 5 illustrates the temperature change of the yolk by time when
shifting between the heating media. When a 60g brown egg kept at 25°C room temperature
breaks away from the 1st heating medium of 59 °C when the yolk reaches
the lowest temperature of 57.5°C, it shifts to the 2nd heating medium
of 57.5°C. As it shifts it inevitably is exposed to the air for 1 min, and every
30 seconds, its temperature is measured.
Pasteurization has not yet been completed (When completed, shifting
is unnecessary), if the planned pasteurization temperature is 56°C, Ym and Yi proceeds
within the planned temperature yet Yo already has broken away from that range and
has the possibility of not being pasteurized. If the planned pasteurization temperature
is 56.5°C, Yi and Yo may not be pasteurized because they have already broken away
from the planned temperature yet not for Ym.
The pasteurization method using the temperature's fall like these
sort of shifting through the heating media to the lower temperature heating medium
or exiting and reentering through one heating medium when the planned temperature
is reached, is efficient and needed. In this instance, even if the yolk's center
is pasteurized, there is a chance that the other parts have not been pasteurized.
The above is an example. Pasteurization through 2 or more of heating media or through
single heating medium not at the same temperature or the repeat of a exiting and
entering is needed (when combining an additional process such as coating), it will
most certainly occur, although the degree will vary. Therefore, the notion of a
lowest temperature classified by time is needed.
More specifically, the desirable pasteurization method of preventing
the excessive pasteurization and ripening of the albumen on the one hand and pasteurizing
the yolk on the other is the following. When heating or refrigerating an egg, the
method is to use the difference of the temperature change of the yolk and albumen
as time passes. That is, utilizing the fact that albumen is heated and cooled faster
than yolk. When using a single temperature heating medium for this, there is a need
for the repeat of entering and exiting. A wiser approach would be to use 2 or more
of heating media with different temperature and in this case the previous one must
have a higher temperature than the next. Thus with the heating medium that has a
higher temperature, the planned temperature can be reached at a quicker time and
then shifted to the heating medium that has a lower temperature. When shifting,
it uses the amount difference of the yolk and albumen in their change of temperature
to prevent the albumen's ripening and to fulfill the time needed for the yolk's
pasteurization. Inevitably for both instances, the temperature change of the egg's
interior while shifting is essential and there is an occurrence of a temperature
reversal among the yolk's points. In Figure 2 where the yolk's Yoo does not fulfill
the time needed to pasteurize and breaks away from the pasteurization condition,
there occurs an instance of Ym continuously fulfilling the pasteurizing condition
within the pasteurizing temperature. Thus, even if the yolk's center is pasteurized,
there is an instance where other points are not pasteurized.
In severe cases, a point of the yolk (Yoo of Figure 2) breaks away
from the pasteurizing temperature range of 54°C and increases the tolerance of the
SE so that even if it re-enters the pasteurizing temperature, pasteurizing cannot
be carried out. Also in this instance, Ym can fulfill the needed pasteurizing time
within the planned pasteurizing temperature and be pasteurized. Therefore the entire
pasteurization of an egg's interior can be ensured through pasteurizing with the
lowest temperature as the standard. Thus, when an egg is exciting and entering a
single heating medium with the same temperature, and when an egg is shifting between
two or more heating media with the same or different temperature, the lowest temperature
change as it has contact with the air or other medium must be reflected. This sort
of entering, exiting, and shifting can prevent the albumen's ripening and is an
effective and needed method to attain the aimed pasteurization level.
Figure 6 is a graph that illustrates the change in the lowest temperature
of the yolk and albumen classified by time. A 60g brown with a pH 8 albumen (the
lowest temperature of the albumen and yolk is 24.1 °C and 24.4°C each) is put in
a 59.5 °C heating medium number 1 and when the yolk's lowest temperature rises and
reaches around 57°C, it is exposed to the air. Then it is shifted to a 57.5°C heating
medium number 2 and the lowest temperature of the yolk and albumen is measured every
If the planned pasteurizing temperature is 54°C, the yolk and albumen's
pasteurizing conditions can be all fulfilled. Yet if the planned pasteurizing temperature
is 55°C, the albumen's pasteurizing conditions cannot be fulfilled. If the planned
pasteurizing temperature is 56°C, all the pasteurizing conditions cannot be fulfilled
because the yolk and albumen have already broken away from the lowest required temperature.
Generally the yolk's pasteurization mostly fulfills the albumen's
pasteurizing conditions yet the above instance displays that it does not happen
all the time. Even when repeating the process of exiting and re-entering the heating
medium for coating inside a heating medium with the same temperature, although there
is a difference in the degree, a similar instance can be seen. Thus, the albumen
can break away although the yolk is within the planned temperature.
Therefore, a notion of a lowest temperature for each time is needed
of the yolk and albumen.
Instance of Pasteurization
When viewing the pasteurizing process of a 60g brown egg with a pH
8 at a 9LOG level, it is exposed in the air of 26°C with a humidity of 63% for 30
min. The heating medium is 59°C and can adjust the temperature up to ±0.1°C. When
putting the egg in the heating medium, the lowest temperature of the albumen and
yolk is 18.1°C and 17.4°C each and the planned temperature is set at 58°C. The temperature
of the heating medium was adjusted so that the lowest temperature of the yolk and
albumen could be maintained within the same water tank when it was reached.
As for the albumen's lowest temperature, after it enters the heating
medium, it reaches 58°C after 31.5 minutes and the pasteurization is completed in
35.9 min including the needed 4.4 min. As for the yolk's lowest temperature, after
it enters the heating medium, it reaches 58°C after 37.8 min and the pasteurization
is completed in 55.5 min including the needed 17.7 min. At this time, it is 55.5
min including the 1.3 min of stagnation above 58°C when refrigerating after exiting
the heating medium. After the pasteurization, the albumen is a bit opaque.
Thus, after exiting the heating medium, taking the 1.3 min of continuous
pasteurizing time into consideration, the pasteurization is completed after exiting
the heating medium at 54.2 min.
In the above instance, there was no shift between the water tanks,
nor exiting or re-entering the heating medium to do additional procedures such as
coating and the temperature after the yolk and albumen reached the planned pasteurizing
temperature was maintained. Thus, there was no break away from the lowest temperature,
and there was merely the change in the point of the yolk's lowest temperature and
time difference in the maintaining of that temperature. If shifting to the next
heating medium or there is a rapid fall in the heating temperature, the yolk and
albumen's lowest temperature must not break away from the planned temperature. Additionally
the lowest temperature of the changed lowest temperature point must fulfill the
time needed to maintain the pasteurization.
Pasteurization takes 17.7 min in time as the yolk's lowest temperature
at 58°C in the pasteurization level of 9LOG requires such time. The time is the
same with no concern with the heating medium or its method, yet in the instance
above, the entire time for pasteurization is 55.5 min. When pasteurizing at the
same temperature, the entire time for pasteurizing differs according to the means
of heating, heating medium, heating method, and the egg's characteristics. Even
in the same level of pasteurization, the actual pasteurizing time may be the same
according to the planned temperature, but as mentioned above, the time it takes
for the entire pasteurizing process is different according to the pasteurizing environment.
Instance of Pasteurization Inspection
Table 2 concerns 60 experiment eggs that weigh 60g each, brown, with
its albumen's pH being 8. The SE is injected into the albumen and yolk's Wm and
Ym at an amount of 100,000 CFU/ml each. The heating medium is set at 58.5°C, and
the 60 eggs, which the albumen and yolk's lowest temperature is 31.3°C and 30.4
°C respectively when they first contact heating medium, are put into 5 groups with
12 eggs in each group. Each group has a 60 second difference and the eggs are pasteurized
at the planned pasteurizing temperature of 56°C at a 5LOG level. Cultured in LB
agar, SCP and Rambach agar at 37°C each for 24 hours. Then, pasteurization is inspected
with the positive sample PCR. In the instance above the yolk and albumen have to
remain at least 28 min and 7.6 min at 56°C or above to pasteurize at 5LOG. In this
experiment the yolk and albumen's lowest temperature will reach 56°C at 12.6 min
and 19.8 min respectively after it enters the heating medium. After it reaches the
planned temperature, it was maintained.
56°C Holding Time
Number of Positive Reactions
Number of Negative Reactions
One problem when pasteurizing shell egg is the damaging of the egg
shell due to the heating. Such damages depend highly on the age of layer when an
egg has been laid, feed consumed, temperature inside the layer house, and the temperature
difference between the heating medium and egg. An egg that was laid by a layer that
was forced to molt needs heating at 54~59.5°C and for that it needs heating in a
direct and indirect method in a heating medium that is at least at or above that
temperature. Even in this case 50% of eggs damage their shells and therefore the
egg of a layer that has been forced to molt is excluded from the present invention's
When pasteurizing an egg such as the one mentioned above, in order
to minimize the problems caused on the egg shell, it is wise to narrow down the
temperature difference of the egg and heating medium as much as possible. It is
also wise to have a preheating stage with a means of heating before pasteurizing
to minimize problems on the cracks of egg shell.
Handling Cracked Eggs
Adding a preheating stage or using the automatic crack detector, which
is commercially used at present, does not entirely solve the crack problems concerned
with damages on the egg shell. Also, the damage condition depends on the feed consumed,
the age of layer when an egg has been laid, and how the egg was kept and pasteurized.
Unexpected crack problems may occur in the actual pasteurizing process and in this
case, it is wise to use the egg as other pasteurizing usage. Thus, this would mean
processing the egg boiled or half-boiled for consumption. Eggs processed in this
way are generally treated in half or in parts and consumed for the purpose of nutrition,
taste, and visual effect for other products. The value is high when the yolk is
located near the center, otherwise it will draw in dislike visual-wise from the
consumer and it will extend onto other products and lessen the product quality.
Therefore, there is a need to add the method of placing the yolk at the geometric
center. In order to do this, the egg needs to be rotated up and down or horizontally
at 180 degrees or more inside or outside the heating medium at an axis perpendicular
to Figure 2's Woo and Wo. A wiser approach would be to rotate it perpendicularly
yet having it rotate 1 time or more so that it intersects in each direction, making
the yolk not be placed in a certain location near the shell due to the centrifugal
force. Thus, at 54~100°C, the pasteurizing range is increased to 5∼300 min,
and 2 or more eggs making 1 or more stacks are carried perpendicularly. They are
rotated up and down at 180 degrees or more inside or outside a heating medium, yet
it must not rotate in the same direction at more than 720 degrees and intersect
rotate by going in the opposite direction one or more times. In this instance also,
it breaks away from Figure 1's pasteurizing temperature range and the egg interior's
lowest temperature expands to 100°C. There is ripening or change of matter of the
yolk and albumen, yet the pasteurizing level and egg edibility as a food product
Shell Eggs for Pasteurization
The range of the present invention has the yolk and albumen's lowest
temperature as the standard and fulfills the temperature and its maintaining time
required by Figure 1. Therefore, is not influenced by the shell's color, weight,
and the temperature of egg storage and applied in the same way.
However, although the pasteurizing time is the same, the more the
weight is and the lower of egg's temperature is when it enters the heating medium,
the longer the entering time to enter the possible pasteurizing temperature range.
Moreover the entire required time will extend longer. A refrigerator egg's pasteurizing
time is longer than an egg that has been kept in room temperature, and when the
refrigerated egg enters a heating medium with the same temperature, its shell has
a higher rate of being damaged by cracks than an egg that has been kept in room
temperature. The entire time difference between the refrigerated egg and the egg
that has been kept in room temperature differs according to the weight, temperature
difference when keeping, and the temperature and method of the heating medium. Yet
the lower the temperature of the heating medium is, the longer the entering time
of the possible pasteurizing temperature the entire time of pasteurization.
The greater the weight, the longer it is to reach the possible pasteurizing
temperature. The entire time will also extend and the yolk and albumen will have
a higher chance of becoming damaged because it will have longer contact with the
heating medium. Therefore, there is a need to select a temperature that will minimize
such problem. The refrigerated egg particularly needs a more cautious approach when
selecting the temperature and time and also restriction. At present, most egg grading
and packing equipments can divide up to ±0.1g and grade/pack the weight in 1g units.
So when pasteurizing, it is wise to minimize the weight difference by using this.
When actually producing mass-produced commercial eggs that have been
pasteurized, the planned means of heating until the refrigeration process, the kind
and number of heating media, the temperature, the shifting time within the heating
media and required time, the method of heating and so on must be the same. The data
obtained through enough repeated experiments serving as a basis, apply it in the
actual mass-production. Thus, measure the yolk and albumen's lowest temperature
by time and set the time, temperature and procedure of each process so that they
will reach the planned pasteurizing temperature and maintain the level of pasteurizing
time intended at that temperature. Apply to mass-production.
After pasteurizing, inspect the pasteurization and through a regular
and repeated measurement, ensure that there is no fall in the function and no solidification
of the yolk and albumen. In order for this to happen, the temperature and the time's
numerical value must be adjusted. There also must be a feedback that can minimize
It is wise not only to do a pasteurization inspection but also to
do a regular quality measurement of the Haugh Unit, Yolk Index, the weight loss
and so forth on which represent the yolk and albumen's quality. However, the shell
eggs that are to be pasteurized must be the same kind, flock, have the same days
passed since being laid, and have the same pH concentration. The weight difference
must be minimized, and it is ideal to pasteurize the egg of the same flock with
the same weight and same days passed since being laid together.
If, due to a sudden environment change such as a power failure pasteurizing
becomes impossible or there is a break away from the normal pasteurizing conditions
such as a lack or pasteurization, excessive pasteurization, or the ripening of the
albumen, it is wise to change the eggs commercially for other usage. This is the
same as the details mentioned above in handling cracked eggs.
Pasteurizing the Egg Shell
Even the shell is much contaminated with the salmonella and germs.
The heat transmitted to the yolk or albumen is transmitted through the egg shell,
and the heat capacity received by the egg shell is higher than the yolk or albumen.
Because the salmonella is pasteurized by the heat, the yolk and albumen's pasteurization
can be expected to fulfill the pasteurization of the egg shell. Additionally, it
can be expected to pasteurize similar germs and harmful microorganisms.
Means of Heating and Heating Medium
The term 'means of heating' in this application implies a heating
equipment including the heating medium and for example, can be a water tank and
so forth. Moreover, 'heating medium' is intended to imply that the medium transfers
heat to the shell egg and makes pasteurization possible. The means of heating and
heating medium must transfer heat evenly to the egg, and must be possible to adjust
the temperature of the heating medium and yolk and albumen for up to ±0.1 degrees.
When adjusting the heating medium's temperature, it includes the indirect, direct,
continuous, and intermittent transfer.
A solid, liquid, or gas can be used as the heating medium and when
considering the facility and economical efficiency it is wise to use liquids such
as water, oil, and salt water. In order to increase the heat transfer efficiency
or to equally heat the entire egg, use a chemical mixture such as a surface activator,
cause friction between the heating medium and egg, or rotate the egg inside the
Having no concern with the means of heating, heating medium, heating
source, and heating method, in order to reach the level of pasteurization required
by the lowest temperature of the yolk and albumen, the required pasteurizing time
must be maintained at the planned temperature. One or two or more means of heating,
heating medium, or method of heating may be used. They may be used together yet
during the pasteurizing process, after the lowest temperature reaches the planned
pasteurizing temperature the shifting within the means of heating or heating medium,
or the continuing time of pasteurization including the refrigerating time within
the heating medium must fulfill the pasteurizing level of temperature and time.
When fixing the shell eggs inside the solid and rotating or reciprocating
them inside the means of heating, this can cause an uneven heating region. Also,
the albumen can solidify in parts according to the difference in thermal conductivity.
Therefore, there has to be an equal heat distribution between the heating medium
and heating method. In order to do this, the uneven heating region needs to be minimized.
In order to increase the heat distribution efficiency of the heating
and to equally reach the temperature, the up and down or left to right bubble circulation
of perturbation equity can be added inside the means of heating or heating medium.
When pasteurizing, these may not be necessary yet the following are
additional wise procedures for the enhancement of pasteurization, production, and
The main purpose of the preheating process is to minimize the damage
of the egg shell. Through the preheating of the refrigerated egg or egg kept in
room temperature, the temperature difference will be decreased when the egg enters
the heating medium. Additionally there is the planned temperature entering time
improvement effect and it is wise to have the temperature of the heating medium
and the egg shell within 22°C.
There is a need for natural refrigeration in the air or forced refrigeration
during or after pasteurization. In order to maintain the best egg quality and minimize
the growth of the living salmonella during refrigeration, the shell eggs remain
in 37±3°C at least and arrive at 5°C or below as earlier as possible and be kept
at this temperature.
When refrigerating, it is wise to use the refrigerating method where
there is no insulation or no restriction in the mutual friction and shifting between
the eggs and the refrigerating medium.
In order to prevent the 2nd contamination of an egg from
harmful microorganisms during or after pasteurization, it is wise for coating. For
effective coating, the moisture or alien substances must first be removed from the
egg's surface. In both of the instances mentioned above, have Figure 2's Woo and
Wo as the axis and rotated on the side horizontal or up and down perpendicular (Woo
and Wo up and down). It is wise to rotate the eggs inside the heating medium or
air during or after pasteurization. This particularly is more productive and efficient
when the moisture is dried. It is possible to dry an egg at a satisfying level within
30 seconds that has broken away from a 55~60°C heating medium during or after pasteurization
and rotated at a speed of 1 rotation per 30 seconds or above in the air with a 60~80%
relative humidity at 15-25°C. However, if there is no rotation, the moisture gathers
due to the egg's gravity at the lowest point and accumulates making the drying process
alone take 25 min or more.
Water, salt water, with its main element being water, and other liquids
can be used as the heating medium due to their convenience in handling and safety
reasons. In this instance water or other liquid substances can dissolve the cuticle
on the egg shell surface, which prevent germs, and there is an increased possibility
of the egg being contaminated by the salmonella and germs again after pasteurizing.
The cuticle is on the egg since it is laid yet when the egg is washed or has contact
with liquid, the cuticle breaks away form the egg- making it susceptible to the
entering of germs. This threatens the quality and safeness of the egg.
Therefore when an egg is pasteurized in liquid, particularly water,
it is wise to block the 2nd contamination of germs through an alternate
protection of coating. To do this, it is wise to coat mineral oil or cooking oil
as the cuticle's substitution. Coating after pasteurizing not only prevents the
re-contamination of germs but also increases the safekeeping of the egg. This coating
process is not necessary yet it is wise to do so, and should be done during pasteurization
or before packaging. To equally coat onto the egg shell, the egg shell must be rotated
on the side and horizontally by having its axis as Figure 2's Woo and Wo and be
in ample contact with the coating material in the process. The egg's rotating axis
must not be exposed from the coating material. Thus, it is wise for the egg's geometric
center to be located in the medium of the coating material and the rotation should
be at least 1 time horizontally.
After pasteurizing the eggs need to be packaged before shipment. The
method of modern packaging is that it can automatically package in 6, 8, 10, 12,
15, 18, 20, 24, 30, and 36 units according to weight. The packaging materials are
recycled paper, PE, PS, PET and plastic that can be reused after washing/pasteurized.
In order to prevent the re-contamination of germs, materials that can be sealed
are used or vacuum packing is possible.
The Difference Between General Eggs and Pasteurized Eggs
When pasteurizing according to the present invention as mentioned
above, the difference between general eggs and pasteurized eggs are as follows.
Figure 7a and 7c illustrates the change in the condition of a general
eggs and eggs that have been pasteurized as the days pass. The Haugh Unit, the rate
of the changes of the weight loss, the Yolk Height was compared and analyzed as
the days passed. Haugh Unit is a representing standard of measuring the interior
quality of an egg, particularly the albumen. Yolk Height measures the quality of
the yolk. Generally eggs are packages according to its weight yet as time passes
there are times when they break away from the indicated weight of packing and therefore
the loss in weight change was also compared.
It is difficult to spot a difference between a pasteurized egg and
one that has not been pasteurized when viewing the egg shell. However, when viewing
the yolk and albumen after breaking the shell, in the case of the pasteurized egg,
when placing it on a see through glass surface or a clear or bright surface, the
albumen looks a bit opaque. The difference of the pasteurized yolk is that it looks
a bit larger than an egg that is not pasteurized.
Figure 7A, 7B, and 7C illustrates the condition change of the eggs
that have been pasteurized according to this research and general eggs. PC (Pasteurized
and cold storage) eggs are eggs that are refrigerated (5°C) after pasteurization,
NC (Not pasteurized and cold storage) are eggs that are refrigerated after not pasteurizing
them, PR (Pasteurized and Room Temperature) are eggs that are kept in room temperature
(24~26°C) after pasteurizing them and NR (Not pasteurized and Room Temperature)
are eggs that are kept in room temperature (24~26°C) after not pasteurizing them
The Haugh Unit is measured by an automatic EGG MUTLI Tester(EMT-5200,
Robotmation Co., Ltd, Japan)and a manual method (measured by micrometer calipers
and equation; Yolk Height=mm; Haugh Unit=100log (Albumen height-1.7 egg weight
0.37 + 7.6). The Isa Brown brown eggs with the weight of 60~70g and albumen's
pH concentration of 8 are (1) pasteurized, coated and refrigerated (5°C) (2) pasteurized,
coated and kept in room temperature (around 25±2°C) (3) not pasteurized and refrigerated
(4) not pasteurized and kept at room temperature. The 4 sample categories have 180
each and after every 1,5,10,20,30,60 days have passed, the Haugh Unit, Yolk Height,
and the average amount of weight is measured and compared.
If water is used as the heating medium or rinse, the cuticle will
be lost so to minimize the contamination of outer germs it is general and ideal
to coat the surface. Therefore mineral oil was coated on the egg after pasteurization.
The standard for an egg's interior quality according to the Haugh
Unit nearly match among Korea, USDA, Japan, and Europe. The highest grade being
(Grade AA >72 Haugh units); the next (Grade A 60-72 Haugh units) and the next
being (Grade B <60 Haugh units), which is the lowest grade range for edible usage.
When comparing to the mentioned Haugh Unit, especially the eggs that
have been kept in room temperature, even if 60 days have passed for an egg that
has been pasteurized, it maintains a Haugh Unit of over 60. This is similar to the
amount of an egg that has not been pasteurized with 5 days passed, and it highly
surpasses in quality in Haugh Units compared to an egg that has not been pasteurized
with 10 days passed. The difference becomes even more severe even in refrigeration
as time passes. When 60 days pass, there is a numerical value difference of 3% or
more. An egg that has been kept in room temperature after pasteurization compared
with an egg that has not been pasteurized and kept in refrigeration in Haugh Units
displays that they both hold similar numerical value. This shows that the pasteurized
egg's interior assessed in Haugh Units has the effect of especially the albumen's
quality enhancement. In the circulation system where the grade difference determines
the difference in price, there can be expectations of the effect of improvement
in gains through a high graded egg.
The Yolk Height, which mostly assesses the yolk's quality, of the
pasteurized egg, has a higher numerical value than the egg that has not been pasteurized
disregarding if it has been kept refrigerated or in room temperature. The difference
increases as time passes. When kept in room temperature for 60 days the numerical
value difference is up to 60% and the pasteurized egg kept in room temperature has
a higher numerical value than the refrigerated egg that has not been pasteurized.
The weight changes of eggs have significant meaning due to the fact
that the eggs are mostly sold according to their weight. Having no concern with
the storage temperature, the pasteurized egg has a lower weight loss than the egg
that has not been pasteurized and having no concern with the storage temperature,
the difference in weight loss between the pasteurized egg and egg that has not been
pasteurized increases as time passes. When in room temperature for 60 days, there
is a weight loss difference of over sevenfold. Even in the case of a refrigerated
egg, a pasteurized egg has a 30% quantity loss improvement compared to an egg that
has not been pasteurized.
As mentioned above, along with the ensuring as a food product, a pasteurized
egg not only has quality yolk and albumen but also has improved the weight loss
problem and thus improved the quality in storing. With this, when there is instability
in supply and demand and a rapid fluctuation in the egg price, it can be confronted
with flexibility and can call for improvement in gains and safeness.
The above mentioned concerning the present invention, within the present
invention's technical ideology according to those who are skilled in this technical
field, can be applied on other bird eggs such as a quail egg. Various substitutions,
modifications, and changes can be made and so the example research and accompanied
Figure is not limited.
As mentioned above, when the invention pasteurized the salmonella,
which inhabit in the shell egg and causes food poisoning within the body, it must
pasteurize the yolk and albumen separately. Through the entire pasteurization, the
lowest temperature of the lowest temperature point according to the points within
the egg's interior is measured and at a pasteurization level of 5~12LOG, the desired
level of pasteurization is reached based on this lowest temperature. This is done
so by maintaining the lowest temperature for the required time of the desired pasteurization
level. This pasteurizes the salmonella within the egg and increases the safeness
of the egg as a food product, increases the quality of the yolk and albumen, improves
the weight loss problem, makes it easier to confront supply and demand fluctuations
with improvement in storing, and increases gains with improved quality. Moreover,
through the pasteurizing method mentioned above, it gives the consumer a safe egg
and enhances the people's health by the safeness and variety of the egg.