JPS5978673A - Method for thermal sterilization - Google Patents

Abstract

PURPOSE:To prevent the deformation and damage of a container during the thermal sterilization in a retort, by cooling the sterilized material to a core temperature of <=100 deg.C by cooling the atmosphere in the retort, and then contacting the sterilized material directly with a cooling medium. CONSTITUTION:The material 12 to be sterilized is placed in a retort 11 and sterilized. The retort 11 is cooled externally with a cooling medium by turning the change-over valve 17 to the external shower device 18. The atmosphere in the retort 11 is cooled by this procedure keeping the pressurized condition until the core temperature of the material 12 reaches <=100 deg.C. The valve 17 is turned to the inner shower device 13 to cool the material by the direct spray of the cooling medium. The cooled material is taken out of the retort. The deformation of the container, etc. can be prevented by this process. When the material is cooled to a core temperature of 60-80 deg.C by the external shower, the breakage of even a glass vessel can be prevented.

Description

[Detailed description of the invention]

This invention relates to an improvement in a heat sterilization method in which an object to be sterilized in a retort is heat sterilized, then cooled and taken out. In general, what to sterilize? There is a retort sterilization method in which the sterilized material is introduced into a retort and then heat sterilized using a heat sterilization medium such as hot water or steam under pressure at a high temperature exceeding 100°C, and then the sterilized material is cooled and taken out. Are known. Conventionally, as a cooling means in this heat sterilization method, as shown in FIG. There is a device 3 that sprays a cooling medium such as water onto objects 2 to be sterilized stacked in multiple stages to cool them. 4 is a supply pipe 5 to the shower device 3? 6 is a supply pump connected through the sterilizer, and 6 is a discharge pipe that discharges the cooling medium inside and below the retort pot 1 after cooling the object. However, this sterilization method is Since the object 2 to be sterilized is brought into direct contact with the cooling medium and rapidly cooled down, it is inevitable that the object 2 to be sterilized may be cooled depending on the position of the object 2 in the retort. When water, etc. is applied directly to a container heated to a high temperature exceeding 100℃, the internal pressure of the container changes rapidly, causing deformation of the container.
Containers that have been heated to temperatures as high as 20 degrees Celsius are likely to be damaged if they come into direct contact with water, and in addition, so-called retort-packed food products made of flexible packaging materials may cause wrinkles and noise in areas that are in direct contact with the cooling medium. However, the contents of this retort/household food product also had various problems, such as the contents of the retort food losing its shape when strongly hit by the cooling medium, and the components separating due to rapid cooling. In addition, in order to avoid the above-mentioned problems, one step, such as heating 1gv to about 120°C and 2kl of the object to be sterilized, and sprinkling a cooling medium to a temperature that does not cause the problems mentioned above, is carried out in the retort without using it. It can also be said that C is left to cool in the trap, but the cooling time at C at a temperature at which the above-mentioned weight loss does not occur is extremely long, which poses a problem in workability. On the other hand, in order to prevent these problems, K sprays the entire cooling medium over the object 2 to be sterilized while controlling the internal power of the retort until the object 2 reaches a temperature at which the above-mentioned problems do not occur. However, this method requires delicate pressure control, but this pressure control operation is difficult, and it is not effective against damage caused by contact with the cooling medium in glass containers. had its limits. The inventors have arrived at this invention as a result of repeated experimental research to solve the problem of cuff 1λ time h91'. In other words, this invention is a method for sterilizing objects in a retort by heating them with a heating sterilization medium and then sterilizing them. In a heating sterilization method in which the object to be sterilized is cooled and taken out, the cooling medium is not brought into contact with the object to be sterilized until the center temperature of the object to be sterilized has cooled to at least 100°C. This heat sterilization method is characterized in that the air surrounding the retort is cooled by the cooling medium, and then the sterilized material is brought into contact with the cooling medium in a conventional manner. The present invention will be described in detail based on the drawings below. Fig. 2 schematically shows an embodiment of the present invention. In one microorganism, 11 is a retort pot, and inside this retort pot 11,
The objects to be sterilized 12 stacked in multiple stages are introduced, and an internal shower device 13 is provided at the top of the retort pot 11 for distributing a cooling medium to cool the objects to be sterilized. The configuration is similar to that of a conventional example in which normal cooling is performed. The supply pipe 15 connected to the supply bond 14 is connected to a switching valve 17, one end of which is connected to the internal shower 1ii17.13, and the other end is used to cool the retort atmosphere provided above the outside of the retort pot 11. It is connected to an external shower device 18. Note that 16 is a discharge pipe for discharging the cooling medium accumulated under the gate of the retort pot 11 and outside the retort pot 1. This embodiment is constructed as described above, and under pressurized conditions V
If this retort sterilization is performed, first switch the switching valve 17 to the external shower device 18 side, spray the cooling medium on the outer surface of the retort pot 11, cool the retort pot 11 from the outside, and cool the retort pot 11 from the outside. Cool the internal retort atmosphere under pressurized conditions until the temperature has cooled to at least 100°C. In this case, the cooling medium sprayed on the outer surface of the retort pot 11 from the external shower device jf18 cools the retort pot 11i, and is then collected at one side of the retort pot 11 and discharged into the discharge pipe 16.
more excreted. Next, the switching valve 171 switches to the internal shower provided in the retort pot 1, and the internal shower device 13 sprays the cooling medium on the object 12 to be sterilized in one area. No lji? conduct,
After that, the 12-keretorto kettle (1) is extracted from the pot. For example, if there is a risk of deformation due to a change in VC of molded containers, large cans, etc. It is appropriate to cut gold when the center V crystallinity is 100℃, and it is suitable for cutting glass containers, etc.
For items that are easily damaged by direct contact with the cooling medium, the temperature at the center of the contents is preferably cooled to 60 to 80°C. In addition, in the case where the object to be sterilized 12 is simply cooled slowly, the temperature of the atmosphere inside the retort is 70°C.
~80° C. [The current value is appropriate. 1. Figure 3 shows another example of cooling the air surrounding the retort by completely cooling the inside of the retort. That is, two internal showers facing each other] 3 b
The YFZ retort pot 11.1 is installed close to the inner wall of the upper part of the tort pot 11' so that the water is ejected toward the direction.
The object to be sterilized 12'fc ('?f) is made so that the cooling medium does not come in direct contact with the object (13b). In order to prevent the cooling medium from accumulating inside, the surrounding air inside the retort is cooled by cooling one side of the retort pot 11' while discharging it from the bottom.
Thereafter, the object to be sterilized 12' is cooled by spraying a cooling medium from the internal shower device 1i13a in a conventional manner. Each configuration of the pond is the same as in the embodiment described in 1111, and corresponding parts are given the same numbers with a dash and their explanation will be omitted.9
) and FIG. 4 further shows that the internal nower device f? Installed in two levels, upper and lower, with a baffle board between them.

[In order to simplify the explanation, the corresponding parts are the same as those in the previous example. The object to be sterilized 12 is placed between j3b and the lower circle 1''2B shower device holder 13a.
The entire baffle plate 19 is large enough to cover the entire upper surface of the object 12', thereby preventing the cooling medium sprayed from the upper internal shower 13b from coming into direct contact with the object 12' to be sterilized.
V? Cool the inner atmosphere of the retort while dropping one drop/, 11
After that, the bag in which the objects to be sterilized (12') and the cough suppressant (2') are taken out by the conventional method W2. Next, Figure 5 shows an example of the temperature change in the retort atmosphere in the above-mentioned embodiment. The atmosphere is 1.4 degrees t plotted, and B is the total cooling of the outer surface of the retort pot 11 by the cooling medium spouted from the external shower L/f.
In the case of t, C is +1 bar ejected from the internal shower head ii # I 31) towards the retort pot circular surface?・, 1 depending on the cooling medium) 1) Shows the change in retort atmosphere lυ1 temperature when the same side of the pot 11' is cooled, and 1) 1) A cooled Ie 1 body is brought into direct contact with the sterilized material 11' ! 1. As is clear from the changes in the retort atmosphere temperature with respect to the cooling time, for example, if the retort atmosphere temperature is 120℃ or more, Cooling time 11 for cooling to 100°C, retort pot outer surface cooling B i- and retort pot inner surface cooling C, both take about 2 minutes, and the cooling time is slightly longer than that of conventional cooling, but leaving cooling A Compared to VC, the time is significantly shorter, and considering the /ζ effect mentioned above, the difference can be considered to be almost negligible in terms of work efficiency. By increasing or decreasing the flow rate of the cooling medium by cooling with a baffle plate provided above the object to be sterilized, the total cooling time can be changed.Furthermore, when cooling the surrounding air inside the retort, fc, A fan is installed inside the retort pot to stir the air inside the retort.
As a result, cooling of the object to be sterilized is made uniform -Ii6. As explained above, the heat sterilization method according to the present invention includes cooling of the object to be sterilized after sterilization, and cooling of the object to be sterilized until the center temperature of the object is cooled to at least 100°C.
Is it a pregnancy? Since the atmosphere inside the tort is cooled without direct contact with the objects to be sterilized, it is possible to avoid deformation of molded containers, etc., breakage of glass containers, etc. that easily occur during cooling from a high temperature of about 120°C to about 100°C, and the retort. Defective products in heat sterilization methods, such as preventing the occurrence of wrinkles in the inner surrounding air, etc., and preventing the contents of the retort inner surrounding air from becoming deformed and roughness due to separation of components, etc. It is effective in preventing the occurrence of

[Brief explanation of drawings]

Fig. 1 is a structural explanatory diagram schematically showing the conventional heating and t< in the germicidal method, and Fig. 2 is a diagram schematically showing an embodiment of the heat sterilization method according to the present method. An explanatory diagram, FIG. 3 is a configuration explanatory diagram showing another embodiment, FIG. 44 is a configuration explanatory diagram 1 showing still another embodiment, and FIG. 5 is a diagram illustrating changes in retort atmosphere temperature depending on the cooling method. . 11, 11'... Retort pot, 12, 12'...
Coating 1 problem, 13, 13 a, 13 b - internal shower device, 18...external shower device, hour hand applicant east 1l-4 蜆筭42) (ceremony part 1 figure 6 figure 3 12 Figure 7 6 Figure 4 17'

Claims (1)

[Claims] In a heat sterilization method in which an object to be sterilized in a retort is heat sterilized with a heat sterilization medium and then the object to be sterilized is cooled and taken out, the temperature of the center of the object to be sterilized during the full cooling wave is at least 100.
The atmosphere in the retort is cooled by the cooling medium without directly contacting the object to be sterilized with the cooling medium until the object is cooled to ℃, and then the object to be sterilized is brought into contact with the cooling medium in a conventional manner. A heat sterilization method characterized by: