JPH01157366A - Sterilization of microwave heating - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is a microwave sterilization method in which a package filled with food is housed in a support made of a microwave-transmissible material and sterilized by irradiating it with microwaves. This invention relates to improvements in heat sterilization methods.

<Prior Art> It has been attempted in the past to heat and sterilize a package filled with food by irradiating it with microwaves. When sterilizing a package filled with food, the package is heated by microwave irradiation and is housed in a support made of a microwave-transmissible material to prevent the package from breaking. ing. In this case, the microwaves pass through the support and directly heat the food product in the package, without heating the support.

Therefore, even if the method of microwave irradiation is devised, as heating progresses, the temperature difference between the food and the support will widen, and the temperature of the food will be rapidly transferred from the surface of the package to the support, and as a result, the temperature of the food will increase. In some cases, the temperature was insufficiently raised near the surface in contact with the support, resulting in poor sterilization.

Problems to be Solved> The present invention provides a method for storing a package filled with food in a support made of a material that can transmit microwaves, and when performing sterilization treatment by irradiating microwaves, the package and the support are separated. An object of the present invention is to provide a sterilization method that does not raise the temperature of a contact surface that comes into contact with an insufficient temperature.

<Means for Solving the Problems> The present invention provides a support that is made of a microwave-permeable material and that is provided with a heat-generating material that generates heat when irradiated with microwaves in the whole or a part of the storage part that stores the package. This microwave heat sterilization method is characterized in that after storing the package in the storage section, microwave irradiation is performed. Further, the package is made of a material that can transmit microwaves and has a storage part for storing the package, and the housing part is entirely or partially provided with a heat-generating material that generates heat when irradiated with microwaves. This is a microwave heating sterilization method characterized by irradiating microwaves after storage.

To further explain the present invention, the first invention is to provide a heat generating material that generates heat by irradiation with microwaves in the housing part of the support that comes into contact with a portion where a large amount of heat is dissipated or a portion where temperature rise is delayed during heating of the package. This was solved by
The support will be explained using the drawings. Fig. 1 is an explanatory diagram of a support plate 1 for heat sterilization used as a support for a bag with a heat-generating material 2 pasted on the periphery, and Fig. 2 is an illustration of a support plate 1 for heat sterilization used as a support for a bag with a heat-generating material 2 pasted on the periphery. It is a sectional view when the body 3 is stored in the support body A, and has a storage part 5 for storing the package 3 inside.

When a molded tray is used as the package, a support opening formed by pasting a heat generating material 2 on the entire surface of the support plate 1 in contact with the lid 4b of the tray 4a may be used, as shown in FIG.

The support plate 1 constituting the support body may be made of any material that transmits microwaves and has heat resistance and bending strength.
For example, reinforced plastics such as glass-filled silicone, glass-filled polyphenylene sulfide, and silicone-impregnated glass cloth laminates are suitable.

As the heat generating material 2, any material that generates heat by microwaves may be used. For example, phyllite mixed rubber, ferrite mixed resin, aluminum vapor deposited film, etc. can be used. The temperature of the contact surface of the package is 0, or the temperature of the contact surface of the package is ferrite. It can be adjusted by the type and mixing ratio, and in the case of an aluminum vapor-deposited film, the thickness of the vapor deposition and the thickness of the heat-resistant film laminated on the aluminum vapor-deposited film.

In the case of the second invention, a heat-generating material that generates heat by irradiation with microwaves may be provided at least in a portion of the bag or molding tray constituting the package where heat radiation is large. This heat generating material may be any ink, adhesive, film, or sheet containing a material that generates heat by microwaves.

The heat generating material 6 can be provided in the outermost layer as shown in FIG. 4 and in the middle layer as shown in FIG. 5, as shown in FIG. This heat generating material 6 may have a multi-layer structure instead of a negative layer.

If the heat generating material 6 is a printed layer, the thickness will be thin, and if it is an adhesive layer, the ferrite content will be low from the viewpoint of adhesive effect, and in some cases, the thickness will be thin (to enhance the heat generation effect by microphone radio waves). , it is preferable to use ferrite having a high Curie temperature. When the heat generating material 6 is a plastic layer, from the viewpoint of processing and moldability, it is preferable that the ferrite content is 60% or less by weight, and as the plastic, polyester is preferably used. , nylon, polypropylene, and other heat-resistant resins can be used. If the container is a bag, the plastic film is thin, so it is necessary to increase the ferrite content or use ferrite with a high Curie temperature. However, if the container is a tray In this case, the thickness of the heat generating material 6 can be increased to a certain extent, so the type and content of ferrite can be easily selected.

Since the purpose of the heat generating material 6 is to prevent heat radiation from the contents, it is only necessary to provide it only in areas where heat radiation is particularly significant. For example, in the case of a bag, it may be provided at the periphery where the thickness becomes thinner, and in the case of a tray, it may be provided near the sealing part between the lid and the main body. Alternatively, the heat generating material 6 may be provided on the entire surface of the container (but even in that case, the microwaves will not all be absorbed by the ferrite and the contents will not be heated.

Since ferrite is brown or black in color, it is not suitable as a color for food containers, but the color of ferrite can be hidden by providing a printed layer or a colored plastic layer on the inner or outer surface of the heat generating material 6. . Further, in that case, by using a temperature-indicating ink in the printing layer, the characters such as sterilized or cooked can be changed color and used as an indicator.

Effects> The present invention prevents heat radiation from the packaging during microwave irradiation by providing a heat generating material in a portion of the packaging that is in contact with the packaging of the support and has a large amount of heat radiation. Can be heated.

In addition, by providing a heat generating material in the package, similar to the above,
It is possible to prevent heat radiation during microwave irradiation in areas where heat radiation is large.

<Example 1> As the support plate 1, a glass filler-filled silicone support body shown in FIG. 1 and having the shape shown in FIG. I compared what was and what wasn't. The heat generating material is aluminum vapor-deposited polyethylene terephthalate (thickness of the vapor-deposited layer is 200 people).
Using this method, polyimide was further laminated on the vapor deposited layer side.

As the package 3, a bag made of stretched nylon film (25μ)/unstretched polypropylene film (70μ) was used, filled with 180g of white sauce, and equipped with a microwave oscillator (with an output of 1.3 - as shown in FIG. 6). Sanyo Electric S
MG-130) is equipped with two first heating chambers in which the irradiation ports of the waveguide are located close to the bottom of the conveyor, and the irradiation port of the waveguide is located in the upper wall surface from the same microwave oscillation device as described above. The temperature is measured at the four points A to D shown in Figure 2 using an optical fiber thermometer (3Z4D made by Juishi Electric). ) was measured continuously. The microwave irradiation conditions were: output 600-5 per bag, total heating time 4 minutes,
The sample was passed through the device for 1 minute and 30 seconds, heated, and then turned once, and then passed through the device for 1 minute and 30 seconds to perform heat sterilization.

Eventually, B and D will be on the lower side. Table showing the average of measurement results.
Shown in 1.

Table 1 As is clear from Table 1, by using the heat generating material, heat radiation was prevented from being dissipated around the sealed portion of the package, and the entire package was heated almost uniformly.

<Example 2> A silicon-impregnated glass cloth laminate support having the shape shown in FIG. 3 was used as the support, and a silicone resin mixed with manganese-magnesium ferrite powder was used as the heat generating material 2 on the support plate on the lid side. A comparison was made with one with a heat generating material attached (Example 2) and one without a heat generating material (Comparative Example 2).

The package 4 is a molded tray 4a made of polypropylene (500 μm)/saponified ethylene-vinyl acetate copolymer (50 μm)/polypropylene (500 μm) filled with 280 g of mixed vegetables, and unstretched nylon (15 μm)/polyvinylidene chloride. (20 μm) / unstretched polypropylene (70 μm) / was sealed with a lid material 4b, and heating and temperature measurements were performed using the same apparatus as in Example 1.

The measurement points are four points ASB, C, and D in Fig. 3. The heating conditions were an output of 600 W per 1 tray, a total heating time of 6 minutes, and after passing through the device for 4 minutes, it was turned over once and the inside of the device was heated 2 times with the lid side finally facing down. The mixture was allowed to pass through for 1 minute and heat sterilized.

The measurement results are shown in Table-2.

Table 2 From Table 2, it can be seen that heat radiation from the lid material side can be prevented by the heat generating material. The tray side is thick and reduces heat radiation.

<Example 3> Same as Example 2 except that the heat generating material provided on the lid side of the support in Example 2 was not provided on the support but on the lid side surface of the package used in Example 2. As for the structure, heat sterilization was performed under the same conditions as in Example 2.

The measurement results are shown in Table 3.

Table 3 <Effects of the invention> By using a support provided with a heat generating material, it is possible to eliminate insufficient heating of the surrounding area due to heat radiation from the package during microwave heat sterilization, and conversely, the heat radiation area due to the heat generated by the heat generating material can be eliminated. The temperature difference between the periphery and the center of the package is small. Uniform heating is possible and accidents due to poor sterilization can be prevented.

Further, even if the heat generating material is provided on the package instead of on the support, uniform heating with a small temperature difference between the periphery and the center of the package can be achieved in the same way as described above.

Furthermore, when providing a heat generating material in a package, there is no risk of deterioration in appearance by providing a printed layer or a colored layer on the inner and/or outer surface of the heat generating material, and if a temperature-indicating ink is used as the printed layer, sterilization is possible. Display and indicator functions can also be added.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing an example of the support plate of the support used in the invention, FIGS. 2 and 3 are sectional views showing how the package is stored in the bag and tray supports, respectively, and FIGS. FIG. 5 is a sectional view showing the material of the package used in the present invention, and FIG. 6 is an explanatory view of the microwave heat sterilization apparatus used in the examples. 1...Support 2.6...Heating material 3...Packaging body (bag) 4a, 4b...Packaging body (tray) 5...・
...Storage part A, opening...Support patent application Person Toppan Printing Co., Ltd. Representative Kazuo Suzuki

Claims (3)

[Claims] (1) After storing the package in the storage part of the support body, which is made of a material that can transmit microwaves, and in which the whole or part of the storage part that stores the package is provided with a heat-generating material that generates heat by microwave irradiation, A microwave heating sterilization method characterized by irradiating microwaves. (2) A support body made of a microwave-transmissible material and having a storage part for storing the package, in which the package is entirely or partially provided with a heat-generating material that generates heat when irradiated with microwaves. A microwave heating sterilization method characterized by irradiating microwaves. (3) A printing layer made of temperature-indicating ink on the surface of the package,
The microwave heating sterilization method according to claim (2).