JPH07114672B2 - Microwave heating sterilization method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a microwave heat sterilization method for a package in which an object to be heated is filled and sealed.

(Prior art) When sterilizing a package filled with a heated object and sealed at a high temperature of 100 ° C or higher under normal pressure, stack heat-resistant and pressure-resistant support plates on top of each other in order to prevent the package from breaking. A method in which microwaves are sterilized by heating and the like is used as a support, and a package is stored in the support and heated. (Japanese Patent Publication Sho 58-2694
(No. 9) Two support plates are usually used, and by stacking the two support plates on top of each other, a package housing part is formed between them. 7 and 8 are cross-sectional views at this time, and (11) (1
2) is a support plate, and (2) is a package housing part. With the two support plates stacked, the ring-shaped holders (3) are fitted from the left and right sides to prevent expansion and rupture of the package due to microwave heating.

(Problems to be Solved by the Invention) However, in the above method, since the support plates are easily slid, it is difficult to fit the support plates together, and after the fit, the support plates may slide to cause rupture.

In addition, warping may occur on the support plate to form a gap, and the gap may rupture the package.

An object of the present invention is to solve the above drawbacks and to provide a microwave heating sterilization method in which there is no slide between support plates in microwave heat sterilization, and the warp of the support plates is prevented so that no rupture occurs. And

(Means for Solving the Problem) To achieve this object, the present invention provides a microwave-transparent package having a sealed object to be heated, which has substantially the same shape as the package inside. In the method of accommodating in the accommodating part of the two support plates forming the accommodating part and then irradiating with microwaves for heat sterilization, the convex part provided on the peripheral part of one supporting plate and the convex part Then, the microwave heating sterilization method is characterized in that the concave portions provided on the other support plate are fitted to each other to bring the two support plates into close contact with each other.

The package according to the present invention is a package in which an object to be heated is sealed.

The object to be heated generates heat by microwaves. Any liquid can be used, but a liquid containing water, a viscous material, a solid, or a mixture thereof can be used. Usually food.

The packaging material may be arbitrary, but is preferably made of a plastic material because it is transparent to microwaves. For example, polystyrene, polypropylene, ethylene-propylene copolymer, ionomer, random copolymer of ethylene or propylene and unsaturated carboxylic acid, polyester, polyamide, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl acetate copolymer or its Saponified,
Polyurethane or a laminate of these.

The packaging material may have any shape. For example, in the case of a flexible film, a bag-shaped package can be obtained.
Further, if it is a tray-shaped packaging material and a lid material, both can be heat-sealed at the periphery to form a package.

In addition, in the present invention, the term “sealed” refers to a state in which bacteria do not enter or leave the inside of the package. This is to prevent recontamination of the heated object after microwave sterilization.

The support plate according to the present invention prevents expansion and rupture of the sealed package during microwave sterilization. Therefore, heat resistance to withstand heat during sterilization and pressure resistance to withstand the expanding force of the package during sterilization without deformation are required. Further, since the microwave is transmitted through the support plate and is irradiated, the microwave must be transparent. For example, it is a laminated product of glass cloth impregnated with a silicone resin, or a molded product of a sheet molding compound containing unsaturated polyester as a main component.

Two support plates are used. This is because the housing portion is formed inside by stacking the two support plates on top of each other, and the package is housed in the housing portion. FIG. 1 (a) is a perspective view of one support plate (11), and FIG. 1 (b) is a perspective view of the other support plate (12). As can be seen from the figure, the support plates (11) (12) both have a recess (2) in the center thereof, and the support plates (11) (12)
A package housing portion is formed by stacking the same. The package housing unit needs to have substantially the same shape and volume as the package in order to prevent the package from expanding due to microwave heating.

In addition, a concave portion and a convex portion that fit with each other are provided on the peripheral portion of the supporting plate to prevent lateral sliding and warping of the supporting plates.

In the supporting plate shown in FIGS. 1 (a) and 1 (b), convex portions (1a) are provided at four corners of one supporting plate (upper supporting plate) (11), and the other supporting plate (lower supporting plate). (12) is provided with recesses (16) at the four corners correspondingly. By overlapping the two, the convex portion (1a) and the concave portion (1b) are fitted to each other (Fig. 2).

Further, FIG. 3 shows a support plate (13) having convex portions at two corners of the four corners located on a diagonal line and concave portions at the other two corners. Use two of this support plate (13),
Convex part (1a) by changing the angle of each other and overlapping
And the recess (1b) can be fitted (Fig. 4).

FIG. 5 and FIG. 6 are cross-sectional views when the packaging body is composed of a tray and a lid body. The upper support plate (14) is provided with a convex portion and the lower support plate (15) is provided with a concave portion. The part and the recess are fitted to each other. FIG. 5 shows an example in which the convex portion and the concave portion are continuous through the tapered connecting portion (1c), and FIG. 6 shows an example in which the convex portion and the concave portion are provided substantially vertically.

The outer surfaces of the support plates (11) (12) (13) (14) (15) are composed of flat parts and inclined parts provided on both sides of the flat parts with a step.

Further, (3) in the figure is a ring-shaped holder for preventing the support plates from opening each other due to the expansion of the package due to heating.
As the holder (3), an epoxy resin molded product obtained by mixing glass fibers can be used.

After holding the support plate (2) together, the holder (3) is
Slide it in from the inclined parts (22) on both sides, fit it, and make sure that it contacts the step and is securely fixed.

In this way, the support containing the package is irradiated with microwaves for sterilization. Along with the microwave irradiation, the object to be heated generates heat and is sterilized by this heat. The temperature is 100 ° C or higher to improve the bactericidal effect. Usually, 100 to 105 ° C is sufficient.

After heat sterilization, in order to prevent the package from bursting, cool it to a temperature of 100 ° C or lower and take out the package from the support. It is desirable to take out after cooling to room temperature. Cooling may be air cooling or water cooling.

(Example 1) As the packaging material, a plastic film bag-shaped packaging material was used. The plastic film has a laminated structure of stretched nylon / unstretched nylon / unstretched polypropylene from the outside.

This packaging material was filled with 180 g of water, and the films were heat-sealed to obtain a hermetically sealed package.

The support plate used had the shape shown in FIGS. 1 (a) and 1 (b). The support is made of unsaturated polyester sheet molding compound. The volume of the package housing was substantially the same as that of the package, and the heat-sealing portion at the periphery of the package was fixed between the support plates. The support plates (11) and (12) are overlapped with each other so that the concave portions (1b) and the convex portions (1a) fit with each other, and the ring-shaped holder is slid from the left and right, and abutted against the step to be fixed. did. The ring-shaped holder is an epoxy resin molded product mixed with glass fiber.

For comparison, the support plate shown in FIG. 7 was used.

As a result, in the comparative example, the supporting plates slide when the holder is inserted, resulting in an insertion failure of 3%.

However, in the example, such a phenomenon did not occur at all.

(Example 2) Example 1 was used except that the support plate shown in Fig. 3 was used.
An experiment was conducted in the same manner as.

As a result, there were no defective insertions.

(Example 3) As a packaging material, a tray and a lid material were used. The tray is made of polypropylene, and the lid is a laminated material of stretched nylon / unstretched nylon / unstretched polypropylene from the outside.

The support plate used was that shown in FIG. On the lower support plate,
A packaging body accommodating portion having substantially the same shape and volume as the tray was provided, and after accommodating the packaging body, the upper support plate was stacked and fixed.

The support plate is a laminated product of glass cloth impregnated with silicone resin.

Then, the ring-shaped holding tool was slid from the left and right, and abutted on the step to be fixed.

For comparison, the support plate shown in FIG. 8 was used.

As a result, in the comparative example, 5% insertion failure occurred when the holder was inserted, but in the example, there was no insertion failure.

Then, the respective packaging materials were subjected to microwave sterilization equipment (M-HT1320) manufactured by Toppan Printing Co., Ltd. at a center temperature of the package of 130.
Heated to 0 ° C. The temperature was measured with a glass fiber thermometer. At the time of heating to 130 ° C., warpage occurred on the upper support plate in the comparative example, and a gap of 2 mm was generated between the support plates. On the other hand, in the example, no warp was generated.

After heating to 130 ° C., it was immersed in water with the holder attached, and the time for cooling to 100 ° C. was measured. As a result, it was 5 minutes in the comparative example and 2 minutes in the example.

(Effect) As described above, according to the present invention, it is possible to obtain a microwave heating sterilization method in which the sliding of the support plates and the warp of the support plates are prevented and the package does not burst.

Also, the cooling rate after heating is high, and efficient sterilization is possible.

[Brief description of drawings]

1 (a) (b) and FIG. 3 are perspective views showing an example of a support plate, FIGS. 2 and 4 are front views showing a state in which a package is housed between two support plates, and FIG. FIG. 6 and FIG. 6 are cross-sectional views showing a case where the packaging body is composed of a tray and a lid material, and FIGS. 7 and 8 are cross-sectional views of a conventional example. (11) (12) (13) (14) (15) …… Support plate (1a) …… Convex part (1b) …… Recessed part (2) …… Package storage part (3) …… Retainer

Claims (1)

[Claims] 1. A housing part of two support plates in which a packaging body, in which an object to be heated is sealed, is transparent to microwaves and is superposed on each other to form a housing part having substantially the same shape as the packaging body. In the method of heat sterilization by irradiating with microwaves and then irradiating with microwaves, the convex portion provided on the peripheral portion of one supporting plate and the concave portion provided on the other supporting plate corresponding to the convex portion are fitted to each other. A microwave heating sterilization method, characterized in that the two support plates are brought into close contact with each other.