JP2000300228A - Sterilization of food - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sterilization process for food that can give a sufficient sterilizing effect without inducing the sterilizing unevenness even in a relatively large-sized food by compensating one defect with the other merit by combining a sterilizing treatment technique with a high temperature steam and sterilizing treatment technique with a microwave irradiation in a shortened time. SOLUTION: This method comprises supplying a food to be subjected to a sterilizing treatment between a pair of chambers at separated positions with each other, relatively transferring these chambers to a direction approaching with each other and forming a closed space to receive the food in the closed space, introducing a steam having a prescribed temperature and a prescribed pressure into the closed space and subjecting the food to the sterilizing treatment at a high temperature under a high pressure for a prescribed time by irradiating a microwave, relatively transferring these chambers to the directions separating with each other and taking out the sterilized food. Preferably, the treatment is repeated for prescribed times as a steam flush treatment for a prescribed time as one cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for sterilizing food.

[0002]

2. Description of the Related Art The present applicant has developed a novel food sterilization technique and filed a patent application.
No. 8198 was established. According to the present invention, food to be sterilized is supplied between a pair of chambers located at a distance from each other, and the chambers are relatively moved in a direction close to each other to form a closed space, and the food is stored in the closed space. After that, steam of a predetermined pressure is introduced into the sealed space, and sterilization is performed for a predetermined time under high-pressure and high-temperature conditions. After the sterilization, the chambers are relatively moved in a direction away from each other to take out the sterilized food. The contents are as follows.
According to a preferred embodiment of the present invention, the above series of steps including the steam flash for 5 to 10 seconds is repeated 6 to 10 times as one cycle. According to such an invention, there is no need to expose the food to high-pressure and high-temperature conditions for a long time as in the case of heat sterilization in an oven, so that the taste is not reduced and heat-resistant bacteria contained in the food are completely killed. Thus, a sufficient bactericidal effect was obtained.

[0003]

The above-mentioned invention proposed by the present applicant exerts an extremely excellent effect mainly as a heat sterilization treatment on packed rice, but depending on the type of food to be sterilized. It was found that some of them did not provide a sufficient bactericidal effect. In particular, this problem becomes apparent in the case of foodstuffs whose one unit is relatively large, such as, for example, Shumai or Gyoza, and in order to heat the central temperature of such foodstuffs to about 130 ° C., a total is required. A sterilization treatment time of about 5 minutes is required, and not only the treatment efficiency is reduced, but also the equipment becomes large-sized, and the disadvantage in cost becomes large.

On the other hand, in recent years, it has been proposed to utilize microwaves for sterilizing foods.
No. 478 discloses that in the process of transporting a hermetically sealed food package on a predetermined transport line, 0.5 to 2.8 k
A method is described in which a food in a package is heated to 100 to 130 ° C. and sterilized by irradiating microwaves from a waveguide provided on a transport line under a pressurized condition of g / cm 2. However, the path of microwaves in food is extremely complicated, and there is a problem that energy is not easily transmitted evenly. That is, it was found that although a sufficient sterilization effect was obtained in the portion where the microwaves passed, the portion where the microwaves did not pass was hardly sterilized, and so-called sterilization unevenness was remarkably observed. In order to solve this problem, it is conceivable to perform microwave irradiation from many directions or to increase the irradiation time. However, it is not preferable because the taste is significantly impaired.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention combines a sterilization treatment technique using high-temperature steam and a sterilization treatment technique with microwave irradiation proposed by the present applicant, and compensates for one of the drawbacks on the other, thereby achieving a relatively large size. It is an object of the present invention to provide a novel food sterilization method that can provide a sufficient sterilization effect in a short time without causing sterilization unevenness even for food.

That is, according to the food sterilizing method of the present invention, the food to be sterilized is supplied between a pair of chambers separated from each other, and these chambers are relatively moved in a direction approaching each other. After forming a sealed space and storing food in the sealed space, a sterilization process under high pressure and high temperature conditions is performed for a predetermined time by introducing steam having a predetermined pressure and a predetermined temperature into the sealed space and irradiating microwaves. After the operation, the chambers are relatively moved in a direction away from each other to take out the sterilized food.

A second aspect of the present invention is the food sterilizing method according to the first aspect, wherein the steam flash treatment for a predetermined time is repeated a predetermined number of times as one cycle.

[0008] As is well known, microwaves are ultrashort waves having a frequency of 1 to 30 GHz, and sterilizing treatment by dielectric heating is performed by irradiating the microwaves with food.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The food sterilization method according to the present invention, as described above, uses sterilization by high-temperature steam described in Japanese Patent No. 2838198, in particular, a combination of sterilization by steam flash and sterilization by microwave irradiation. As an embodiment of the invention, the former configuration is described in Patent No. 2
It is possible to employ the configuration described in Japanese Patent No. 833198 as it is.

That is, a plate capable of accommodating a plurality of heat-resistant containers each filled with food to be sterilized is moved along a predetermined circulation path, and a sterilization station is provided at a predetermined position in the circulation path. The plate is stopped for a predetermined time to perform a sterilization process. The sterilization station is provided with a pair of upper and lower chambers at opposing positions across the circulation path, and after the plate reaches the sterilization station and stops, the upper and lower chambers are relatively moved in a direction approaching each other to form a closed space, By introducing a vapor of a predetermined vapor pressure into the closed space in a saturated state, food in a container supported by a plate in the closed space is heated and sterilized. The temperature of the steam is correlated to the pressure, 3 kg / cm2
At a pressure of about 140 ° C. This temperature is a temperature sufficient to achieve complete sterilization by killing not only general viable bacteria but also heat-resistant viable bacteria contained in the food in the container.

Particularly preferably, the introduction of the high-temperature saturated steam having the predetermined vapor pressure is repeated a plurality of times with a predetermined time as one cycle. That is, a plurality of sterilization stations are provided at equal intervals in the circulation path, the pair of chambers is provided in each sterilization station, and the above processing is repeatedly performed. The steam flash time of one cycle and the number of repetitions thereof vary depending on the processing conditions such as the type and amount of food to be sterilized and the pressure (temperature) of the steam used. 6
It can be repeated up to 10 times.

In the present invention, microwave sterilization means is added to the configuration of the above-mentioned steam sterilization apparatus, and more specifically, a wave guide penetrated through one or both of the upper and lower chambers. Microwaves are introduced into the enclosed space from the magnetron through the tube, and the food in the container is irradiated. Alternatively, in some cases, microwaves can be irradiated from outside the chamber without opening the waveguide.

[0013]

According to the food sterilizing method of the present invention, even for relatively large foods, a sufficient sterilizing effect can be provided in a short time without causing uneven sterilization.

Claims (2)

[Claims] 1. A food to be sterilized is supplied between a pair of chambers located at a distance from each other, and the chambers are relatively moved in a direction approaching each other to form a closed space, and the food is placed in the closed space. After being housed, a steam of a predetermined pressure and a predetermined temperature is introduced into the sealed space, and a sterilization process under high pressure and high temperature conditions is performed for a predetermined time by irradiating microwaves. A method for disinfecting food, wherein the disinfected food is taken out by moving. 2. The food sterilizing method according to claim 1, wherein the steam flash treatment for a predetermined time is repeated a predetermined number of times as one cycle.