JP2000102370A - Method for continuous sterilization of food material and continuous rotating device to be used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for sterilization capable of sterilizing a food material by irradiating low energy electron beams on the surface of the food material with a little amount of irradiation and in a homogeneous manner, and to provide a rotating device to be used for the sterilization. SOLUTION: When a food material is sterilized, the food material of a sample is allowed to rotate on an inclined sample tray on which vibration is applied at least in the longitudinal direction and allowed to roll down continuously, and further when the sample is rolling down, low energy electric beams having energy of 160-300 keV are irradiated on the surface of the sample to continuously sterilize the food material. The continuously rotating device to be used for the sterilization comprises the following units: a sample tray 1; a vibrator 2 having a tray table of an adjustable height; a vibrator 3 having a tray table of a fixed height; a shaker 4 having a tray table of a fixed height; power switches 5, 6 and 7, and speed controllers 8, 9 and 10 for actuating the vibrators and the shaker; a sample feeder 11 for feeding the sample to the sample tray; and a controller 12 with a switch for actuating the sample feeder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously sterilizing food materials such as cereals, spices and seeds, and a continuous rotating device used for the method.

[0002]

2. Description of the Related Art In order to prevent spoilage of processed foods and food poisoning caused by processed foods, it is necessary to prevent microbial contamination of processed foods. Therefore, sterilization of raw materials is an important matter in preventing microbial contamination of processed foods. Conventionally, food ingredients have been sterilized by chemical or physical methods, but the ethylene oxide, methyl bromide, hydrogen peroxide, etc. used in these methods have harmful effects on the human body and the environment. In addition to the use of these substances, various problems have been pointed out regarding safety, such as concerns about the effects of these residues on the human body.Many of them have been banned or restricted in use. Is being done.

[0003] Many microorganisms contaminating the surface of dry food ingredients such as grains are heat-resistant bacteria, and these bacteria form spores, which are durable cells. These spores are more resistant to heat, germicides or drying than the growing bacteria, so they cannot be easily sterilized even when heated while keeping the grain dry, affecting the quality. It is very difficult to heat sterilize without affecting. On the other hand, sterilization by radiation irradiation, which has an excellent sterilizing effect and can easily sterilize dry grains, is not susceptible to quality deterioration due to heat because the temperature rise of the food itself is slight, but for complete sterilization Since a relatively large dose is required, many foods are difficult to put into practical use, for example, causing component changes such as damage to starch and oxidation of lipids, thereby losing value as a raw material for processing.

As described above, it is harmless to the human body and the environment, and does not cause a change in components such as starch and lipid in the grain, in other words, does not cause a change in the quality of the grain.
No sterilization method has been developed yet. for that reason,
There has been a demand for the development of a method of sterilizing grains and providing aseptic grains without changing the quality, as well as the human body and the environment.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and focused on the fact that the sterilizing effect of electron beams and the penetration power of electrons depend on energy, and a method of sterilizing grains using electron beams. Has been completed, and a grain rotating device used in the method has been studied, and a patent application has already been filed (Japanese Patent Application No. 9-311081).

The method for sterilizing grain and the grain rotating apparatus irradiate an electron beam with a minimum energy required for sterilization while rotating a sample by simultaneously applying vibration and shaking in a batch system. By employing such a configuration, microorganisms adhering to the grain surface can be sterilized without damaging the starch of the grain component.

[0007] However, in this grain rotating device, the sample sometimes stays and overlaps, so that
The efficiency with which low-energy electron beams are irradiated deteriorates, the uniformity of the dose is poor, and when trying to completely sterilize, there is a possibility that quality deteriorates because a certain portion is irradiated with more electrons than necessary for sterilization.

[0008]

SUMMARY OF THE INVENTION The present invention is an improvement of such a prior invention, and provides a smaller dose
Moreover, it is an object of the present invention to provide a sterilization method capable of uniformly irradiating the surface of a food material with a low-energy electron beam to sterilize the food material, and a rotating device used for the method.

The present inventors have conducted intensive studies in order to solve the problems of the above invention. As a result, vibration and shaking are applied to the tray installed at an angle, and a continuous rotating device in which the sample rolls (slides) while rotating on the tray is developed, and such a continuous rotating device is used. We have developed a method that can efficiently irradiate a low energy electron beam by transporting the sample while rotating it without overlapping.

[0010]

According to a first aspect of the present invention, in sterilizing a food material, a food material serving as a sample is turned on at least a tilted sample tray which is given a longitudinal vibration. The present invention provides a method for continuously sterilizing food raw materials, characterized in that the material is continuously rolled down while being moved, and when the sample is rolled down, a low energy electron beam having an energy of 160 to 300 keV is applied to the surface of the sample. is there.

According to a second aspect of the present invention, there is provided a sample tray, a vibrator with a tray mounting table whose height can be adjusted, a vibrator with a tray mounting table having a constant height, and a vibrator with a tray mounting table having a constant height. Provided is a continuous rotation device including a shaker, a power switch and a speed controller for operating the shaker and the shaker, a sample supply device for supplying a sample to a sample tray, and a control unit with a switch for operating the sample supply device. Is what you do.

According to the first aspect of the present invention, in sterilizing a food material, the food material as a sample is continuously rolled down while rotating at least on a tilted sample tray to which a longitudinal vibration is applied. In addition, when the sample rolls down, a low energy electron beam having an energy of 160 to 300 keV is applied to the surface of the sample.

[0013] The food material which is the object of the present invention according to claim 1 is not particularly limited. For example, grains such as brown rice, paddy, wheat, buckwheat with husk, red beans, soybeans, black beans, grain pepper, coriander, It can be applied to various kinds of seeds, such as spices such as sage, and leaves for eating and drinking such as tea leaves. Examples of the seeds include seeds of cruciferous and leguminous plants, and specific examples include black mappe seeds and radish seeds.

The present invention described in claim 1 can be suitably implemented by the continuous rotation device according to the second aspect of the present invention. Therefore, the continuous rotation device according to the second aspect of the present invention will be described below. This will be described with reference to FIG. FIG. 1 is a front view showing one embodiment of the continuous rotation device according to the present invention.
Is a plan view thereof, and FIG. 3 is a left side view thereof.

According to a second aspect of the present invention, there is provided a continuous rotating device comprising:
A sample tray 1, a vibrator 2 with a tray mounting table whose height can be adjusted, a vibrator 3 with a tray mounting table having a constant height, a shaker 4 with a tray mounting table having a constant height, and the vibrator and the shaker The apparatus includes power switches 5, 6, 7 and speed controllers 8, 9, 10 for operation, a sample supply device 11 for supplying a sample to the sample tray 1, and a control section 12 with a switch for operating the sample supply device.

In the continuous rotating apparatus according to the second aspect of the present invention, a sample tray 1 suitable for each sample is selected in consideration of the type, shape, specific gravity, size and the like of the food material to be processed. At the same time, by applying vibration and shaking at an appropriate speed, the food material as a sample can be uniformly rotated.

Further, by appropriately selecting the inclination angle and the vibration speed of the sample tray 1, the falling speed (rolling speed) of the food material as a sample can be adjusted.

According to a second aspect of the present invention, there is provided a continuous rotating device comprising:
For example, it is typically of the structure shown in FIGS.
The sample tray 1, the vibrators 2 and 3 with the tray mounting tables having different heights, the shakers 4 with the tray mounting tables, and the vibrator and the shaker are operated in order to set the sample tray obliquely. Power switches 5, 6, and 7, speed controllers 8, 9, and 10, a sample supply unit 11 for supplying a sample to the sample tray 1, and a control unit 12 with the switch are main components.

That is, by combining a vibrator 2 with a tray mounting table whose height can be adjusted and a vibrator 3 with a tray mounting table having a constant height as a vibrator with a tray mounting table, an obliquely inclined sample is provided. Tray 1 is installed. As a result, the sample continuously rolls down on the inclined sample tray 1 while rotating. In FIG. 1, the sample rolls continuously while rotating from the right side to the left side on the inclined sample tray 1.

It should be noted that the shaker 4 with a tray mounting table for giving horizontal shaking can be omitted as necessary, for example, when it is necessary to reduce the cost. In this case, since the sample tray 1 is installed at an angle, if there are the vibrators 2 and 3 with a tray mounting table that generates vertical vibrations, the samples are rolled and rolled down without overlapping without overlapping. This is because you can do it. Therefore,
According to the present invention, even when the shaker 4 with a tray mounting table for giving horizontal shaking is installed, unlike the previous invention, the vibrators 2 and 3 with a tray mounting table for generating vertical vibrations are provided.
They are arranged not in series but in parallel.
However, the dose distribution of the electron beam may vary depending on the position of the tray, and in order to perform more uniform sterilization treatment, it is preferable to install a shaker 4 with a tray mounting table that provides horizontal shaking.

The power switches 5, 6, and 7 each include a vibrator with a tray mounting table whose height can be adjusted, a vibrator with a tray mounting table with a fixed height 3, and a tray mounting table with a fixed height. This is a power switch of the shaker 4. Similarly, the speed controllers 8, 9, and 10 are a vibrator with a tray mounting table whose height can be adjusted, a vibrator with a tray mounting table with a constant height 3, and a shaker with a tray mounting table with a constant height. 4 speed controller. In FIG. 1, the power switches 5, 6, 7 and the speed controllers 8, 9, 10 are arranged on the instrument panel A on the left side of the apparatus, but the present invention is not limited to this.

The sample feeder 11 is for continuously feeding a sample to the upper portion of the sample tray 1 with a constant vibration, and the amount of the sample fed is adjusted by the size of the outlet of the sample feeder 11. Can be. This sample supply device 11
Usually, as shown, the (unprocessed) sample supply tray unit 1
1A and a transfer electromagnetic vibration drive unit 11B. The sample supply unit 11 includes a control unit 12 with a switch.
Is controlled by In FIG. 1, the electromagnetic vibration drive unit 11B for conveyance is omitted from the drawing.

As described above, the material and dimensions of the continuous rotating device according to the second aspect of the present invention may be appropriately set according to the purpose of use. The dimensions of the apparatus main body used in the examples described later are 60 cm wide × 90 cm deep × 43 cm high. The sample tray 1 is not particularly limited, such as one made of stainless steel or plastic, but is preferably made of stainless steel. In the embodiment described later, the member is made of stainless steel and has a width of 62 cm × a depth of 7.5 c.
m × 2 cm height was used. In addition, two types of trays having a thickness of stainless steel of 0.4 mm and 0.6 mm were used. Further, the amplitude of the tray on the tray mounting table was set to 3 cm, and the vertical movement was set to 0.2 cm.

A method for sterilizing a food material as a sample using the continuous rotating device according to the present invention will be described. First, as described in claim 3, the continuous rotation device of the present invention is placed under an electron beam generator (not shown), and a power supply (FIG. (Not shown). After setting the speed controllers 8, 9, and 10 and adjusting the size of the outlet of the sample supplier 11, the sample food material is stored in the sample supplier 11. In this case, the food ingredients to be sterilized are:
It is accommodated in the sample supply device 11 so as not to overlap as many as possible. Next, the electron beam generator is operated to generate an electron beam. Switches 5, 6, 7, and 12 are set to O
Set to N. In this case, the sample tray 1
The distance to the bottom is up to about 30 cm, preferably 5
Adjust to ~ 20cm. In the examples described later, this distance was set to 14 cm. If the distance is too short, it becomes difficult to uniformly sterilize the food material as a sample, while if it is too far, a sufficient sterilizing effect cannot be obtained.

The radiations currently used include γ-rays (electromagnetic waves) which have a high penetrating power and can sterilize deep parts of food materials, electron beams obtained from an electron beam accelerator, and X-rays generated by an X-ray generator.
There are lines (electromagnetic waves). Among them, the electron beam used in the present invention has a property of being inherently weak in permeation power and capable of reaching only the surface layer of a food material. As the electron beam source, it is preferable to use a scan type electron beam irradiation device and an area beam type electron beam irradiation device.
In the present invention, low-energy electron beams, that is, soft electrons, are used because the purpose is to sterilize microorganisms growing on the surface layer of the food material. Here, as the low energy electron beam, an electron beam having an energy of 160 to 300 keV is preferable, and an appropriate low energy electron beam is selected within this range in consideration of the type and shape of the target food material. Just do it. For example, it is appropriate to irradiate brown rice or wheat with soft electrons of 160 to 180 keV, and to paddy, buckwheat with husks, beans and the like with soft electrons of 200 to 250 keV.

By the way, the electron energy of a low energy electron beam (soft electron) received by a certain substance is
It can be calculated by the following formula.

[0027]

[Equation 1] · Electron energy (keV) received by a substance = electron energy at generation (keV)-electron stopping power (keV · cm ² / g)
× thickness (cm) × specific gravity (g / cm ³⁾

An example of a calculation method using the above formula will be described below. Near the exit of the electron beam generator (inside the titanium window foil)
Assuming that the electron energy of the device is 160 keV, the electron energy at the outlet of the device (outside the titanium window foil) is first determined from the above equation. The electron stopping power of the material (titanium) that constitutes the window foil is 2287 keV · cm ² / g (IGRU REPORT 37, Stopping Powe
rs for Electrons and Positions, 84, October 1, 1984
Day reference issued), the thickness of the material (titanium window foil) 0.005 cm, when a specific gravity 4.54 g / cm ^3, by substituting respective numerical values 108.1ke
V. This numerical value is used below as the electron energy at the time of generation.

The sample tray 1 is moved from the electron beam generator by 5c.
When located at a distance of m, the electronic energy received by the food material is the electron energy at the time of generation, 108.1 keV
, Electronic stopping power of the air ^{3637keV · cm 2 / g (IGRU} REPORT 3
7, Stopping Powers for Electrons and Positions, 12
Page 0, published October 1, 1984), the thickness of the substance (air layer) (distance from the outlet of the device to the food material) is 5 cm, and the specific gravity of air is 1.20 × 10 ^-3 g / cm ³ 86.3k from the formula
eV is calculated. When the sample tray 1 is located at a position 20 cm away from the electron beam generator, the electron energy received by the food material is the same as that described above except that the thickness of the substance (the distance from the outlet of the device to the food material) is 20 cm. By calculation
It becomes 20.8keV.

On the other hand, when the electron energy near the exit of the electron beam generator (inside the titanium window foil) is 250 keV,
The distance from the device to the bottom of the sample tray is 5cm or 20c
m, the electron energy when hitting food ingredients is
By similar calculations, they are 194.2 keV and 149.6 keV, respectively. Thus, the energy of soft electrons is
Attenuated by the resistance between the titanium window foil of the electron beam generator and the air, and the greater the distance between the electron beam generator and the tray bottom, the lower the energy of the soft electrons hitting the food ingredients.

The food ingredients contained in the sample supplier 11 are as follows:
(Unprocessed) Samples are sequentially supplied to the sample tray 1 from the sample supply tray section 11A. Also in this case, it is preferable that the food material to be sterilized be supplied to the sample tray 1 so as not to overlap as many as possible. Sample feeder 1
The feed speed of the food material from No. 1 to the sample tray 1 is not particularly limited, but is usually about 5 to 50 g / min. Since the speed controllers 8, 9, and 10 have already been set and the switches 5, 6, 7, and 12 have been turned ON, the continuous rotation device of the present invention has been activated, and the sample tray 1 has at least a vertical position. A directional vibration (usually a longitudinal vibration and a lateral shaking as defined in claim 3) is provided. The food material supplied to the sample tray 1 is continuously rotated while rotating on the sample tray 1 to which at least the vertical vibration (normally, the vertical vibration and the horizontal shaking) is given. Roll down. In FIG. 1, the food material as a sample is continuously rolled down while rotating from the right side to the left side on the inclined sample tray 1.
The strength (speed) of the vibration or shaking given to the sample food material is determined in consideration of the type, shape, specific gravity, etc. of the sample food material, and also the inclination angle of the sample tray 1. Should be selected so that a rotation suitable for the food ingredient is obtained.

Further, since the electron beam is already generated by operating the electron beam generator, when the food material as a sample rolls down, a low energy electron beam is uniformly applied to the surface of the food material as a sample. In this way, the food material can be continuously sterilized. The sterilized food material falls onto the sample collection tray 13 and is collected. However, depending on the beam amount, the inclination angle of the sample tray 1, and the like, the total irradiation amount of the electron beam to the food material as the sample may be slightly insufficient.
3 is the (unprocessed) sample supply tray 11 of the sample supply 11
A can be connected with a conveyor or the like, and sterilization can be performed a plurality of times continuously. When the sample collection tray 13 and the (unprocessed) sample supply tray section 11A of the sample supply device 11 are connected by a conveyor or the like, a switch may be provided to control the traveling of the conveyor. Usually, the beam amount of a practical machine is about 20 to 50 mA, but is not limited thereto.

After the sterilization of the surface of the food material is completed as described above, the switches 5, 6, 7, and 12 are set to O, respectively.
FF. ADVANTAGE OF THE INVENTION According to the continuous sterilization method and continuous rotation apparatus of this invention, food materials can be continuously sterilized normally at a rate of about 5 to 50 g / min.

Next, the present invention will be described with reference to examples.
The present invention is not limited by this.

[0035]

EXAMPLES Example 1 Sterilization of Tea Leaves According to the Present Invention Sterilization treatment was continuously performed using the continuous rotating device of the present invention shown in FIGS. In this example, the distance from the electron beam generator to the bottom of the sample tray 1 was set to 14 cm. That is, 5 g of tea leaves are put into the sample supply device 11,
The sample was continuously supplied to the sample tray 1 having a thickness of 0.4 mm at a speed of 10 g / min. Simultaneously, the continuous rotation device shown in FIGS. 1 to 3 is operated to continuously slide down the tea leaves while rotating them, and the low energy electron beam of 200 keV (software) using a Van de Graaff type electron accelerator as a source. (Electron) at a beam amount of 12 μA. This operation was continuously repeated several times, and each time the number of viable bacteria in the tea leaves was measured. The time required for the sample to completely slide down the continuous rotating device was 30 seconds.

The number of viable cells was measured by the following method.
A 2.5% sample was homogenized in 25 mL of 0.9% sodium chloride aqueous solution (physiological saline) (manufactured by Nippon Seiki Co., Ltd.
"Ace homogenizer" was used. 0.2 mL of this suspension was applied on a normal agar medium (Nissui Normal Agar Medium, manufactured by Nissui Pharmaceutical Co., Ltd.)
After culturing at 0 ° C. for 48 hours, it was determined from the number of colonies formed on the medium. When the viable count was 10 or less per 1 g of the sample, it was determined that the bacteria had been almost completely sterilized. Table 1 shows the measurement results of the viable cell count.

[0037]

[Table 1]

According to Table 1, when the sterilization treatment was performed using the continuous rotating device of the present invention under the conditions of Example 1, the viable count of the tea leaves was 5.8 kGy (30 seconds × 4 times). processing)
To less than 100 CFU / g, total irradiation dose 7.3 kGy
(30 seconds x 5 treatments) reduces to less than 10 CFU / g.

Comparative Example 1 [Sterilization of Tea Leaves by Conventional Rotating Apparatus] 5 g of tea leaves were used by using a conventional grain rotating apparatus (Japanese Patent Application No. 9-311081; see Japanese Patent Application Laid-Open No. 10-215765; the same applies hereinafter). While rotating, the source was a Van de Graaff-type electron accelerator.
A low-energy electron beam (soft electron) of 00 keV was irradiated at a beam amount of 12 μA with changing the time. The viable count of tea leaves was measured in the same manner as in Example 1. Table 2 shows the measurement results of the viable cell count.

[0040]

[Table 2]

Consider Table 2 based on the results of Table 1. Comparative Example 1 was performed under the same irradiation conditions as in Example 1 except that only a conventional rotating device was used. In this case, in order to reduce the number of bacteria in the sample to less than 10 CFU / g. Required irradiation of about 11.6 kGy (4 minute treatment). This is because, in the case of Example 1, the total irradiation dose was 7.
Compared with 3 kGy (30 seconds × 5 times), it can be seen that the irradiation dose is large and it takes a long time. From this, it is clear that the use of the continuous rotation device of the present invention can efficiently sterilize tea leaves with a small amount of irradiation and in a short time.

Comparative Example 2 [Sterilization of tea leaves by gamma rays] In Example 1, ⁶⁰ Co was used as a radiation source instead of an electron beam.
All were performed in the same manner as in Example 1 except that a predetermined dose of gamma rays was irradiated using. The viable count of tea leaves was measured in the same manner as in Example 1. Table 3 shows the viable cell count measurement results.

[0043]

[Table 3]

According to Table 3, the number of viable bacteria in tea leaves after gamma irradiation treatment was 10 CFU / g at an irradiation dose of 7.5 kGy.
Less than the above, which was almost the same as the result of Example 1. From this, it is understood that when the continuous rotation device of the present invention is used, a sterilization effect equivalent to that of gamma ray irradiation can be obtained. However, in the case of gamma ray irradiation,
As shown in Japanese Patent No. 1081 (see Japanese Patent Application Laid-Open No. 10-215765), there is a disadvantage that starch is decomposed and the viscosity of cereal is remarkably reduced.

Example 2 [Sterilization of Brown Rice According to the Present Invention] 20 g of brown rice was put into the sample feeder 11 and continuously supplied to the sample tray 1 having a thickness of 0.6 mm at a speed of 20 g per minute. Simultaneously, the brown rice is continuously dropped while rotating the brown rice by operating the continuous rotating device of the present invention shown in FIGS. 1 to 3, and a low energy electron beam of 170 keV using a Van de Graaff type electron accelerator as an irradiation source. (Soft Electron) with 4μ beam
A. This operation was continuously repeated several times, and the viable count of brown rice was measured each time. The time required for the sample to completely slide down the continuous rotating device is 60 minutes.
Seconds. The viable count of brown rice was measured in the same manner as in Example 1. Table 4 shows the measurement results of the viable cell count.

[0046]

[Table 4]

According to Table 4, when the treatment using the continuous rotating apparatus of the present invention was performed under the conditions of Example 2, the viable count of brown rice was 5.7 kGy (1 minute × 12 treatments). ) To less than 100 CFU / g, total irradiation dose 7.6 kGy
It can be seen that (1 minute x 16 treatments) reduces to less than 100 CFU / g. From this, it was found that a satisfactory bactericidal effect can be obtained with a total irradiation dose substantially equal to that in the case of the tea leaves of Example 1.

Comparative Example 3 [Sterilization of Brown Rice by Conventional Rotating Apparatus] While rotating 20 g of brown rice using the conventional rotating apparatus,
170k using a Van de Graaff electron accelerator as the irradiation source
An electron beam (soft electron) having a low energy of eV was irradiated at a beam amount of 4 μA for various times. The viable count of brown rice was measured in the same manner as in Example 1. Table 5 shows the results of measuring the viable cell count.

[0049]

[Table 5]

Consider Table 5 based on the results of Table 4. Comparative Example 3 has the same irradiation conditions as Example 2 except that only the conventional rotating device is used. In this case, in order to reduce the number of viable bacteria in the sample to less than 10 CFU / g, It is necessary to irradiate a total irradiation dose of about 19.0 kGy (processing for 40 minutes). This means that the total irradiation dose is large and that it takes a long time as compared with the total irradiation dose of Example 2 being 7.6 kGy (1 minute x 16 treatments = 16 minutes). I understand. From this, it is clear that the use of the continuous rotation device of the present invention can efficiently sterilize brown rice with a small irradiation dose and in a short time as in the case of tea leaves.

Comparative Example 4 [sterilization of brown rice with gamma rays] In Example 2, ⁶⁰ Co was used as a radiation source instead of an electron beam.
Was carried out in the same manner as in Example 2 except that gamma rays were irradiated at a predetermined dose. The viable count of brown rice was measured in the same manner as in Example 1. Table 6 shows the viable cell count measurement results.

[0052]

[Table 6]

According to Table 6, the viable cell count in brown rice after irradiation with gamma rays was 10 CFU / g at an irradiation dose of 7.5 kGy.
, Which was almost the same as the result of Example 2. From this, it can be seen that the same sterilizing effect as gamma rays can be obtained for brown rice as well as tea leaves when the continuous rotation device of the present invention is used.

Example 3 [Sterilization of buckwheat with husk according to the present invention] 20 g of buckwheat with husk was put into the sample feeder 11 and continuously supplied to the sample tray 1 at a speed of 40 g / min. At the same time, the continuous rotating device of the present invention shown in FIGS. 1 to 3 is operated to rotate the buckwheat husk continuously and drop it, and a low energy electron beam of 300 keV using a Verdegraf type electron accelerator as a source. (Soft electrons) was irradiated at a beam amount of 36 μA. This operation was continuously repeated several times, and the number of viable bacteria in the buckwheat with husk was measured each time. The time required for the sample to completely slide down the rotating device was 30 seconds.
The viable cell count of the buckwheat with husk was measured in the same manner as in Example 1.
Table 7 shows the results of measuring the viable cell count.

[0055]

[Table 7]

According to Table 7, when the treatment using the continuous rotating device of the present invention was performed under the conditions of Example 3, the viable cell count of the buckwheat with husk was determined to be 18.6 kGy (30 seconds × 30 seconds). It can be seen that the amount decreases to less than 10 CFU / g by four treatments). From this, when the treatment using the continuous rotation device of the present invention is performed, the total irradiation dose and time are slightly more than in the case of tea leaves and brown rice, but a satisfactory bactericidal effect is also obtained for buckwheat with shells. Was obtained.

Comparative Example 5 [Sterilization of buckwheat with husk using conventional rotating device] While rotating 20 g of buckwheat with husk using a conventional rotating device, 300 k using a Van de Graaff-type electron accelerator as a radiation source.
An electron beam (soft electron) having a low energy of eV was irradiated at a beam amount of 36 μA for various times. The viable cell count of the buckwheat with husk was measured in the same manner as in Example 1. Table 8 shows the measurement results of the viable cell count.

[0058]

[Table 8]

Consider Table 8 based on the results in Table 7. Comparative Example 5 has the same irradiation conditions as Example 3 except that only a conventional rotating device is used.
In order to reduce the number of viable bacteria in a sample to less than 10 CFU / g,
The irradiation dose needs to be about 37.2 kGy (4
Minute processing). This is because the total irradiation dose in Example 3 was 18.6.
Compared to kGy (30 seconds × 4 processing = 2 minutes), it can be seen that the irradiation dose is twice or more and the processing time is twice as long. From this, it is clear that the use of the continuous rotation device of the present invention can efficiently sterilize buckwheat buckwheat with a small total irradiation dose and in a short time as in the case of tea leaves and brown rice. .

Comparative Example 6 [Sterilization of buckwheat with shell by gamma ray] In Example 3, ⁶⁰ Co was used as a radiation source instead of an electron beam.
Was carried out in the same manner as in Example 3 except that a predetermined dose of gamma rays was applied using The viable cell count of the buckwheat with husk was measured in the same manner as in Example 1. Table 9 shows the viable cell count measurement results.

[0061]

[Table 9]

According to Table 9, the viable cell count in the buckwheat husk after the gamma ray irradiation treatment was 10 CF at an irradiation dose of 20.0 kGy.
It is less than U / g, which indicates that a slightly higher dose is required than in Example 3. From this fact, it can be seen that even for buckwheat with shells, when the continuous rotation device of the present invention is used, a sterilization effect equivalent to or higher than that of gamma rays can be obtained.

Example 4 [Sterilization of black pepper according to the present invention] 10 g of black pepper was put into the sample feeder 11 and 40 g / min.
, And was continuously supplied to the sample tray 1. At the same time, FIGS.
By operating the continuous rotating device of the present invention as shown in Fig. 4, black pepper is continuously dropped while rotating, and a low energy electron beam (soft electron) of 300 keV using a Verdegraf type electron accelerator as a beam source is beamed. Irradiation was performed at an amount of 36 μA. This operation was continuously repeated several times, and the number of viable cells of black pepper was measured each time. The time required for the sample to completely slide down the continuous rotating device was 15 seconds. The viable cell count of black pepper was measured in the same manner as in Example 1. Table 10 shows the measurement results of the viable cell count.

[0064]

[Table 10]

According to Table 10, when the treatment using the continuous rotating apparatus of the present invention was performed under the conditions of Example 4, the total number of viable bacteria of black pepper was 9.3 kGy (15 sec × 4). It can be seen that the number of treatments decreases to less than 10 CFU / g. From this result, it was found that in the case of black pepper, a satisfactory bactericidal effect can be obtained in a short time with a total irradiation dose lower than that of tea leaves, brown rice, and buckwheat with shells.

COMPARATIVE EXAMPLE 7 Sterilization of Black Pepper Using a Conventional Rotating Apparatus While rotating 10 g of black pepper using a conventional rotating apparatus, 300 g of the black pepper was set using a Van de Graaff-type electron accelerator as a radiation source.
KeV low energy electron beam (soft electron)
Was irradiated at a beam amount of 36 μA for various irradiation times. The viable cell count of black pepper was measured in the same manner as in Example 1. Table 11 shows the measurement results of the viable cell count.

[0067]

[Table 11]

Consider Table 11 based on the results of Table 10. Comparative Example 7 is the same irradiation conditions as in Example 4 except that only the conventional rotating device is used, but in this case, in order to reduce the number of viable bacteria in the sample to less than 10 CFU / g, It is necessary to irradiate a total irradiation dose of about 23.3 kGy (2.5-minute treatment). This means that the total irradiation dose is about 2.5 times and the irradiation time is 2.5 times as compared with the total irradiation dose of 9.3 kGy in Example 4 (15 seconds × 4 treatments = 1 minute). It turns out that it requires. From this,
It is clear that the use of the continuous rotating apparatus of the present invention can efficiently sterilize black pepper with a small total irradiation dose and in a short time as in the case of other samples.

Comparative Example 8 [sterilization of black pepper by gamma rays] In Example 4, ⁶⁰ Co was used as a radiation source instead of an electron beam.
Was carried out in the same manner as in Example 4 except that gamma rays were irradiated at a predetermined dose. The viable cell count of black pepper was measured in the same manner as in Example 1. Table 12 shows the viable cell count measurement results.

[0070]

[Table 12]

According to Table 12, the number of viable bacteria in black pepper after irradiation with gamma rays was 1 at an irradiation dose of 10.0 kGy.
The result is less than 0 CFU / g, which indicates that a slightly higher irradiation dose is required than the result of Example 4. From this, it can be seen that even with black pepper, when the continuous rotating device of the present invention is used, a germicidal effect equal to or higher than gamma rays can be obtained.

Example 5 [sterilization of black pepper according to the present invention] 10 g of black pepper was put into the sample feeder 11 and the speed was 10 g / min.
, And was continuously supplied to the sample tray 1. At the same time, FIGS.
The black pepper is continuously dropped while being rotated by operating the continuous rotation device of the present invention shown in Fig. 1 and a low energy electron beam (soft electron) of 300 keV using a Verdegraf type electron accelerator as a radiation source is beamed. Irradiation was performed at an amount of 36 μA. This operation was continuously repeated several times, and the number of viable cells of black pepper was measured each time. The time required for the sample to completely slide down the continuous rotating device was 60 seconds. The viable cell count of black pepper was measured in the same manner as in Example 1. Table 13 shows the results of measuring the viable cell count.

[0073]

[Table 13]

From Table 13, when the treatment using the continuous rotating apparatus of the present invention was performed under the conditions of Example 5, the viable count of black pepper was 9.3 kGy, that is, the total irradiation dose was 1
It can be seen that the number of treatments decreases to less than 10 CFU / g. From this, the required irradiation dose can be obtained by one irradiation by reducing the sample supply speed, so that the continuous irradiation can be performed without installing a conveyor or the like connecting the sample collection tray 13 and the sample supply device 11. It became clear that the sterilization treatment can be performed.

Example 6 [Disinfection of Wheat According to the Present Invention] 10 g of wheat was put into the sample feeder 11 and was continuously supplied to the sample tray 1 at a rate of 10 g per minute. Simultaneously, the wheat is continuously dropped while rotating by operating the continuous rotating device of the present invention shown in FIGS. 1 to 3, and a low energy electron beam of 225 keV (software) using a Verdegraf type electron accelerator as a source. (Electron) at a beam amount of 22 μA. This operation was repeated several times continuously, and the number of viable bacteria of wheat was measured each time. The time required for the sample to completely slide down the rotating device was 60 seconds. The viable bacterial count of wheat was measured in the same manner as in Example 1. First measurement of viable cell count
The results are shown in Table 4.

[0076]

[Table 14]

According to Table 14, when the treatment was performed using the continuous rotating apparatus of the present invention under the conditions of Example 6, the viable bacterial count of wheat was 6.4 kGy in total irradiation dose, that is, one irradiation. It can be seen that the treatment reduces to less than 10 CFU / g.
From this, as in the case of the black Kosho, also in the case of wheat, the required irradiation dose can be obtained by one irradiation by reducing the sample supply speed, so that the sample collection tray 13 and the sample supplier 11 It has been clarified that the sterilization process can be performed continuously without installing a conveyor or the like for connecting.

Comparative Example 9 [Sterilization of Wheat by Conventional Rotating Apparatus] While rotating 10 g of wheat using the conventional rotating apparatus,
225k using a Van de Graaff electron accelerator as an irradiation source
An electron beam (soft electron) having a low energy of eV was irradiated at a beam amount of 22 μA for various times. The viable bacterial count of wheat was measured in the same manner as in Example 1. Table 15 shows the results of measuring the viable cell count.

[0079]

[Table 15]

Consider Table 15 based on the results of Table 14. Comparative Example 9 is the same irradiation conditions as in Example 6 except that only a conventional rotating device is used. In this case, in order to reduce the number of viable bacteria in the sample to less than 10 CFU / g, It is necessary to irradiate a total irradiation dose of about 9.6 kGy (1.5 minute treatment). This indicates that both the irradiation dose and the irradiation time require 1.5 times as compared with the total irradiation dose of Example 6 being 6.4 kGy (1 minute × 1 time). From this, using the continuous rotation device of the present invention, as with other samples, compared with the conventional rotation device, with a small irradiation dose, and in a short time, can efficiently sterilize wheat. It is clear that it can be done.

Comparative Example 10 [sterilization of wheat with gamma rays] In Example 6, ⁶⁰ Co was used as a radiation source instead of an electron beam.
Was performed in the same manner as in Example 6 except that gamma rays were irradiated at a predetermined dose using The viable bacterial count of wheat was measured in the same manner as in Example 1. Table 16 shows the viable cell count measurement results.

[0082]

[Table 16]

According to Table 16, the number of viable bacteria in wheat after irradiation treatment with gamma rays was 10 CFU / kg at an irradiation dose of 5.0 kGy.
g, which was almost the same as Example 6. From this, it can be seen that also for wheat, when the continuous rotation device of the present invention is used, a sterilizing effect equivalent to that of gamma rays can be obtained.

Example 7 [Sterilization of Japanese radish seeds according to the present invention]
It was continuously supplied to the sample tray 1 at a rate of 10 g per minute. Simultaneously, the seeds are continuously dropped while rotating by operating the continuous rotating device of the present invention shown in FIGS. 1 to 3, and a low energy electron beam (software) of 170 keV using a Verdegraf type electron accelerator as a source. (Electron) at a beam amount of 4 μA. This operation was continuously repeated several times, and the number of viable bacteria of the Japanese radish seed was measured each time. The time required for the sample to completely slide down the rotating device was 60 seconds. The viable cell count of the seed was measured in the same manner as in Example 1. Table 17 shows the measurement results of the viable cell count.

[0085]

[Table 17]

According to Table 17, when the treatment using the continuous rotating apparatus of the present invention was performed under the conditions of Example 7, the viable count of the seeds of the Japanese radish, the total irradiation dose was 1.43 kGy.
It can be seen that (1 minute × 3 times treatment) reduces to less than 10 CFU / g. From this result, it was found that in the case of the Japanese radish seed, by performing the condition of Example 7, a satisfactory bactericidal effect was obtained in a short time.

Comparative Example 11 Sterilization of Japanese Radish Seeds by Conventional Rotating Apparatus Low energy of 170 keV using a Van de Graaff type electron accelerator as an irradiation source while rotating 10 g of Japanese radish seeds using a conventional rotating apparatus. (Soft electron) was irradiated at a beam amount of 4 μA for various times. In the same manner as in Example 1, the viable cell count of the Japanese radish seed was measured. Table 18 shows the measurement results of the viable cell count.

[0088]

[Table 18]

Consider Table 18 based on the results of Table 17. Comparative Example 11 has the same irradiation conditions as Example 7 except that only the conventional rotating device is used, but in this case, in order to reduce the number of viable bacteria in the sample to less than 10 CFU / g, It is necessary to irradiate a total irradiation dose of about 1.90 kGy (4-minute processing). This indicates that both the total irradiation dose and the irradiation time require much more than the total irradiation dose of Example 7 was 1.43 kGy (1 minute × 3 times treatment). From this, the use of the continuous rotation device of the present invention can efficiently sterilize the Japanese radish seeds with a small irradiation dose and in a short time as compared with the conventional rotation device, as in the case of other samples. Obviously it can be done well.

Comparative Example 12 (Sterilization of Radish Seeds by Gamma Ray) The same procedure as in Example 7 was carried out except that gamma rays were irradiated using ⁶⁰ Co as a radiation source instead of an electron beam. In the same manner as in Example 1, the viable cell count of the Japanese radish seed was measured. Table 19 shows the viable cell count measurement results.

[0091]

[Table 19]

According to Table 19, the viable cell count in the Japanese radish seeds after the irradiation treatment with gamma rays was determined by the irradiation dose of 2.0 kG
y was less than 10 CFU / g, which was almost equivalent to Example 7. From this fact, it can be seen that the use of the continuous rotation device of the present invention also provides a germicidal effect equivalent to that of gamma rays for the Japanese radish seeds.

According to the results shown in Tables 1 to 19,
With the continuous rotation device of the present invention, the dose required for sterilization with a low energy electron beam (soft electron) is much lower than when using a conventional grain rotation device, and is almost the same as when using gamma rays. Is the same. From this,
It is clear that the continuous rotation device of the present invention can efficiently sterilize food raw materials with a small irradiation dose.

As is clear from Tables 10 and 13, the dose required for sterilization was not related to the speed at which the sample passed through the continuous rotating device. This indicates that the use of the continuous rotation device of the present invention makes it possible to rotate the food raw material very efficiently and to uniformly irradiate the surface of the food raw material with low-energy electrons. This is a result observed for tea leaves, brown rice, buckwheat with husk, black pepper, wheat, and Japanese radish seeds. ing. Further, as shown in Tables 13 and 14, if the speed at which the sample passes through the continuous rotation device is reduced, the sample can be sterilized by one process. Alternatively, if the electron dose per unit time is increased, sterilization can be performed in one treatment without changing the passing speed. This indicates that the sample can be continuously sterilized by using the continuous rotation device of the present invention.

[0095]

According to the method of the present invention described in claim 1,
The food raw material can be transported while rotating uniformly and very efficiently, and can be efficiently and continuously sterilized using low-energy electron beams (soft electrons). Moreover, in the method of the present invention according to the first aspect of the present invention, the electron beam of the minimum energy required for sterilization is irradiated, and therefore the starch adheres to the grain surface without damaging the starch of the grain component. Microorganisms can be killed efficiently.

Further, according to the continuous rotating device of the present invention, the food raw material can be transported while rotating uniformly and very efficiently, and the low energy electron beam (soft electron) can be produced. It can be used for efficient and continuous sterilization. In addition, the continuous rotating device according to the present invention uses an electron beam having the minimum energy required for sterilization. Therefore, the continuous rotating device adheres to the grain surface without damaging the starch of the grain component. Microorganisms can be efficiently killed.

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of a continuous rotation device according to the present invention described in claim 2;

FIG. 2 is a plan view of FIG.

FIG. 3 is a left side view of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sample tray 2 Vibrator with a tray mounting table whose height can be adjusted 3 Vibrator with a tray mounting table whose height is constant 4 Shaker with a tray mounting table whose height is constant 5 Vibration with a tray mounting table whose height can be adjusted Power switch for operating the vibrator 6 Power switch for operating the vibrator with a fixed tray mounting table 7 Power switch for operating the shaker with a fixed tray mounting table 8 Speed for the vibrator with a tray mounting table whose height can be adjusted Controller 9 Speed controller for vibrator with tray mounting table with constant height 10 Speed controller for shaker with tray mounting table with constant height 11 Sample supply 11 11A (unprocessed) Sample supply tray section 11B Electromagnetic vibration drive for transport Unit 12 Control unit with switch for operating sample supply unit 13 Sample collection tray

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tohru 1-8-8 Sakuradai, Ushiku-shi, Ibaraki Pref. (72) Inventor Setuko Suzuki 4-1-1, Namiki, Tsukuba-shi, Ibaraki F-term (reference) 4B021 LA41 LP10 LT03 LT06 LW07 LW09

Claims (3)

[Claims] When sterilizing a food material, the food material, which is a sample, is continuously rolled down while rotating at least on a tilted sample tray to which a vertical vibration is applied, and when the sample is rolled down. A method for continuously sterilizing food raw materials, which comprises applying a low-energy electron beam having an energy of 160 to 300 keV to the surface of a sample. 2. A sample tray, a vibrator with a tray mounting table whose height can be adjusted, a vibrator with a tray mounting table having a constant height, a shaker with a tray mounting table having a constant height, said vibrator and a shaker And a speed controller, a sample supply device for supplying a sample to a sample tray, and a control unit with a switch for operating the sample supply device. 3. The continuous rotating device according to claim 2 is placed under an electron beam generator, and continuously rotated by applying a vertical vibration and a horizontal shaking to a sample stored in a sample tray. The continuous sterilization method according to claim 1, wherein the low-energy electron beam is irradiated while rolling down.