JP2019180249A - Germination guide method and sterilization method - Google Patents

Abstract

To provide a germination guide method for inducing germination of sporulation germs in sterilizing sporulation germs which a processed object such as food has, capable of achieving germination in short time without a chemical substance, and a sterilization method using the germination guide method.SOLUTION: The germination guide method comprises: a cleaning step for removing impure particles adhered to a surface of a processed object to which sporulation germs are adhered; and a light radiation step for, after the cleaning step, radiating light to the processed object for germination.SELECTED DRAWING: Figure 1

Description

  The present invention particularly relates to a method for inducing germination of spore-forming bacteria having spores attached to an object to be treated such as food, and a sterilization method using the method for inducing germination.

2. Description of the Related Art Conventionally, methods for inactivating bacteria contained in objects such as food and utensils and bacteria contained in beverages are known.
For example, a powder sterilization method using ozone is known. According to this sterilization method, since sterilization can be performed in a non-heated state, deterioration of the sterilization target can be suppressed.
However, in such a sterilization method, reproducibility of sterilization may not be obtained. That is, even if the object to be sterilized is exposed to ozone to the same extent, there arises a situation in which the degree of sterilization varies from process to process.
When the inventor diligently investigated the phenomenon that the reproducibility of sterilization cannot be obtained,
(1) Bacteria possessed by the sterilization target form spores.
(2) The spore formation state varies depending on the timing of treatment.
I found out that it was caused by that.

In order to solve the above problems, it is conceivable to sterilize the spores after germination (= germination induction). For example, JP 2002-153247 A (Patent Document 1) describes spraying an aqueous solution of a germination inducer (L-alanine) onto an object to be sterilized and then sterilizing with ozone or ultraviolet light.
JP-A-2015-199723 (Patent Document 2) describes a method for causing germination of spores by bringing spore-forming bacteria into contact with dipicolinic acid or a salt thereof under a pH of 6 or less. .
Furthermore, Japanese Patent Laid-Open No. 3-038857 (Patent Document 3) discloses a method of holding for several hours at a temperature (20 ° C. to 40 ° C.) suitable for growth of the number of bacteria in a moisture-rich state. .
By the way, such a known germination inducing method uses a chemical substance (nutrient) or requires a long-time treatment. For example, it is not suitable as a method for inducing germination of food and is practically used. This is not preferable.

JP 2002-153247 A JP-A-2015-199723 JP-A-3-0388857

  In view of the above-mentioned problems of the prior art, the present invention is a method for inducing germination of spore-forming bacteria in an object to be treated such as food, without using a chemical substance, and It is an object of the present invention to provide a germination induction method capable of germination in a short time and a sterilization method using this germination induction method.

In order to solve the above problems, the germination inducing method according to the present invention comprises a cleaning step for removing impure particles adhering to the surface of an object to which spore-forming bacteria adhere, and the object to be processed after the cleaning step. And a light irradiation step for irradiating light to germinate.
Further, the cleaning step is characterized in that an impure particle removing gas is blown onto the object to be processed.
In addition, a moisture supply step for supplying moisture to the object to be processed is included between the cleaning step and the light irradiation step.
Further, the water supply step is characterized in that a water supply gas is supplied to the object to be processed.
Moreover, the sterilization method according to the present invention includes a first step comprising the germination induction method according to any one of the above and a second step of sterilizing the workpiece.

According to the germination induction method according to the present invention, when spore-forming bacteria possessed by an object to be treated such as food are sterilized, the impure particles adhering to the surface of the object to be treated and the spore-forming bacteria are separated from the object to be treated by a cleaning process. After the removal, the object to be processed is irradiated with light, so that the object is uniformly irradiated without being blocked by the impure particles, so that an efficient germination induction process is performed.
And since the bacteria which the to-be-processed object germinates effectively are germinated, the variation in the degree of inactivation of the bacteria after a sterilization process reduces.

FIG. 3 is a flowchart of the first embodiment of the germination induction method of the present invention. The flowchart of 2nd Example of the germination induction method of this invention. The side view of the germination induction apparatus which achieves the first embodiment. The side view in the other position similar to FIG. BB sectional drawing of FIG. The side view of the germination induction apparatus which achieves Example 2. FIG. 1 is a flowchart of a first embodiment of a sterilization method of the present invention. The flowchart of 2nd Example of the sterilization method of this invention. 1 is a side view of a sterilization apparatus that achieves a first embodiment of a sterilization method of the present invention. FIG. The side view of the sterilizer which achieves 2nd Example of the sterilization method of this invention.

An example of a flow chart of the germination induction method of the present invention is shown in FIG. In the first embodiment, the object to be sterilized is a food, for example, a solid material such as black pepper.
Spore-forming bacteria adhere to the surface of the object to be treated, and the spore-forming bacteria are germinated so that the subsequent sterilization by ozone is effective.
The process is shown in Figure 1.
<Cleaning process>
Impurity particles such as dust are attached to the surface of the processing target such as food (black pepper) to be sterilized, and the impure particles are separated and removed in the light irradiation process, for example, dry air A cleaning gas such as is sprayed on the object to be processed.
<Light irradiation process>
This is a step of inducing germination of spore-forming bacteria by irradiating near-infrared light to the object to be sterilized from which the impure particles have been removed. Impurity particles adhering to the surface of the spore-forming bacteria are removed by the preceding cleaning process, and near-infrared light is uniformly irradiated to the spore-forming bacteria without being blocked by the impurity particles, so that germination treatment is performed. Done effectively.

As the wavelength of the near infrared light irradiated to the object to be processed, a wavelength of 650 nm to 1400 nm can be used. In the present embodiment, an LED that emits near-infrared light having a peak wavelength at a wavelength of 850 nm is used as a light source. As the light source, a halogen lamp or the like can be used in addition to the LED.
However, when irradiating near infrared light, it is preferable that the temperature of a to-be-processed object exists in the range of 5 to 50 degreeC. When it is outside this range, the germination efficiency of the spore may be reduced. As a method of setting the above temperature range when irradiating near-infrared light, the light irradiated to the object to be processed does not include light having a wavelength that is absorbed by the object to be processed. Alternatively, a method of preventing the temperature rise of the object to be processed by turning on the light source intermittently can be adopted. A structure using an LED as the light source is preferable because it is easy to make the light irradiated to the object to be processed not include light having a wavelength that is absorbed by the object to be processed.
The light source that emits near infrared light preferably does not emit light (ultraviolet light) having a wavelength of 400 nm or less. In the case of emitting ultraviolet light in this range, near-infrared light and ultraviolet light are irradiated at the same time, which may reduce the germination efficiency of the spores.

FIG. 2 shows a flowchart of the second embodiment of the germination induction method of the present invention.
In the second embodiment, after the cleaning step in the first embodiment shown in FIG. 1, a moisture application step for applying moisture to the object to be processed is provided prior to the light irradiation step.
It is known that a spore-forming bacterium is efficiently induced to germinate when it contains a certain amount of water, and an appropriate water content can be imparted to an object to be treated by providing a water content imparting step. As the water supply means, appropriate means such as humidified air, air containing water droplets (mist) (mist aerosol), or water droplet spraying can be used.

3 to 5 show an example of an apparatus for achieving the first embodiment of the germination induction method of FIG.
3 is a side cross-sectional view, FIG. 4 is a side cross-sectional view at a different position, and FIG. 5 is a cross-sectional view taken along the line BB in FIGS. 3 is a cross-sectional view taken along line A1-A1 of FIG. 5, and FIG. 4 is a cross-sectional view taken along line A2-A2 of FIG.
Spore-forming bacteria are attached to the surface of the object to be treated, and impure particles such as dust are attached to the spore-forming bacteria. After removing the impure particles, near infrared light is irradiated to the spores. The germs are germinated and the subsequent sterilization by ozone is effective.

3-5, the germination induction apparatus (processing apparatus) 1 has the cylindrical housing | casing 2 which can rotate, The to-be-processed object M, such as a black pepper, is accommodated in the inside.
The housing 2 can be rotated about a rotation axis X by a rotation mechanism 4 including a support base 41 placed on the gantry 3 and a rotation roller 42 rotatably supported on the support base 41. It is supported. This rotation may be rotation in one direction, or may be peristaltic rotation that rotates in the opposite direction after rotating in one direction.

A light source 5 is inserted and supported in the housing 2, and the light source 5 includes a substrate 51 extending in the direction of the rotation axis X of the housing 2 and a near-red color arranged on the substrate 51. The LED 52 emits external light (light having a wavelength in the range of 650 nm to 1400 nm).
The substrate 51 of the light source 5 extends to the outside through the openings 21 at both ends of the housing 2, and is supported on the gantry 3 by the support legs 6.
The power supply line 53 is electrically connected at both ends of the substrate 51, and power is supplied to the LED 52. The LED 52 emits light, and near infrared light is emitted. Here, the near infrared light emitted from the LED 52 is preferably light having a peak wavelength in a wavelength region of a wavelength of 650 nm to 1400 nm.

4 and 5, an air knife 8 is provided in the housing 2 so as to extend in the direction of the rotation axis X so as to be parallel to the light source 5. The air knife 8 has a number of outlets 81 that open downward. The outlet 81 may be a large number of small holes scattered in the tube axis direction, or may be formed by slits extending in the tube axis direction. A cleaning gas supply unit 11 is connected to the air knife 8, and a gas such as dry air from the gas supply unit 11 is ejected from the outlet 81 of the air knife 8 toward the object M to be processed below.
As shown in FIGS. 3 to 5, a cylindrical screen (screen) 9 is provided in the housing 2. The cylindrical screen 9 is formed by a cylindrical perforated plate or a wire net that is slightly smaller in diameter than the casing 2, and a predetermined gap S is formed between the cylindrical screen 9 and the cylindrical inner wall 22.

In the above configuration, the housing 2 is rotated by the rotating mechanism 4 as shown in FIG. 5 prior to the light irradiation from the light source 5. Thereby, the to-be-processed object M inside is once pulled up in the rotation direction, and then slides down due to gravity. Thereafter, while the housing 2 is rotating, the workpiece M repeats its operation.
Then, a gas such as dry air from the cleaning gas supply means 11 is blown out from the outlet 81 of the air knife 8 toward the object to be processed M, and adheres to the object to be processed M and spore-forming bacteria attached thereto. Separating and removing so as to blow off impure particles such as dust. The removed impure particles pass through the screen 9 and fall into the gap S and reach the inner wall 22 of the housing 2.
The light source 5 (LED 52) is turned on and the near-infrared light is irradiated to the object to be processed M from which the impure particles have been removed, and the spore-forming bacteria of the object to be processed germinate.

In the first embodiment of the germination inducing apparatus 1, germination induction processing of spore-forming bacteria is performed by the following operation procedure, for example.
Start of housing rotation → Start supply of cleaning gas → (After a certain time has elapsed) Stop supply of cleaning gas → Turn on the light source → (After a certain time has elapsed) Turn off the light source → Stop the housing rotation.

FIG. 6 shows an example of an apparatus for achieving the second embodiment of the germination induction method of FIG.
The water supply means 12 is connected to the air knife 8 to which the cleaning gas supply means 11 is connected.
These cleaning gas supply means 11 and moisture supply means 12 are selectively communicated with the air knife 8.
First, the cleaning gas supply means 11 is communicated with the air knife 8, and the cleaning gas is blown out from the outlet 81 of the air knife 8 toward the workpiece M to blow off the impure particles adhering to the workpiece M. To separate and remove.
Next, the water supply means 12 is communicated with the air knife 8, and a water-containing gas such as humidified air is blown out from the blowout port 81, so that predetermined moisture is given to the workpiece M.
Then, the light (near infrared light) from the light source 5 is irradiated to the to-be-processed object M, and a spore formation microbe is germinated.

The moisture supply unit 12 may be connected to a moisture blowing unit (not shown) provided separately from the air knife 8.
Alternatively, the moisture in the moisture-containing gas may be condensed and condensed on the surface of the workpiece M by cooling the housing 2 using the moisture-containing gas from the moisture supply means 12 as highly humidified air.

That is, in the second embodiment of the germination inducing apparatus 1, germination induction processing of spore-forming bacteria is performed by the following operation procedure, for example.
Case rotation start → Cleaning gas supply start → (After a certain time has passed) Cleaning gas supply stopped → Humidified air blowing → (After a certain time has passed) Humidified air supply stopped → Light source turned on → (After a certain time has passed) Light source turned off → Housing Stop body rotation.

Below FIG. 7, the Example of the sterilization method which performs a sterilization process after a germination induction process is shown.
FIG. 7 shows a first embodiment of the sterilization method, in which sterilization treatment is performed after the germination induction method of FIG. 1 described above.
<Sprouting induction process (first process)>
A cleaning process for removing impure particles adhering to the object to be processed by blowing a cleaning gas on the object to be processed, followed by irradiating light (near-infrared light) to the object to be processed. The germination induction step comprising the light irradiation step for inducing germination of the forming bacteria is the same as that in the embodiment of FIG.
<Sterilization process (second process)>
This is a step of sterilizing a workpiece to be sterilized, and in this embodiment, ozone sterilization treatment is performed by sterilizing the workpiece having spore-forming bacteria germinated in the germination induction step by exposing it to ozone. This is an example of adoption.
As the sterilization means, from the viewpoint of suppressing the deterioration of the object to be sterilized, particularly food, the sterilization target does not increase in temperature, and examples include ozone sterilization and sterilization by ultraviolet irradiation.

FIG. 8 shows a second embodiment of the sterilization method, in which sterilization treatment is performed after the germination induction method of FIG. 2 described above.
That is, after removing the impure particles of the object to be treated with the cleaning gas, moisture is given to the object to be treated, and then the spore-forming bacteria are germinated by light irradiation (germination induction step). This is sterilized with ozone (sterilization process).

FIG. 9 shows an example of an apparatus for achieving the first embodiment of the sterilization method of FIG.
The ozone supply means 13 is connected to the air knife 8 to which the cleaning gas supply means 11 is connected, and the cleaning gas supply means 11 and the ozone supply means 13 are selectively communicated with the air knife 8.
First, the cleaning gas supply means 11 communicates with the air knife 8, and the impure particles adhering to the workpiece M are blown off and separated by the cleaning gas blown from the blowout port 81 of the air knife 8.
Next, light from the light source 5 shown in FIGS. 3 and 5 is irradiated onto the object to be processed M, and spore-forming bacteria germinate.
Thereafter, the ozone supply means 13 is communicated with the air knife 8 and ozone is blown out from the blowout port 81 to sterilize the workpiece M.

In the first embodiment of the sterilizer 1, spore-forming bacteria are sterilized by the following operation procedure, for example.
Case rotation start → Cleaning gas supply start → Cleaning gas supply stop (after a certain time) → Light source turned on → (After a certain time has passed) Light source turned off → Ozone supply → (After a certain time has passed) Ozone supply stopped → Housing rotation stopped .

FIG. 10 shows an example of an apparatus for achieving the second embodiment of the sterilization method of FIG.
A water supply unit 12 and an ozone supply unit 13 are connected to the air knife 8 to which the cleaning gas supply unit 11 is connected. The cleaning gas supply unit 11, the water supply unit 12 and the ozone supply unit 13 are selectively used as the air knife 8. Communicated with
That is, after cleaning gas from the cleaning gas supply means 11 is blown from the air knife 8 to the object to be processed M to remove impure particles, moisture is given to the object to be processed M by the water supply gas from the water supply means 12. Thereafter, spore-forming bacteria are germinated by light irradiation (germination induction step). This is sterilized with ozone from the ozone supply means 13 (sterilization process).

In the second embodiment of the sterilizer 1, spore-forming bacteria are sterilized by the following operation procedure, for example.
Housing rotation start → Cleaning gas supply start → (After a certain time has passed) Cleaning gas supply stopped → Humidified air blowing → (After a certain time has passed) Humidified air supply stopped → Light source turned on → (After a certain time has passed) Light source turned off → Ozone Supply → (After a certain period of time) Ozone supply stop → Housing rotation stop.

Also in this embodiment, the cleaning gas supply means 11 to the cleaning gas blowing means (air knife 8), the moisture supply gas blowing means from the moisture supply means 12 and the ozone blowing means from the ozone supply means have different structures. It can also be.
Further, the ozone supply means 13 has been described as supplying ozone itself into the housing 2, but an ultraviolet lamp is disposed in the housing, and ozone is generated in the housing by the ultraviolet rays from the lamp. May be.

As described above, according to the germination inducing method according to the present invention, impure substances adhering to the surface of the object to be treated or the spore-forming bacteria when germinated by irradiating light to the spore-forming bacteria of the object to be treated. Since a cleaning process for separating and removing the particles is provided, and light is then irradiated to induce germination, the spore-forming bacteria adhering to the object to be treated are uniformly irradiated with light and can effectively induce germination.
Further, since the spore-forming bacteria are sterilized in a germinated state, an efficient sterilization process is performed and the degree of inactivation does not vary.

Claims (5)

A cleaning step for removing impure particles adhering to the surface of the object to which spore-forming bacteria adhere;
A method of inducing germination of spore-forming bacteria, comprising: a light irradiation step of irradiating the object to be treated with light after the cleaning step.   The germination induction method according to claim 1, wherein the cleaning step is a step of spraying an impurity particle removing gas onto the object to be processed.   The germination induction method according to claim 1, further comprising a moisture supply step of supplying moisture to the object to be processed between the cleaning step and the light irradiation step.   The germination induction method according to claim 3, wherein the water supply step supplies a water supply gas to the object to be processed. A sterilization method comprising a first step comprising the germination induction method according to claim 1 and a second step of sterilizing the object to be treated.

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