WO2015129467A1

WO2015129467A1 - Method for producing sterilized vegetable

Info

Publication number: WO2015129467A1
Application number: PCT/JP2015/053843
Authority: WO
Inventors: 末松　孝章; 能登　一彦; 後藤田　龍介; 栄次東; 光男新宮; 修一森; 賢司斎藤
Original assignee: 株式会社日立製作所
Priority date: 2014-02-28
Filing date: 2015-02-12
Publication date: 2015-09-03
Also published as: JP6267004B2; JP2015159793A

Abstract

　Provided is a method for producing a sterilized vegetable in which it is possible to minimize occurrence of browning while making more use of the sterilizing power of ozone water than in conventional methods. A method for producing a sterilized vegetable characterized in including a sterilization step (step S3) for bringing a vegetable into contact with ozone water and sterilizing the vegetable in a sterilization device, and a heat shock step (step S4) for applying a heat shock treatment, in a heat shock device, to the vegetable which has been sterilized in the sterilization step. It is thereby possible to provide a method for producing a sterilized vegetable in which it is possible to minimize occurrence of browning while making more use of the sterilizing power of ozone water than in conventional methods.

Description

Production method of pasteurized vegetables

The present invention relates to a method for producing sterilized vegetables.

Demand for cut vegetables that can be cooked and eaten as they are without cutting them is increasing against the backdrop of becoming a nuclear family and increasing working together. Cut vegetables are produced by cutting vegetables harvested from the field, and the harvested vegetables are contaminated with dirt such as mud and dust and viable bacteria. Therefore, the vegetables harvested from the field are often washed and sterilized and then cut to obtain cut vegetables. And the obtained cut vegetables are packaged (bagging etc.) and shipped as a product.

As a method for sterilizing cut vegetables, there is a method using a sodium hypochlorite aqueous solution described in a mass cooking facility hygiene management manual. Specifically, the vegetables are sterilized by being immersed in a sodium hypochlorite aqueous solution for a predetermined time. However, when a chlorine-based disinfectant such as sodium hypochlorite is used, a chlorine odor may remain in vegetables. In addition, organochlorine by-products may be generated, which may require the vegetables to be rinsed with a large amount of water to remove the by-products.

Therefore, ozone water having strong sterilizing power has attracted attention in recent years. Ozone has an advantage that it is quickly decomposed by a catalyst or the like and hardly remains. Therefore, a sterilization method using ozone water in which ozone gas is dissolved in water is known. Specifically, for example, Patent Document 1 describes that leaf vegetables after washing are sterilized using ozone water.

Japanese Patent No. 4381349

Ozone has a strong bactericidal power (oxidizing power), so it has a bactericidal effect and may affect the vegetables themselves. Therefore, when using ozone water for sterilization, the upper limit of ozone content in ozone water may be restrict | limited from a viewpoint of suppressing the influence on vegetables. Therefore, the characteristic of strong bactericidal power that ozone has is not fully utilized.

Also, when sterilization is performed using ozone water, the surface of vegetables is damaged by the strong sterilization power of ozone. Therefore, when preserving vegetables after sterilization, browning may easily occur in, for example, cut surfaces of vegetables. Moreover, the water | moisture content in vegetable cells may leak out (water separation) centering on a damaged part. In addition, the appetite of consumers may be averted by the occurrence of browning or water separation. Therefore, it is desired to suppress the occurrence of quality deterioration such as browning.

This invention is made | formed in view of the said subject, The subject which this invention tends to solve provides the production method of the sterilized vegetable which can suppress generation | occurrence | production of browning, fully utilizing the bactericidal power which ozone water has. There is to do.

As a result of intensive studies to solve the above problems, the present inventors have found the following findings. That is, the present invention provides a sterilization process in which a vegetable is brought into contact with ozone water to sterilize the vegetable in the sterilization apparatus, and a heat shock process in which heat shock processing is performed on the vegetables sterilized in the sterilization process in the heat shock apparatus. And a method for producing sterilized vegetables.

According to the present invention, it is possible to provide a method for producing sterilized vegetables that can suppress the occurrence of browning while making better use of the sterilizing power of ozone water than before.

It is a systematic diagram of the sterilization system of a 1st embodiment. It is a flowchart explaining the production method of the sterilized vegetable performed in the sterilization system of 1st Embodiment. It is a systematic diagram of the sterilization system of 2nd Embodiment. It is a systematic diagram of the sterilization system of 3rd Embodiment. It is a systematic diagram of the sterilization system of 4th Embodiment. It is a systematic diagram of the sterilization system of 5th Embodiment. It is a systematic diagram of the sterilization system of 6th Embodiment. It is a systematic diagram of the sterilization system of 7th Embodiment. It is a systematic diagram of the sterilization system of 8th Embodiment.

Hereinafter, a mode for carrying out the present invention (this embodiment) will be described with reference to the drawings as appropriate.

[1. First Embodiment]
FIG. 1 is a system diagram of a sterilization system 100 according to this embodiment. The sterilization system 100 includes a prewash tank 1, a sterilization tank 2, a warm water layer 3, and a rinse tank 4. Cut vegetables are processed in this order in each tank, and pasteurized cut vegetables are obtained. Any cut vegetables that can be sterilized by the sterilization system 100 may be used, but from the viewpoint that browning is particularly likely to occur, in this embodiment, sterilization is performed on leafy vegetables such as cabbage and lettuce. .

In addition, the sterilization system 100 includes a cooling device 5 and an ozone water preparation tank 6 for preparing ozone water supplied to the sterilization tank 2, a recovered ozone gas tank 7 for storing the recovered ozone gas, and a hot water circulation line. Are provided with a heating device 8 and a mixing device 9 for preparing the hot water circulated and a cooling device 10 for preparing the cold water supplied to the rinsing tank 4.

As the water supply source, tap water is used, and well water that has been sterilized, for example, is supplied to the sterilization system 100. The water supplied to the sterilization system 100 is supplied to the prewash tank 1 as it is, and after being cooled by the cooling device 5 and the cooling tank 10, is supplied to the ozone water preparation tank 6 and the rinsing tank 4. In addition, although not shown, a part of the supplied water is also supplied to the heating device 8, and after being heated, is supplied to the hot water tank 3 and flows through the hot water circulation line.

Moreover, as waste water, the water after being used in the pre-washing tank 1, the water after being used in the sterilization tank 2 and the dissolved ozone gas being recovered, and the water after being used in the rinsing tank 4 are appropriately treated as wastewater. And discharged to the outside. Although not shown, the hot water flowing through the hot water circulation line is discharged to the outside according to the degree of contamination.

In FIG. 1, main devices are illustrated, and various sensors such as a pump, a flow rate adjusting valve, a transport device, a flow meter and a thermometer used for feeding each liquid are illustrated for simplification of illustration. Not shown.

The pre-washing tank 1 performs pre-washing (hereinafter referred to as pre-washing) of cut vegetables, which are sterilization objects, before sterilization. That is, vegetables (cut vegetables) cut by a cutting device (not shown) are supplied to the prewash tank 1. Pre-washing is performed using water. In the prewash tank 1, mud, dust, etc. adhering to the cut vegetables are washed. Then, cut vegetables that are clean to some extent are supplied to the sterilization tank 2.

The sterilization tank 2 performs sterilization processing on cut vegetables from which dirt such as mud has been removed. Specifically, the sterilization treatment is performed by immersing (contacting) cold water (ozone water) in which ozone gas is dissolved in cut vegetables. The soaking time varies depending on the ozone content of ozone water, the mass of the cut vegetables, etc., but is, for example, about 0.2 to 15 minutes, preferably about 0.2 to 5 minutes.

The temperature of the ozone water is preferably about 4 ° C. to 20 ° C., for example, from the viewpoint of maintaining the freshness of the cut vegetables. However, the temperature of the ozone water may be, for example, about 20 ° C. to 40 ° C. close to normal temperature. Here, the amount of ozone gas dissolved in water increases as the temperature of water decreases. Therefore, by using ozone water in such a temperature range, the amount of ozone water dissolved can be increased, and a more powerful sterilization treatment can be performed.

In addition, the ozone gas content in the ozone water used is, for example, 1 mg / L to 30 mg / L. Therefore, in the ozone water preparation tank 6, ozone water is prepared so that the content of ozone gas falls within this range, for example. Here, when the cut vegetables are immersed in ozone water in the sterilization tank 2, ozone may be separated from the ozone water to generate ozone gas. Therefore, the ozone gas generated from the ozone water generated in the sterilization tank 2 is recovered in the recovery ozone gas tank 7.

The hot water tank 3 performs heat shock treatment on the vegetables sterilized in the sterilization tank 2. Moreover, in the hot water tank 3, cut vegetables are rinsed and the ozone water adhering in the sterilization tank 2 is removed. The cut vegetables are damaged by the sterilization treatment with ozone water in the sterilization tank 2. Therefore, in order to recover this damage, the heat shock treatment is performed by immersing the cut vegetables in warm water and changing the temperature of the cut vegetables. The soaking time varies depending on the mass of the cut vegetables, but is, for example, about several tens of seconds to several minutes.

The temperature of the hot water is preferably higher than the temperature of the ozone water from the viewpoint of performing an appropriate heat shock treatment on the cut vegetables. Specifically, the temperature of the hot water can be about 40 ° C. to 60 ° C., for example, and is preferably about 45 ° C. to 55 ° C.

Here, the advantages obtained by performing heat shock treatment after sterilization with ozone water will be described. From the viewpoint of energy saving, considering that the final cut vegetable product is stored at a low temperature, it is preferable to perform heat shock treatment first and then sterilize with cold ozone water. This sterilization treatment also serves as a cooling treatment for lowering the temperature of the cut vegetables raised by the heat shock treatment.

However, in this embodiment, as described above, first, sterilization with ozone water is performed, and then heat shock processing is performed. And although mentioned later for details, cooling is performed about the cut vegetables by which the heat shock process was carried out, and cut vegetables will be shipped as a product after cooling. According to a study by the present inventors on the reason why an excellent effect is obtained by performing the heat shock treatment after the sterilization treatment with ozone water, it is considered as follows.

By using ozone water, the strong sterilization power enables sufficient sterilization even in a short time or at a low temperature. In addition, since ozone becomes oxygen when it is decomposed, there is an advantage that there are few by-products and residues. However, since ozone has strong oxidizing power, the cut vegetable surface and cut surface are damaged as described above by bringing the cut vegetable into contact with ozone water.

However, by performing a heat shock treatment after that, wax components (such as pectin) that may exist on the surface of the cut vegetables are melted by heat and act to cover the damaged part. Thereby, the part which received the damage of cut vegetables recovers, and it is thought that the browning in the surface and cut surface as a biological defense reaction is suppressed. In addition, by changing the temperature of the cut vegetables by heat shock treatment, a change occurs in biosynthetic pathways such as proteins involved in browning in the cut vegetables, and this is considered to suppress browning.

Thus, by performing heat shock treatment after sterilization with ozone water, for example, browning of cut vegetables can be suppressed. Therefore, even when sterilized using ozone water having a stronger oxidizing power than that of the prior art, that is, ozone water having a high ozone content, browning can be suppressed because damage is recovered by the heat shock treatment. Therefore, sterilization using ozone water can be performed more sufficiently than before, and the strong sterilization power of ozone can be fully utilized. And since it can sterilize more reliably than before, the preservability of cut vegetables can be improved or the appearance, flavor, texture, etc. can be maintained well. This is an advantage that is particularly excellent in the case of leafy vegetables such as cabbage and lettuce, in which browning and leakage of nutrients are likely to occur at the portion rubbed against the inner wall of the apparatus during washing, in addition to the cut surface.

Furthermore, as a result of the study by the present inventors, it was found that even in vegetables damaged by ozone water, the vegetables absorb moisture by the heat shock treatment, and the vegetables are sharpened. It has also been found that it is difficult to brown. For this reason, it is considered that the heat shock treatment gives a firmness and improves the shelf life.

Further, as described above, ozone water has the advantage that there are few residues, and the sterilized cut vegetables do not have any sterilizing components. On the other hand, if the component which has bactericidal property does not remain, when a live microbe begins to proliferate after sterilizing cut vegetables, a proliferation rate will become quick. However, as in this embodiment, when sterilization was performed using ozone water with little residue, and then heat shock treatment was performed, it was found that the growth of viable bacteria in cut vegetables after heat shock was suppressed. . The reason for this is not clear, but according to the study by the present inventors, it is considered as follows.

The heat shock treatment performed in the present embodiment is not usually performed under conditions that can sufficiently exhibit sterilizing power. Therefore, rather than the sterilizing effect by heat shock treatment, it is considered that the washing out effect of viable bacteria (including bacteria entangled with waxy substances) by contacting with warm water is increased. Thereby, the number of viable bacteria remaining in the cut vegetables after the heat shock can be reduced, and it is considered that the time until the viable cell count reaches a predetermined reference value can be delayed after the cut vegetables are shipped. .

In addition, by contacting with warm water, substances that become nutrients for viable bacteria (such as cell fluids of vegetables leaking from cut surfaces and parts damaged by ozone water) can be removed from the surface of cut vegetables. Conceivable. Therefore, it is thought that the nutrient for viable bacteria to grow decreases, thereby effectively inhibiting the proliferation of viable bacteria.

Also, the hot water after washing the cut vegetables will contain bacterial cells. And this microbial cell does not die at the temperature and time normally used for a heat shock process as mentioned above. Therefore, in this embodiment, sterilization using ozone gas is performed on the hot water to be reused. In addition, it is conceivable that the used hot water is heated to, for example, 75 ° C. or more and treated for 1 minute or longer, or is removed using a filtration membrane having a pore size that bacteria cannot permeate (these points will be described later). And by using such sterilization and sterilization, it becomes possible to reuse the used hot water.

As described above, the hot water tank 3 performs heat shock treatment on the cut vegetables sterilized in the sterilization tank 2. And a heat shock process is performed by immersing a cut vegetable in warm water. Here, the sterilization treatment with ozone water and the heat shock treatment with warm water are usually performed continuously in a cut vegetable production factory or the like. In such a factory, in order to handle vegetables which are fresh food, the factory is often managed at a low temperature. Therefore, there may be no heat source in the factory, and enormous energy may be required for preparation of hot water. Here, it is also possible to collect the heat of the hot water discharged using the heat exchanger and reuse the heat. However, it is impossible to completely recover the heat, and the cost and maintenance of the heat exchanger are required.

Therefore, in the sterilization system 100, the hot water used for the heat shock treatment in the hot water tank 3 is not drained as it is after use but is used again. However, the hot water once used may contain viable bacteria that have not been completely killed in the sterilization tank 2. Therefore, the hot water discharged from the hot water tank 3 is sterilized by the mixing device 9 with ozone gas, and then reheated by the heating device 8 and supplied again to the hot water tank 3 as treated hot water. ing. It is preferable that the heating amount in the heating device 8 be equal to the amount of heat that decreases when the vegetable is immersed in the hot water tank 3. Thus, in the sterilization system 100, the hot water tank 3, the mixing device 9, and the heating device 8 form a hot water circulation line.

The sterilization treatment for the hot water discharged from the hot water tank 3 is performed using surplus ozone gas generated in the sterilization system 100. Specifically, surplus ozone gas that did not dissolve in cold water in the ozone water preparation tank 6, ozone gas generated from the ozone water used when processing cut vegetables in the sterilization tank 2, and exhausted from the sterilization tank 2 Dissolved ozone gas in used ozone water is used. That is, first, these ozone gases are recovered in the recovered ozone gas tank 7. Here, for example, the dissolved ozone gas can be recovered by diffusing air to the used ozone water using an air diffuser. And the used warm water is sterilized by the collected ozone gas contacting (mixing) the used warm water from the warm water tank 3 by the mixing device 9.

Conventionally, surplus ozone gas in the system and dissolved ozone gas in used ozone water have been decomposed using a catalyst or the like and then released into the atmosphere as oxygen gas. However, the production of ozone gas takes time and cost. In addition, some processing may be required for discharging to the outside, and labor and cost may be required. Therefore, it is preferable that the ozone gas produced with such labor and cost is consumed within the system as much as possible to reduce the emission amount as much as possible and avoid labor and cost. Therefore, in the sterilization system 100, sterilization of warm water discharged from the warm water tank 3 is performed using the collected ozone gas. Thereby, the manufactured ozone gas can be utilized without wasting it. In addition, heat loss and labor can be saved compared to using a heat exchanger for recovering heat from hot water as described above.

Further, according to the study by the present inventors, it has been found that the bactericidal effect by ozone is larger than the bactericidal effect on the bacterial cells adhering to the solid, compared to the bacterial cells present in the liquid. It was done. Therefore, even when the amount of ozone gas recovered in the system is small, it is possible to sufficiently sterilize the used hot water by bringing the recovered ozone gas into contact with the used hot water (specifically, aeration, etc.). it can. Thereby, warm water can be circulated and used repeatedly.

Returning to FIG. 1, the configuration of the sterilization system 100 will be continuously described.
The rinsing tank 4 performs rinsing with cold water on the cut vegetables that have been subjected to the heat shock treatment in the hot water tank 3. The rinsing tank 4 also cools the cut vegetables subjected to the heat shock treatment. Thereby, the temperature of cut vegetables is lowered. Thereafter, the cut vegetables are handled at a low temperature in order to proliferate viable bacteria and maintain the freshness of the cut vegetables. In addition, the rinse time in the rinse tank 4 is shortened by supplying the cut vegetables sterilized in the said sterilization tank 2 to the warm water tank 3 which also has a role as a rinse tank.

The cut vegetables cooled in the rinsing tank 4 are then dehydrated by a centrifugal dehydrator (not shown). Then, the dehydrated cut vegetables are packaged and stored as appropriate, and then shipped as sterilized vegetables.

FIG. 2 is a flowchart illustrating a method for producing sterilized vegetables, which is executed in the sterilization system 100 of the first embodiment. First, the uncut vegetables conveyed to the factory are cut by a cutting device (not shown) after the surface dirt is removed to become cut vegetables (step S1). And the sterilization is performed about the obtained cut vegetable using the sterilization system 100 shown in FIG.

First, the cut vegetables are prewashed in a prewash tank 1 (see FIG. 1, hereinafter the same in other apparatuses). This removes mud and dirt that could not be removed in the uncut state. Next, the pre-washed cut vegetables are sterilized with ozone water in the sterilization tank 2 (step S3, sterilization step). Thereby, the microbial cells adhering to the cut vegetable surface are sterilized. In particular, in the present embodiment, since the heat shock treatment using warm water is performed as described above, it is possible to sterilize using ozone water having a higher concentration than in the past, and more sufficient sterilization is possible.

The heat-shock process using warm water is performed in the warm water tank 3 with respect to the pasteurized cut vegetables (step S4, heat shock process). Thereby, the browning etc. which may arise with the said ozone water sterilization can be suppressed. After the heat shock treatment, the cut vegetables are rinsed with rinsing water in the rinsing tank 4 and cooled (step S5, cooling step). After cooling, the cut vegetables are packaged after centrifugal dehydration, stored as appropriate at a low temperature, and then shipped as a product (step S6).

Although not shown in FIG. 2, in the present embodiment, the used hot water used for the heat shock process in the hot water tank 3 is sterilized using the ozone gas collected in the system 100 (hot water Processing step). And the warm water obtained through the warm water treatment process is supplied to the warm water tank 3 again.

According to the above sterilization system 100, since the vegetables damaged by the heat shock treatment can be recovered, it is possible to sterilize using ozone water having a higher concentration than before. Therefore, it can sterilize more reliably than before, and the preservability and shelf life of sterilized vegetables are improved. Moreover, since browning etc. can be suppressed, an external appearance, a flavor, food texture, etc. can be maintained favorable.

[2. Second Embodiment]
Next, the sterilization system 200 of 2nd Embodiment is demonstrated, referring FIG. In the sterilization system 200, components similar to those of the sterilization system 100 are denoted by the same reference numerals, and detailed description thereof is omitted.

The sterilization system 100 was provided with the cooling device 5 for preparing the cold water supplied to the sterilization tank 2 and the cooling device 10 for preparing the cold water supplied to the rinse tank 4. Moreover, the heating apparatus 8 for maintaining the temperature of warm water was provided in the middle of the warm water circulation line. However, the sterilization system 200 is provided with the heat pump 11 in which the heat of the water supplied from the water supply source is supplied to the used hot water from the hot water tank 3 instead of being provided with these.

That is, in the sterilization system 200, the used hot water from the hot water tank 3 is supplied to the heat pump 11 provided in the middle of the hot water circulation line. And the hot water supplied to the heat pump 11 is heated using the heat | fever collect | recovered when cooling the water supplied from the water supply source to the temperature of cold water. The heated warm water is supplied again to the warm water tank 3 via a warm water circulation line (more specifically, a warm water supply line formed between the heat pump 11 and the warm water tank 3). As described above, by using the heat pump 11, cold water can be obtained without using the

cooling devices

5 and 10, and hot water can be obtained without using the heating device 8. Thereby, further energy saving can be achieved. In addition, it is used in the rinse tank 4 in order to cool the warmed vegetables brought in from the warm water tank 3 as a water supply source, and the cold water which temperature rose may be diverted, and reuse of rinse water may be aimed at.

[3. Third Embodiment]
Next, a sterilization system 300 according to the third embodiment will be described with reference to FIG. In the sterilization system 300, components similar to those of the

sterilization systems

100 and 200 are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, in FIG. 4, the modification with respect to the sterilization system 200 shown in FIG. 3 is shown.

In the

sterilization systems

100 and 200, the chilled water after ozone removal from the ozonic water discharged from the sterilizing tank 2 and the cold water discharged from the rinsing tank 4 were directly drained to the outside. However, the sterilization system 300 does not drain the cold water as it is, but uses the cold heat of the cold water. Specifically, the sterilization system 300 is provided with a heat exchanger 12 for cooling water supplied from a water supply source by the cold heat of the cold water.

That is, the cold water supplied to the rinse tank 4 after being cooled by the heat pump 11 and the ozone water prepared in the ozone water preparation tank 6 using the cold water are used in the sterilization tank 2 and the rinse tank 4. It is still sufficiently cold. Therefore, used ozone water and cold water are supplied to the heat exchanger 12 after the ozone contained therein is recovered as necessary. In the heat exchanger 12, the water supplied from the water supply source is cooled by the supplied cold water, and the cooled water is supplied to the heat pump 11 and the ozone water preparation tank 6.

That is, in the sterilization system 300, ozone water is prepared in the ozone water preparation tank 6 using water cooled by the heat exchanger 12 and the heat pump 11. The prepared ozone water is supplied to the sterilization tank 2 via an ozone water supply line connecting the ozone water preparation tank 6 and the sterilization tank 2. By doing in this way, the heat energy in the sterilization system 300 can be utilized more wastefully, and energy consumption can be reduced further.

[4. Fourth Embodiment]
Next, a sterilization system 400 according to the fourth embodiment will be described with reference to FIG. In the sterilization system 400, components similar to those of the sterilization systems 100 to 300 are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, in FIG. 5, the modification with respect to the sterilization system 300 shown in FIG. 4 is shown.

In the sterilization systems 100 to 300, the cut vegetables from the hot water tank 3 were rinsed and cooled in the rinse tank 4 with cold water. However, the sterilization system 400 includes an air cooling tank 13 that cools by air cooling rather than cooling by cold water.

That is, in the sterilization system 400, the rinsing tank 4 is not provided. The cold water obtained by the heat pump 11 is supplied only to the ozone water preparation tank 6 and is used only in the sterilization tank 2. On the other hand, the cut vegetables subjected to the heat shock process in the hot water tank 3 are cooled by air (cold air or the like) in the air cooling tank 13. Therefore, for example, when the sterilization system 400 is operated in a cool environment such as a plateau area or a winter period, the cut vegetables can be cooled by air having a relatively low temperature such as outside air without using cold water. Further, it is not necessary to supply cold water to the rinsing tank 4, and cold water may be supplied only to the sterilization tank 2. Therefore, a sufficient amount of cold water can be supplied to the sterilization tank 2 more reliably.

[5. Fifth Embodiment]
Next, the sterilization system 500 of the fifth embodiment will be described with reference to FIG. In the sterilization system 500, components similar to those in the sterilization systems 100 to 400 are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, in FIG. 6, the modification with respect to the sterilization system 100 shown in FIG. 1 is shown.

In the sterilization system 100, the ozone gas in the system was recovered, and the used hot water discharged from the hot water tank 3 was sterilized using the ozone gas. However, the sterilization system 500 shown in FIG. 6 includes a heat sterilization apparatus 14 (hot water treatment apparatus) that heats and sterilizes used hot water. And the heat sterilizer 14 fully heats and sterilizes a part or all of used hot water, and the hot water after the sterilization is supplied to the hot water tank 3 again.

The heating temperature in the heat sterilizer 14 is, for example, 60 ° C. to 150 ° C. Further, although the heating time varies depending on the heating temperature, the residence time in the heat sterilizer 14 can be set to, for example, 1 second to 30 minutes. Heating in the heat sterilizer 14 can be performed using a heat exchanger using steam or hot water as a heating source. Further, heating with an electric heater, microwave heating, and dielectric heating can also be applied.

Since the heat sterilization device 14 is provided, the hot water supplied to the heating device 8 has a sufficiently high temperature. Therefore, the amount of heat given by the heating device 8 can be reduced. In addition, when warm water having a sufficiently high temperature can be supplied to the hot water tank 3 without heating in the heating device 8, the installation of the heating device 8 can be omitted. Accordingly, the provision of the heat sterilization apparatus 14 enables sterilization of used hot water, and supplies hot water at an appropriate temperature to the hot water tank 3 without performing new heating (or reducing the amount of supplied heat). can do.

[6. Sixth Embodiment]
Next, the sterilization system 600 according to the sixth embodiment will be described with reference to FIG. In the sterilization system 600, components similar to those in the sterilization systems 100 to 500 are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, in FIG. 7, the modification with respect to the sterilization system 500 shown in FIG. 6 is shown.

In the sterilization system 500, the heat sterilizer 14 for sterilizing used hot water was provided. However, the sterilization system 600 shown in FIG. 7 includes a filtration device 15 (hot water treatment device) that filters and removes bacterial cells (including both live and dead bacteria) and contaminants from used hot water. . As a result, the used hot water is filtered to remove the bacterial cells and contaminants and becomes a filtrate. And after this filtrate is heated with the heating apparatus 8, it is supplied to the hot water tank 3 again. On the other hand, the water that has not been permeated by the filtration device 15 is drained to the outside via a pipe or the like (not shown).

The filtration device 15 includes, for example, a filtration membrane. Specifically, although not shown, the filtration device 15 is configured to include a water tank for storing used hot water from the hot water tank 3, a filtration unit including a filtration membrane and a housing, and the like. Yes. In addition, you may make it provide several filtration membranes from which a hole diameter differs as needed. The filtration device 15 is also provided with a pipe connecting the water tank and the filtration unit, a water supply pump for sending used hot water to the filtration unit, a flow meter for measuring the amount of water supply, a pressure gauge for measuring the water supply pressure, etc. Configured.

As the filtration membrane to be used, for example, a microfiltration membrane, an ultrafiltration membrane, or a reverse osmosis membrane can be applied. Further, the pore diameter of the filtration membrane is preferably 0.1 μm or less when, for example, a microfiltration membrane is used. Either a dead-end filtration method or a cross-flow filtration method may be selected as the filtration method. In the case of the cross-flow filtration method, a circulation line that connects a part of the supply liquid that has not been filtered by the filtration unit to the water tank. Is built.

By providing the filtration device 15, it is possible to sterilize used hot water and remove impurities. Therefore, clearer warm water can be supplied to the warm water tank 3.

[7. Seventh Embodiment]
Next, the sterilization system 700 according to the seventh embodiment will be described with reference to FIG. In the sterilization system 700, components similar to those of the sterilization systems 100 to 600 are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, in FIG. 8, the modification with respect to the sterilization system 500 shown in FIG. 6 is shown.

In the sterilization system 500, the heat sterilizer 14 for sterilizing used hot water was provided. However, the sterilization system 700 shown in FIG. 8 includes an ultraviolet sterilizer 16 (hot water treatment apparatus) that sterilizes using ultraviolet rays. Thereby, the used warm water from the warm water tank 3 is sterilized by irradiating with ultraviolet rays. The sterilized warm water is heated by the heating device 8 and then supplied to the warm water tank 3 again.

In the ultraviolet irradiation device 16, for example, light having a wavelength of 253.7 nm is irradiated to the used hot water. By this ultraviolet light, the DNA of live bacteria in warm water is cut and sterilized.

The provision of the ultraviolet irradiation device 16 enables efficient sterilization even if the amount of used hot water to be processed is large.

[8. Eighth Embodiment]
Next, the sterilization system 800 of the eighth embodiment will be described with reference to FIG. In the sterilization system 800, components similar to those in the sterilization systems 100 to 700 are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, in FIG. 9, the modification with respect to the sterilization system 500 shown in FIG. 6 is shown.

In the sterilization system 500, the heat sterilizer 14 for sterilizing used hot water was provided. However, the sterilization system 800 shown in FIG. 9 includes a chemical sterilization apparatus 17 (hot water treatment apparatus) that sterilizes used hot water using a chemical. A medicine tank 18 is connected to the medicine sterilization apparatus 17, and a medicine stored in the medicine tank 18 is added to the medicine sterilization tank 17. Thereby, the used warm water from the warm water tank 3 is sterilized, and the sterilized warm water is heated by the heating device 8 and then supplied to the warm water tank 3 again.

Examples of the agent to be added include hydrogen peroxide solution, ethanol, peracetic acid solution, and the like. These may be appropriately mixed and used. Moreover, when using a peracetic acid solution as a chemical | medical agent, it is preferable that the warm water after the added peracetic acid solution is removed is supplied to the warm water tank 3, for example.

By providing the chemical sterilization apparatus 17, a more reliable sterilization treatment can be performed on a larger amount of used hot water.

Although not shown, after sterilization by the chemical sterilization apparatus 17, the sterilized warm water can be irradiated with ultraviolet rays. By doing in this way, the unreacted chemical | medical agent is activated by ultraviolet irradiation. Therefore, the bactericidal action on live bacteria is promoted, and more powerful sterilization can be performed.

Although not shown in the figure, the sterilized hot water can be heated after sterilization by the chemical sterilization apparatus 17. By doing in this way, like the said ultraviolet irradiation, a chemical | medical agent is activated by heating and more powerful disinfection can be performed. Furthermore, when the added chemical | medical agent is volatile, the unreacted chemical | medical agent in warm water can be vaporized by heating, and the residual chemical | medical agent of the warm water supplied to the warm water tank 3 can be reduced easily.

[9. Modified example]
Although the present embodiment has been specifically described with reference to the eight embodiments, the present embodiment is not limited to the above example. That is, the present invention can be implemented by appropriately modifying the above-described embodiments and by appropriately combining the above-described embodiments.

For example, in the first to fourth embodiments, three of the ozone gas from the ozone water preparation tank 6, the ozone gas generated in the sterilization tank 2, and the ozone gas in the ozone water discharged from the sterilization tank 2 are recovered. However, any one or two ozone gases may be recovered. That is, these ozone gases correspond to the ozone gas recovered from the ozone water used for sterilization in the sterilization tank 2. In addition to these, any ozone gas may be recovered as long as it is an ozone gas recovered from ozone water used for sterilization in the sterilization tank 2.

Furthermore, in the ozone water preparation tank 6, ozone gas is supplied to cold water to prepare ozone gas, but the method of preparing ozone water is not limited to this. Therefore, ozone water may be prepared, for example, by a so-called electrolytic ozone water system. The electrolytic ozone water system is a system in which ozone water is generated directly from water by causing an electrode to act on the water in the ozone water preparation tank 6. In this case, the surplus ozone gas from the generated ozone water is negligibly small, and the surplus gas that is the exhaust gas from the sterilization tank 2 and the ozone gas from the effluent may be recovered in the recovery ozone gas tank 7.

Further, as a method for sterilizing the used hot water from the hot water tank 3, in the first to fourth embodiments, ozone gas is mixed by the mixing device 9. Furthermore, the heat sterilizer 14 is used in the fifth embodiment, the filter device 15 is used in the sixth embodiment, the ultraviolet sterilizer 16 is used in the seventh embodiment, and the drug sterilizer 17 is used in the eighth embodiment. Accordingly, each of these devices is a hot water treatment device that sterilizes or sterilizes used hot water. However, the hot water treatment apparatus is not limited to these, and is an apparatus that can obtain used hot water (ie, treated hot water) that has been sterilized by performing at least one of sterilization and sterilization on the used hot water. Anything is acceptable.

Furthermore, a part of the ozone water prepared in the ozone water preparation tank 6 may be supplied to the mixing device 9. In this case, it can be considered that a part of the ozone gas dissolved in the ozone water in the ozone water preparation tank 6 is in contact with the hot water circulating in the hot water circulation line in the mixing device 9. That is, ozone water (including dissolved ozone gas) used to sterilize vegetables in the sterilization tank 2 is sent to the mixing device 9 by a liquid feed pump (ozone gas recovery device) that sends (recovers) ozone water. As a result, the ozone gas in the ozone water comes into contact with the hot water.

Moreover, in the sterilization tank 2, the usage form of ozone water when sterilizing vegetables using ozone water is not limited to the above immersion. That is, for example, sterilization of vegetables may be performed by spraying ozone water on vegetables. Similarly, the heat shock in the hot water tank 3 is not limited to the form in which the vegetable is immersed in the hot water. For example, the heat shock process may be performed on the vegetable by spraying the hot water on the vegetable. Similarly, the form of sterilization of hot water in the mixing device 9 is not limited to the mixing as described above, and any form may be used as long as the recovered ozone gas can be sterilized by contacting with circulating hot water.

The cooling method in the rinsing tank 4 is the same, and the form in which the cold water is brought into contact is not limited to the method of immersing in the cold water, and examples thereof include a method of spraying cold water. Furthermore, ozone water supplied from the outside may be used instead of providing the ozone water preparation tank 6.

Furthermore, in the above-described embodiment, the recovery ozone gas tank 7 is provided as the ozone gas recovery device. However, as long as the device can recover ozone gas, it is not limited to the form of the tank. Further, an apparatus necessary for recovering ozone gas can be provided as appropriate.

For example, in the above-described embodiment, the pre-washing tank 1 and the rinsing tank 4 are provided, but these devices may not be provided. Furthermore, in the said embodiment, the cold water supplied to the ozone water preparation tank 6 and the cold water supplied to the rinse tank 4 are prepared with the

separate cooling devices

5 and 10. FIG. However, these may be combined into one and the cold water adjusted by one cooling device may be branched and supplied to them. Moreover, in the said embodiment, the waste_water | drain from the prewash tank 1, the sterilization tank 2, and the rinse tank 4 is discharge | released outside, after recovering cold heat as needed. However, this water may be returned to the water supply source and reused.

Furthermore, the vegetables to be sterilized are not limited to cut vegetables, and may be uncut vegetables.

2 Sterilization tank (sterilization equipment)
3 Hot water tank (heat shock device)
4 Rinse tank (cooling device)
6 Ozone water preparation tank 7 Recovery ozone gas tank 9 Mixing device (hot water treatment device)
11 Heat pump 12 Heat exchanger 14 Heat sterilizer (hot water treatment device)
15 Filtration equipment (hot water treatment equipment)
16 UV sterilizer (hot water treatment equipment)
17 Drug mixing device (hot water treatment device)
18 Chemical tank 100 Sterilization system 200 Sterilization system 300 Sterilization system 400 Sterilization system 500 Sterilization system 600 Sterilization system 700 Sterilization system 800 Sterilization system

Claims

In a sterilizer, a sterilization step of sterilizing vegetables by bringing the vegetables into contact with ozone water;
A heat shock device, comprising: a heat shock process for performing a heat shock process on the sterilized vegetables in the sterilization process.
The method for producing sterilized vegetables according to claim 1, wherein the heat shock treatment is performed by bringing warm water into contact with the vegetables in the heat shock device.
The pasteurized vegetable according to claim 1 or 2, comprising a cooling step of cooling the vegetable that has been subjected to heat shock processing in the heat shock step using a cooling device. Production method.
The method for producing sterilized vegetables according to claim 1 or 2, wherein the vegetables are leafy vegetables.
The production of pasteurized vegetables according to claim 1 or 2, characterized by including a warm water treatment step of sterilizing used warm water discharged from the heat shock device using a warm water treatment device. Method.