JP2017212901A - Vegetable sterilization method and cut vegetable producing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vegetable sterilization method that sufficiently sterilizes vegetables while suppressing ozone concentration in environment.SOLUTION: A vegetable sterilization method includes a sterilization step of sterilizing cut vegetables by sterilization liquid containing microbubble ozone water of which dissolved ozone concentration is 0.1 mg/L or more and 0.5 mg/L or less.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vegetable sterilization method and a cut vegetable manufacturing method.

  As a conventional sterilizing method for cut vegetables, hypochlorite is generally used as a sterilizing agent, but a method of sterilizing with ozone water in consideration of damage to leafy vegetables has been proposed. Patent Document 1 discloses that a leaf-like vegetable in a hole state is cut, shredded, washed with fresh water, and then sterilized with ozone water.

JP 2006-333732 A

However, the following problems exist in the conventional technology as described above.
Since ozone water has a low sterilizing effect on vegetables, a concentration of several mg / L is required, which causes a problem that the ozone concentration in the environment is high.

  The present invention has been made in consideration of the above points, and an object of the present invention is to provide a vegetable sterilization method and a cut vegetable manufacturing method that can sufficiently sterilize vegetables while suppressing the ozone concentration in the environment.

  According to the first aspect of the present invention, it includes a sterilization step of sterilizing the cut vegetables with a sterilization solution containing microbubble ozone water having a dissolved ozone concentration of 0.1 mg / L or more and 0.5 mg / L or less. The vegetable sterilization method characterized by this is provided.

  In the vegetable sterilization method according to one embodiment of the present invention, the sterilizing liquid contains a surfactant.

  The vegetable sterilization method according to one aspect of the present invention includes a step of pre-washing the vegetable before the sterilization step.

  Moreover, in the vegetable sterilization method according to one aspect of the present invention, measuring the dissolved ozone concentration in the sterilizing solution, adjusting the dissolved ozone concentration in the sterilizing solution according to the measured dissolved ozone concentration, It is characterized by including.

  The vegetable sterilization method according to one aspect of the present invention is characterized in that the sterilization treatment of the vegetable is stopped when the dissolved ozone concentration in the sterilizing solution falls below a predetermined lower limit value.

  In the vegetable sterilization method according to one embodiment of the present invention, the vegetable is sterilized with the sterilizing liquid having a chemical oxygen demand of 300 mg / L or less.

Moreover, in the vegetable sterilization method according to one aspect of the present invention, the vegetable having a chemical oxygen demand measured by the following chemical oxygen demand measurement method for vegetables of 100 mg / L or less is added to the sterilization solution. It is characterized by.
Chemical oxygen demand measurement method of vegetables 720g of vegetable as a measurement sample is put in a pre-cleaning part containing 20L of tap water at 15 ° C and stirred for 90 seconds, and then 50mL of the cleaning solution is collected and filtered with a 450nm membrane filter. About the washing | cleaning liquid obtained by filtration, 17. JIS K0102 (2013 version) factory waste water test method. The chemical oxygen demand is measured based on the oxygen consumption by potassium permanganate at 100 ° C.

  According to the second aspect of the present invention, the step of primary sterilization of the vegetable before cutting, the step of removing foreign matter adhering to the primary sterilized vegetable, and the vegetable from which the foreign matter has been removed to a predetermined size A step of cutting, and a step of secondary sterilizing the cut vegetables with a sterilizing solution containing microbubble ozone water having a dissolved ozone concentration of 0.1 mg / L or more and 0.5 mg / L or less. A cut vegetable manufacturing method is provided.

  In this invention, the vegetable sterilization method and cut vegetable manufacturing method which can fully sterilize vegetables can be provided, suppressing the ozone concentration in environment.

It is a figure which shows embodiment of this invention, Comprising: It is a top view which shows schematic structure of the vegetable sterilizer 1. FIG. It is a front view which shows schematic structure of the vegetable sterilizer 1. FIG. It is a figure which shows typically the circulation system of the sterilization liquid in the sterilization part.

  Hereinafter, embodiments of the vegetable sterilization method and cut vegetable production method of the present invention will be described with reference to FIGS. 1 to 3. The following embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each configuration easy to understand, the actual structure is different from the scale and number of each structure.

  FIG. 1 is a plan view showing a schematic configuration of the vegetable sterilizer 1, and FIG. 2 is a partial front view showing a schematic configuration of the vegetable sterilizer 1. The vegetable sterilizer 1 includes an input table 100, two pre-cleaning units 110A and 110B, a sterilizing unit 120, two rinsing units 130A and 130B, a discharge unit 140, and an ozone exhaust system 160. The loading table 100, the pre-cleaning units 110A and 110B, the sterilizing unit 120, the rinsing units 130A and 130B, and the discharging unit 140 are arranged in the processing order (upstream side (right side of the drawing in FIG. 1)) It is arranged linearly on the downstream side (the left side of the drawing in FIG. 1) at the discharge portion 140).

  The pre-cleaning units 110A and 110B are areas for pre-cleaning the vegetables V before being sterilized by the sterilizing unit 120. The sterilizing unit 120 is an area for sterilizing the vegetable V pre-cleaned by the pre-cleaning units 110A and 110B using microbubble ozone water. The rinsing units 130A and 130B are areas in which the vegetables V sterilized by the sterilizing unit 120 are rinsed to wash out ozone (ozone water).

  The pre-cleaning unit 110A removes foreign matter from the plurality of nozzles 112A that inject the pre-cleaning water, the storage unit 113A that stores the pre-cleaning water that has overflowed in the pre-cleaning unit 110A, and the pre-cleaning water that flows into the storage unit 113A. A filter 111A is provided. The prewash water circulates in the prewash unit 110A, and a part of the prewash water that has overflowed is stored in the reservoir 113A and then sprayed from the nozzle 112A and reused for prewashing the vegetables V. A portion of the prewash water that has overflowed is drained and water is replenished through the water supply pipe 76. The pre-cleaning unit 110A holds the vegetables V put in the pre-cleaning water while the pre-cleaning is being performed, and when the pre-cleaning process is completed, as shown in FIG. It has a bucket 4 that rotates around and throws the vegetables V into the downstream tank. In FIG. 2, the bucket 4 provided in the rinse part 130B is illustrated. The bucket 4 is formed of, for example, a stainless material having a plurality of through holes, and pre-wash water can be distributed. In addition, since the same thing is installed in the pre-cleaning part 110B, the sterilization part 120, and the rinse parts 130A and 130B, the bucket 4 abbreviate | omits description below.

  The pre-cleaning unit 110B removes foreign substances from the plurality of nozzles 112B that inject the pre-cleaning water, the storage unit 113B that stores the pre-cleaning water that has overflowed in the pre-cleaning unit 110B, and the pre-cleaning water that flows into the storage unit 113B. A filter 111B is provided. The prewash water is circulated in the prewash section 110B, and a part of the prewash water that has overflowed is stored in the storage section 113B and then sprayed from the nozzle 112B and reused for prewashing the vegetables V. A portion of the prewash water that has overflowed is drained and water is replenished through the water supply pipe 76.

  The rinsing unit 130A includes a plurality of nozzles 132A for injecting rinsing water, a storage unit 133A for storing rinsing water overflowed in the rinsing unit 130A, and a filter 131A for removing foreign substances from the rinsing water flowing into the storage unit 133A. Yes. Rinsing water circulates in the rinsing section 130A, and a part of the overflowing rinsing water is sprayed from the nozzle 132A after being stored in the storage section 133A and reused for rinsing the vegetables V. A portion of the rinse water that has overflowed is drained, and clean water is replenished by the water supply pipe 76.

  The rinsing unit 130B includes a plurality of nozzles 132B that inject rinsing water, a storage unit 133B that stores rinsing water that has overflowed in the rinsing unit 130B, and a filter 131B that removes foreign substances from the rinsing water flowing into the storage unit 133B. Yes. The rinsing water circulates in the rinsing section 130B, and a part of the overflowing rinsing water is sprayed from the nozzle 132B after being stored in the storage section 133B and reused for rinsing the vegetables V. A portion of the rinse water that has overflowed is drained, and clean water is replenished by the water supply pipe 76.

  The sterilization unit 120 includes a plurality of nozzles 122 that inject sterilization liquid, a storage unit 123 that stores the sterilization liquid overflowed by the sterilization unit 120, and a filter 121 that removes foreign substances from the sterilization liquid flowing into the storage unit 123. ing. As the sterilizing liquid, a liquid containing microbubble ozone water is used. The sterilizing liquid circulates in the sterilizing unit 120, and a part of the overflowed sterilizing liquid is sprayed from the nozzle 122 after being stored in the storage unit 123 and reused for sterilizing the vegetables V. A part of the overflowing sterilizing liquid is drained and water is replenished by the water supply pipe 76.

FIG. 3 is a diagram schematically showing a sterilizing liquid circulation system in the sterilizing unit 120.
As shown in FIG. 3, the drainage pipe 11 and the liquid introduction pipe 12 are connected to the bottom of the sterilization tank 124 in the sterilization unit 120. The liquid guide pipe 12 is branched from the drain pipe 11. A pump 13 and an ejector 18 are connected to the liquid guide pipe 12. A branch pipe 17 is connected between the pump 13 and the ejector 18 in the liquid guide pipe 12. An ozone concentration sensor 14 is connected to the branch pipe 17. The ozone concentration sensor 14 measures the dissolved ozone concentration of the sterilizing liquid flowing through the branch pipe 17 and outputs the measurement result to the concentration adjusting unit 16. An ozone supply unit 15 is connected to the ejector 18. The concentration adjusting unit 16 adjusts the ozone supply by the ozone supplying unit 15 as described later according to the dissolved ozone concentration of the sterilizing solution measured by the ozone concentration sensor 14.

  The pump 13 sends a part of the sterilizing liquid drained from the drainage pipe 11 toward the sterilizing tank 124. The ozone concentration sensor 14 measures the dissolved ozone concentration in the sterilizing liquid sent to the sterilizing tank 124 and outputs the measured concentration to the concentration adjusting unit 16. The sterilizing liquid sent to the sterilizing tank 124 includes ozone dispersed as bubbles (microbubbles) in the sterilizing liquid in addition to ozone dissolved in the sterilizing liquid. The dissolved ozone concentration in the sterilizing solution can be measured using a polarographic dissolved ozone concentration meter as described later. In that case, for example, it is possible to take out a part of the liquid feeding tank 12 and take out a part of the liquid fed into the liquid feeding bowl 12 and guide it to the sensor unit of the dissolved ozone concentration meter.

  For example, the ozone supply unit 15 introduces an aqueous solution containing a chemical that assists the generation and dispersion of fine bubbles into the ozone gas generated by the ozone gas generator via the ejector 18, and guides it as a mixed phase flow of ozone gas and the aqueous solution. Supply to the liquid pipe 12. Supply of ozone gas and medicine by the ozone supply unit 15 is adjusted by the concentration adjustment unit 16. The concentration adjustment unit 16 adjusts the operation of the ozone supply unit 15 so that the dissolved ozone concentration in the sterilizing solution measured by the ozone concentration sensor 14 is within a predetermined range. Specifically, the concentration adjusting unit 16 adjusts the operation of the ozone supply unit 15 so that the dissolved ozone concentration of the sterilizing liquid is 0.1 mg / L or more and 0.5 mg / L or less. The concentration adjustment unit 16 switches the operation of the ozone gas generator on or off as the operation adjustment of the ozone supply unit 15. Microbubble ozone water in which ozone gas is dissolved and dispersed in water as fine bubbles (microbubbles) by supplying ozone gas and chemicals to the sterilization tank 124 through the liquid introduction pipe 12 by the operation of the ozone supply unit 15. Can be supplied to the sterilization liquid in the sterilization tank 124. Moreover, by installing the liquid introduction tank 12 at the bottom of the sterilization tank 124, leakage of ozone into the environment can be further prevented, and the ozone concentration in the environment can be suppressed.

As the drug, a surfactant can be used, and for example, triacetin, fatty acid glycerin (for example, polysorbate, monocaprylylline) and the like can be preferably used.
Microbubbles are fine bubbles having a bubble diameter of 10 to 200 μm, and microbubble water refers to water in which microbubbles are dispersed in water.
The microbubble ozone water refers to water in which ozone gas containing about 2 to 40 g / Nm ^{3 of} ozone in oxygen or air is dispersed in water as microbubbles. In microbubble ozone water, ozone gas is partly dissolved in water and partly dispersed as microbubbles.

  The discharge unit 140 includes a container 141, from which the vegetables V that have been sterilized and washed (rinsing process) are collected.

  The ozone exhaust system 160 includes an exhaust pipe 161, a filter unit 162, and an exhaust pump 163. The exhaust pipe 161 has an exhaust port 161A. The exhaust port 161 </ b> A is locally provided above the filter 121 in the sterilization unit 120, that is, above the inflow port to the storage unit 123.

  Next, a method for cleaning and sterilizing the vegetables V using the vegetable sterilizer 1 having the above-described configuration will be described. For example, the vegetables V cut to the eating size are put into the bucket 4 in the pre-cleaning unit 110A from the loading table 100. In the pre-cleaning unit 110A, the pre-clean water in the bucket 4 can be fluidized with a large fluid force by the pre-clean water sprayed from the spray nozzle 112A, and the vegetables V can be stirred with a large stirring force.

  After the vegetable V that has been pre-cleaned for a predetermined time in the pre-cleaning unit 110A is put into the pre-cleaning unit 110B by the rotation of the bucket 4 and pre-cleaning for a predetermined time is performed in the same manner as the pre-cleaning unit 110A, The sterilization unit 120 is charged. The amount and time of pre-cleaning water when pre-cleaning is performed in the pre-cleaning units 110A and 110B are as follows. ) "Is set based on the COD (chemical oxygen demand) measured. If the pre-cleaning is not sufficient, the amount of organic matter such as lye that exudes from the vegetable V put into the sterilization unit 120 increases, and the “vegetable COD” increases. In this case, ozone contained in the sterilizing liquid is consumed in the reaction with organic substances such as lye so that the predetermined dissolved ozone concentration cannot be satisfied and the vegetables V cannot be sufficiently sterilized. In particular, when the vegetable V is continuously charged, sterilized, and discharged in one sterilization tank as in the present embodiment, organic substances such as lye are accumulated in the sterilization liquid in the sterilization tank. It is necessary to increase the replenishment amount of drinking water and replace a part of the sterilizing liquid, or temporarily stop the sterilizing process and replace the sterilizing liquid in the sterilizing tank. This causes waste of chemicals and sterilizing solutions that supplement the generation and dispersion of microbubble ozone introduced into the inside. Therefore, the amount and time of the pre-cleaning water when the pre-cleaning is performed in the pre-cleaning units 110A and 110B can be determined according to the “vegetable COD” of the vegetable V after the pre-cleaning process is finished, but the lower it is, Preferably, it is preferably set to 300 mg / L or less, and more preferably 100 mg / L or less when sterilizing continuously.

In the sterilizing unit 120, the vegetables V are sterilized with a sterilizing liquid containing microbubble ozone water. At the time of sterilization of the vegetables V, ozone contained in the sterilization liquid is consumed by reaction with organic substances such as fungi and lye from the vegetables, and the dissolved ozone concentration decreases. The concentration adjusting unit 16 has an upper limit (for example, 0.4 mg / L) and a lower limit (for example, 0) corresponding to a dissolved ozone concentration of 0.1 mg / L or more and 0.5 mg / L or less to be maintained in the sterilizing solution. .2 mg / L). Then, when the dissolved ozone concentration measured by the ozone concentration sensor 14 falls below the lower limit value, the concentration adjusting unit 16 turns on the operation of the ozone gas generator and supplies microbubble ozone water to the sterilization tank 124. On the other hand, when the dissolved ozone concentration measured by the ozone concentration sensor 14 exceeds the upper limit value, the concentration adjusting unit 16 turns off the operation of the ozone gas generator and stops the supply of the microbubble ozone water to the sterilization tank 124. In this way, the concentration adjusting unit 16 adjusts the operation of the ozone supply unit 15 according to the dissolved ozone concentration measured by the ozone concentration sensor 14, thereby setting the dissolved ozone concentration of the sterilizing liquid in the sterilizing unit 120 to a predetermined range (0). .1 mg / L or more and 0.5 mg / L or less).
When sterilization is repeated in one sterilization tank, organic matter such as lye accumulates and reacts with ozone to be consumed to consume ozone. Therefore, it may be difficult to keep the dissolved ozone concentration within the predetermined range. Therefore, the COD of the sterilizing liquid in the sterilizing tank is preferably low, and is appropriately determined according to the purpose. However, in order to stably maintain the dissolved ozone concentration, the COD of the sterilizing liquid is preferably 100 mg / L or less. .

  In the sterilizing unit 120, the sterilized vegetables V are sequentially put into the rinsing units 130A and 130B, respectively, and after sterilizing with a sterilizing solution by rinsing water to be cleaned, they are transported to the discharging unit 140. The

<Evaluation method, measurement method>
(Measurement method of COD)
(1) Vegetable COD (vegetable washing degree COD)
720 g of vegetables as a measurement sample was placed in a pre-cleaning part containing 20 L of tap water at 15 ° C. and stirred for 90 seconds for washing. 50 mL of the washing solution was collected and filtered through a 450 nm membrane filter. About this cleaning liquid, 17. JIS K0102 (2013 edition) factory drainage test method. The COD was measured based on the oxygen consumption by potassium permanganate at 100 ° C.
(2) COD of sterilized water in sterilization tank
50 mL of sterilized water in the sterilization tank was collected and filtered through a 450 nm membrane filter. About this disinfectant, 17. JIS K0102 (2013 edition) factory drainage test method. The COD was measured based on the oxygen consumption by potassium permanganate at 100 ° C.

(Method for measuring the number of bacteria in vegetables)
25 g of vegetables were weighed into a sterilized homogenization bag, 225 g of sterilized physiological saline was added, and treated with an ELMEX homogenizer (SH-IIM) to obtain a bacterial solution. Dispense 1 mL of a bacterial solution appropriately diluted with sterilized physiological saline into a sterilized disposable dish, mix with a standard agar medium sterilized at 121 ° C. and 1.4 atm for 25 minutes, and mix at 48 ° C. at 37 ° C. Incubate for hours. Colonies cultured in the petri dish were counted in the range of 30 to 300, and multiplied by the dilution factor to obtain the viable cell count.

≪Evaluation criteria≫
The number of general viable bacteria in vegetables that had not been sterilized was measured and used as the number of untreated bacteria. The difference between the number of general viable bacteria and untreated sterilized vegetables was defined as “vegetable sterilization effect”. About the bactericidal effect of vegetables, the number of living bacteria obtained by the measuring method of the number of bacteria of vegetables was described by the logarithmic value, and it was set as 1.5 digits or more.

(Method for measuring the number of bacteria in the sterilizing cleaning solution)
4.5 mL of the cleaning solution was collected from the sterilization tank into a sterilized tube containing 0.5 mL of 0.1N sodium thiosulfate and mixed. 1 ml of this bacterial solution was dispensed into a sterilized disposable dish, mixed with a standard agar medium sterilized at 121 ° C. and 1.4 atm for 25 minutes, and cultured at 37 ° C. for 48 hours. Colonies cultured in the petri dish were counted in the range of 30 to 300, and multiplied by the dilution factor to obtain the viable cell count.

≪Evaluation criteria≫
Regarding the bactericidal effect in the bactericidal solution, those in which the number of general viable bacteria obtained by the method for measuring the number of bacteria in the bactericidal washing solution was not detected were described as “ND” and passed.

(Vegetable sterilization test method using microbubble ozone)
(1) Pre-cleaning In Experimental Example 1, each part was cleaned for 90 seconds in two tanks according to the conditions and conditions shown in the table below (that is, cleaning was performed twice in total).
In Experimental Example 2, 720 g of shredded cabbage was pre-washed (20 times) with 20 L of tap water for 90 seconds. I gave this to a colander and drained the water.
(2) Ozone sterilization The pre-cleaned shredded cabbage was sterilized with microbubble ozone water for 90 seconds. Each of Experimental Examples 1 and 2 was performed under the conditions shown in the table below. Ozone gas was introduced from an ejector into an aqueous solution containing 0.05% by weight of a surfactant. The ozone gas source gas to be introduced was oxygen gas in an oxygen cylinder. Ozone gas is generated with an ozone generator (OZSD-3000A manufactured by Sugawara Jitsugyo), and the flow rate of oxygen gas containing ozone gas with an ozone gas concentration of 10-21.4 g / Nm ³ is measured with an ozone gas monitor (EG-600 manufactured by Ebara Jitsugyo) 0.4- 4 L / min was measured with a mass flow controller (MODEL 8500 manufactured by Cofrock). The concentration of ozone water dissolved in the sterilizing solution was measured with a polarographic dissolved ozone concentration meter (ELP-200 manufactured by Sugawara Jitsugyo). The sterilized vegetables were rinsed with tap water for 90 seconds, and after dehydration, the number of viable bacteria of general bacteria was measured by the method for measuring the number of bacteria in the vegetables and the sterilization washing liquid.

(Disinfection with ozone water: Experimental example 2)
Ozone water with a predetermined concentration was produced with a direct electrolysis type ozone water production apparatus (production of ozone water by electrolysis, manufactured by Kobe Steel). It was supplied with a metering pump.

(Details of dissolved ozone concentration measurement method)
The dissolved ozone concentration was measured using a polarographic dissolved ozone concentration meter (ELP-200 manufactured by Sugawara Jitsugyo). In the measurement method, a constant amount of water was passed through a flow cell provided with an ozone sensor in a range of a specified amount of water (0.5 to 1.0 L / min) with a tube pump and a regulating valve. The dissolved ozone concentration was confirmed on the data display part of the monitor (Experimental Example 2). In the case of Experimental Example 1 described later, the circulation pipe of the sterilization liquid circulation pump of the sterilization tank was branched, and the sterilization liquid flowing through the branch pipe was adjusted in flow rate with an adjustment valve and flowed through the flow cell.

(Experimental Examples 1-1 to 1-4)
Experiments were conducted on microbubble ozone sterilization experiments on cut vegetables and the amount of ozone in the working environment during ozone sterilization.
<Experiment method>
(1) Pre-cleaning method for cut vegetables A predetermined amount of cut vegetables is put into the pre-cleaning section and stirred for 90 seconds. This was repeated twice.
(2) Microbubble ozone sterilization method The pre-washed cut vegetables were put into a sterilization tank (15 ° C., compounded with chemicals), stirred for a predetermined time and sterilized. In Experimental Examples 1-1 to 1-4, the set dissolved ozone concentration was set to a different value. Thereafter, the mixture was put into a rinse part and stirred and washed for 90 seconds. The rinse was repeated twice. Thereafter, the vegetables were put in a sterilized laundry net and dehydrated for 90 seconds with a commercial dehydrator.
(3) Measurement method of ozone concentration in the work environment (measurement location, measurement method)
The environmental ozone concentration was measured using an ultraviolet absorption ozone gas monitor (EG-700 manufactured by Sugawara Jitsugyo). The measurement position was 40 cm above the surface of the sterilization tank.

  From the results in Table 2, it was found that if the dissolved ozone concentration is 0.1 mg / L or more, the sterilizing effect of the vegetables and the sterilizing effect of the cleaning solution are sufficiently obtained. On the other hand, it was found that when the dissolved ozone concentration exceeds 0.5 mg / L, the working environment ozone concentration exceeds 0.1 ppm of the allowable concentration (Japan Society for Occupational Health; allowable concentration 4). Therefore, it was found that if the dissolved ozone concentration is 0.1 mg / L or more and 0.5 mg / L or less, the ozone concentration in the environment can be suppressed to an allowable range while ensuring a sufficient bactericidal effect on vegetables. Therefore, it is possible to deal with ozone with a simple device such as the ozone exhaust system 160 shown in FIG.

(Experimental examples 2-1 to 2-5)
The comparative experiment of the bactericidal effect of ozone water and microbubble ozone water (MBO) was conducted.
<Experiment method>
(Experimental examples 2-1 and 2-2) 720 g of shredded cabbage prewashed with tap water (vegetable washing degree COD = 75) and 0.05% by weight of microbubble ozone water (drug: triacetin (manufactured by Inoue Fragrance)) (Mixed) was introduced into 15 ° C. sterilized water (20 L), and sterilized at a predetermined dissolved ozone concentration for 90 seconds. As shown in FIG. 3, the supply of microbubble ozone water was replenished through a circulation system line. Thereafter, it was poured into 20 L tap water and rinsed for 90 seconds. This was repeated twice. Thereafter, the vegetables were put in a sterilized laundry net and dehydrated for 90 seconds with a commercial dehydrator.
(Experimental Examples 2-3 to 2-5) Similarly, shredded cabbage was put into a sterilization tank filled with ozone water having a predetermined ozone concentration and sterilized. In the case of ozone water sterilization, the circulation system was not used, and the mixture was sterilized by stirring for 90 seconds while supplying ozone water of a predetermined concentration. The ozone water used was a direct electrolysis type ozone water production apparatus (production of ozone water by electrolysis, manufactured by Kobe Steel). Next, it was poured into 20 L tap water and rinsed for 90 seconds. This was repeated twice. This was then repeated twice. Thereafter, the vegetables were put in a sterilized laundry net and dehydrated for 90 seconds with a commercial dehydrator.

  From the results in Table 4, it was found that when the vegetables were sterilized using ozone water, the working environment ozone concentration exceeded the allowable concentration of 0.1 ppm in order to make the sterilization effect of the vegetables 1.5 digits or more. did. On the other hand, when sterilizing vegetables using microbubble ozone water having a dissolved ozone concentration of 0.1 mg / L or more and 0.5 mg / L or less, while ensuring a sufficient sterilizing effect on vegetables, the environment It was found that the ozone concentration in the inside could be kept within an acceptable range.

(Experimental example 3)
Experiments were conducted on the effect of COD on microbubble ozone sterilization.
<Experiment method>
Vegetables were sterilized by batch processing using the apparatus and conditions of Experimental Examples 1-1 to 1-4. In the experiment, the vegetables were pre-cleaned and then sterilized continuously in one tank. The batch treatment was continuously performed a plurality of times, and the predetermined sterilizing solution COD, the maximum dissolved ozone concentration (mg / L), and the dissolved ozone concentration increase rate (mg / L / second) were measured.
The COD of the pre-washed vegetables is 66 mg / L
Setting of dissolved ozone concentration; 0.1 mg / L or more, 0.5 mg / L or less Dissolved ozone concentration increase rate: slope of increase of dissolved ozone concentration when ozone generator is on (mg / L / sec)

  From the results in Table 5, the ozone consumption increases when the vegetables are added, and the dissolved ozone concentration decreases rapidly. Therefore, if the number of batch processing exceeds 60 times, the dissolved ozone concentration will not increase even if ozone is supplied at the maximum capacity of the ozone generator. It was found that the value was below the set lower limit. The COD in the sterilizing solution at this time was 320 mg / L. Therefore, when sterilizing vegetables in batch processing, if the dissolved ozone concentration falls below the set lower limit value, it is preferable to temporarily stop the sterilization processing of vegetables and replace the sterilizing solution in the sterilization tank. In addition, it is preferable that the number of batch processes in which the dissolved ozone concentration is lower than the set lower limit value is obtained in advance, and the number of batch processes less than the set lower limit value is set as the upper limit value of the batch process number. For example, in the above experimental results, it is preferable to operate the sterilization treatment by setting the upper limit value of the number of batch processes to 60 times (COD upper limit value of the sterilizing solution; 300 mg / L). In addition, the initial COD at the time of batch processing in the sterilizing liquid has a correlation with the upper limit value of the batch processing number, so that the cleaning degree COD of the pre-cleaning is 100 mg / L or less to increase the upper limit value of the batch processing number. It is preferable to make it.

[Cut vegetable manufacturing method]
Although the above embodiment has been described by using an example in which washing and sterilization processing is performed on vegetables that have been cut in advance to a predetermined size (for example, eating size), the present invention is also applied to a cut vegetable manufacturing method that includes cutting of vegetables. Is applicable. In this case, as shown in FIG. 1, the pre-cleaning process, the sterilizing process, and the rinsing process are continuously performed using the continuous vegetable sterilizer having the same number of pre-cleaning parts and rinsing processes as the pre-cleaning process and the rinsing process. In addition to the configuration for performing the treatment, the present invention can also be applied to a configuration using a batch-type vegetable sterilizer that performs pre-cleaning processing, sterilization processing, and rinsing processing in a single tank.

  As an example, the cut vegetable production method for shredded cabbage includes a whole vegetable pre-sterilization step, a pre-cut step, a foreign matter removal step, a eating size cut step, a preliminary washing step, an ozone sterilization step, and a rinsing step.

  In the pre-sterilization process for whole vegetables, the cabbage from which the outer leaves have been removed is immersed in a 200 ppm aqueous sodium hypochlorite solution stored in a pre-sterilization tank for sterilization.

  In the pre-cut process, the cabbage is taken out from the pre-sterilization tank and cut into half or ¼.

  In the foreign matter removing step, the cabbage that has been cut in half or ¼ is put into a foreign matter removing and washing machine to remove foreign matters (insects, dust, etc.).

  In the eating size cutting process, the cabbage is cut into eating sizes (chopped) using a slicer.

  When using a continuous vegetable sterilizer in the pre-cleaning process, for example, a 5 tank type ground raccoon made by Hosoda Industry, use the 1st and 2nd tanks to perform pre-cleaning while adding makeup water to remove vegetable lye . When a batch type vegetable sterilizer is used in the preliminary washing step, washing is performed while adding makeup water to remove lye. This operation is performed twice more with the water exchanged.

  When a continuous vegetable sterilizer is used in the ozone sterilization step, a chemical is added so that the chemical concentration of the cleaning liquid becomes constant while adding makeup water to the third tank, and ozone gas is blown into the cleaning liquid. When a batch-type vegetable sterilizer is used in the ozone sterilization step, after three times of preliminary cleaning, water is changed, a chemical is added by the fourth cleaning, and ozone gas is blown into the cleaning liquid. The sterilization process using the microbubble ozone water described above can be applied when using any of the continuous vegetable sterilizer or the batch vegetable sterilizer.

When a continuous vegetable sterilizer is used in the rinsing process, rinsing is performed while adding makeup water in the fourth and fifth tanks. When a batch type vegetable sterilizer is used in the rinsing process, after the fourth ozone sterilization, water is exchanged and rinsing is performed while adding makeup water.
By sequentially performing such steps, it becomes possible to produce a cut vegetable having a food size that is sufficiently sterilized while suppressing the ozone concentration in the environment from the whole vegetable before cutting.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  As a method for introducing microbubbles without using a surfactant, pressure-dissolved ozone microbubbles manufactured by Nikuni may be introduced. In addition, as a method of introducing microbubbles using a surfactant, as a method of introducing a gas from a porous body such as a diffuser plate, or a method of utilizing a surfactant in a method not using the above surfactant Also good.

  DESCRIPTION OF SYMBOLS 1 ... Vegetable sterilizer, 14 ... Ozone concentration sensor, 15 ... Ozone supply part, 16 ... Concentration adjustment part, 110A, 110B ... Pre-cleaning part, 120 ... Sterilization part, V ... Vegetable

Claims (8)

  The vegetable sterilization method characterized by including the sterilization process which sterilizes the cut vegetables by the sterilization liquid containing micro bubble ozone water whose dissolved ozone concentration is 0.1 mg / L or more and 0.5 mg / L or less.   The vegetable sterilization method according to claim 1, wherein the sterilizing liquid contains a surfactant.   The vegetable sterilization method according to claim 1, further comprising a step of pre-cleaning the vegetables before the sterilization step. Measuring the dissolved ozone concentration in the sterilizing solution;
The vegetable sterilization method according to any one of claims 1 to 3, further comprising adjusting a dissolved ozone concentration in the sterilizing liquid according to the measured dissolved ozone concentration.   The vegetable sterilization method according to claim 4, wherein the sterilization treatment of the vegetable is stopped when the dissolved ozone concentration in the sterilization solution falls below a predetermined lower limit value.   The vegetable sterilization method according to any one of claims 1 to 5, wherein the vegetable is sterilized with the sterilizing liquid having a chemical oxygen demand of 300 mg / L or less. 7. The vegetable according to claim 1, wherein a chemical oxygen demand measured by a chemical oxygen demand measurement method for the following vegetables is 100 mg / L or less, is added to the sterilizing solution. The vegetable sterilization method as described.
Chemical oxygen demand measurement method of vegetables 720g of vegetable as a measurement sample is put in a pre-cleaning part containing 20L of tap water at 15 ° C and stirred for 90 seconds, and then 50mL of the cleaning solution is collected and filtered with a 450nm membrane filter. About the washing | cleaning liquid obtained by filtration, 17. JIS K0102 (2013 version) factory waste water test method. The chemical oxygen demand is measured based on the oxygen consumption by potassium permanganate at 100 ° C. A process of primary sterilization of vegetables before cutting;
Removing foreign matter adhering to the primary sterilized vegetables;
Cutting the vegetable from which the foreign matter has been removed into a predetermined size;
And a step of secondarily sterilizing the cut vegetables with a sterilizing solution containing microbubble ozone water having a dissolved ozone concentration of 0.1 mg / L or more and 0.5 mg / L or less. .

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