JP5193907B2 - Cleaning method for cut vegetables or fruits - Google Patents

Description

  The present invention relates to a food cleaning method.

Ozone has the strongest oxidizing power after fluorine. For this reason, conventionally, a method for treating (ozone treatment) a processing object using this oxidizing power is used in various fields such as semiconductor cleaning, food cleaning (sterilization), or water purification.
In addition, ozone decomposes into oxygen and has an environmentally friendly aspect, so its use tends to expand.

  By the way, in recent years, the market of cut vegetables and fruits (hereinafter, sometimes referred to as vegetables) has been growing, and many of them are displayed at retail stores such as supermarkets and convenience stores. However, since these cut vegetables tend to be less fresh than usual when cut, the cut vegetables have a high rate of being discarded. This is thought to be due to the fact that microorganisms propagate on the cut surfaces of vegetables and are easily denatured. For this reason, the cut vegetables are desired to be improved from the viewpoint of profitability and the environment.

Conventionally, as a method for maintaining the freshness of vegetables, treatments such as using various freshness-keeping agents such as a shelf life improver and a preservative have been performed. For example, a shelf life improver for foods containing alcohol, organic acid, amino acid and vinegar has been proposed (for example, Patent Document 1). Further, for example, a food preservative using caprylic acid monoglyceride has been proposed (for example, Patent Document 2). The use of such a freshness-preserving agent requires an additive label in order to leave the preparation in food, and the producer tends to avoid it. Improvements in packaging and storage methods are also being considered, but it was too costly, including capital investment, which was economically disadvantageous.
For such problems, attempts have been made to suppress spoilage and denaturation by sterilizing cut vegetables and reducing the initial number of bacteria. In general, sodium hypochlorite is used for sterilization of food, but there are concerns about the generation of chlorine odor and trihalomethane. For this reason, a technique using ozone gas as a highly safe sterilization method has been studied. As a sterilization method using ozone gas, it is known that the sterilization effect can be improved by performing ozone treatment in the presence of a compound having a specific dynamic surface tension (for example, Patent Documents 3 and 4). .

JP 2008-220345 A JP-A-6-217748 International Publication No. 2007/040260 Pamphlet JP 2008-201992 A

However, when the cut vegetables were processed according to the inventions described in Patent Documents 3 and 4, the bactericidal effect on the vegetables was still not sufficient. In addition, with the cleaning method using ozone treatment, after cutting, the cut surface of vegetables cut in a short period of time is discolored, or the cut vegetables are easily discolored as a whole, and the freshness cannot be maintained. was there.
Then, this invention aims at the washing | cleaning method of a foodstuff with the high bactericidal effect and the freshness maintenance effect.

  The food washing method of the present invention is characterized by washing food in the presence of an amino acid having an isoelectric point of more than 5 and ozone under conditions of pH 3-5. The amino acid is preferably glycine, and more preferably used together with a fatty acid glyceride having 1 to 10 carbon atoms.

  According to the food washing method of the present invention, the sterilization effect and the freshness maintenance effect of food can be improved.

It is a schematic diagram which shows the ozone treatment apparatus of the foodstuff concerning 1st embodiment of this invention. It is a schematic diagram which shows the ozone treatment apparatus used for the Example.

The food cleaning method of the present invention (hereinafter sometimes simply referred to as a cleaning method) is an amino acid having an isoelectric point of more than 5 (hereinafter also referred to as component (A)) and ozone under pH 3 to 5 conditions. It cleans food in the presence.
Hereinafter, the cleaning method of the present invention will be described by way of examples, but the present invention is not limited to this embodiment.

(First embodiment)
A food ozone treatment apparatus (hereinafter sometimes simply referred to as an ozone treatment apparatus) according to a first embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the ozone treatment apparatus 10 includes a water tank 12, an aeration unit 14, and a stirring unit 18. The aeration means 14 includes a supply pipe 15 and an air diffuser 16 provided at the tip of the supply pipe 15. The air diffuser 16 is immersed in the water stored in the water tank 12, and the supply pipe 15 is connected to the ozone-containing gas supply means 13. The stirring means 18 is provided in the water tank 12.

The material of the water tank 12 is not particularly limited, but because the oxidizing power of ozone is strong, for example, glass, Teflon (registered trademark) (polytetrafluoroethylene), titanium, ozone treatment (a strong oxide film formation by high-concentration ozone) It is preferable to use aluminum or stainless steel. When using a material such as nitrile rubber or urethane having low resistance to ozone, it is necessary to pay sufficient attention to deterioration of the water tank 12.
The size of the water tank 12 can be determined in consideration of the amount of food to be washed and the ability of the stirring means 18.

The ozone-containing gas supply means 13 only needs to be able to supply ozone-containing gas containing ozone, and examples thereof include an ozone generator and a cylinder filled with ozone-containing gas. Moreover, for example, a device that generates ozone with an ozone generator, sends the generated ozone to a mass flow controller via a regulator, and supplies ozone into the water to be treated while adjusting the flow rate with the mass flow controller.
The ozone generator is not particularly limited, and examples thereof include a method of irradiating oxygen with high energy light such as an electron beam, radiation, and ultraviolet rays, a chemical method, an electrolytic method, a discharge method, and the like. Industrially, the silent discharge method is often used because of generation cost and generation amount. As such a commercially available ozone generator, for example, YGR-50 (trade name) manufactured by Lacey Co., Ltd. is commercially available as a low concentration ozone generator, and ED- manufactured by Ecodesign Co., Ltd. is used as a high concentration ozone generator. OG-PSA1 (trade name) and the like are commercially available.

  The aeration means 14 is not particularly limited as long as the ozone-containing gas can be supplied to the water to be treated as fine bubbles, and for example, known devices such as a diffuser plate, a diffuser cylinder, a diffuser, and an ejector can be used. By using such a device and generating as fine bubbles as possible, the sterilization efficiency of the food can be increased.

  The stirring means 18 may be anything that can stir the water to be treated in the water tank 12, may be one using a stirring blade, or may be one that generates a water flow with a pump or the like.

  The cleaning method of this embodiment will be described with reference to FIG. The cleaning method of the first embodiment is a method of immersing food in water to be treated in which component (A) is dissolved in water, and introducing an ozone-containing gas containing ozone into the water to be treated.

  First, an arbitrary amount of water to be treated is stored in the water tank 12, and the food 19 to be cleaned is placed. Next, ozone-containing gas is circulated from the ozone-containing gas supply means 13 to the supply pipe 15, and ozone-containing gas bubbles 17 are generated from the diffuser 16 in the water to be treated. Then, a water flow is generated in the water to be treated in the water tank 12 by the stirring means 18. Thereafter, the ozone-containing gas bubble 17 is generated for an arbitrary time, and the food 19 is washed.

  The food to be washed of the present invention may be any food that can be washed with water and generally subjected to ozone treatment. Examples thereof include fresh vegetables and cut processed products thereof. In particular, the present invention can be suitably used for cut vegetables. In addition, the food to be cleaned may be a product to which organic matter such as bacteria, pigments, fats and oils, amines, proteins, humus, sludge, surfactants or agricultural chemicals are attached.

The water to be treated is an aqueous solution containing the component (A).
The water used for to-be-processed water is not specifically limited. Ozone reacts with dissolved metals, chlorine, organic substances, etc. because of its strong oxidizing power, and therefore, the water to be treated is preferably water having a low content (high purity) of these impurities. Examples of such water include ultrapure water having a resistivity of preferably 0.00001 MΩ · cm or more, more preferably 0.001 MΩ · cm or more, and further preferably 1 MΩ · cm or more.

The component (A) used in the present invention is an amino acid having an isoelectric point exceeding 5.
As the component (A), glycine (isoelectric point: 5.97), alanine (isoelectric point: 6.00), methionine (isoelectric point: 5.74), cysteine (isoelectric point: 5.07) , Phenylalanine (isoelectric point: 5.48), leucine (isoelectric point: 5.98), valine (isoelectric point: 5.96), isoleucine (isoelectric point: 6.02), glutamine (isoelectric point) : 5.65), histidine (isoelectric point: 7.59), proline (isoelectric point: 6.30), tyrosine (isoelectric point: 5.66), tryptophan (isoelectric point: 5.89), Serine (isoelectric point: 5.68), threonine (isoelectric point: 6.16), asparagine (isoelectric point: 5.41), arginine (isoelectric point: 10.76), lysine (isoelectric point: isoelectric point: 9.74). Of these, glycine is preferable. Among amino acids, glycine is very excellent because its molecular weight is small, and even when the same mass as other component (A) is added, the frequency of contact with microorganisms increases.
Such component (A) is amphoteric, and many molecules are positively charged at pH 5 or lower. By adsorbing to the cell membrane surface of the food to be washed having a negative potential, the surface charge of the food becomes very small, and the bactericidal effect is achieved because ozone bubbles are easily adsorbed on the cell surface of microorganisms. It is thought to improve.
The isoelectric point is a value listed in the Chemical Handbook Basic Edition 4th edition edited by the Chemical Society of Japan (Maruzen Co., Ltd., Basic Edition I, P.431-434, 1993).

  The density | concentration of (A) component in to-be-processed water can be determined according to the kind of (A) component to add, for example, it is preferable that it is 10-1000 mass ppm, and it is 20-200 mass ppm. Is more preferable. If the concentration of the component (A) is too low, the component (A) has an increased adsorptivity to foods under acidic conditions, and thus the sterilization effect tends to be difficult to improve. If the concentration of the component (A) is too high, the component (A) and ozone tend to react and the sterilization effect of ozone tends to be lost. Even if the component (A) is added excessively, the sterilization effect is saturated. End up. In addition, the osmotic pressure of the water to be treated tends to increase and the quality of the food tends to be impaired.

A C1-C10 fatty acid glyceride (hereinafter may be referred to as component (B)) can be further added to the water to be treated. By using the component (B) in combination, the ozone-containing gas can be refined and the bactericidal effect can be enhanced. Various microbubble generators can be used to make ozone-containing gas finer, but it is possible to make it finer with lower mechanical force by using chemicals such as salt, surfactant and solvent. . In cleaning for food, it is preferable to select a drug that is a food additive and has no restriction on use, in the unlikely event of residual. In addition, when the foam accumulates, the sterilizing effect is reduced due to overflow and a decrease in mechanical force applied to the food.
For these reasons, it is preferable to use a glycerin fatty acid ester having 1 to 10 carbon atoms in the aeration method, and since it is water-soluble, caprylic acid glycerides such as triacetin, diacetin, monoacetin and monocaprylin, and capric acid glycerides such as monocaprin Among them, triacetin, diacetin, and monoacetin are preferable because bubbles do not accumulate even when the aeration amount is increased. In addition, the wettability is improved due to a decrease in the surface tension of the water to be treated, and an improvement in cleanability can be expected.

  As the ozone-containing gas, ozone generated by an ozone generator may be used as it is, or a gas diluted with a dilution gas may be used. As the dilution gas, a gas inert to ozone or poor in reactivity is preferable, and examples thereof include helium, argon, carbon dioxide, oxygen, air, and nitrogen. Since ozone is self-degrading, it is desirable to use it immediately after it is prepared with an ozone generator.

  The concentration of ozone in the ozone-containing gas is not particularly limited, but is preferably 5000 ppm by volume or less and more preferably 1000 ppm by volume or less in consideration of work safety. The lower limit is not particularly limited, but is preferably 1 ppm by volume or more and more preferably 10 ppm by volume or more in consideration of the efficiency of ozone treatment. The present invention is particularly useful when the concentration of ozone is low, for example, in the range of 50 to 5000 ppm by volume, which effectively provides a bactericidal effect.

The supply amount of the ozone-containing gas to the water to be treated can be determined according to the purpose of cleaning and the type and amount of food.
The bubble diameter of the ozone-containing gas when aerated to the water to be treated is not particularly limited, but the bubble diameter is preferably as small as possible from the viewpoint of improving the sterilization efficiency.

  The pH of the water to be treated is pH 3 to 5 while the ozone-containing gas is aerated in the water to be treated, and more preferably pH 3.5 to 4.5. In cleaning using ozone, it is known that lowering the pH suppresses decomposition of dissolved ozone. In addition, by setting the water to be treated to a pH lower than the isoelectric point of amino acids, the proportion of positively charged amino acids increases, the action efficiency on microorganisms increases, and the bactericidal effect can be improved synergistically. On the other hand, fresh foods such as vegetables are composed of cells, and if the pH is too low, the food will be altered, for example, membrane protein denaturation will occur. For this reason, coexistence of a freshness maintenance effect and a bactericidal effect improvement can be aimed at by adjusting to-be-processed water to pH 3-5.

The pH indicates the pH value of the water to be treated itself measured at 25 ° C. using a hydrogen electrode or the like.
The pH of the water to be treated can be adjusted by adding an alkali agent such as sodium hydroxide or potassium hydroxide; an acid such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, or citric acid.

  The time (cleaning time) for aeration of ozone-containing gas to the water to be treated is determined in consideration of the purpose of treatment, the ease of decomposition of the object to be treated, the amount of food in the water to be treated, the temperature of the water to be treated, etc. For example, it is preferably determined in the range of 0.5 to 10 minutes. This is because the damage given to the food is extremely small if it is within the above range.

  The temperature (cleaning temperature) of the water to be treated during aeration with ozone-containing gas takes into account the purpose of the treatment, the type of food, the ease of decomposition of the treatment object, the amount of food in the water to be treated, the washing time, etc. For example, it is preferable to determine in the range of 0 to 55 ° C. If it is in the said range, it can prevent that a foodstuff denatures and deteriorates by partial freezing and heating.

As described above, the present invention can be sterilized efficiently in a short time without deteriorating the food by washing the food in the presence of the component (A) and ozone under the conditions of pH 3 to 5. For this reason, the food after washing does not cause discoloration or the like over a long period of time, and an excellent effect of maintaining freshness can be obtained.
In addition, the sterilization efficiency can be further improved by using the component (B) in combination.

Here, it is easily analogized that ozone has strong oxidizing power and high sterilizing power. On the other hand, since ozone is a gas, it is difficult to handle, and its use as ozone water in which ozone is dissolved in water is common in this field.
However, when using ozone water, when preparing ozone water, the ozone which was not able to melt | dissolve in water will be discarded, and waste will increase. In addition, ozone dissolved in water has a fast reaction rate. For this reason, if it supplies to an ozone treatment apparatus as ozone water, it will react with the contaminant in water immediately, and most ozone in ozone water will be consumed. Furthermore, ozone water is likely to permeate (enter) foods and is therefore often consumed in large quantities.
On the other hand, ozone is less reactive in the gas state. For this reason, when ozone is supplied into water as ozone-containing gas bubbles, which are fine bubbles in a gaseous state as in this embodiment, the bubbles are uniformly dispersed in the water. Then, the whole food can be sterilized by the ozone dissolved in the surface of the bubbles and water acting on the sterilization. Further, by sterilizing mainly the surface of the food with the bubbles of ozone, damage to the food due to the penetration of ozone into the cells of the food can be reduced. For this reason, in the present invention, it is preferable to use a method in which ozone-containing gas is aerated in the water to be treated.

(Second embodiment)
The washing | cleaning method concerning 2nd embodiment of this invention is a method of wash | cleaning foodstuffs using the wash water which melt | dissolved (A) component and ozone in water.
Examples of the washing of food include a method of immersing food in a water tank containing the washing water and stirring the food together with the washing water, or a method of washing the washing water by pouring the washing water over the food.

The washing water contains the component (A) and ozone.
The concentration of ozone in the wash water can be determined in consideration of the cleaning method, the purpose of treatment, and the like. For example, it is preferably determined in the range of 0.01 to 1 mass ppm. This is because, within the above range, a sufficient sterilizing effect can be obtained, and surplus ozone generated when ozone is dissolved in water can be reduced.

The concentration of the component (A) in the washing water is the same as the concentration of the component (A) in the water to be treated in the first embodiment.
The pH of the washing water is pH 3-5, preferably pH 3.5-4.5. This is because both the freshness maintaining effect and the sterilizing effect can be improved within the above range.

  The method for dissolving ozone in the washing water is not particularly limited, and examples thereof include a method in which ozone is aerated and dissolved in water or an aqueous solution in which the component (A) is dissolved in water.

  According to this embodiment, there is no need for a device that cleans food while aeration of ozone. Therefore, it is possible to easily maintain the freshness of food and improve sterilization efficiency by washing without large-scale capital investment. I can plan.

(Other embodiments)
The present invention is not limited to the embodiment described above.
The first and second embodiments can be provided with a rinsing step as necessary. (A) component, such as glycine, exhibits sweetness, etc., and the remaining (A) component may affect the flavor of the food after washing. For this reason, after wash | cleaning foodstuffs in presence of (A) component and ozone, the (A) component which remains in foodstuffs can be removed by providing the rinse process wash | cleaned with water further.
The method of the rinsing process is not particularly limited, and a known method can be used. The water used in the rinsing process is not particularly limited as long as it is clean water, and tap water, pure water, or the like can be used.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
(Raw materials used)
The raw materials used in the examples and comparative examples are shown below.
[(A) component: an amino acid having an isoelectric point exceeding 5]
-Glycine: Special grade reagent, isoelectric point; 5.97, manufactured by Kanto Chemical Co., Ltd.-Alanine: Special grade reagent, isoelectric point: 6.00, manufactured by Kanto Chemical Co., Ltd.-Serine: Special grade reagent, isoelectric point; 68, manufactured by Kanto Chemical Co., Ltd. ・ Leucine: Special grade reagent, isoelectric point; 5.98, manufactured by Kanto Chemical Co., Ltd.

[(A ′) component: amino acid having an isoelectric point of 5 or less]
・ Aspartic acid: special grade reagent, isoelectric point; 2.77, manufactured by Kanto Chemical Co., Inc.

[(B) component: C1-C10 fatty acid glyceride]
・ Triacetin: Special grade reagent, manufactured by Kanto Chemical Co., Ltd. ・ Monocaprilin: Poem M-100, Riken Vitamin Co., Ltd.

[Others]
-0.1N sodium hydroxide: manufactured by Kanto Chemical Co., Ltd.-0.1N hydrochloric acid aqueous solution: manufactured by Kanto Chemical Co., Ltd.-Malic acid: manufactured by Kanto Chemical Co., Ltd.-5N hydrochloric acid aqueous solution: manufactured by Kanto Chemical Co., Ltd.

(Examples 1-7, Comparative Examples 1-3)
[Sterilization test]
<Preparation of sample solution>
E. coli (NBRC 3972 strain) was cultured at 37 ° C. for 24 hours (pre-culture) on an SCD agar medium (manufactured by Nissui Pharmaceutical Co., Ltd.), and the cultured E. coli was cultured again in the same manner (pre-culture). The cultured E. coli was used for the bactericidal test. A pre-cultured Escherichia coli buffer solution containing peptone (3.56 g potassium dihydrogen phosphate, 18.2 g disodium hydrogen phosphate dodecahydrate, 4.3 g sodium chloride, 1.0 g peptone in 1 L of purified water was prepared. , Neutralized to pH 7.0), and a bacterial solution with a bacterial count of about 1.0 × 10 ⁸ cfu / mL was prepared using the transmittance at 660 nm as an index.
Using a glass test tube, dissolve each component in pure water according to the composition shown in Table 1, and add SIGMA BSA (bovine serum albumin) as a contaminant to 100 ppm by mass. Water was prepared. Immediately before ozone aeration, 100 μL of the bacterial solution was added to the water to be treated to prepare a sample solution in which an initial bacterial count of 1.0 × 10 ⁶ cfu / mL was set. The pH of the sample solution was adjusted with a 0.1N hydrochloric acid aqueous solution and a 0.1N sodium hydroxide aqueous solution (both manufactured by Kanto Chemical Co., Inc.). The pH was measured using a pH meter (SevenEasy, manufactured by METTLER TOLEDO).

<Aeration conditions for sterilization test>
Aqua zone 200 (manufactured by Red Sea Fish Pharm Ltd.) was used as the ozone generator, and PG-620MA (manufactured by Sugawara Jitsugyo Co., Ltd.) was used as the ozone monitor. The source gas introduced into the ozone generator was dry air dehumidified with 500 mL of silica gel. Moreover, Kinoshita-type glass filter 501G (No. 4, Kinoshita Rika Kogyo Co., Ltd.) was used as the aeration means. 20 mL / min. At a flow rate of 100 ppm by volume, ozone-containing gas (dilution gas: air) was aerated in the test tube for 2 minutes. The treatment temperature was 25 ° C. (above, ozone aeration treatment).

<Evaluation of sterilization power in sterilization test>
5 mL of the sample solution after the ozone aeration treatment was immediately collected in a test tube sterilized in advance, and serial dilution was performed 10 times using a buffer containing peptone. 1 mL of each diluted solution was collected with a micropipette, dropped into a petri dish, and then mixed with an SCD agar medium (Nissui Pharmaceutical Co., Ltd.) kept at about 50 ° C. After confirming that the agar has solidified and culturing at 37 ° C. for 24 hours in an incubator, the number of remaining viable cells (number of bacteria) is determined by counting the number of colonies on the medium for those in the range of 300 cfu or less per dish. ). Two plates were cultured at each dilution stage, and the counted number of bacteria was averaged. In addition, the number of bacteria before ozone aeration process was measured similarly to the above, and this was measured as an initial number of bacteria. The bactericidal power was expressed by -log (number of remaining bacteria / number of initial bacteria). In this test, 0 is shown when no sterilization is performed, and 6 is shown when the bacteria are completely annihilated.
Table 1 shows the evaluation results of sterilizing power.

(Examples 8-13, Comparative Examples 4-5)
[Freshness test]
<Cleaning by ozone treatment>
The food (lettuce) was washed according to the following processing sequence with reference to ozone treatment in a general fresh food factory.
(Pre-washing process) → (Washing process) → (First rinsing process) → (Second rinsing process) → (Dehydration process)

In the pre-washing process, 500 g of lettuce cut to 1/8 (about 5 cm square) is put into an electric bucket (product name: N-Bk2, manufactured by Panasonic Corporation) in which 7 L of tap water is stored, and washing is performed for 2 minutes. Went.
In the washing step, water to be treated was prepared according to the composition shown in Table 2 using a washing machine (product name: CW-C30A1, manufactured by Mitsubishi Electric Corporation; 2-tank washing machine) in which 40 L of tap water was stored. Vegetables (lettuce) were put in and the mixture was stirred by stirring for 5 to 10 minutes under the ozone aeration conditions described later. The pH of the water to be treated was prepared using malic acid. However, only the comparative example 1 adjusted the pH of to-be-processed water using 5N hydrochloric acid aqueous solution.
The first rinsing step was performed by storing 40 L of tap water in the two-tub washing machine and stirring for 1 minute.
In the second rinsing step, 20 L of water was stored in a bucket, and lightly stirred using a sterilized stainless steel colander (diameter 15 cm, mesh 2 mm).
In the dehydration step, dehydration was performed for 1 minute in the dewatering tank of the 2-tank washing machine.
For the movement of the lettuce between each operation, a stainless colander sterilized with ethanol was used.

≪Ozone aeration conditions≫
The cleaning process in the above “<cleaning by ozone treatment>” is an ozone treatment device 100 shown in FIG. 2 that is self-made using a washing machine (product name: CW-C30A1, manufactured by Mitsubishi Electric Corporation; 2-tank washing machine). Was treated with ozone.
The ozone treatment apparatus 100 includes a two-tank washing machine 110 having a washing tub 111 and a dehydration tub 112, ozone-containing gas supply means 120, and water to be treated sucked from the washing tub 111. And a circulation system 140 that circulates while supplying ozone-containing gas from 120.
The washing machine 110 has a pulsator 113 as a stirring means at the bottom of the washing tub 111.
The ozone-containing gas supply means 120 includes an air cylinder 121 that sends out air, a regulator 122 that controls the flow rate (ozone concentration) of air, and an ozone generator 123 that generates ozone in the sent-out air to prepare an ozone-containing gas. (Product name: OZSD-3000A, manufactured by Sugawara Jitsugyo Co., Ltd.) and a mass flow controller 124 (Product name: MODEL5100, manufactured by Coflock Co., Ltd.) for controlling the flow rate of ozone-containing gas. The air cylinder 121 is connected to an ozone generator 123 via a regulator 122, and the ozone generator 123 is connected to a mass flow controller 124. The ozone generator 123 includes an ozone monitor (product name: EG-600, manufactured by Sugawara Jitsugyo Co., Ltd.) not shown.

The mass flow controller 124 is connected to a circulation pump 134, the pump 134 is connected to a pipe 132, and the pipe 132 is connected to a turning accelerator 135 that mixes gas and liquid by a spiral flow. The turning accelerator 135 is connected to a pipe 133, and the pipe 133 is connected to an air diffuser 137 provided in the washing tub 111. In this way, the aeration means 130 is configured by the pump 134, the turning accelerator 135, the air diffuser 137, and the pipes 132, 133.
The pump 134 is connected to a pipe 131, and the pipe 131 is connected to a strainer 136 (made of Teflon (registered trademark), mesh having a diameter of 1 mm) provided near the bottom of the washing tub 111. Thus, the aeration means 130, the pipe 131, and the strainer 136 constitute a circulation system 140 that circulates the water to be treated.
In addition, all the piping used for the ozone treatment apparatus 100 was made from vinyl chloride.

In the ozone treatment of this example, the water to be treated was circulated by the pump 134 at 10 L / min. The flow rate was as follows.
The ozone-containing gas was prepared by adjusting the amount of air sent out from the air cylinder 121 by a regulator 122 so that the ozone concentration was 5000 ppm by volume.
Supply of the ozone-containing gas to the water to be circulated is performed through the aeration means 130, and the flow rate of the ozone-containing gas is set to 0.4 L / min. The ozone-containing gas was supplied (aerated) to the water to be treated in the washing tub 111. The bubbles of ozone-containing gas generated in the water to be treated had an average bubble diameter of 50 μm.

<Evaluation of freshness retention effect>
Put the lettuce after “<cleaning by ozone treatment>” into a plastic bag with fasteners, and store it at BioCooler (trade name, UKS-3600HC, manufactured by Nippon Freezer Co., Ltd.) for 3 days at 10 ° C. did.
The state before washing was set to 5 points, and the evaluation was made on a five-point scale using the three items of elasticity, browning (mainly reddish of the cut surface), and discoloration (overall browning) as indices. Regarding the above three items, three or more points were evaluated as ◯ (pass). In addition, the total score of these three items was 10 (or better). The results are shown in Table 2. In Table 2, the values in parentheses indicate points.

(1) Tightness ... The volume of the vegetables in the preserved bag was visually determined.
5 points; almost no decrease in volume 4 points; almost no decrease in volume but slightly soft vegetables 3 points; decrease less than 20% volume 2 points; decrease 20% or more volume 1 point; 50% or more volume Decrease in

(2) Browning (mainly red color of the cut surface) ... The red part was evaluated visually with the cut surface of the preserved vegetable as the center.
5 points; no red color on the whole 4 points; redduce with less than 20% vegetable pieces 3 points; reddish with less than 50% vegetable pieces 2 points; reddish with 50% or more vegetable pieces 1 point; almost all Deep red with vegetable pieces

(3) Discoloration (overall browning): The overall color tone was visually evaluated under a fluorescent lamp.
5 points; keeps the original color overall 4 points; overall there is a slight dullness 3 points; some vegetable pieces turn brown 2 points; almost all vegetable pieces turn light brown 1 point; almost All vegetable pieces turn brown

From the results of Table 1, in Examples 1 to 7 in which the component (A) was added and the ozone-containing gas was aerated under the conditions of pH 3 to 5, the bactericidal power against the sample solution was 1.3 or better. Among them, in Examples 6 and 7 in which the component (B) was added to the sample solution, a significant improvement in sterilizing power was observed.
On the other hand, Comparative Example 1 in which the water to be treated was pH 7, Comparative Example 2 using aspartic acid having an isoelectric point of 5 or less instead of the component (A), and Comparative Example 3 not using the component (A) In either case, sufficient bactericidal power was not obtained.

From the results of Table 2, in Examples 8 to 13 according to the present invention, the total of the three items of the freshness maintaining effect was 11 points or more, and an excellent freshness maintaining effect was obtained.
On the other hand, in Comparative Example 4 in which the water to be treated was pH 2, Comparative Example 5 in which the water to be treated was pH 6, and Comparative Example 6 in which the component (A) was not used, the total of the three items of the freshness maintaining effect was 8 points. It was the following and was inferior in comparison with any of Examples 8-13.

  From the results of Tables 1 and 2, it was found that the cleaning method of the present invention can achieve both an excellent bactericidal effect and a freshness maintaining effect on food.

DESCRIPTION OF SYMBOLS 10,100 Ozone processing apparatus 12 Water tank 13,120 Ozone supply means 14,130 Aeration means 18 Stirring means 123 Ozone generator

Claims (4)

pH3~5 conditions, in the presence of an amino acid and ozone isoelectric point exceeds 5, characterized by washing the cut vegetable or fruit, cut vegetable or fruit cleaning method. The cut vegetables or fruits according to claim 1, wherein the cut vegetables or fruits are washed with water containing 10 to 1000 ppm by mass of the amino acid and ozone and having a pH of 3 to 5. How to wash vegetables or fruits. The method for washing a cut vegetable or fruit according to claim 1 or 2 , wherein the amino acid is glycine. Furthermore, the C1-C10 fatty acid glyceride is used together, The cutting method of the cut vegetables or fruits of any one of Claims 1-3 characterized by the above-mentioned.

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