JP2023004434A - Dish washing method - Google Patents

Abstract

To suppress increase in recontamination of dishes and the like by contaminants in washing liquid when washing dishes under a washing condition that contaminants are mixed in the washing liquid by using an automatic dishwasher equipped with a washing liquid tank for storing washing liquid and a washing tank where the washing liquid supplied from the washing liquid tank is caused to be brought into contact with the dishes.SOLUTION: At least a part of washing liquid used for washing dishes is recovered in a washing liquid tank, and is reused at least as a part of new washing liquid. After a protein in the reused washing liquid is degraded, the washing liquid is brought into contact with dishes.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for washing dishes and a detergent composition for automatic dishwashers. In particular, it relates to a method of washing dishes using an automatic dishwasher.

In recent years, among automatic dishwashers, water-saving automatic dishwashers that use less than half the rinsing water of conventional automatic dishwashers have become popular.
Automatic dishwashers include a conveyor type in which tableware and the like are set on a conveyor, a door type in which a door is opened and closed to take in and out dishes and the like, and an under-counter type which is provided under the counter. In hotels, catering establishments, restaurants, pubs, convenience stores, and the like, automatic dishwashers of a preferred type are used according to the amount of dishes to be washed, installation space, and the like. From the viewpoint of reducing the amount of detergent used and running costs, efforts are being made to reduce the amount of water used in all automatic dishwashers. In an automatic dishwashing machine, for example, the cleaning liquid in the cleaning liquid tank is circulated to wash dishes, etc., and then this cleaning liquid is collected in the cleaning liquid tank for reuse in the next wash, and all or part of the rinse water is used. is made to flow into the cleaning liquid tank, and the dirt accumulated in the cleaning liquid tank is overflowed and discharged.

Patent Document 1 discloses (A-1) methylglycine diacetate and its alkali metal salt, (A-2) citric acid and its alkali metal salt, and (B-1) a predetermined nonionic surfactant, An automatic dishwashing detergent composition is disclosed.
Patent Document 2 discloses (A) a predetermined nonionic surfactant, (B) a predetermined nonionic surfactant, (C) alkanolamine, (D) an enzyme, (E) n-hexyl glycoside, (F) Disclosed is a liquid hard surface cleaner composition for use in an automatic dishwashing machine containing a calcium additive, (G) water.
U.S. Pat. No. 5,400,000 discloses an automatic dishwashing detergent composition comprising (a) a predetermined ester and (b) a bleach activator.
Patent Document 4 describes a dishwasher containing (a) a nonionic surfactant, (b) a polymer chelating agent, (c) a specific weakly acidic or weakly alkaline water-soluble electrolyte, and a detergent enzyme. Disclosed is a cleaning composition for .

WO2013/175659 JP 2018-024723 A JP 2012-214539 A JP 2005-154716 A

In water-saving automatic dishwashers, rinsing water is also conserved, so there is a tendency for the reused washing liquid to accumulate more dirt. In particular, automatic dishwashing machines for business use have a large number of times of washing, so this tendency is remarkable, and dirt tends to accumulate on tableware and the like due to repeated use and washing of tableware.
When the dishes, etc. are washed repeatedly under the washing condition that dirt is mixed in the washing liquid, the re-contamination of the dishes, etc. due to the dirt in the washing liquid increases, and the repeated washing tends to accumulate the dirt on the dishes, etc.
Therefore, in automatic dishwashers, it is required to suppress an increase in recontamination of tableware and the like due to dirt in the washing liquid when washing is performed under washing conditions in which dirt is mixed in the washing liquid.

SUMMARY OF THE INVENTION The present invention provides a method for washing tableware that suppresses an increase in recontamination of the tableware and the like due to dirt in the washing liquid when washing is performed under washing conditions in which dirt is mixed in the washing liquid.

The present invention relates to a method for washing dishes using an automatic dishwasher, comprising a washing liquid tank containing a washing liquid, and a washing tank for bringing the washing liquid supplied from the washing liquid tank into contact with the dishes, comprising:
At least part of the cleaning liquid used for washing the dishes is collected in the cleaning liquid tank and reused as at least part of the new cleaning liquid, and after decomposing proteins in the reused cleaning liquid, the cleaning liquid is brought into contact with the dishes. related to a method for washing tableware.

The present invention also provides a detergent composition for automatic dishwashers used in the above method for washing dishes, comprising (a) a proteolytic enzyme, (b) an alkaline agent and (c) a nonionic surfactant. It relates to a detergent composition for automatic dishwashers containing.

According to the present invention, it is possible to provide a method for washing tableware that suppresses an increase in recontamination of the tableware and the like due to dirt in the washing liquid when washing is performed under washing conditions in which dirt is mixed in the washing liquid.

The inventors analyzed the dirt accumulated in the washing liquid of the automatic dishwasher and the adhered components of the dishes recontaminated by the dirt in the washing liquid. It was found that the composition ratio of the adhering dirt was different. For example, it was found that even if the constituent ratios of stains accumulated in the washing liquid were lipid, protein, and sugar in descending order, protein stains were relatively abundant in the redeposited components adhering to the tableware. This is because when the protein is exposed to high temperatures in the washing process of tableware, especially in the process of rinsing, where the amount of proteolytic enzymes is extremely small, the protein becomes hydrophobic due to heat denaturation, making it easier to stick to the tableware. Conceivable.
Based on these findings, the inventors have made intensive studies and completed the present invention. In the method of washing tableware of the present invention, the washing liquid used for washing is recovered and reused as a new washing liquid. decompose. As a result, it is possible to suppress reattachment of dirt accumulated in the cleaning liquid to the tableware, and also to suppress the accumulation of dirt on the tableware even when the tableware is washed repeatedly. That is, when washing is performed under washing conditions in which dirt is mixed in the washing liquid, it is possible to suppress the increase in recontamination of the tableware, etc. due to the dirt in the washing liquid, and it is thought that the finish of the tableware, etc. is improved. In addition, when repeatedly washing and using the dishes using the cleaning solution, the parts of the dishes that are not in direct contact with the ingredients, such as the back of the dishes and the glass cups used to drink water, etc. Adhesion and accumulation of dirt in the cleaning liquid are suppressed. As a result, it is considered that the degree of deterioration of the finish of the tableware is reduced, and the finish of the tableware and the like is improved.

A method for washing dishes according to the present invention is a method for washing dishes using an automatic dishwasher comprising a washing liquid tank containing a washing liquid, and a washing tank for bringing the washing liquid supplied from the washing liquid tank into contact with the dishes. ,
At least part of the cleaning liquid used for washing the dishes is collected in the cleaning liquid tank and reused as at least part of the new cleaning liquid, and after decomposing proteins in the reused cleaning liquid, the cleaning liquid is brought into contact with the dishes. It is a method of washing tableware that allows

In the tableware washing method of the present invention, the washing liquid is reused one or more times. From the viewpoint that the effects of the present invention can be obtained more remarkably, the dishwashing method of the present invention is preferably a dishwashing method in which the cleaning liquid is reused two or more times, more preferably three times or more, and still more preferably. It is 4 times or more, and more preferably 5 times or more. As the number of times the washing liquid is reused increases, the effect of the method for washing tableware of the present invention becomes more pronounced.
From the standpoint that the effects of the present invention can be obtained more remarkably, the method for washing tableware of the present invention is preferably a method of washing tableware in which the same tableware is washed twice or more using the washing liquid, and more preferably three times. or more, more preferably 4 times or more, and even more preferably 5 times or more. The effect of the method for washing tableware of the present invention becomes more pronounced as the number of times the same tableware is washed using the washing liquid again increases. Here, washing the same tableware twice or more by using the washing liquid again includes using the tableware after washing and then subjecting the used tableware to the next washing.

Decomposition of proteins in the cleaning solution can be carried out by adding (a) a proteolytic enzyme (hereinafter referred to as component (a)) or a cleaning composition containing component (a) to the cleaning solution in the cleaning tank and/or the cleaning solution tank. . Component (a) or a cleaning composition containing component (a) can be added directly to the cleaning liquid in the cleaning tank and/or cleaning liquid tank, or to the cleaning liquid sent to the cleaning tank and/or cleaning liquid tank.

First, the component (a) used in the method for washing tableware of the present invention will be described.

<(a) Protease>
Component (a) is a proteolytic enzyme. As component (a), one or more proteolytic enzymes selected from proteases and peptidases can be used, and proteases are preferred. Component (a) is not particularly limited as long as it is commonly used in detergent compositions. carboxypeptidase A, carboxypeptidase B, aminopeptidase, aspergylopeptidase A, aspergylopeptidase B and the like. Crude enzymes and their granules can be used as well as their purified fractions. Commercially available enzymes (protease formulations) include, for example, alkaline proteases such as Ovozyme, Savinase, Evalase, Alcalase, Esperase, Kannase, Durazyme (registered trademark; manufactured by Novozyme), Maxatase, Maxapem, Maxacal, Properase, Plafect, Profect OX (registered trademark; manufactured by Genencore), Brap (registered trademark; manufactured by Henkel), KAP (manufactured by Kao Corporation), API21 (manufactured by Showa Denko Co., Ltd.), Neutrase (registered trademark; Novozyme) as a neutral protease company). As component (a), alkaline protease can be particularly preferably used.

Next, the detergent composition for automatic dishwashers (hereinafter also referred to as the detergent composition of the invention) used in the method for washing tableware of the invention will be described.

<Cleaning agent composition>
The cleaning composition of the present invention contains component (a). The cleaning composition of the present invention can contain one or more of the components (a) as described above. In addition to component (a), the detergent composition of the present invention contains (b) an alkaline agent [hereinafter referred to as component (b)], (c) a surfactant [hereinafter referred to as component (c)] and (d). ) one or more selected from chelating agents [hereinafter referred to as component (d)].
The detergent composition of the present invention is a detergent composition for automatic dishwashers used in the method of washing dishes of the present invention, comprising (a) a proteolytic enzyme, (b) an alkaline agent and (c) a nonionic It may be an automatic dishwashing detergent composition containing a surfactant.
Further, the detergent composition of the present invention is a detergent composition for automatic dishwashers used in the method of washing dishes of the present invention, comprising (a) a proteolytic enzyme, (b) an alkaline agent and (d) It may be an automatic dishwashing detergent composition containing a chelating agent.

Component (b) is an alkaline agent. As the alkaline agent, one or more selected from alkali metal hydroxides, alkali metal carbonates, alkali metal silicates and amine compounds can be used.
Examples of alkali metal hydroxides include sodium hydroxide and potassium hydroxide.
Alkali metal carbonates include sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate. Anhydrous salt of sodium carbonate known as soda ash may also be used as component (b).
Examples of alkali metal silicates include sodium silicate and potassium silicate. Examples of sodium silicate include sodium orthosilicate, sodium metasilicate, sodium silicate No. 1, sodium silicate No. 2, sodium silicate No. 3, sodium metasilicate pentahydrate, sodium metasilicate nonahydrate and the like. Potassium silicates include potassium orthosilicate, potassium metasilicate, A potassium silicate, B potassium silicate, and C potassium silicate. Specifically, as the component (b), crystalline layered sodium silicate (manufactured by Tokuyama Co., Ltd., "PURIFEED") and the like can be used. Also, an amorphous alkali metal silicate may be used. The alkali metal silicate is also effective as an antioxidant for tableware.
Alkanolamine can be mentioned as an amine compound. In the present invention, primary alkanolamines are particularly preferred, and specific examples include monoethanolamine. Among these alkali agents, alkali metal carbonates are preferred.
The alkaline agent can be used in the form of powder or granules. Granules can be used by appropriately adjusting the particle size and bulk specific gravity by granulation treatment or the like.

Component (c) is a surfactant. Component (c) includes one or more selected from nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. , and anionic surfactants are preferred, and nonionic surfactants are more preferred.

Nonionic surfactants include, for example, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyalkylene dialkyl ethers, polyoxyethylene alkenyl ethers, polyoxyalkylene alkylphenyl ethers, reverse pluronic block polymers, reverse Tetronic block polymer, sucrose fatty acid ester, sorbitan fatty acid ester, polyethylene glycol fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, propylene glycol fatty acid ester, polypropylene glycol fatty acid ester, coconut fatty acid diethanolamide, lauric acid diethanolamide, lauric acid myristic acid diethanolamide, myristic acid diethanolamide, oleic acid diethanolamide, palm kernel fatty acid diethanolamide, alkyl glucosides, amine oxides and the like. A reverse pluronic block polymer and a reverse tetronic block polymer are preferred. These nonionic surfactants may be used alone or in combination of two or more.

(d) Component is a chelating agent. As component (d), one or more chelating agents selected from aminocarboxylic acid-based, hydroxycarboxylic acid-based, phosphoric acid-based, ether carboxylate, and phosphonic acid-based chelating agents can be used.

Aminocarboxylic acid-based chelating agents include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), methylglycinediacetic acid (MGDA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylethylenediaminetriacetic acid (HEDTA), triethylene Tetraminehexaacetic acid (TTHA), glutamic diacetic acid (GLDA), hydroxyethyliminodiacetic acid (HIDA), dihydroxyethylglycine (DHEG), 1,3-propanediaminetetraacetic acid (PDTA), 1,3-diamino-2- Hydroxypropanehexaacetic acid (DPTA-OH), aspartic acid diacetic acid (ASDA), ethylenediaminesuccinic acid (EDDS), salts thereof, and the like.

Examples of hydroxycarboxylic acid-based chelating agents include malic acid, succinic acid, citric acid, lactic acid, tartaric acid, gluconic acid, and salts thereof.
Examples of phosphoric acid-based chelating agents include tripolyphosphoric acid and hexametaphosphate.

Phosphonic acid-based chelating agents include hydroxyethylidene diphosphonic acid (HEDP), nitrilotrismethylene phosphonic acid (NTMP), phosphonobutanetricarboxylic acid (PBTC), ethylenediaminetetramethylene phosphonic acid (EDTMP), salts thereof, and the like. mentioned.

Salts in the chelating agent include, for example, salts of alkali metals such as potassium and sodium, and salts of alkaline earth metals such as magnesium and calcium. Among them, alkali metal salts are preferable, and sodium salts or potassium salts are more preferable.

In the detergent composition of the present invention, the concentration of component (a) at the time of use is preferably 0.000005% by mass or more, more preferably 0.000007% by mass or more, in terms of enzyme protein, from the viewpoint of proteolytic performance. , more preferably 0.000009 mass % or more, still more preferably 0.00003 mass % or more, still more preferably 0.00005 mass % or more, still more preferably 0.0001 mass % or more, still more preferably 0.00001 mass % or more 0002% by mass or more, and from the viewpoint of reducing skin irritation, preferably 0.05% by mass or less, more preferably 0.045% by mass or less, even more preferably 0.04% by mass or less, and even more preferably 0.04% by mass or less. 035% by mass or less, more preferably 0.03% by mass or less. The enzyme protein of component (a) can be quantified using, for example, the Lowry method. For quantification of enzyme protein using the Lowry method, for example, Protein Assay Lowry Kit (manufactured by nacalai tespue) can be used.

When the cleaning composition of the present invention contains the component (b), the concentration of the component (b) at the time of use is preferably 0.00010% by mass or more from the viewpoint of detergency. , more preferably 0.0005% by mass or more, more preferably 0.0010% by mass or more, and from the viewpoint of reducing skin irritation, preferably 0.30% by mass or less, more preferably 0.28% by mass or less, More preferably, it is 0.26% by mass or less.

When the cleaning composition of the present invention contains component (c), the concentration of component (c) in the cleaning composition of the present invention is preferably 0.00001% by mass or more from the viewpoint of detergency at the time of use. , More preferably 0.00002% by mass or more, more preferably 0.00003% by mass or more, and from the viewpoint of blending stability, preferably 0.075% by mass or less, more preferably 0.070% by mass or less, and further Preferably, it is 0.065% by mass or less.

When the cleaning composition of the present invention contains the component (d), the cleaning composition of the present invention preferably has a concentration of the component (d) at the time of use of 0.0001 mass from the viewpoint of scale adhesion suppression performance. % or more, more preferably 0.0002% by mass or more, more preferably 0.0004% by mass or more, and from the viewpoint of blending stability, preferably 0.25% by mass or less, more preferably 0.23% by mass or less , and more preferably 0.20% by mass or less.

When the detergent composition of the present invention contains component (c), the mass ratio (a)/(c) of the content of component (a) to the content of component (c) is, from the viewpoint of proteolytic performance, Preferably 0.00015 or more, more preferably 0.00017 or more, still more preferably 0.00020 or more, and from the viewpoint of washability, preferably 4.5 or less, more preferably 4.0 or less, still more preferably 3.0 or less. The component (a) is the amount in terms of enzyme protein.

The pH of the detergent composition of the present invention at 25°C is preferably 9 or more and 12 or less. The cleaning composition of the present invention preferably has a pH of 10 or more and 12 or less at 25° C. in a 0.1 mass % aqueous solution of the following concentrated cleaning composition. The pH of the diluted washing solution can be measured according to JIS K3362.

The detergent composition of the present invention may also contain bleaching agents, antifoaming agents, rust preventives, hydrotropic agents, surface modifiers, fragrances and the like.

The cleaning composition of the present invention can be used by diluting a concentrated cleaning composition. The cleaning composition of the present invention can be diluted and used so that the concentration of the concentrated cleaning composition is, for example, 0.01% by mass or more and 0.5% by mass or less.

In the concentrated detergent composition, component (a) is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, and still more preferably 0% by mass, in terms of enzyme protein, from the viewpoint of proteolytic performance. 0.09% by mass or more, more preferably 0.10% by mass or more, still more preferably 0.15% by mass or more, and from the viewpoint of reducing skin irritation, preferably 12% by mass or less, more preferably 11% by mass % or less, more preferably 10% by mass or less, even more preferably 9% by mass or less, even more preferably 8% by mass or less, even more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably is 1% by mass or less. The enzyme protein of component (a) can be quantified using, for example, the Lowry method. For quantification of enzyme protein using the Lowry method, for example, Protein Assay Lowry Kit (manufactured by nacalai tespue) can be used.

When the detergent composition of the present invention contains component (b), the component (b) in the concentrated detergent composition is preferably 1% by mass or more, more preferably 3% by mass, from the viewpoint of detergency. Above, more preferably 5% by mass or more, and from the viewpoint of reducing skin irritation, preferably 70% by mass or less, more preferably 68% by mass or less, and even more preferably 66% by mass or less.

When the cleaning composition of the present invention contains component (c), the concentration of component (c) in the concentrated cleaning composition is preferably 0.1% by mass or more, more preferably 0%, from the viewpoint of detergency. .2% by mass or more, more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, and from the viewpoint of blending stability, preferably 15% by mass or less, more preferably 14% by mass or less , more preferably 13% by mass or less, still more preferably 10% by mass or less.

When the detergent composition of the present invention contains the component (d), the component (d) in the concentrated detergent composition is preferably 1% by mass or more, more preferably 3% by mass, from the viewpoint of anti-scaling performance. % by mass or more, more preferably 5% by mass or more, and from the viewpoint of blending stability, preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

Concentrated detergent compositions may be in either solid or liquid form. The detergent composition of the present invention is preferably in the form of a solid, that is, a solid block, granules, powder, or the like, and is more preferably powdery from the viewpoint of ensuring workability and storage stability of the detergent.

<How to wash dishes>
Next, the method for washing tableware of the present invention will be described in detail. In the explanation of the method for washing dishes, an automatic dishwasher provided with a washing liquid tank containing washing liquid and a washing tank for bringing the washing liquid supplied from the washing liquid tank into contact with the dishes will be described as an example. It should be noted that the dishwashing method of the present invention is not limited to the disclosed embodiments.

When washing dishes, the washing liquid stored in the washing liquid tank is sent to the washing tank, and the dishes are washed by bringing the washing liquid into contact with the dishes in the washing tank. The cleaning liquid stored in the cleaning liquid tank contains the component (a) in advance, and at least part of the protein contained in the cleaning liquid from the previous cleaning has been decomposed before being sent to the cleaning tank. be. When washing tableware, if necessary, component (a) or a detergent composition containing component (a) may be added to the washing tank or the washing liquid sent to the washing tank. In washing dishes, for example, the washing liquid can be sprayed to bring the washing liquid into contact with the dishes.
Tableware to be washed includes, for example, cups, glasses, bowls, bowls, chopsticks, plates, knives, forks, spoons, etc. made of various materials such as ceramics, glass, melamine resin, polycarbonate resin, wood, metal, etc. Items that can be washed with an automatic dishwasher, such as cooking utensils, can be mentioned. Any of the dishes to be washed is a dish to which at least protein stains are adhered.

The temperature of the washing liquid during dishwashing is preferably 40° C. or higher, more preferably 42° C. or higher, and still more preferably 44° C. or higher from the viewpoint of washing performance, and preferably 70° C. or lower, more preferably 70° C. or higher from the viewpoint of protein decomposition performance. It is preferably 68° C. or lower, more preferably 66° C. or lower.

From the viewpoint of cleaning power, the supply amount of the cleaning liquid during dishwashing is preferably 0.008 L/sec or more, more preferably 0.010 L/sec or more, still more preferably 0.012 L/sec or more, and even more preferably 0. 0.03 L/sec or more, still more preferably 0.04 L/sec or more, still more preferably 0.05 L/sec or more, still more preferably 0.08 L/sec or more, still more preferably 0.10 L/sec or more, Even more preferably 0.12 L/sec or more, and from the viewpoint of workability, preferably 200 L/sec or less, more preferably 190 L/sec or less, still more preferably 180 L/sec or less, and even more preferably 160 L/sec or less. , still more preferably 8.0 L/sec or less, still more preferably 7.8 L/sec or less, still more preferably 7.6 L/sec or less, still more preferably 3.0 L/sec or less, still more preferably 2 0.8 L/sec or less, more preferably 2.6 L/sec or less.

In addition, from the viewpoint of workability, the supply time of the cleaning liquid per one washing process for tableware is preferably 5.0 seconds or longer, more preferably 5.5 seconds or longer, still more preferably 6.0 seconds or longer, and still more preferably 6.0 seconds or longer. preferably 7.0 seconds or more, more preferably 20 seconds or more, still more preferably 22 seconds or more, still more preferably 24 seconds or more, and from the viewpoint of workability, preferably 180 seconds or less, more preferably 170 seconds seconds or less, more preferably 160 seconds or less, even more preferably 125 seconds or less, even more preferably 120 seconds or less, even more preferably 115 seconds or less, even more preferably 110 seconds or less, even more preferably 100 seconds or less, Still more preferably 95 seconds or less, still more preferably 90 seconds or less, still more preferably 60 seconds or less, still more preferably 55 seconds or less, and even more preferably 50 seconds or less.

When the automatic dishwashing machine is of the undercounter type, the supply amount of the cleaning liquid during dishwashing is preferably 0.008 L/sec or more, more preferably 0.010 L/sec or more, and still more preferably 0, from the viewpoint of washing power. 012 L/sec or more, and from the viewpoint of workability, it is preferably 3.0 L/sec or less, more preferably 2.8 L/sec or less, and even more preferably 2.6 L/sec or less.
In addition, when the automatic dishwasher is an undercounter type, the supply time of the washing liquid per washing step is preferably 20 seconds or longer, more preferably 22 seconds or longer, and still more preferably 24 seconds or longer, from the viewpoint of workability. From the viewpoint of workability, it is preferably 120 seconds or less, more preferably 115 seconds or less, and even more preferably 110 seconds or less.

When the automatic dishwasher is a door type, the amount of washing liquid supplied during washing dishes is preferably 0.03 L/sec or more, more preferably 0.04 L/sec or more, and still more preferably 0.04 L/sec or more, from the viewpoint of washing power. 05 L/sec or more, and from the viewpoint of workability, it is preferably 8.0 L/sec or less, more preferably 7.8 L/sec or less, and even more preferably 7.6 L/sec or less.
In addition, when the automatic dishwasher is a door type, the supply time of the washing liquid per washing step is preferably 20 seconds or longer, more preferably 22 seconds or longer, and still more preferably 24 seconds or longer, from the viewpoint of workability. , from the viewpoint of workability, it is preferably 100 seconds or less, more preferably 95 seconds or less, and still more preferably 90 seconds or less.

When the automatic dishwashing machine is of the conveyor type, the supply amount of the cleaning liquid during dishwashing is preferably 0.08 L/sec or more, more preferably 0.10 L/sec or more, and still more preferably 0.08 L/sec or more, from the viewpoint of washing power. 12 L/sec or more, and from the viewpoint of workability, it is preferably 200 L/sec or less, more preferably 190 L/sec or less, still more preferably 180 L/sec or less.
In addition, when the automatic dishwasher is of conveyor type, the supply time of the washing liquid per washing step is preferably 5.0 seconds or more, more preferably 5.5 seconds or more, and still more preferably 6 seconds or more, from the viewpoint of workability. 0 seconds or more, and from the viewpoint of workability, it is preferably 60 seconds or less, more preferably 55 seconds or less, and even more preferably 50 seconds or less.

When washing the dishes, the washing liquid after contacting the dishes can be pumped up by a pump and brought into contact with the dishes again. In other words, the washing liquid to be brought into contact with the dishes can be circulated in the washing tank to bring the washing liquid into contact with the dishes a plurality of times.

After washing the dishes, the dishes are rinsed. For example, after washing dishes, the washing liquid in the washing tank is collected in the washing tank, and then rinsing water such as tap water is supplied to the washing tank. Then, the dishes are rinsed by contacting the dishes with rinsing water in the washing tank. When rinsing the dishes, the rinse water can be sprayed to bring the rinse water into contact with the dishes.
Some or all of the rinse water can be directed to the wash liquid tank after contacting the dishes. The amount exceeding the capacity of the washing liquid tank is discharged to the outside of the automatic dishwasher as waste water. In this way, the washing liquid collected from the washing tank into the washing tank and diluted with the rinsing water is reused as the washing liquid for washing the next tableware. When the rinsing water is sent to the washing tank, the rinsing water can also be collected in the washing tank after previously discharging part of the washing liquid in the washing tank.

The total amount of rinsing water used in one rinsing step is preferably 0.3 L or more, more preferably 0.5 L or more, and still more preferably 0.7 L per ¹ m3 of the washing tank from the viewpoint of finish. From the viewpoint of reducing the amount of water used, it is preferably 300 L or less, more preferably 250 L or less, and even more preferably 200 L or less.

When the temperature of the rinse water is high, proteins, which are slightly present in the rinse water, are more likely to be denatured, and re-staining of the stains on tableware is more likely to occur. The temperature of the rinsing water is preferably 50°C or higher, more preferably 53°C or higher, and even more preferably 55°C or higher, from the viewpoint of easily obtaining the effect of the present invention, that is, the effect of lowering the degree of increase in recontamination due to repeated washing. And, from the viewpoint of reducing redeposition of tableware due to suppression of heat denaturation of proteins, the temperature is preferably 95° C. or lower, more preferably 93° C. or lower, and still more preferably 90° C. or lower.

The ratio of the total amount of rinsing water used in one rinsing process to the total amount of cleaning liquid present in the cleaning liquid tank is preferably 0.0004 or more, more preferably 0.0005 or more, and still more preferably 0.0005 or more, from the viewpoint of finish quality. 0.0007 or more, more preferably 0.0009 or more, and from the viewpoint of saving water, it is preferably 0.40 or less, more preferably 0.38 or less, and still more preferably 0.36 or less.
In addition, the amount of rinse water supplied during rinsing is preferably 0.008 L/sec or more, more preferably 0.010 L/sec or more, and still more preferably 0.012 L/sec or more, from the viewpoint of finish quality. from the viewpoint of, it is preferably 3.5 L/sec or less, more preferably 3.3 L/sec or less, and still more preferably 3.1 L/sec or less.
In addition, the supply time of rinsing water per rinsing step is preferably 2 seconds or longer, more preferably 3 seconds or longer, and still more preferably 4 seconds or longer from the viewpoint of cleaning performance, and from the viewpoint of water saving, preferably It is 60 seconds or less, more preferably 58 seconds or less, still more preferably 56 seconds or less.

When the automatic dishwasher is an under-counter type, the ratio of the total amount of rinse water used per rinse step to the total amount of cleaning liquid present in the cleaning liquid tank is preferably 0.03 or more from the viewpoint of finish. It is more preferably 0.04 or more, still more preferably 0.05 or more, and from the viewpoint of saving water, it is preferably 0.40 or less, more preferably 0.38 or less, and still more preferably 0.36 or less.
In addition, when the automatic dishwasher is an under-counter type, the amount of rinse water supplied during rinsing is preferably 0.08 L/sec or more, more preferably 0.10 L/sec or more, and still more preferably, from the viewpoint of finish quality. is 0.12 L/sec or more, and from the viewpoint of water saving, it is preferably 1.0 L/sec or less, more preferably 0.9 L/sec or less, and still more preferably 0.8 L/sec or less.
In addition, when the automatic dishwasher is an undercounter type, the rinse water supply time per rinse step is preferably 4.0 seconds or more, more preferably 4.5 seconds or more, from the viewpoint of cleaning performance. It is preferably 5.0 seconds or longer, and from the viewpoint of saving water, is preferably 20 seconds or shorter, more preferably 18 seconds or shorter, and still more preferably 16 seconds or shorter.

When the automatic dishwasher is a door type, the ratio of the total amount of rinse water used per rinse process to the total amount of cleaning liquid present in the cleaning liquid tank is preferably 0.010 or more, more It is preferably 0.012 or more, more preferably 0.014 or more, and from the viewpoint of saving water, it is preferably 0.20 or less, more preferably 0.18 or less, and still more preferably 0.16 or less.
In addition, when the automatic dishwasher is a door type, the amount of rinse water supplied during rinsing is preferably 0.08 L/sec or more, more preferably 0.10 L/sec or more, and still more preferably It is 0.12 L/sec or more, and from the viewpoint of saving water, it is preferably 1.0 L/sec or less, more preferably 0.9 L/sec or less, and still more preferably 0.8 L/sec or less.
In addition, when the automatic dishwasher is a door type, the rinse water supply time per rinse step is preferably 4.0 seconds or longer, more preferably 4.5 seconds or longer, and still more preferably 4.5 seconds or longer, from the viewpoint of cleaning performance. is 5.0 seconds or more, and preferably 20 seconds or less, more preferably 18 seconds or less, still more preferably 16 seconds or less from the viewpoint of saving water.

When the automatic dishwasher is a conveyer type, the ratio of the total amount of rinse water used per rinse step to the total amount of cleaning liquid present in the cleaning liquid tank is preferably 0.0004 or more, from the viewpoint of finish quality. It is preferably 0.0005 or more, more preferably 0.0006 or more, and from the viewpoint of saving water, it is preferably 0.08 or less, more preferably 0.07 or less, and still more preferably 0.06 or less.
When the automatic dishwashing machine is of conveyor type, the amount of rinse water supplied during rinsing is preferably 0.008 L/sec or more, more preferably 0.010 L/sec or more, and still more preferably 0.012 L/sec or more, and from the viewpoint of saving water, it is preferably 2.5 L/sec or less, more preferably 2.4 L/sec or less, and still more preferably 2.3 L/sec or less.
In addition, when the automatic dishwasher is a conveyor type, the rinse water supply time per rinse step is preferably 2.0 seconds or longer, more preferably 2.2 seconds or longer, and still more preferably 2.2 seconds or longer, from the viewpoint of cleaning performance. is 2.4 seconds or more, and from the viewpoint of saving water, preferably 60 seconds or less, more preferably 58 seconds or less, even more preferably 56 seconds or less, even more preferably 20 seconds or less, and even more preferably 18 seconds or less, Even more preferably, it is 16 seconds or less.

The washing liquid stored in the washing liquid tank after washing the dishes contains at least proteins removed from the dishes by washing the dishes. In the method for washing tableware of the present invention, in the washing liquid collected in the washing liquid tank after washing the dishes, after the proteins in the washing liquid contained in the washing liquid due to the washing of the dishes are decomposed, the washing liquid is re-dissolved. , is sent from the washing liquid tank to the washing tank and reused as the washing liquid for washing the next tableware.
That is, in the method for washing dishes of the present invention, at least part of the washing liquid used for washing the dishes is recovered and reused as at least part of the washing liquid for the next tableware. Then, before contacting the reused cleaning liquid with the dishes again, the proteins in the cleaning liquid that are contained in the cleaning liquid due to the previous washing of the dishes are decomposed, and the protein-decomposed cleaning liquid is used as the next cleaning liquid. Used as a washing liquid for tableware.

Decomposition of proteins in the reusable cleaning fluid can be performed, for example, by adding component (a) to the cleaning fluid stored in the cleaning fluid tank. Here, the decomposition of protein refers to reducing the molecular weight of protein. Reduction of the molecular weight of a protein means, for example, decomposing the protein into those having a relative molecular mass of less than 25 kDa.

The smaller the content of proteins with a relative molecular mass of 25 kDa or more in the reused washing solution, the better the finished product. Therefore, the content of proteins with a relative molecular mass of 25 kDa or more in the reusable washing solution is preferably 3% by mass or less, more preferably 0.3% by mass or less, and even more preferably 0.3% by mass or less, from the viewpoint of finish quality. 03% by mass or less, more preferably 0.003% by mass or less, and even more preferably 0.0003% by mass or less. The content of protein in the cleaning liquid to be reused may be the content of protein in the cleaning liquid stored in the cleaning liquid tank (content of components (a) to (e) in the cleaning liquid to be reused). The same is true for quantity). The content of proteins of 25 kDa or more in the reused wash solution can be quantified, for example, by the following method. The above content may be the content of the cleaning liquid before being subjected to cleaning.

(Method for quantifying protein in washing solution)
To 16 μL of washing solution, 8 μL of sample buffer (3×SDS-PAGE Loading Buffer, Biovision) is added, stirred, and heated at 90° C. for 5 minutes. 15 μL of the sample is injected into a polyacrylamide gel (Mini-PROTEAN TGX Any kD Stain-Free Gel 12well, manufactured by Bio-Rad) and subjected to electrophoresis at 200 V for 25 minutes (PowerPac™ HC Basic, manufactured by Bio-Rad). TRIS/GLYCINE/SDS x10 BUFFER (manufactured by Bio-Rad) can be used as the running buffer, and Ezstain Aqua (manufactured by ATTA) can be used as the staining solution. Then, the band in the range from 25 kDa to 250 kDa is analyzed with image analysis software ImageJ. Based on a calibration curve obtained using albumin (Fuji Film Wako Pure Chemical Industries, Ltd.), proteins of 25 kDa or more in the reused washing solution are quantified.

The content of protein having a relative molecular weight of 25 kDa or more in the cleaning liquid recovered in the cleaning liquid tank (hereinafter referred to as the initial protein amount) is compared with the relative molecular weight in the cleaning liquid to be subjected to the next cleaning after being recovered in the cleaning liquid tank. The mass ratio [(undegraded protein amount) / (initial protein amount)] of the protein content of 25 kDa or more (hereinafter referred to as the undegraded protein amount) is, from the viewpoint of suppressing recontamination and dirt accumulation on the tableware, Preferably 0.0001 or more, more preferably 0.0002 or more, still more preferably 0.0003 or more, and from the viewpoint of suppressing recontamination of tableware and accumulation of dirt, preferably 0.7 or less, more preferably is 0.65 or less, more preferably 0.55 or less. In addition, after performing the 1st washing process which wash|cleans tableware by the washing method of this invention, you may perform the 2nd washing process once or more additionally. In the second washing step, the treatment liquid satisfies the condition that the mass ratio of the undegraded protein amount in the treatment liquid in the second step to the initial protein amount in the first washing step is 0.0001 or more and 0.7 or less. , it is preferable to wash dishes.

Component (a) is added to the washing solution so that the content of proteins with a relative molecular weight of 25 kDa or more in the washing solution to be reused or the mass ratio of [(amount of undegraded protein)/(amount of initial protein)] falls within the above range. The concentration and the concentration of the cleaning composition containing the component (a) are adjusted. These components can be added to the cleaning solution in the cleaning solution tank and/or cleaning bath or en route to the cleaning solution tank and/or cleaning bath.

The content of component (a) in the reusable washing solution is preferably 0.000005% by mass or more, more preferably 0.000007% by mass or more, more preferably 0.000007% by mass or more in terms of enzyme protein, from the viewpoint of proteolytic performance. 0.000009 mass % or more, more preferably 0.00003 mass % or more, still more preferably 0.00005 mass % or more, still more preferably 0.0001 mass % or more, still more preferably 0.0002 mass % or more And, from the viewpoint of reducing skin irritation, it is preferably 0.05% by mass or less, more preferably 0.045% by mass or less, even more preferably 0.04% by mass or less, and even more preferably 0.035% by mass or less. , and more preferably 0.03% by mass or less. The enzyme protein content of component (a) can be quantified using, for example, the Lowry method. For quantifying the enzyme protein by the Lowry method, for example, Protein Assay Lowry Kit (manufactured by nacalai tespue) can be used.

In the cleaning solution to be reused, the content of component (b) is preferably 0.00010% by mass or more, more preferably 0.0005% by mass or more, and still more preferably 0.0010% by mass or more, from the viewpoint of cleaning performance. And, from the viewpoint of reducing skin irritation, it is preferably 0.30% by mass or less, more preferably 0.28% by mass or less, and still more preferably 0.26% by mass or less.

The content of component (c) in the reusable cleaning liquid is preferably 0.00001% by mass or more, more preferably 0.00002% by mass or more, and still more preferably 0.00003% by mass or more, from the viewpoint of cleaning performance. And, from the viewpoint of blending stability, it is preferably 0.075% by mass or less, more preferably 0.070% by mass or less, and still more preferably 0.065% by mass or less.

The content of component (d) in the reusable cleaning liquid is preferably 0.0001% by mass or more, more preferably 0.0002% by mass or more, and still more preferably 0.0004% by mass, from the viewpoint of scale adhesion suppression performance. % or more, and from the viewpoint of blending stability, it is preferably 0.25% by mass or less, more preferably 0.23% by mass or less, and even more preferably 0.20% by mass or less.

The pH of the reusable cleaning solution is preferably 9.0 or higher, more preferably 9.2 or higher, and still more preferably 9.4 or higher from the viewpoint of cleaning performance, and preferably 9.4 or higher from the viewpoint of reducing skin irritation. It is 12.0 or less, more preferably 11.8 or less, still more preferably 11.6 or less. The pH is the pH at the temperature of the wash solution, but the wash solution may have a pH of 25°C. The pH of the cleaning solution can be measured according to JIS K3362. The amount of component (b) to be added may be determined so that the pH of the cleaning solution falls within this range.

The temperature of the washing liquid in the washing liquid tank is preferably 40° C. or higher, more preferably 42° C. or higher, still more preferably 44° C. or higher from the viewpoint of washing performance, and preferably 70° C. or lower from the viewpoint of proteolytic performance. It is more preferably 68° C. or lower, still more preferably 66° C. or lower.

If necessary, the cleaning liquid contained in the cleaning liquid tank and the cleaning liquid or rinsing water sent to the cleaning liquid tank may be added with the components (a) and (a) so that the components (a) to (d) are within the above ranges. ) component can be provided.

From the viewpoint of sufficiently decomposing or denaturing the protein in the cleaning solution to be reused, the time for which the cleaning solution is retained in the cleaning solution tank is preferably 10 seconds or longer, more preferably 60 seconds or longer, and still more preferably 300 seconds or longer, and From the viewpoint of enzyme stability, it is preferably 50,000 seconds or less, more preferably 40,000 seconds or less, and even more preferably 30,000 seconds or less.

In the dishwashing method of the present invention, the tableware washing step, the tableware rinsing step, the step of decomposing proteins in the reused cleaning liquid, and the step of subjecting the protein-decomposed cleaning liquid to the next tableware washing step, Washing of dishes is repeated several times. After the tableware rinsing process, washed tableware is taken out, and before the tableware washing process, dirty tableware is brought in. Further, after the tableware rinsing process, if the concentration of the component (a) and the detergent composition in the cleaning liquid contained in the cleaning liquid tank is sufficient, the component (a) and the detergent composition are supplied before the tableware washing process. can be omitted.

Thus, in the method for washing tableware of the present invention, the protein in the reusable washing liquid is decomposed to reduce the molecular weight of the protein, thereby suppressing the hydrophobization (heat denaturation) of the protein and allowing the protein to adhere to the tableware. It is thought that it suppresses the re-adhesion of stains or the accumulation of stains on tableware. In other words, the method for washing tableware of the present invention can suppress an increase in recontamination of the tableware due to dirt in the washing liquid when washing is performed under washing conditions in which dirt is mixed in the washing liquid, and the washing finish of the tableware is improved. . In addition, the content of component (a) in the cleaning liquid is very small compared to the content of protein derived from stains on the dishes, so the effect on the finish can be ignored, so the protein content in the cleaning liquid is ( It is the content excluding the a) component.

The method for washing tableware of the present invention can be used for automatic dishwashing machines for commercial and domestic use. is suitable for commercial automatic dishwashing machines that require a large amount of washing and are washed many times a day. At that time, the washing method of the tableware of the present invention can reattach accumulated dirt in the washing liquid to the tableware even when the amount of rinsing water used is small (for example, 2 to 3 L per 2500 cm ² horizontal tableware setting/per rinsing). It is possible to suppress the accumulation of dirt on dishes and tableware. In other words, the method for washing tableware of the present invention can suppress an increase in recontamination of the tableware due to dirt in the washing liquid when washing is performed under washing conditions in which dirt is mixed in the washing liquid, and the washing finish of the tableware is improved. .

The tableware washing method of the present invention is suitable for a water-saving automatic dishwashing machine. A water-saving automatic dishwashing machine is, for example, an automatic dishwashing machine that can perform water-saving washing by rinsing with less water than a conventional automatic dishwashing machine. Also includes automatic dishwashers with functions. For example, in a conventional automatic dishwasher, the amount of water required for one rinse is 4 to 6 L per 2500 cm ² horizontal tableware installation surface, but in a water-saving automatic dishwasher, the amount of water required for one rinse is It is 2 to 3 L per 2500 cm ² horizontal tableware installation surface, further less than 2 L, further less than 1 L. Therefore, a water-saving automatic dishwashing machine that can perform rinsing with an amount of water per rinsing of 2 to 3L per 2,500 cm ² horizontal tableware installation surface, further less than 2L, and further less than 1L may be used.

[Method for evaluating degree of contamination]
Put 55 L of warm water (German hardness 3 ° dH) at 60 ° C. into the washing liquid tank of a commercial dishwasher (manufactured by Hoshizaki Co., Ltd., JWA-680A), and in the case of Table 1, fresh cream ( Product name: fresh pure milk fat, manufactured by Megmilk Snow Brand Co., Ltd.) 55.6 g, curry powder (product name: curry mix, manufactured by Isbee Foods Co., Ltd.) 55.6 g, margarine (product name: Neosoft, manufactured by Megmilk Snow Brand Co., Ltd.) ) 55.6 g, 27.8 g of rapeseed oil (Fujifilm Wako Pure Chemical Co., Ltd.), 27.8 g of ketchup (trade name: tomato ketchup, manufactured by Kagome Co., Ltd.), and 55.6 g of raw eggs (Akita Foods Co., Ltd.). and stirred until uniform. Similarly, in the case of Tables 2 and 3, 55 L of warm water (German hardness 3 ° dH) of 60 ° C. is put in the cleaning liquid tank, and further albumin (Fujifilm Wako Pure Chemical Co., Ltd.) 10 g (initial protein amount 182 mg/L) or 60 g (initial protein amount 1091 mg/L) was added and stirred to be uniform.
Next, the detergent composition shown in the table was added to this hot water, and the detergent composition shown in the table was put in and left at 60° C. for 30 minutes. value × 10 (mg/kg)], hereinafter referred to as a washing solution) was prepared. A transparent glass plate (manufactured by Kennis Co., Ltd., 10 cm wide, 10 cm long, 2 mm thick) was set on the rack of the washing tank of a commercial dishwasher. Then, the cleaning liquid was supplied from the cleaning tank to the cleaning tank, and the cleaning liquid was brought into contact with the transparent glass plate to wash for 40 seconds. The transparent glass plate was removed from the rack and dried at 25°C for 30 minutes. This washing and rinsing process was performed five times at 30 minute intervals. The evaluation of the degree of contamination of the transparent glass plate was carried out on the transparent glass plate after the cumulative number of washings was 1 time, 3 times, and 5 times.

[Method for quantifying protein adhered to transparent glass plate]
Sodium dodecyl sulfate (hereinafter referred to as SDS, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was diluted with ion-exchanged water to obtain a 0.3% by mass SDS aqueous solution. The washed and dried transparent glass plate was immersed in this SDS aqueous solution, and the protein attached to the transparent glass plate was collected in the SDS aqueous solution. Then, the protein recovered in the SDS aqueous solution was quantified using the Protein Assay Lowry Kit (manufactured by nacalai tespue).

[Method for quantifying undegraded protein]
Quantitation of undegraded protein in the wash liquid was performed before each wash liquid was brought into contact with the dishware. To 16 μL of washing solution, 8 μL of sample buffer (3×SDS-PAGE Loading Buffer, Biovision) was added, stirred, and then heated at 90° C. for 5 minutes. 15 μL of the sample was injected into a polyacrylamide gel (Mini-PROTEAN TGX Any kD Stain-Free Gel 12well, manufactured by Bio-Rad) and subjected to electrophoresis at 200 V for 25 minutes (PowerPac™ HC Basic, manufactured by Bio-Rad). TRIS/GLYCINE/SDS x10 BUFFER (manufactured by Bio-Rad) was used as the running buffer, and Ezstain Aqua (manufactured by ATTA) was used as the staining solution. Then, the bands of 25 kDa to 250 kDa were analyzed with image analysis software ImageJ. Based on a calibration curve obtained using albumin (Fujifilm Wako Pure Chemical Industries, Ltd.), the quality of the undegraded protein was quantified.
The method for creating a calibration curve is shown below. Put 55 L of hot water (German hardness 3°dH) at 60°C into the washing liquid tank of a commercial dishwasher (manufactured by Hoshizaki Co., Ltd., JWA-680A). Or 60 g was added and stirred so as to be uniform to prepare a washing liquid. To 16 μL of washing solution, 8 μL of sample buffer (3×SDS-PAGE Loading Buffer, Biovision) was added, stirred, and then heated at 90° C. for 5 minutes. 15 μL of the sample was injected into a polyacrylamide gel (Mini-PROTEAN TGX Any kD Stain-Free Gel 12well, manufactured by Bio-Rad) and subjected to electrophoresis at 200 V for 25 minutes (PowerPac™ HC Basic, manufactured by Bio-Rad). TRIS/GLYCINE/SDS x10 BUFFER (manufactured by Bio-Rad) was used as the running buffer, and Ezstain Aqua (manufactured by ATTA) was used as the staining solution. Then, the bands of 25 kDa to 250 kDa were analyzed with image analysis software ImageJ. The added albumin was determined as the amount of protein.
As the initial amount of protein in the cleaning liquid, the undegraded protein in the cleaning liquid before adding the cleaning composition was quantified by the same method as described above. The initial protein content is a model for the amount of protein in the recycled wash fluid (ie, the mass of protein contained in the wash fluid collected in the wash fluid tank). The initial protein amount was 131 mg/L.

The following were used as the components (a) to (d).
・(a) component, enzyme (trade name: Savinase 18T, manufactured by Novozyme)
・(b) component, anhydrous sodium carbonate (soda ash (dense), manufactured by Tokuyama Co., Ltd.)
・ (d) component, trisodium citrate dihydrate (trade name “purified sodium citrate M”, manufactured by Fuso Chemical Industry Co., Ltd.)

In the examples of Tables 1 and 2, when the initial amount of protein after one cumulative washing is compared with the undegraded protein, it can be seen that the protein in the washing solution is preliminarily decomposed in the washing solution to be subjected to washing. . In other words, in the examples of Tables 1 and 2, by decomposing the protein in the cleaning liquid that is reused in advance, the amount of dirt adhering to the dishes after washing is reduced, and recontamination of the dishes is suppressed. Understand. In addition, it is presumed that when the amount of adhered dirt (that is, the amount of protein adhered) is reduced, the total amount of adhered composite dirt including lipid dirt is also reduced.
In addition, as in the examples of Tables 1 and 2, by decomposing the protein in the cleaning solution that is reused in advance, the degree of contamination at the 3rd and 5th cumulative cleaning times is lower than that of the comparative example. The value is close to the reference value. In other words, by decomposing the protein in the cleaning liquid that is reused in advance, the degree of suppression of recontamination of the tableware is higher than in the case of the comparative example. From this, it is presumed that the increase in recontamination of dishes (that is, the accumulation of dirt on dishes) can be suppressed even when the dishes are washed and used repeatedly using an automatic dishwasher. can.
In other words, when the dishes are washed with washing water having a high ratio of the undegraded protein amount/initial protein amount with a relative molecular mass of 25 kDa or more, proteins adhering to the surface of the tableware during the washing process and the rinsing process at particularly high temperatures are thermally denatured. As a result, proteins tend to adhere to the tableware, and the surface of the tableware is considered to be hydrophobized. It is thought that repeated washing with dirty washing water will further accumulate dirt on the surface of the tableware that has been rendered hydrophobic, resulting in deterioration of the finish of the tableware. On the other hand, even with washing water containing a large amount of dirt, by reducing the ratio of the amount of undegraded protein with a relative molecular mass of 25 kDa or more to the amount of initial protein, the thermal denaturation of proteins adhering to the surface of the tableware is suppressed. It is thought that the hydrophobization of is suppressed. It can be seen from the results of the example that the accumulation of dirt on the surface of the tableware does not increase even after repeated washing with dirty washing water.

Table 3 shows the cleaning conditions used in the cleaning method of the present invention. In washing under these washing conditions, after the protein in the reused washing liquid is decomposed by the component (a), the washing liquid is used for washing the dishes, so that dirt in the washing liquid reattaches to the dishes or It is considered that the accumulation of dirt on the surface is suppressed, and the finish of the automatic dishwasher is improved.

Claims (16)

A method for washing dishes using an automatic dishwasher comprising a washing liquid tank containing a washing liquid and a washing tank for bringing the washing liquid supplied from the washing liquid tank into contact with the dishes, comprising:
At least part of the cleaning liquid used for washing the dishes is collected in the cleaning liquid tank and reused as at least part of the new cleaning liquid,
After decomposing proteins in the recycled cleaning liquid, contacting the cleaning liquid with the tableware;
How to wash dishes. 2. The method of washing dishes according to claim 1, wherein the washing liquid collected in said washing liquid tank contains proteins removed by washing the dishes. 3. The tableware washing method according to claim 1 or 2, wherein washing water of 40°C or higher and 70°C or lower is brought into contact with the dishes in a washing tank at a rate of 0.008 L/second or more and 200 L/second or less and 5 seconds or more and 180 seconds or less. Method. After bringing the dishes into contact with the cleaning liquid in the washing tank, rinse water at 50 ° C. or higher and 90 ° C. or lower is brought into contact with the dishes for 0.008 L / sec or more and 3.5 L / sec or less for 4 seconds or more and 20 seconds or less, and then The tableware washing method according to any one of claims 1 to 3, wherein at least part of the rinsing water is collected in a washing liquid tank. 5. The tableware washing method according to claim 4, wherein the amount of rinsing water used is 0.3 L or more and 300 L or less per 1 m< ³ > of washing tank per one rinsing step. The tableware washing method according to claim 4 or 5, wherein the ratio of the total amount of rinsing water used in one rinsing process to the total amount of washing liquid in the washing liquid tank is 0.0005 or more and 0.4 or less. The method for washing tableware according to any one of claims 1 to 6, wherein the content of proteins having a relative molecular mass of 25 kDa or more in the reusable washing liquid is 3.0% by mass or less. (a) The method for washing tableware according to any one of claims 1 to 7, wherein a proteolytic enzyme is used to decompose proteins in the washing liquid to be reused. (a) A proteolytic enzyme is added in the washing tank and/or the washing liquid tank to decompose proteins in the recycled washing liquid. (a) A cleaning composition containing a proteolytic enzyme is added in the cleaning tank and/or cleaning liquid tank to decompose proteins in the recycled cleaning liquid. How to wash the tableware described. A cleaning composition comprising (a) a proteolytic enzyme, (b) an alkaline agent and (c) a nonionic surfactant is added in the cleaning tank and/or cleaning liquid tank to remove proteins in the recycled cleaning liquid. The tableware washing method according to any one of claims 1 to 10, wherein the tableware is disassembled. 12. Any one of claims 1 to 11, wherein (a) a protease is added to the washing liquid so that the content of proteins with a relative molecular mass of 25 kDa or more in the washing liquid to be reused is 3% by mass or less. A method for washing tableware according to the above item. (a) The method for washing tableware according to any one of claims 8 to 12, wherein the protease is one or more selected from protease and peptidase. (a) The method for washing tableware according to any one of claims 8 to 13, wherein the protease is an alkaline protease. After collecting the cleaning liquid in the cleaning liquid tank, the collected cleaning liquid is held at a temperature of 40° C. or higher and 70° C. or lower for 10 seconds or more and 50,000 seconds or less, and then the washing liquid is brought into contact with the tableware. The method for washing tableware according to any one of items 1 and 2. A detergent composition for an automatic dishwasher used in the method for washing dishes according to any one of claims 1 to 15,
A detergent composition for automatic dishwashers, comprising (a) a proteolytic enzyme, (b) an alkaline agent and (c) a nonionic surfactant.