A METHOD FOR WAREWASHING WITHOUT BLEACH

Description

Field of the Invention

[0001] The present invention relates to a method of warewashing in industrial or institutional systems, as opposed to domestic automatic dishwashing machines.

Background of the Invention

[0002] A typical conventional industrial warewashing system consists of a conveyor system separated into prewash, wash, rinse and drying stations. Wash water is typically introduced into the rinse zone of this system and is passed cascade fashion toward a prewash zone, while dishware is transported in a countercurrent direction.

[0003] Dishwashing compositions used in such systems generally contain a chlorine bleaching agent combined with a cleaning ingredient such as an aqueous solution of a caustic agent and a sequestering agent or builder such as sodium tripolyphosphate.

[0004] While these systems provide excellent levels of tea stain removal, incomplete removal of starchy soils is a problem. Starchy soils are especially difficult to remove when dishware is subject to high temperatures during food preparation and such foods are left for a long time on heated substrates during distribution.

[0005] A proposed solution to this problem is described in EP-A-282,214 (Diversey). This document discloses a process for cleaning dirty dishware with a non-directional mist-like spray of a strongly alkaline solution. However, a highly alkaline spray is potentially hazardous for an operator.

[0006] An industrial dishwashing process using a low alkaline detergent and an enzyme dosed into either a rinsing or a washing bath of the system is described in WO-A-94/27488 (Henkel-EcoLab). The publication describes a means of compensating for the degradation of the enzyme, particularly an amylase, during standstill phases of the system by adding intermittent doses of the enzyme to the washing zone.

[0007] DE-C-4324106 discloses a method of warewashing for industrial or institutional dishwashing machines, wherein an enzyme component Thermamyl 300L and a phosphate or NTA-based low alkaline cleaning component are added to the cleaning liquor in order to optimize the cleaning results.

[0008] German patent specification DE-A-4 219 620 describes a domestic dishwasher in which bleach- and enzyme- containing components are dosed in different stages of the wash process. The enzyme is added during the prerinse or at the very beginning of the wash cycle. The bleach is added only during the cleaning cycle after a predetermined time after which the wash liquor reaches a desired temperature. Thus the negative interaction between the bleach and the enzyme is avoided. This approach is not feasible in an industrial dishwasher where a cascade flow of water occurs from one tank to another and wherein the cleaning operation is a continuous process.

[0009] An approach which is feasible to minimize negative interactions between active ingredients while maximizing cleaning performance in institutional industrial warewashing is the introduction of the active ingredients sequentially into the system. In sequential dosing, components of the cleaning composition are separately introduced into different compartments of the machine. Thus sequential dosing separates active ingredients to minimize negative interactions and thereby maximize cleaning performance of each individual component.

[0010] Bleach agents have been removed from warewashing detergent compositions to minimize the deactivation of enzyme ingredients. It is known in the absence of a bleach that good stain removal (e.g., tea stain removal) may be effected across a range of water hardness by utilizing a strong builder or sequestrant at a relatively high wash pH. Thus, the negative interaction between bleach and enzyme may be avoided while maintaining a good cleaning performance.

[0011] However, it is also known in the art that many enzymes, particularly amylase enzymes useful for starch removal, are unsuitable for use in cleaning systems where the pH value of the composition is above 10. Such high pH values diminish enzyme activity and stability. See GB-A-1 296 839 (Novo).

[0012] Therefore, there exists a need for a cleaning system that provides effective cleaning performance for both starch and tannin removal and which at the same time minimizes those negative interactions responsible for deactivation of the active ingredients within the system.

Summary of the Invention

[0013] One object of the invention is to provide an industrial or institutional warewashing process involving a chemical cleaning system which contains at least two separate components. Each component is dissolved or diluted in an aqueous solution to a concentration useful for cleaning. The chemical cleaning system has substantially no bleaching agents among its components.

[0014] Accordingly, the present invention provides a method of warewashing in a multi-tank industrial or institutional machine, said method comprising the steps of:

a) selecting a chemical cleaning system comprising at least two separate components for aqueous dissolution or dilution to respective use concentration in two separate zones of a warewashing machine, the first component comprising a cleaning agent and the second component comprising an enzyme, the system being substantially free of an added bleaching agent and a 1% aqueous solution of the first component being at least 1 pH unit more alkaline than a 1% aqueous solution of the second component;

b) introducing the first component into a washing zone to clean dirty dishware;

c) subsequently introducing the second component into a second washing zone to further clean the dishware; and

d) rinsing the dishware with an aqueous solution to substantially rinse away the chemical cleaning system.

Detailed Description of Preferred Embodiments

[0015] Typical industrial warewashing processes are either continuous or non-continuous and are conducted in either a single tank or a multi-tank/ conveyor type machine. In the conveyor system a prewash, wash, rinse and drying zone are generally established using partitions. Wash water is introduced into the rinsing zone and is passed cascade fashion back toward the prewash zone while the dirty dishware is transported in a countercurrent direction.

[0016] The inventive method of warewashing is especially effective in the multi-tank/ conveyor type systems. In these types of systems, contact time between the cleaning composition and the articles to be washed is relatively short. Means of maximizing these contact times are constantly sought while at the same time any negative interaction time of the actives of the cleaning composition needs to be minimized to provide the best cleaning performance.
Adequate cleaning performance has been achieved in the present invention in spite of the elimination of a bleaching agent. Reason is that bleaches generally create a negative interaction with other cleaning components such as enzymes.

Enzymatic Component

[0017] Amylolytic enzymes are used to remove starch stains. The amylolytic enzymes usable can be derived from bacteria or fungi. Preferred amylolytic enzymes are those prepared and described in GB-A-1 296 839 which are cultivated from the strains of Bacillus licheniformis NIB 8061 NIB 8059, ATCC 6334. ATCC 6598, ATCC 19945, ATCC 8480 and ACTT 9945 A. Examples of such amylolytic enzymes are those produced and supplied under the trademark Termamyl® by Novo Industri A/S, Copenhagen, Denmark.

[0018] Also useful in the invention are α-amylase enzymes which have been mutated by modifying one or more amino acid sequences as described in WO-A-94/14951 and WO-A-94/02597 and supplied by Novo Industri under the tradename Durmamyl. Other α-amylase enzymes useful in the invention are described in EP-A-208,491 (Genencor Int'l).

[0019] The amylolytic enzymes may be used in either granular or liquid form and have enzymatic activities of from 2 to 25 Maltose units/milligram. They may be incorporated in the cleaning system of the invention in amount such that the final composition has an amylolytic activity of from 10³ to 10⁸ Maltose units/kilograms, preferably from 10⁵ to 10⁸ Maltose units per kilogram(s), and more preferably 10⁶ to 10⁸ Maltose units per kilogram.

[0020] The amylolytic activity referred to herein can be determined by the method described by in P. Bernfeld in "Method of Enzymology", Vol 1 (1955), pg. 149.

[0021] Proteolytic enzymes may also be incorporated in the cleaning system to remove protein stains. Usable proteolytic enzymes include the subtilisin obtained from strains of Bacillus Subtilis licheniformis, such as the commercially available subtilisins Maxatase supplied by Gist-Brocades N.V., Delft, Holland and Alcalase supplied by Novo Industri A/S, Copenhagen, Denmark. Particularly suitable proteases are those obtained from a strain of Bacillus having maximum activity throughout a pH range of 8 to 12 and are commercially available from Novo Industri A/S under the tradenames of Esperase and Savinase. Also useful is a protease supplied under the tradename of OxP by Genencor Int'1. The preparation of these analogue enzymes is described in GB-A-1 243 784. Proteolytic enzymes are generally presented as granules, such as marumes, prills or p-granulates, or in liquid form. The proteolytic enzyme activities of these samples are from 500 to 6000 glycine units per milligram. Proteolytic enzyme activity can be determined by the method described M.L. Anson in "Journal of General Physiology", Vol 22 (1938), pg. 79 (1 Anson unit/gram=733 glycine units per milligram).

[0022] In the cleaning composition of the invention, proteolytic enzymes may be present in amounts such that the final composition has a proteolytic enzyme activity of from about 10³ to 10¹⁰ glycine units per kilogram, preferably from 10⁵ to 10¹⁰, more preferably 10⁶ to 10⁹.

[0023] Other enzymes which may be incorporated in the cleaning system are lipolytic enzymes useful to improve fat removal. Commercially available lipolytic enzymes include Lipase YL, Amano CE, Wallerstein AW, Lipase MY and Lipolase supplied by Novo Industri.

[0024] The enzyme containing component, especially amylolytic enzyme containing component, is dosed into the warewashing system so that upon aqueous dissolution or dilution to its use concentration, the pH value of a 1% aqueous solution is desirably less than 9, preferably 7 to 9, most preferably 8 to 9. The enzyme containing component should be introduced into the system separately from the other active components of the cleaning system. Generally, the component will be applied in a washing zone of the system using any conventional means such as suitable spray nozzles or jets which are directed upwards or downwards toward the dishware. In a preferred embodiment, the enzyme containing component is sprayed directly onto the dishware as it moves in a countercurrent direction from the dosed component. A thorough rinsing of the enzyme from the dishware once the contact time is completed should follow.

[0025] To avoid undue exposure to the cleaning agents of the second component, the enzyme containing component is sequentially dosed into the warewashing process after the cleaning agent containing component in a separate tank from the tank in which the cleaning agent containing component is introduced.

Cleaning Agent Containing Component

[0026] An aqueous solution of the component which contains the cleaning agent must have a higher alkalinity than that of the enzyme component by at least one unit, preferably more than one pH unit. Thus a 1% aqueous solution of the cleaning component which results from its dissolution or dilution to its use concentration should have a pH of at least 1 pH unit more alkaline than a pH value of a 1% aqueous solution of the enzymatic component. Preferably, the cleaning agent component solution has a pH of 9.5 or greater, preferably 9.5 to 13.

[0027] It is understood that more than one component may contain a cleaning agent so that the component which contains the greatest total amount (that is % by weight) of the cleaning agent is referred to by the phrase "that component which contains the cleaning agent or the cleaning agent containing component". It will also be appreciated that the total cleaning agent in any given component may comprise two or more different and individual cleaning agents as described below.

[0028] The concentration of the cleaning agent following its dissolution or dilution is such that the weight of the component per volume unit of water should be in the range of 1 to 5 grams per liter, preferably from 1 to 4 grams per liter, more preferably from 1 to 3 grams per liter.

[0029] The cleaning agent may be selected from a caustic or strongly alkaline material, a detergency builder, a surfactant or a mixture thereof.

[0030] Suitable caustic agents include alkaline metal hydroxides such as sodium or potassium hydroxides, alkaline metal silicates such as metasilicates, preferably sodium metasilicate, and other alkaline caustic materials such as borax. Especially effective is sodium silicate having a mole ratio of SiO₂:Na₂O of from 1 to 3.3, preferably from 1.8 to 2.2 generally referred to as sodium disilicate.

[0031] Suitable builder materials are well known in the art and many types of organic and inorganic compounds have been extensively described in the literature. Builder materials include both the phosphate and non-phosphate compounds. They are generally used in cleaning compositions to provide alkalinity and buffering capacity, prevent flocculation, maintain ionic strength, extract metals from soils, remove alkaline earth metal ions from washing solutions.

[0032] The builder material usable herein can be any one or mixtures of the various phosphate and non-phosphate builder materials. However, non-phosphate builder materials can also be used, such as, for example, the alkali metal citrates carbonates and bicarbonates; and the salts of nitrilotriacetic acid (NTA); dipicolinic acid (DPA), oxydisuccinic acid (ODS), alkyl and alkenyl succinates (AKS); ethylenediamine tetraacetates, oxidized heteropolymeric polysaccharides, polycarboxylates such as polymaleates, polyacetates, polyhydroxyacrylates, polyacrylate/polymaleate and polyacrylate; polymethacrylate copolymers and the terpolymer of polyacrylate/polymaleate and vinylacetate (ex Huls), as well as zeolites; layered silicas and mixtures thereof. They may be present in more than one component of the system but in the only component which contains builder, or in that component which contains the most total builder material (in % by wt.), in the range of from 1 to 50, preferably from 5 to 40, more preferably from 10 to 30.

[0033] Particularly preferred builders are citrates, DPA, ODS, alkenyl succinates, carbonates, bicarbonates, the higher molecular weight block copolymers ITA/VA having Mw greater than 60,000, maleic anhydride/(meth)acrylic acid copolymers, e.g. Sokalan CP5 ex. BASF; NTA and the terpolymer of polyacrylate/polymaleate and vinylacetate (ex. Huls).

[0034] Scale formation on dishes and machine parts is an important problem that needs to be resolved or at least mitigated in formulating a machine warewashing product, especially in the case of low-phosphate (e.g. less than the equivalent of 20% by weight, particularly 10% by weight of sodium triphosphate) and phosphate-free machine warewashing compositions, particularly zero-P machine warewashing compositions.

[0035] In order to reduce this problem, co-builders, such as polyacrylic acids or polyacrylates (PAA), and the various organic polyphosphonates, e.g. of the Dequest range, may be incorporated in one or more system components. For improved biodegradability, (as such co-builders), the block copolymers of formula (I) as defined in published PCT patent specification WO-A-94/17170 may also be used. In any component, the amount of co-builder may be in the range of from 0.5 to 10, preferably from 0.5 to 5, and more preferably from 1 to 5% by weight.

[0036] Further, the cleaning agent may comprise one or more surfactants. Surfactant may also be present in one or more of components of the system. However, in the component(s) which contain the most surfactant, they may be present in the range of from 0.5 to 20, preferably from 1 to 15, and more preferably from 3 to 15% by weight. Such surfactant (if present) is of course separate from any surfactant used as rinse aid in the rinse phase, after use of a system according to the present invention.

[0037] Normally, in a properly built or highly built composition as is conventional, only small amounts of low- to non-foaming nonionic surfactant, to aid detergency and particularly to suppress excessive foaming caused by some protein soil. Higher amounts of highly detersive surfactants, such as the high HLB nonionic surfactants, the anionic sulphate or sulphonate surfactants and the alkyl polyglycoside class of surfactants, may be used in lower builder-containing active/enzyme-based compositions.

[0038] These compositions may further include a defoamer. Suitable defoamers include mono- and distearyl acid phosphate, silicone oil and mineral oil.

[0039] The compositions may include 0.02 to 2% by weight of defoamer, or preferably 0.05 to 1.0%.

[0040] In the method of the invention, it will be normal to follow application of all system components by a final rinse using water, preferably containing a rinse aid.

[0041] Any known silver anti-tarnish agents may also be included such as benzotriazole or 1,3-N azole compounds described in WO-A-95/10588.

[0042] Minor amounts of various other components may be present in the chemical cleaning composition. These components include solvents, and hydrotropes such as ethanol, isopropanol and xylene sulfonates, flow control agents; enzyme stabilizing agents; soil suspending agents; anti-redeposition agents; anti-tarnish agents; anti-corrosion agents; colorants, bleach scavengers (e.g. sulfite) and other functional additives. The use of bleach scavengers in the method and system of the invention could be advantageous, since even in a non-bleach system traces of bleach could unexpectedly be present as a residue from previous runs.

[0043] Components used in the present invention may independently be formulated in the form of solids, (optionally to be dissolved before use), aqueous liquids or non-aqueous liquids, also to be diluted before use.

[0044] The present invention will now be described in more detail by way of the following non-limiting examples, in which parts and percentages are by weight unless otherwise indicated.

Example 1

[0045] In a non-bleach system it was observed that tea stain removal was significantly improved when formulations contained a builder formulated at a high alkalinity wash pH, that is greater than about 10. The following warewashing compositions were prepared:

Ingredient	Sample 1	Sample 2
Nitrilotriacetate(NTA)	20%	---
Huls polymer1	---	10%
Nonionic surfactant	2%	2%
Potassium hydroxide (50%)	75%	75%
Water   to balance

1A terpolymer of acrylate/maleate and vinyl acetate supplied by Huls.

[0046] Neither of the sample formulations contained a bleaching 30 agent or an enzyme. The pH value of a 1% aqueous solution of each of the samples was adjusted by the addition of either NaOH or H₂SO₄ to a pH value of between 7 and 11.

[0047] The cleaning performance of the two compositions were compared using a residual tea stain test.

[0048] Porcelain cups were stained with tea three times prior to washing. Cleaning experiments were conducted in a dishwashing machine. The temperature of the water in the main wash was 55°C and the wash time was 1 min.

[0049] The cleaned dishware was then observed by a panel which rated tea stain removal on a scale from 0 to 5 with 0 indicating no visible tea stain and 5 indicating heavy staining. The panel results are as follows:

Residual Tea Stain
Solution pH	Sample 1	Sample 2
7.0	3.0	2.2
7.5	2.5	1.8
8.0	1.8	1.5
8.5	1.3	1.0
9.0	1.5	0.8
9.5	0.8	0.8
10.0	0.5	0
11.0	0	0

[0050] It was thus observed that as the pH of the aqueous solutions of the detergent compositions increased tea stain removal improved for both compositions containing NTA or Huls polymer builder materials, without the presence of either bleach or an enzyme. Thus, at high alkalinity tea stain removal is very effective in the presence of only a builder.

Example 2

[0051] High alkalinity and the presence of a builder material can, however, have a negative impact on amylase enzyme stability and on starch removal, as demonstrated below.

[0052] Sample 1 described in Example 1 was prepared with the addition of an amylase enzyme (supplied as Termamyl 300L by Novo) to provide an enzymatic activity of 2x10⁷ Maltose units per kilogram. A second sample was prepared with the Termamyl enzyme, but no builder was present. Each sample was adjusted to pH values of 8.5 and 10 and the four samples were observed for enzyme stability and starch removal as follows.

[0053] Porcelain plates were soiled with potato starch. A single tank Industrial dishwashing machine was run over a period of about 30-40 minutes during which time 11 wash cycles were completed. At the end of each wash cycle, fresh product was dosed to compensate for the dilution of the wash solution by the rinse water.

[0054] The enzyme stability of the amylase was measured by conventional means.

[0055] Residual starch on the cleaned dishware was rated by a panel on a percentage scale with 100% indicating residual soil over the entire area of the plate and 0 indicating complete removal of the soil. The observed amylase stability and cleaning effectiveness in the four samples were as follows:

	Samples (% Loss of Amylase Activity)
Elapsed time (minutes)	NTA and Amylase pH 10	NTA and Amylase pH 8.5	Amylase pH 10	Amylase pH 8.5
0	0	0	0	0
5	30	15	5	5
10	30	15	0	0
15	40	10	0	0
20	40	10	0	0
25	50	10	0	0
30	50	5	0	0

Sample	Residual Starch (% Area)
NTA and Amylase pH 10	80%
NTA and Amylase pH 8.5	45%
Amylase pH 10	60%
Amylase pH 8.5	25%

[0056] This data shows that starch removal benefits are generally greater at pH 8.5 compared to pH 10 and that at both wash pHs the NTA builder has a detrimental effect on starch removal. The presence of NTA leads to a significant reduction in the stability of the enzyme at a wash pH of 10. A less detrimental effect of the builder on the enzyme stability was observed at a pH of 8.5.

Example 3

[0057] The significant effect of the presence of a strong builder on the amylase enzyme stability at a high alkalinity was again observed in wash solutions of 65°C. High temperature washes are conventionally used in industrial and institutional warewashing and in a multi-chamber machine are most likely to be encountered in the final wash tank. The four compositions of Example 2 were prepared and the amylase stability was measured at a temperature of 65°C with the following results (expressed as % residual Amylase Activity):

Elapsed Time	NTA & Amylase pH 10	NTA & Amylase pH 8.5	Amylase pH 10	Amylase pH 8.5
0	100	100	100	100
10	30	82	92	98
20	20	70	87	100
30	18	60	80	98
40	18	55	76	100
50	19	45	72	98
60	17	43	63	100

[0058] Thus, at pH 10 and 65°C the effect of the presence of a strong builder on the amylase stability is devastating and would have a significant negative impact on starch removal by the enzyme.

[0059] Furthermore, while amylase stability is improved significantly at pH 8.5 compared to pH 10, even at pH 8.5 there are clear benefits for not having a strong sequestrant present in the wash tank wherein the amylase enzyme is dosed.

Example 4

[0060] The cleaning efficiency of a composition as used according to the invention was compared to the cleaning of a commercial composition used in warewashing. The evaluation was carried out in a multi-chamber machine (ex. Hobart) to assess the real benefits to be gained from a sequential dosing of ingredients and a pH differential between the washing zones into which the cleaning and enzyme components are dosed.

[0061] The composition used according to the present invention (hereinafter referred to as inventive composition) having two (2) components and no bleaching agent was prepared as follows:

A. Cleaning Agent Component

[0062] 

Ingredients	% Active
potassium hydroxide	2.8
antiscalant (Dequest-2000)	1.0
nitrilotriacetate (NTA)	28.0
potassium silicate	4.0
water	to balance

[0063] The pH of a 1% aqueous solution of the cleaning component was adjusted to pH 9.8. The cleaning agent component was dosed into a wash zone in an amount of 2 grams per liter followed by a sequential dosing of an enzymatic component.

B. Enzymatic Component

[0064] 100 ppm of an amylase (Termamyl 300L supplied by Novo) was dosed into the last washing zone following the dosing of the cleaning component. The pH of a 1% aqueous solution of the enzymatic component was 8.5.

[0065] The cleaning efficiency of the inventive composition was compared to a commercial composition of the prior art having the following cleaning and bleach components:

A. Cleaning Component

[0066] 

Ingredients	% Active
sodium hydroxide (50%)	70
phosphono 1,2,4, butanetricarboxylic acid	6
polyacrylic acid, sodium salt	8
water	to 100

B. Beach Component

[0067] 

Ingredients	% Active
Potassium hydroxide	3.0
Potassium triphosphate	1.5
Neutral sodium silicate	4.0
sodium hypochlorite (as active Chlorine)	6.0
water	to 100

[0068] The pH of a 1% aqueous solution of the cleaning component was about 11. The bleach containing component was first dosed into a prewash or wash zone in an amount of 0.5 g/liter, followed by a sequential dosing of the cleaning component into a wash zone in an amount of 2 grams per liter.

[0069] Porcelain cups were stained with tea three times prior to washing. Porcelain plates were soiled with potato starch. To mimic the gradual buildup of starch soil due to incomplete starch removal in one wash, the starch plates were resoiled after the first wash and then subjected to further consecutive wash/starch soiling procedures.

[0070] The cleaning performance of the two compositions was evaluated by a panel. The following results were observed:

	% Cleaning after 10 soil/wash cycles
Soil	Inventive Composition	Commercial Composition
tea	100	100
starch	97	30

[0071] Thus the inventive formula which does not contain a bleaching agent but does have an enzymatic component which has a pH of at least one unit less than the pH value of the cleaning component shows significantly improved cleaning performance over the performance of the commercial product with bleach.

Example 5

[0072] The cleaning efficiency of a composition used according to the invention, wherein the cleaning agent and enzymatic component were sequentially dosed into separate wash tanks, was compared to a system wherein the same cleaning agent and enzyme components were used, but instead were dosed into the same (final) wash tank. The composition of the cleaning agent and enzyme component and the test protocol are as described in Example 4. Both systems are free of bleach. The following results were observed:

	% Cleaning after 10 soil/wash cycles
Soil	Inventive Composition (Sequential dosing)	Same tank dosing
tea	100	100
starch	97	75

[0073] Sequential dosing of the cleaning agent and enzyme components into separate wash tanks gives significantly improved starch removal compared to the situation where cleaning agent and enzyme are separately dosed into the same wash tank.

Claims

1. A method of warewashing in a multi-tank industrial or institutional machine comprising the steps of:

a) selecting a chemical cleaning system comprising at least two separate components for aqueous dissolution or dilution to respective use concentration in two separate zones of a warewashing machine, the first component comprising a cleaning agent and the second component comprising an enzyme, the system being substantially free of an added bleaching agent and a 1% aqueous solution of the first component being at least 1 pH unit more alkaline than a 1% aqueous solution of the second component;

b) introducing the first component into a washing zone to clean dirty dishware;

c) subsequently introducing the second component into a second washing zone to further clean the dishware; and

d) rinsing the dishware with an aqueous solution to substantially rinse away the chemical cleaning system.

2. A method according to claim 1, wherein the aqueous solution of the first component has a pH value of 9.5 or greater.

3. A method according to claim 1 or 2, wherein the aqueous solution of the second component has a pH value of less than 9.0.

4. A method according to any of claims 1-3, wherein the first component is selected from the group consisting of a caustic or strongly alkaline material, a detergency builder, a surfactant and a mixture thereof.

5. A method according to claim 4, wherein the detergency builder is a phosphate or non-phosphate material.

6. A method according to claim 5, wherein the non-phosphate builder is selected from the group consisting of the salts of nitrilotriacetic acid, dipicolinic acid, oxydisuccinic acid, alkyl succinate, alkenyl succinate, ethylenediamine tetraacetate, oxidized heteropolymeric polysaccharides, polycarboxylates, zeolites, layered silicas and mixtures thereof.

7. A method according to any of claims 1-6, wherein the enzyme is selected from the group consisting of an amylase, a protease, a lipase, and mixtures thereof.

Ansprüche

1. Verfahren zum Geschirrwaschen in einer industriellen Mehrbehältermaschine oder einer Mehrbehältermaschine für größere Einrichtungen, umfassend die Schritte von:

a) Auswählen eines chemischen Reinigungssystems, umfassend mindestens zwei getrennte Komponenten zur wässerigen Auflösung oder Verdünnung für die entsprechende Verwendungskonzentration in zwei getrennten Zonen einer Geschirrwaschmaschine, wobei die erste Komponente ein Reinigungsmittel umfaßt und die zweite Komponente ein Enzym umfaßt, wobei das System im wesentlichen frei von zugegebenem Bleichmittel ist und eine 1%ige wässerige Lösung der ersten Komponente mindestens 1 pH-Einheit alkalischer ist als eine 1%ige wässerige Lösung der zweiten Komponente;

b) Einführen der ersten Komponente in eine Waschzone zum Reinigen von schmutzigem Geschirr;

c) anschließendes Einführen der zweiten Komponente in eine zweite Waschzone zum weiteren Reinigen des Geschirrs und

d) Spülen des Geschirrs mit einer wässerigen Lösung, um das chemische Reinigungssystem im wesentlichen abzuspülen.

2. Verfahren nach Anspruch 1, wobei die wässerige Lösung der ersten Komponente einen pH-Wert von 9,5 oder mehr aufweist.

3. Verfahren nach Anspruch 1 oder 2, wobei die wässerige Lösung der zweiten Komponente einen pH-Wert von weniger als 9,0 aufweist.

4. Verfahren nach einem der Ansprüche 1 - 3, wobei die erste Komponente ausgewählt ist aus der Gruppe, bestehend aus einem basischen oder stark alkalischen Material, einem Waschmittelbuilder, einem Tensid und einem Gemisch davon.

5. Verfahren nach Anspruch 4, wobei der Waschmittelbuilder ein Phosphat- oder Nichtphosphatmaterial darstellt.

6. Verfahren nach Anspruch 5, wobei der Nichtphosphatbuilder ausgewählt ist aus der Gruppe, bestehend aus den Salzen von Nitrilotriessigsäure, Dipicolinsäure, Oxydibernsteinsäure, Bernsteinsäurealkylester, Bernsteinsäurealkenylester, Ethylendiamintetraacetat, oxidierten heteropolymeren Polysacchariden, Polycarboxylaten, Zeolithen, Schichtsilikaten und Gemischen davon.

7. Verfahren nach einem der Ansprüche 1 - 6, wobei das Enzym ausgewählt ist aus der Gruppe, bestehend aus einer Amylase, einer Protease, einer Lipase und Gemischen davon.

Revendications

1. Procédé de lavage de vaisselle dans une machine équipée de plusieurs cuves, dans le secteur industriel ou collectif comprenant les étapes consistant:

a) à choisir un système de lavage chimique comprenant au moins deux composants séparés pour faire une dissolution ou une dilution aqueuse à leur concentration d'utilisation respective, dans deux zones séparées d'un lave-vaisselle, le premier composant comprenant un composant de lavage et le second composant comprenant une enzyme, le système étant essentiellement exempt d'agent de blanchiment ajouté et une solution aqueuse à 1% du premier composant étant d'au moins 1 unité pH plus basique qu'une solution aqueuse à 1% du second composant;

b) à introduire le premier composant dans la zone de lavage pour laver la vaisselle sale;

c) à introduire ensuite le second composant dans une seconde zone de lavage pour mieux laver encore la vaisselle; et

d) à rincer la vaisselle avec une solution aqueuse pour éliminer essentiellement le système de lavage chimique.

2. Procédé selon la revendication 1, dans lequel la solution aqueuse du premier composant possède un pH de 9,5 ou supérieur.

3. Procédé selon les revendications 1 ou 2, dans lequel la solution aqueuse du second composant possède un pH inférieur à 9,0.

4. Procédé selon l'une quelconque des revendications 1 à 3, dans lequel le premier composant est choisi dans le groupe composé d'une matière caustique ou fortement basique d'un adjuvant de détergence, d'un tensio-actif et un mélange de ceux-ci.

5. Procédé selon la revendication 4, dans lequel l'adjuvant de détergence est une matière phosphate ou non phosphate.

6. Procédé selon la revendication 5, dans lequel l'adjuvant non phosphate est choisi dans le groupe formé par les sels de l'acide nitrilotriacétique, l'acide dipicolinique, l'acide oxydisuccinique, le succinate d'alkyle, le succinate d'alcényle, l'éthylènediaminetetraacétate, les polysaccharides hétéropolymères oxydés, les polycarboxylates, les zéolithes, les silices en couches et leurs mélanges.

7. Procédé selon l'une quelconque des revendications 1 à 6, dans lequel l'enzyme est choisie dans le groupe formé d'une amylase, d'une protéase, d'une lipase ou leurs mélanges.