AU719542B2 - A composition for cleaning surfaces - Google Patents

Description

"A Composition for Cleaning Surfaces" This invention relates to a composition for cleaning surfaces soiled with milk or milk products and to its use.

Deposits containing protein and fatty residues with a high calcium content attributable to physiological factors are formed on surfaces of containers, pipes and processing equipment which come into contact with milk or milk products in the production and further processing of milk and are extremely difficult to remove.

Milking machines, dairy tanks, milk tankers, tanks, pipelines, heaters and other equipment required for the production and processing of milk are particularly affected by such deposits.

Hitherto, two cleaning strategies have largely been adopted in order to eliminate the deposits.

On the one hand, highly alkaline and highly acidic cleaners have been used in alternation to clean the surfaces soiled with milk deposits. The highly alkaline cleaners are used to eliminate protein-containing residues. On account of the alkalinity of the cleaning solution and the phenomenon of intrinsic "water hardness" coupled with the presence of calcium in the residues, characteristic deposits of, in particular, poorly soluble calcium salts are formed. These deposits can only be removed with acidic cleaners so that an alternating procedure is necessary.

On the other hand, alkaline cleaners containing complexing agents to stabilise water hardness are used These alkaline "single-phase cleaners" ie. cleaners which remove residues of milk products without the additional use of acidic products are environmentally less preferred because they contain complexing agents.

Accordingly, it may be concluded that, hitherto, it has been necessary to use alkaline cleaners to eliminate protein-containing soil/ residues, for example milk products. The use of alkaline cleaners either involves an additional cleaning step (cleaning with acid-based compositions) or the addition of problematical complexing agents.

Accordingly, the problem addressed by the present invention was to provide a cleaning composition which would effectively remove protein- and fat-containing deposits accumulating on surfaces in the production and further processing of milk without any need to use complexing agents or to apply one or more additional cleaning steps with other cleaning compositions. The effectiveness of the compositions according to the invention in the cleaning of soiled surfaces would be at least comparable with that of known cleaning compositions.

On the one hand, therefore, the invention provides a composition for cleaning surfaces soiled with milk or products which contains at least one protease and/or at Sleast one lipase as enzyme(s), at least one surfactant component and at least one c"id cmponent.

C04445 In one preferred embodiment, anionic, cationic, amphoteric or nonionic surfactants or mixtures thereof may be used as the surfactant component.

Preferred nonionic surfactants are such compounds as fatty alcohol polyglycol ethers, fatty acid amides, fatty acid ethoxylates and fatty acid esters of polyols, more especially sugars (glucose), fatty alcohol alkoxylates with EO/PO or commercial mixtures thereof.

Among the proteases, aspartate proteases are used in one preferred embodiment as the acidic proteases for eliminating protein-containing residues.

They have a catalytic optimum in the acidic pH range because a catalytically active aspartate residue in the active centre of the enzyme has to be protonated. Among the aspartate proteases, enzymes of animal, fungal and bacterial origin are suitable for eliminating the residues (EC Examples of such enzymes include, in particular, pepsin, gastricsin, rennin or chymosin of animal origin, penicillopepsin of bacterial origin and aspartate proteases of various fungi, more especially of Mucor spp., Aspergillus niger, Rhizopus spp. and Endothia parasitica.

If acidic proteases are used in admixture, the ratio of pepsin to protease is 10:1 to 1:10 and preferably 5:1 to Among the lipases, those with a pH optimum in the acidic range are preferably used. Particularly preferred examples are lipases of fungi, more especially Humicola insolens.

In one preferred embodiment, the pH of the solution to be applied is adjusted to a value of 0.5 to 4.0 and, more particularly, to a value of 1.5 to 3.5. The pH of the solution applied can be adjusted by using typical pH buffer mixtures. The acid base may be selected from any commercially available organic and inorganic acids, such as nitric acid, phosphoric acid, citric acid, lactic acid, acetic acid, methane sulfonic acid, formic acid, amidosulfonic acid. However, the solution to be applied should preferably be phosphate- and nitrate-free.

In one preferred embodiment, additives are introduced into the acidic cleaning composition for eliminating milk-based soils, one or more disinfectants and/or one or more antifoam agents and/or one or more enzyme stabilisers being used.

Particularly preferred disinfectants from the class of cationic surfactants are in particular straight-chain or cyclic C8- 18 tetraalkyl ammonium compounds, C8s-i benzalkonium chlorides, quaternary C8- 18 alkyl phosphonium salts. Particularly preferred disinfectants from the class of amphoteric surfactants are, for example,

C

81 8 fatty acid amine derivatives of betaine structure, more particularly glycine derivatives, and cocoalkyl dimethyl ammonium betaine. Particularly preferred disinfectants from the class of anionic substances, such as alk3240688, ether .carboxylic acids according to DE-A-42 25 626, and from the class of anionic s1-u ctants are those produced from aromatic sulfonic acids, alkyl sulfonic acids, alkyl ether sulfonic acids, fatty alcohol sulfuric acid esters and sulfonated fatty acids CT 4445 (for example alkyl benzenesulfonic acid, dodecyl benzenesulfonic acid, naphthalene sulfonic acid, alkane sulfonic acids).

Suitable antifoam agents are C 12 16 fatty alcohol alkylates, fatty alcohol block polymers EO/PO, C 12 1 6 fatty alcohol EO/PO adducts and C 12 16 fatty alcohol polyglycol ethers which may be used either individually or in the form of mixtures.

Typical enzyme stabilisers, such as glycols (for example 1,2-propanediol), borate salts and/or .carboxylic acids, may optionally be added to the enzyme mixtures.

Disinfectants, antifoam agents and enzyme stabilisers are used in the usual well-known concentrations.

In one preferred embodiment, the total concentration of enzyme(s), surfactant(s), acid(s) and additive(s) in the solution applied is from 0.5 to 10% by weight and preferably from 1 to 5% by weight.

In one preferred embodiment, the ratio by weight of the enzyme component(s) to the surfactant component(s) is between 1:10,000 and 1:10 and preferably between 1:10,000 and 1:1,000 while the ratio by weight of the enzyme and surfactant component(s) to the acid component(s) is between 1:1 and 1:99 and preferably between 1:5 and 1:50.

In one preferred embodiment, the ratio by weight of the enzyme, surfactant and acid components to the additive(s) is between 10:90 and 90:10 and preferably between 20:80 and 80:20.

In one preferred embodiment, the cleaning composition according to the invention is made up in liquid form as an aqueous solution, in semisolid form as a paste, in solid form as tablets or in powder form. A powder-form or tablet-form product is preferred from the point of view of active-substance concentration while a liquid product is preferred from the point of view of convenient handling.

If the acidic cleaning composition is a powder-form or tablet-form product, it is preferably made up of about 20 to about 80% by weight of an organic or inorganic substance which shows an acidic reaction when dissolved in water, about 0.1 to about 5% by weight of nonionic surfactants, about 0.1 to about 10% by weight and preferably about 0.1 to 5% by weight of one or more microbicidal compounds belonging to groups bl) to b4), the balance to 100% by weight consisting, for example, of sodium sulfate and/or other active substances or auxiliaries. Since the cleaning composition is intended to be a powder, the organic or inorganic substance showing an acidic reaction when dissolved in water must be a solid.

Examples of such inorganic solids are acidic salts, such as dihydrogen phosphates or hydrogen sulfates. Suitable organic substances are, for example, carboxylic acids, such as tartaric acid or citric acid, or for example sulfonic acids, such as .Riamnidosulfonic acid. Preferred nonionic surfactants are products of the addition of ethylene oxide and/or propylene oxide onto fatty alcohols, fatty amines or fatty C04445 acids containing 12 to 18 carbon atoms in the alkyl group or fatty acid esters of polyols, more especially of sugars, for example glucose. Products of the addition of ethylene oxide and/or propylene oxide onto fatty alcohols are particularly preferred.

Examples of such addition products are products of the addition of, on average, 8 or 6 ethylene oxide units onto fatty alcohol mixtures containing 12 to 18 carbon atoms in the alkyl chain. Other examples are adducts of ethylene oxide and propylene oxide with such fatty alcohols, for example an adduct of 5 moles of ethylene oxide and 4 moles of propylene oxide with a fatty alcohol mixture containing 12 to 14 carbon atoms in the alkyl chain. Another suitable nonionic surfactant is an adduct of 5 moles of ethylene oxide with oleyl alcohol.

If it is intended to formulate the acidic cleaner as a liquid, it is preferably made up of about 20 to about 80% by weight of phosphoric acid, formic acid, acetic acid, glycolic acid, lactic acid, citric acid and/or methane sulfonic acid as such, in the form of a solution in one another or in the form of an aqueous solution with an acid content of at least 5% by weight, about 0.1 to about 5% by weight of nonionic surfactants as described above, about 0.1 to about 10% by weight and preferably about 0.1 to about 5% by weight of one or more microbicidal compounds belonging to groups bl) to b4), the balance to 100% by weight being water or an aqueous solution of other active substances or auxiliaries. Liquid acids may be used as such either individually or in the form of mixtures with one another. Solid acids, for example citric acid, may be dissolved in another liquid acid or in water. If acids are used in the form of an aqueous solution, they should have an acid content of at least 5% by weight so that the dilute solution applied still has an adequate acid concentration. If it is desired to use a phosphate-free acidic cleaner in the interests of environmental protection, the cleaner preferably contains a combination of several of the organic acids mentioned. Examples are mixtures of methane sulfonic acid, citric acid and formic acid, acetic acid, lactic acid and citric acid, acetic acid, glycolic acid and methane sulfonic acid and other combinations. Water is optionally added to these acid combinations in such a quantity that a clear solution is formed.

In one preferred embodiment, the cleaner is formulated as a compact cleaner containing all the component or as a set of complementary partial compositions each containing one or more components. A combination of separate partial compositions is particularly appropriate for liquid products.

The invention also relates to the use of the composition according to the invention for cleaning surfaces soiled with milk or milk products.

In one preferred embodiment, the cleaning composition according to the invention is used as a cleaning solution at temperatures of 20'C to 70'C and preferably at temperatures of 40'C to C04445 Examples The general test conditions for the following four Examples are described in the following: Cleaning was carried out in an immersion-type apparatus with a hydraulic mechanism. A temperature of 40 0 C was selected for the cleaning process. The water had a hardness of 16'd. The cleaning process took 15 minutes. The test soils used were a) condensed milk and b) milk scale (referred to as and in the description of the results). The results expressed as percentages represent the degree of soil removal after cleaning by comparison with the standard soil before cleaning. The results were determined by gravimetric measurements.

The cleaning effect of various enzyme-containing compositions was tested in comparison to alkaline standard compositions containing complexing agents and acidic standard cleaners.

Comparison Example 1 Alkaline "single-phase" standard cleaner (in-use concentration all figures are percentages by weight and are based on the cleaner as a whole.

The cleaner had the following composition: 30% KOH, 20% EDTA, 3% antifoam agent and distilled water.

99.5% soil removal was achieved under test conditions and 91% soil removal under test conditions Comparison Example 2 Comparison formulation of an acidic standard cleaner (in-use concentration The cleaner had the following composition: 30% H 3 P0 4 3% nonionic surfactants, 10% H 2 S0 4 and distilled water.

62% soil removal was achieved under test conditions and 41% soil removal under test conditions Example 1 (invention) Formulation of an acidic enzyme-containing powder-form cleaner according to the invention (in-use concentration The cleaner had the following composition: 40% amidosulfonic acid, 10% citric acid, 3% nonionic surfactants, 1% pepsin, 2% acidic protease (acidic protease in this context is protease NWG (Amano)), protease A (Amano) from fungi (for example Aspergillus niger), 1% lipase and, for the rest, sodium sulfate.

99.5% soil removal was achieved under test conditions and 98% soil removal under test conditions 9b).

Example 2 (invention) Formulation of an acidic enzyme-containing liquid two-phase cleaner of ALi~~.

9 mponents and (in-use concentration 0.5% 0.25% of each component) C04445 6 The components of the cleaner had the following compositions: 30% formic acid, 10% citric acid, 3% nonionic surfactants (in this case ethoxylated fatty alcohols) and distilled water.

5% pepsin, 10% acidic protease (in this case NWG (Amano) or protease A (Amano) from fungi (for example Aspergillus niger)), 2% lipase, 40% propylene glycol and distilled water.

99% soil removal was achieved under process conditions and 98.5% soil removal under process conditions Comparison of Examples 1 and 2, which are based on cleaning with known compositions, with the cleaning performance of the acidic enzyme-containing compositions according to the invention (Examples 3 and 4) shows that the compositions according to the invention are at least as effective (as Example 1) or even more effective (than Example 2) in removing soils containing milk or milk products.

C04445

Claims (14)

1. A composition for cleaning surfaces soiled with protein and/or fatty soils, characterised in that at least one protease and/or at least one lipase as enzyme(s), at least one surfactant component and at least one acid component are used, characterised in that the acid component is present in a quantity which gives the solution to be applied a pH value of 0.5 to 4.

2. A composition as claimed in claim 1, characterised in that the protease(s) is/are selected from the class of acidic proteases.

3. A composition as claimed in claim 2, characterised in that the proteases are aspartate proteases.

4. A composition as claimed in any one of claims 1 to 3, characterised in that the solution to be applied has a pH value of 1.5 to A composition as claimed in any one of the preceding claims, characterised in that one or more disinfectants and/or one or more antifoam agents f5 and/or one or more stabilisers is/are present as additives.

6. A composition as claimed in any one of the preceding claims, S:i characterised in that the total concentration of enzyme(s), surfactant(s), acid(s) and additive(s) in the composition is gauged in such a way that the total concentration of these components in the solution to be applied from 0.5 to 10% by weight.

7. A composition as claimed in claim 6, characterised in that the total concentration of enzyme(s), surfactant(s), acid(s) and additive(s) in the composition is gauged in such a way that the total concentration of these components in the solution to be applied from 1 to 5% by weight.

8. A composition as claimed in any of the preceding claims, characterised S:P, in that the ratio by weight of the enzyme component(s) to the surfactant component(s) is between 1:10,000 and 1:10 while the ratio by weight of the enzyme and surfactant component(s) to the acid component(s) is between 1:1 and 1:99. 0 9. A composition as claimed in claim 8, characterised in that the ratio by weight of the enzyme component(s) to the surfactant component(s) is between 1; 1:10,000 and 1:1,000. A composition as claimed in claim 8 or claim 9, characterised in that the ratio by weight of the enzyme and surfactant component(s) to the acid component(s) is between 1 1:5 and 1:50.

11. A composition as claimed in any one of the preceding claims, characterised in that the ratio by weight of the enzyme, surfactant and acid components to the additive(s) is between 10:90 and 90:10.

12. A composition as claimed in claim 11, characterised in that the ratio by eiglht of the enzyme, surfactant and acid components to the additive(s) is between 20:8,and 80:20. C04445 8

13. A composition as claimed in any one of the preceding claims, characterised in that it is made up in liquid form as an aqueous solution, in semisolid form as a paste, in solid form as tablets or in powder form.

14. A composition as claimed in any one of the preceding claims, characterised in that it is formulated as a compact cleaner containing all components or as a set of complementary partial compositions each containing one or more components. A composition for cleaning surfaces soiled with protein and/or fatty soils, substantially as hereinbefore described with reference to any one of the examples.

16. The use of the composition claimed in any one of the preceding claims, characterised in that it is used to clean surfaces soiled with milk or milk products.

17. The use claimed in claim 16, characterised in that the composition is used as a cleaning solution at temperatures of 20°C to 70 0 C.

18. The use claimed in claim 16, characterised in that the composition is S" 5 used as a cleaning solution at temperatures of 40°C to Dated 22 April 1999 HENKEL-ECOLAB GMBH Co. OHG Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON o o• 0 o C04445