WO2023213521A1

WO2023213521A1 - Hard surface cleaning composition

Info

Publication number: WO2023213521A1
Application number: PCT/EP2023/059920
Authority: WO
Inventors: Nagaraja ACHARYA I S; Samiran Mahapatra; Shanthi APPAVOO
Original assignee: Unilever Ip Holdings B.V.; Unilever Global Ip Limited; Conopco, Inc., D/B/A Unilever
Priority date: 2022-05-06
Filing date: 2023-04-17
Publication date: 2023-11-09
Also published as: WO2023213523A1; WO2023213522A1

Abstract

The invention is in the field of detergent compositions, in particular detergent composition providing a hygiene benefit, more in particular detergent compositions comprising active ingredients derived from natural origins. It is therefore an object of the present invention to provide a biodegradable cleaning composition, and advantageously provides hygiene active against both gram-positive and gram-negative organisms. It has been found that a composition comprising low amounts of hydrogen peroxide and low amounts of an amino acid surfactant, in the presence of a low amount of alkyl polyglycoside (APG) and organic acid provide high hygiene efficacy against both gram-positive and gram-negative organisms.

Description

HARD SURFACE CLEANING COMPOSITION

Field of the invention

The invention is in the field of detergent compositions, in particular detergent composition providing a hygiene benefit, more in particular detergent compositions comprising active ingredients derived from natural origins.

Background of the invention

Fast moving consumer goods for household cleaning have traditionally provided hygiene. Cleaning hard surfaces, such as kitchen tops, floors, windows, bathrooms and toilets, regularly reduces the spread of diseases caused by amongst others viruses and pathogenic bacteria. The widespread use of household cleaning products has contributed to an increased life expectancy.

Present day consumers are becoming more and more concerned about the burden of synthetic hygiene ingredients to the environment and nowadays prefer more natural ways for providing hygiene.

Hydrogen peroxide is naturally occurring hygiene ingredient that can be formed from water by exposure to sunlight and is naturally occurring in plant and animal cells. It is biodegradable into water and oxygen.

At low concentration, hydrogen peroxide is an active disinfectant against some gramnegative bacteria, but activity against most gram-positive bacteria remains to be desired.

Synthetic surfactants have been used for providing hygiene benefits for over a century. Such surfactants are typically made from mineral oil and one or more synthesis steps to provide the required head group. These surfactants contribute to the carbon footprint, are usually not biodegradable and end up in wastewater treatment plants or surface water. An alternative to synthetic surfactants are amino acid based surfactants, which have become available at larger scale in the recent years and provide detergent activity based on a naturally derived backbone of an amino acid and an oily chain. EP 109279 discloses an improved hydrogen peroxide based sterilizing and disinfecting solution which is stabilized to prevent decomposition of hydrogen peroxide and to prevent corrosion damage to medical instruments contacted with the solution. As pointed out in this application the stabilisation of peroxide is a concern and one solution is a high peroxide concentration, which is not preferred in household cleaning compositions.

CN111793530 discloses high-performance, safe and environment-friendly foam cleaning agent for bracket-free invisible appliance, and preparation method thereof, comprising hydrogen peroxide and sodium lauryl sarcosinate and relatively high concentrations.

US2009324508AA discloses a composition for use in a foam dispenser comprising hydrogen peroxide, alcohol and a foam booster. The foam booster is capable of providing a stable foam. The composition provided as a foam is suitable for disinfecting skin and/or mucous membranes.

US 2019/0297881 A1 discloses antimicrobial composition having a pH of from about 0 to about 4.5, and comprising a synergistic combination of at least one peroxygen compound, and at least one anionic surfactant selected from the group consisting of alkyl sarcosines and salts thereof. The solutions are free of percarboxylic acids and precursors thereof, essential oils, bleaching agents, low molecular weight organic diamines, cationic surfactants, C1 -C4 aldehydes, ferrous salts, parabens, enzymes, and a poly(alkylene glycol) alkyl ethers containing four or more ether linkages. Dry compositions, uses and methods for sanitization, disinfection and sterilization are also disclosed. However, there is still a need for phosphorous free acid compositions.

An effective hygiene composition at low peroxide and low amino acid surfactant levels remains to be desired.

It is therefore an object of the present invention to provide a biodegradable cleaning composition. It is a further object of the invention to provide a low hydrogen peroxide, low amino acid surfactant based hygiene composition.

It is yet a further object of the invention to provide a hygiene composition that is active against both gram-positive and gram-negative organisms.

Surprisingly, it has been found that a composition comprising low amounts of hydrogen peroxide and low amounts of an amino acid surfactant, in the presence of a low amount of alkyl polyglycoside (APG) and organic acid provides high hygiene efficacy against both gram-positive and gram-negative organisms.

Summary of the invention

Accordingly, in a first aspect the invention provides a hard surface detergent composition comprising 0.1 -0.5 % wt based on the total detergent composition of hydrogen peroxide; 0.1-1 % wt based on the total detergent composition of an amino acid surfactant; 0.1-1 % wt based on the total detergent composition of an alkyl polyglycoside non-ionic surfactant; 1-5 % wt based on the total detergent composition of an organic acid; and wherein the composition has a pH of between 2.5 and 5.

In a second aspect the invention provides a packaged detergent composition comprising the composition according to anyone of the preceding claims at a volume of 50 to 1500 ml in a closable container.

In a third aspect the invention provides a concentrate of the composition according to the first aspect, that provides the composition of the first aspect after 2-20 times dilution with water.

In a fourth aspect the invention provides a kit comprising a concentrated composition according to the third aspect and instructions for dilution to obtain the composition according to the first aspect. These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word “comprising” is intended to mean “including” but not necessarily “consisting of” or “composed of.” In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word “about”.

Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

Detailed description of the invention

The present invention provides a hard surface detergent composition comprising hydrogen peroxide, an amino acid surfactant, an alkyl poly glycoside non-ionic surfactant, and an organic acid.

In particular, the invention relates to compositions comprising low amounts of hygiene agents, to reduce the level of aggressive chemicals in the composition, while still maintaining a high hygiene efficacy. Hygiene efficacy for the purpose of this invention is determined by the bacterial kill rates of both gram-positive and gram-negative bacteria. The bacterial kill is generally measured in a “log kill number”, wherein the log refers to the logarithmic scale, that is measured as 1 point on the log scale, equalling a 10-fold change; for instance, a log kill of 1 , equals a 10 fold (=10¹) reduction in bacteria, or a log kill of 3 indicates a 1000 fold (=10³) reduction in bacteria. To provide hygiene in the context of this invention, the log kill rate is at least 2, more preferably at least 3, still more preferably at least 4 or even at least 5. Ultimately a full bacterial inhibition and full bacterial kill is the most preferred. The contact time at which the kill is achieved is also a relevant factor for use as a household cleaning formulation. Therefore, the contact time for obtaining the above bacterial kill is preferably less than 15 min, more preferably less than 10 min, still more preferably less than 5 min, even more preferably less than 3 min, yet more preferably not more than 2 min, even still more preferably not more than 1 min.

Hydrogen peroxide

The hydrogen peroxide is present in the composition in a concentration of 0.1 -0.5 % wt based on the total detergent composition. Preferably the hydrogen peroxide is present in a concentration of at least 0.15 % wt, more preferably at least 0.2 % wt, but typically not more than 0.4 % wt based on the total detergent composition. By % wt is meant percent by weight.

Without wishing to be bound to a theory, it is found that the peroxide at low concentration provides anti-microbial (i.e. anti-bacterial) activity, in particular it provides the highest activity against gram-negative bacteria.

Amino acid surfactant

Amino acid surfactants are surfactants that may be produced by biotechnological and chemical methods using amino acids and (vegetable) oils or fat. Because amino acids and vegetable oils or fats are renewable sources, the class of amino acid surfactants are a suitable material in detergent compositions that are made from renewable sources. The combination of a polar amino acid and non-polar oil or fat chain provides molecules with high surface activity. Due to the wide variety of amino acids (and peptide) structures and the variety in the chain length of the oily or fat group, the properties of amino acid surfactant also vary, allowing for specific amino acid surfactants for specific purposes.

Without wishing to be bound to a theory, it is found that amino acid surfactants at low concentration provide anti-microbial (i.e. anti-bacterial) activity, in particular they provide enhanced activity against gram-positive bacteria. The amino acid surfactant is present in the composition in a concentration of 0.1-1 % wt based on the total detergent composition. Preferably the amino acid surfactant is present in a concentration of at least 0.15 % wt, more preferably at least 0.2 % wt, still more preferably at least 0.3 % wt, or even more preferably at least 0.4 % wt, but preferably not more than 0.9 % wt, more preferably not more than 0.8 typically not more than 0.7 % wt, or even not more than 0.6 % wt based on the total detergent composition.

The amino acid in the amino acid surfactant is preferably selected from glutamates, sarcosinates or taurates. The oily of fatty chain is preferably a C6 - C16 fatty acid chain, more preferably C10 to C16, the most preferred fatty acid chains are lauroyl and cocoyl chains. The amino acid is preferably selected from disodium lauroyl glutamate, sodium lauroyl sarcosinate and sodium methyl cocoyl taurate.

Since the oily or fatty chain is typically derived from natural sources, the fatty acids and alcohols they are made of are not always a pure single chain length ingredient. By Cx- Cy is generally meant that at least 50% of the alkyl chains comprise of between x and y carbon atoms, preferably at least 60%, more preferably at least 70%, still more preferably at least 80%, even more preferably at least 90%, yet more preferably at least 95%, or even at least 98%, or ideally at least 99% of the alkyl chains comprise of between x and y carbon atoms.

Non-ionic surfactant

Without wishing to be bound by a theory, it is found that a low concentration of a specific class of non-ionic surfactants, alkyl polyglycosides, enhance the hygiene efficacy imparted by the combination of peroxide and amino acid surfactant; in particular, the alkyl polyglycoside provides for faster hygiene efficacy, requiring a shorter contact time.

The alkyl chain length is generally defined as an average alkyl chain length. The alkyl chain length of the alkyl poly glycoside preferably comprises between 4 and 18 carbon atoms, more preferably at least 6 carbon atoms, still more preferably at least 8 carbon atoms, but preferably not more than 14 carbon atoms, more preferably not more than 12 carbon atoms. The most preferred is 8 - 10 carbon atoms, such as a mixture of a C8 and C10 alkyl chains. The alkyl chain is preferably a linear alkyl chain. The alkyl chain is preferably derived from fatty alcohols, more preferably the alkyl chain is derived from natural fatty alcohols.

Other non-ionic surfactants, such as ethoxylated alcohols, to an extent also provide a similar benefit, but have been found to lead to a slower hygiene efficacy than alkyl polyglycosides. Present day consumers prefer a fast hygiene effect.

Surprisingly, the alkyl polyglycosides provides their hygiene efficacy enhancement effect at very low levels. Even more surprisingly, the effect is the strongest on hard-to- kill gram negative bacteria, such as E. coli. The amount of alkyl polyglycoside is therefore preferably present in a lower amount than the sum of the amount of peroxide and the amino acid surfactant; i.e. in a lower concentration than the sum of the concentrations of peroxide and amino acid surfactant taken together.

The alkyl polyglycoside (APG) is present in the composition in a concentration of 0.01 to 1 % wt based on the total detergent composition. Preferably, the alkyl poly glycoside is present in a concentration of at least 0.02 % wt, more preferably at least 0.05 % wt, but preferably not more than 0.5 % wt, or even not more than 0.25 % wt based on the total detergent composition.

Preferably, the ratio of alkyl polyglycoside to the amino acid surfactant is between 2:1 and 1 :5.

Preferably, the ratio of alkyl polyglycoside to the peroxide is between 2:1 and 1:10.

Organic acid

The composition further comprises an organic acid. Without wishing to be bound by a theory, the organic acid is considered to have both a buffering effect on the composition and a stabilising effect on the hygiene agents, reducing degradation. The organic acid is further active in the dissolution of lime scale, which typically is a suitable substrate for bacteria. Without wishing to be bound by a theory, it is thought that by dissolving lime scale, the bacteria are released from the surface and are more vulnerable to the hygiene agents in the composition (peroxide and amino acid surfactant).

Suitable organic acids in the present invention are preferably selected from organic acids having their lowest dissociation constant (pKai) in water at a pK_a value of between 2.5 and 4, measured at a temperature of 20 degrees Celsius (20 °C), more preferably at least 2.75, but preferably not more than 3.75, or even not more than 3.5. The most preferred organic acids are naturally sourced organic acids.

The organic acid is present in the compositions according to the invention in a concentration of between 0.1 and 5 % wt based on the total detergent composition, preferably at least 0.2 % wt, still more preferably at least 0.4 % wt, or even at least 0.5 % wt, but preferably not more than 4 % wt, more preferably not more than 3 % wt. still more preferably not more than 2% wt or even not more than 1.5 % wt based on the total detergent composition.

Preferred organic acids include citric acid, lactic acid, glycolic acid, formic acid, glyceric acid, galaturonic acid, itaconic acid, tartaric acid, benzoic acid and malic acid, or combinations thereof. The most preferred are citric acid, lactic acid and glycolic acid, or combinations thereof.

The pH of the composition is therefore between 2.5 and 5, to be at a pH of around the value of the organic acid dissociation constant. More preferably the pH of the composition is at least 2.75, or even at least 3, while it is preferably not more than 4.5, still more preferably not more than 4, even more preferably not more than 3.5.

Further ingredients.

The composition may further comprise common additives such as preservative, hydrotrope, solvent, chelating agent, buffer, salt, perfume and/or dye. Without wishing to be bound to a particular theory, it is noted that additives having a negative influence one the hygiene efficacy if the composition are not preferred in the composition. The composition may advantageously comprise a peroxide stabiliser. Such peroxide stabiliser may be preferably selected from phosphonate based stabilisers, stabilisers that are selected from natural, naturally derived, bio-sourced, bio-degradable, also referred to a “green” stabilisers; or combinations thereof.

When present, the stabiliser preferably present in an effective amount. An effective amount of stabiliser is depending on the type of stabiliser, but is preferably within a molar ratio of stabiliserperoxide of between 2:1 and 1 :5 more preferably between 3:2 and 1:4, or even more preferably between 1 :1 and 1:3.

Application and format

The composition is preferably applied to a surface as is, without dilution. The surface may be wiped before and after application, but may also be left to dry after application of the composition.

The composition may be applied in any conventional means, such as by means of a cloth, wipe or sponge, or by means of a trigger spray dispenser or any mechanical means for ejecting the liquid in spray or aerosol form. Application by means of a trigger spray dispenser is the most preferred, as trigger spray application enables fast and easy use for the consumer. The composition is therefore preferably applied using a trigger spray dispenser.

The composition may be packaged in a closable container, such as a bottle of any conventional shape or form. The container preferably has a volume of between 50 and 1500 ml, preferably at least 100 ml, more preferably at least 150 ml, or even at least 200 ml. In a trigger spray format, the container has a volume of preferably not more than 1000 ml, more preferably not more than 750 ml, or even more preferably not more than 500 ml. As a general purpose composition, the container is preferably a bottle for pouring the composition onto a cloth or wipe, the volume of the bottle is preferably not more than 1500 ml, more preferably not more than 1000 ml.

In a further aspect the invention provides a concentrate of the composition, for dilution by the consumer. A concentrate composition is sold in a smaller bottle, and therefore has a lower environmental footprint due to the smaller packaging, that uses less packaging material, which often contains plastic. The lower volume also results in a lower weight and therefore lower weight to be transported, and therefore lower fuel consumption of the transport trucks.

In the aspect of the concentrated composition the composition is preferably concentrated between 2 and 20 times, more preferably at least 3 times, more preferably at least 4 times, still more preferably at least 5 times, but preferable not more than 18 times, or even not more than 15 times. By a “x” times concentration is meant that the composition of the invention is obtainable after a “x” times dilution with water. By x times dilution with water is understood that 1 part by volume of the concentrate is mixed with x-1 parts by volume of water; e.g. a 10 times dilution thus means that 1 part of the concentrate is mixed with 9 parts (i.e. 10 minus 1) of water, to form 10 parts of the composition according to the invention.

In a related aspect there is provided a kit comprising a concentrated composition and instructions for dilution to obtain the composition according to the invention.

Examples

The invention will now be illustrated by means of the following non limiting examples.

In these examples, the compositions according to invention are compared to comparative compositions by means of a suspension test.

The suspension test in this example is according to the common test protocol of EN1276.

The bacterial cultures as used have a bacterial count of having 10⁸ bacteria per ml)

In this test 8ml of formulation was used together with 1 ml of bacterial and 1 ml of BSA solution. The BSA solution is at a concentration of 0.03% to mimic a “clean” surface condition. Therefore after mixing 1 ml of culture with 8 ml of formulation and 1 ml of BSA solution the bacterial count is diluted 10 times, thus resulting in a bacterial count at the start of the experiment of 10⁷ bacteria per ml.

The formulation and bacteria are in contact for appropriate time points (1 to 15 min, as specified in the examples below) and then neutralized (to quench the efficacy of the actives and stop its action against bacteria). With respect to a water control, the bacterial log reduction through formulations is be calculated and marked in the respective tables in the examples below. Evaluation of antimicrobial efficacy is done as such or after dilutions as specified in the data set. The examples are carried out at room temperature of 23 °C.

Target organism:”

Pseudomonas aeruginosa ATCC 15442 Staphylococcus aureus ATCC 6538 Enterococcus hirae ATCC 10541 Escherichia coli ATCC 10536

E. coli and P. aeruginosa are gram-negative bacteria and S. aureus and E. hirae are gram-positive.

Example 1: anti-bacterial efficacy test; variation of non-ionic surfactant.

The following formulations were prepared:

Example formulations 1 and 2 are according to the invention. Comparative example formulations A and B are comparative examples with a different non-ionic surfactant. The ingredients in the above table are generic pure ingredients, available from Sigma Aldrich, except those in the table below, which are specifically defined.

All the ingredients are homogenised in a conventional manner for 15 min. The final pH of the formulation is adjusted using 10 % Sodium Hydroxide solution, before mixing with the bacterial culture and BSA solution.

The below results were all carried out under clean surface conditions, after 1, 2 or 5 min contact time with the compositions, before being neutralised to quench the hygiene activity

Results after 1 min contact time before quenching

Results after 2 min contact time before quenching

Results after 5 min contact time before quenching

The tables above shows the log kill number for all experiments after 1 min of contact time before quenching. Considering that the cell culture had a bacterial count of 10⁸ bacteria per ml, and that it was diluted 10 times by mixing with the cleaning composition and BSA solution, the starting amount of bacteria was 10⁷ per ml (i.e. 10,000,000), while a 5 log reduction means a reduction by a factor 10⁵ (i.e. a factor 100,000). At a kill rate of >5 it is difficult to get a reliable count on the remaining bacteria. Therefore, no specific count numbers are given above 5 log kill.

The results show that at a contact time of more than 5 min, bacterial kill is achieved regardless of the formulation with APG vs an alternative non-ionic, however, in household cleaning the contact time matters a lot, as present day consumers do not want to wait for 5 min, but want to see immediate action.

After a 2 min contact time, the compositions according to the invention still show a >5 log reduction, while the comparative composition does not reach a 5 log kill anymore on E. coli. When reducing the contact time to 1 min, the comparative compositions fail at both E. coli and E hirae, while the compositions with the alkyl polyglycoside nonionic surfactant still show a greater than 5 log kill.

Example 2: Anti-bacterial efficacy test - variation of peroxide level.

The same tests were done with different compositions, al test conditions are the same, except where specified otherwise.

In this example the following compositions were used.

*) Similar to composition 2 of example 1 , but normalised to the same concentration of amino acid surfactant and APG as composition 1.

The results are shown in the tables below.

Results after 30 sec contact time before quenching

Results after 1 min contact time before quenching

The results in the tables above show that all compositions according to the invention achieve a greater than 3 log reduction on all target bacteria, even after 30 seconds, and greater than 5 log after 1 min. The sarcosinate amino acid surfactant performs slightly better than the glutamate surfactant.

Example 3: Anti-bacterial efficacy test - variation of organic acid. The same tests were done with different compositions, al test conditions are the same, except where specified otherwise.

In this example the following compositions were used.

The results are shown in the tables below. In this example only the two most difficult bacteria were tested (E. coli and E. hirae).

Results after 1 min contact time before quenching

The results in the tables above show that also with lactic acid, the bacterial kill of the compositions according to the invention achieve a greater than 4 log reduction on all target bacteria, even after 1 min, while the compositions with the alternative non-ionic surfactant provide a lower hygiene efficacy under the same conditions.

Example 4: Anti-bacterial efficacy test - variation of organic acid.

The same tests were done with different compositions, al test conditions are the same, except where specified otherwise. In this example the following compositions were used.

The results are shown in the tables below. In this example only the two most difficult bacteria were tested (E. coli and E. hirae). Results after 1 min contact time before quenching

The results in the tables above show that also with glycolic acid, the bacterial kill of the compositions according to the invention achieve a greater than 4 log reduction on all target bacteria, even after 1 min, while the compositions with the alternative non-ionic surfactant provide a lower hygiene efficacy under the same conditions.

Example 5: Anti-bacterial efficacy test - variation of pH.

In this example the following compositions were used.

The results are shown in the tables below.

Results after 15 min contact time before quenching

The results in the tables above show that the amount of organic acid has an optimum level at around 1%. While the efficacy at 0% or 2% is still well within the acceptable range, the optimum appears to be at about two times the peroxide concentration.

However, the composition without organic acid performs worse against two important pathogenic bacteria (E. coli and S. aureus).

Example 6: Comparison to US 2019/0297881 A1.

An attempt has been made to make a comparison to US 2019/0297881 , examples 5 and 22. The tests were done with different compositions, all test conditions are the same, except where specified otherwise.

In this example the following compositions were used.

Comparative example I shows a composition according to US 2019/0297881 , example 5, where the concentrations are corrected for the ingredient purities used in US 2019/0297881. Phosphoric acid was was maintained also in the inventive composition (10) even though it serves no purpose, to maintain the comparison. Comparative example J is a representation of US 2019/0297881 , example 22, while example 11 is the inventive equivalent, without etidronic acid (HEDP). The results are shown in the tables below.

Results after 1 min contact time before quenching

The table above shows the log kill number for all experiments after 1 min of contact time before quenching. Considering that the cell culture had a bacterial count of 10⁸ bacteria per ml, and that it was diluted 10 times by mixing with the cleaning composition and BSA solution, the starting amount of bacteria was 10⁷ per ml (i.e. 10,000,000), while a 5 log reduction means a reduction by a factor 10⁵ (i.e. a factor

100,000). At a kill rate of >5 it is difficult to get a reliable count on the remaining bacteria. Therefore, no specific count numbers are given above 5 log kill.

The results in the tables above show that phosporous containing acid (etidronic acid, HEDP) is detrimental to the performance of the hygiene composition under otherwise equal conditions.

Claims

1 A hard surface detergent composition comprising: a 0.1 -0.5 % wt based on the total detergent composition of hydrogen peroxide; b 0.1-1 % wt based on the total detergent composition of an amino acid surfactant; c 0.1-1 % wt based on the total detergent composition of an alkyl polyglycoside non-ionic surfactant; d 1-5 % wt based on the total detergent composition of an organic acid; and wherein the composition has a pH of between 2.5 and 5.

2 A composition according to claim 1 , wherein the amino acid surfactant is selected from disodium lauroyl glutamate, sodium lauroyl sarcosinate and sodium methyl cocoyl taurate.

3 A composition according to claim 1 or 2, further comprising a peroxide stabiliser (e.g. selected from phosphonate stabilisers or green stabilisers).

4 A composition according to anyone of the preceding claims, wherein the organic acid has a first pKa of between 2.5 and 4.

5 A composition according to anyone of the preceding claims, wherein the alkyl group of the alkyl poly glycoside comprises between 4 and 18 carbon atoms.

6 Packaged detergent composition comprising the composition according to anyone of the preceding claims at a volume of 50 to 1500 ml in a closable container.

7 A concentrate of the composition according to anyone of claims 1 - 5, that provides the composition of anyone of claims 1 - 5 after 2-20 times dilution with water.

8 Kit comprising a concentrated composition according to claim 7 and instructions for dilution to obtain the composition according to anyone of claims 1 to 5.