GB2487298A

GB2487298A - A composition for controlling malodours comprising enzyme producing bacteria

Info

Publication number: GB2487298A
Application number: GB201200532A
Authority: GB
Inventors: Iwan Fisher; Anthony Clive Umfreville Fisher
Original assignee: FISHER RES Ltd
Current assignee: FISHER RES Ltd
Priority date: 2011-01-13
Filing date: 2012-01-13
Publication date: 2012-07-18
Also published as: GB201100550D0; GB201200532D0

Abstract

A composition for controlling malodours comprises bacteria producing one or more enzymes selected from the group of enzymes comprising protease, esterase, cellulase, lipase, amylase, urease, xylanase and mixtures thereof; an olfactory receptor inhibitor; a malodour masking composition adapted to absorb malodours and a fragrance. Preferably, the bacteria comprise one or more strains of Bacillus, whilst the olfactory receptor inhibitor may comprise a mixture of 1-cyclohexyl-1-ethyl-n-butyrate and 1-cyclohexyl-ethanol. The malodour masking composition can comprise a salt or other derivative of ricinoleic acid, wherein the salt may be a zinc salt or sodium salt. A surfactant may also be included in the composition. The surfactant may be a non-ionic surfactant or amphoteric surfactant, such as Polyoxyethylene (6) C9-C11 alcohol or a disodium salt of an alkylamine dicarboxylic acid, such as Caflon (RTM) AA30 respectively. The composition may further comprise a malodour neutralising composition that traps the malodour molecules, such as Odouraze (RTM). Suitably, the composition also includes a thickening agent, such as Carbopol (RTM) Ultrez 21 and a dye.

Description

I

Improved Formulations and Methods

Field of the Invention

The present invention relates to odour neutralising formulations and methods. The present invention is particularly applicable, but in no way limited, to liquid odour neutralising formulations for use in toilets in vehicles, such as trains, and to methods of reducing or eliminating malodours in such situations.

Background to the invention

Odours from chemical retention type toilets present problems for their operators.

Such toilets are generally located in a confined space, such as within a toilet cubicle in a train, in a caravan or in a portable building. The flushings from such toilets, including urine and solids such as faeces and paper, are generally stored in a tank or other receptacle until the receptacle can be emptied. In the case of toilets on a train this generally means at the end of the train's journey or during an extended stopover, or when the train is taken out of service to be cleaned.

The pipework between the toilets and the tank are typically fitted with one way valves and/or traps to prevent any odours travelling back from the tank and its associated pipework to the toilet cubicle. However, this arrangement of one way valves and/or traps does not always completely prevent the build up of malodours in the environment of the toilet. In addition the storage tanks are usually fitted with one or more vent pipes in order to prevent pressure build up in the tank. The vapours from these vent pipes are also generally foul smelling, and themselves can create malodours which can be drawn back into the train, or may even be released within the train, depending on where the vent pipes terminate. Even if vented externally, these malodours can be unpleasant for those near the train, such as people on a station platform when the train is stationary.

It is therefore usual to add some chemical composition to the toilet tank which is intended to substantially neutralise or eliminate such malodours at source. Such compositions are usually dosed through the toilet, and make their way naturally into the associated tank. However, current formulations are not completely successful at achieving this and there remains a requirement for improved formulations, and improved methods of dealing with such malodours, which neutralise malodours in and around a toilet cubicle and in toilet systems to a greater extent and over a longer period of time than is at present possible.

Summary of the Invention

According to a first aspect of the present invention there is provided a composition for controlling malodours, said composition comprising:- (i) a bacterial composition producing one or more of the enzymes selected from the group of enzymes comprising:-protease esterase cellulase lipase amylase urease xylanase; and mixtures thereof; (ii) an olfactory receptor inhibitor; (iii) a malodour masking composition adapted to absorb malodours; (iv) a fragrance.

By utilising a composition which includes all four active ingredients malodours are controlled to a significantly greater extent than with previous known compositions.

Formulations according to the present invention are significantly more effective at controlling malodours than previous formulations, or equivalent formulations containing only malodour neutralising/masking components and without an olfactory receptor inhibitor. This surprising result indicates that there is a synergy between the various components not previously reported or recognised.

Preferably the bacterial composition comprises one or more strains of bacillus.

Bacillus strains which are generally harmless to humans are available, and can be formulated as their spores together with a suitable surfactant, and are capable of producing the enzymes required. Optionally, a purified enzyme extract can be added to the composition, in addition to the bacterial composition. Examples of suitable enzyme preparations for use in such a composition include isolated enzyme preparations containing protease, esterase, cellulase and/or lipase enzyme isolates as sold by Novozymes A/S, Krogshoejvej 36, 2880 Bagsvaerd, Denmark. It will be understood that suitable enzyme preparations may contain more than one enzyme of a particular category and may also contain enzymes from two or more categories.

Preferably the olfactory receptor inhibitor blocks an observer's olfactory receptor sites for malodours without blocking the receptor sites for other odours. A preferred olfactory receptor inhibitor formulation is sold under the trade mark FOREST FRESH by International Flavours & Fragrances of Haverhill, Suffolk, CB9 8LG, United Kingdom. These products include a fragrance or perfume, so can provide two of the essential ingredient types.

In a particularly preferred embodiment the olfactory receptor inhibitor comprises a mixture of 1-cyclohexyl-1-ethyl-n-butyrate and 1-cyclohexyl-ethanol, and preferably in a ratio of between 80:20 and 20:80.

In a particularly preferred embodiment the malodour masking composition comprises a salt or other derivative of ricinoleic acid. Ricinoleic acid is an unsaturated omega-9 fatty acid that occurs naturally in nature in the Castor plant and is relatively non-toxic. Preferably the malodour masking composition comprises a zinc salt or a sodium salt of ricinoleic acid. Zinc and sodium salts are particularly effective in this application but other metal salts may also be used.

Preferably the composition further comprises one or more surfactants or detergents.

Suitable non-ionic surfactants include biodegradable non-ionic detergents such as ethoxylated alcohols. Various ethoxylated alcohols can be used in this application but it has been found that an alcohol ethoxylated with 6 moles of ethylene oxide is particularly effective. A suitable example is polyoxyethylene(6) C9-C11 alcohol available as Synperonic 91/6, available from Croda Europe Limited, Cowick Hall, Snaith, Goole, DNI4 9AA United Kingdom; or CAFLON NE-0600 available from Univar Limited, Argyle House Epsom Avenue, Stanley Green Trading Estate, Wilmslow, Cheshire, 5K9 3RN, United Kingdom.

It will be appreciated that there are a number of alternative biodegradable non-ionic detergents that could be used in this application and the appropriate materials specialist will make a choice of which surfactant, or which combination of surlactants to use.

In addition, or as an alternative, an amphoteric surfactant/detergent can be used.

Suitable examples include disodium salts of an alkylamine dicarboxylic acid such as CAFLON AA3O supplied by Univar Limited, Argyle House, Epsom Avenue, Stanley Green Trading Estate, Wiimslow, Cheshire SK9 3RN, United Kingdom. It wiIJ again be appreciated that a wide range of amphoteric surfactants are available which could be used in this application and the choice of surfactant or surfactants will be made by the appropriate formulation specialist.

Preferably the composition further comprises a malodour neutralising composition that interacts with malodour molecules to trap the malodour molecules. In a particularly the malodour neutralising composition comprises a volatile component which interacts with malodour molecules to change their characteristics. A suitable neutralising composition is sold under the trade name ODOURAZE (RTM) by Fragrance Oils PLC, 2 Bloomsbury Street, London, WCI B 3ST, United Kingdom.

Preferably the composition further includes one or more components from the group comprising:-a dye; a thickening agent; a water softener; a crystallisation suppressant; and a buffer.

It will be understood that the present invention extends to methods of preparing compositions for controlling malodours according to the first aspect of the invention.

According to a further aspect of the present invention there is provided a method of reducing or eliminating malodours in chemical retention type toilets, said method comprising introducing into the toilet flushing system an effective amount of a composition according to a first aspect of the present invention.

In a particularly preferred embodiment there is provided a method of reducing or eliminating malodours in chemical retention type toilets, said method comprising the steps of:- (a) introducing into the toilet flushing system an effective amount of a composition according to the first aspect of the present invention; (b) introducing into the air space of the toilet cubicle a sustained release fragrance designed to mask any malodours in the air within the toilet cubicle.

This combined approach has proved particularly effective. The sustained release fragrance is preferably located where there is some air movement, such as in or associated with an air vent. However, opening and closing a cubicle door, and or the action of an extractor fan, can provide sufficient air movement to reiease sufficient fragrance over time. Suitable sustained release or controlled release fragrances can be sourced from Hydroemission Corporation FTE Limited of 65A Jalan Tenteram #05-04, St Michael's Industrial Estate, Singapore 328958.

Controlled release fragrances in a wide variety of fragrances are available and a fragrance can be chosen which is similar to the fragrance in the composition that is added to the toilet. Alternatively a fragrance could be used that is different to and contrasts with the fragrance in the toilet composition. For example, a pine-type odour could be used in the composition added to the toilet system and a citrus or fruit fragrance could be used in the controlled release air fragrance within the cubicle.

The invention also extends to methods of manufacturing compositions for controlling malodours and to methods of controlling malodours using compositions according to the present invention.

Description of the preferred embodiments

Known formulations for use in such toilets often contain paraformaldehyde, for example formulations such as those described in GBI,192,979 (Elsan Limited).

These formulations, whilst going some way to suppress odours, are potentially hazardous and can present a serious health risk, due to the formaldehyde vapour which is released over time. Formaldehyde, which is classified as a probable human carcinogen, can also irritate the eyes and mucous membranes, resulting in watery eyes. When inhaled, formaldehyde may cause headaches, a burning sensation in the throat, and difficulty breathing, as well as triggering or aggravating asthma symptoms.

Furthermore, these formulations do not have any significant effect on reducing the amount of solid waste present in the waste stream. Thus, systems treated with this known type of odour suppressant still suffer from blockages as well as malodour problems from time to time.

It has surprisingly been found that a combination of four different active ingredients, each with a different mode of action, provides a composition for controlling malodours that is significantly more effective than known compositions for this application. The four types of active ingredient are:- 1. Enzyme producing bacteria Malodours are caused by volatile molecules which generally have a molecular weight of less than about 300. These molecules can contain a wide range of chemical functional groups such as sulphides, mercaptans, thioethers, acids, esters, amines, aldehydes and ketones. These functional groups are susceptible to modification or cleavage by certain specific enzymes. Such enzymes are known to be produced by certain bacteria and it is therefore possible to formulate a mixture of bacterial species, preferably as their spores together with a suitable surfactant, and to incorporate this bacterial mix into compositions according to the present invention for addition to tanks containing human waste. The bacteria selected are generally harmless to humans. One suitable formulation of Bacillus spores is sold under the trade name Genzyme Mu (RTM) by Genesis Biosciences Limited of Capital Business Park, Capital Point, Parkway, Cardiff, CF3 2PU, United Kingdom. It will be understood that other bacterial species could equally well be used.

It is important that there is a range of enzymes produced by the replicating bacteria or bacterial mix and the bacterial species are selected on that basis.

Suitable enzymes include proteases, esterases, cellulases, lipases, amylases, ureases and xylanases.

These bacteria can also assist in breaking down the solid waste present in the waste stream. This helps to prevent blockages in the pipework system.

2. Olfactory Receptor Inhibitors This class of inhibitors operate by decreasing the perception of a malodour by an observer, whilst reducing or not contributing to the overall perceived odour level. Examples of such inhibitors are 1-cyclohexyl-1-ethyl-n-butyrate and 1-cyclohexyl-ethanol, or mixtures thereof. Such compounds are thus conveniently referred to as malodour counteractants. Furthermore, the use of these malodour counteractants appears to leave unaffected the perception of other odours by the observer. Without wishing to be bound by any particular theory of action, it is thought that these compounds may act by blocking the observer's olfactory receptor sites for the malodour without blocking the receptor sites for other odours. Suitable olfactory receptor inhibitors are sold under the brand name Fresh Concentrate 290978 or Forest Fresh 273 by International Flavours & Fragrances I.F.F. (Great Britain) Limited of Duddery Hill, Haverhill, Suffolk, CB9 8LG, England.

However, this disclosure is intended to encompass all known olfactory receptor inhibitors, and those yet to be discovered.

3. A malodour masking composition In addition to compositions which react with or complex with volatile malodour compounds, there are a number of compositions which can absorb or neutralise smells in the liquid phase. One such composition contains a zinc salt or a sodium salt of ricinoleic acid. These salts are particularly effective at reducing or eliminating smells caused by hydrogen sulphide, mercaptans, thioethers, isovaleric acid and ammonia. Suitable formulations are sold by Goldschmidt GmbH, Goldschmidtstrasse 100, D45127 Essen, Germany under the trade mark TEGO (RTM) Sorb Conc. 50.

4. Afracirance To complete the essential components for a composition for controlling malodours, a fragrance is added. A wide variety of fragrances can be used, to suit the location in which the product is to be used. The nature of the fragrance is important. It needs to possess a long lasting fresh smell which gives a general lift to the person smelling it. It is also important that the perception of this fragrance is not blocked by the olfactory receptor inhibitor detailed in Section 2 above. This can be tested for using standard olfactory acuity test methods. The materials expert will determine suitable fragrance options, and such fragrances are available from a wide range of suppliers such as International Flavours & Fragrances I.F.F. (Great Britain) Limited of Duddery Hill, Haverhill, Suffolk, CB9 8LG, England.

5. A malodour neutralizing composition (optional) As described above, compounds that cause malodours are voiatile compounds with a molecular weight of less than about 300 and which may contain a variety of functional groups. It is possible to provide malodour neutralising compounds which are specifically designed to react with, or interact with, functional groups in the malodours and thus chemically modify or mask the malodorous compounds such that they no longer possess a malodour smell. One such composition is sold under the trade mark ODOURAZE (RTM) by Fragrance Oils International Limited, Eton Hill Industrial Estate, Eton Hill Road, Radcliffe, Manchester, M26 2FR, England.

6. Other optional ingredients In addition to the four classes of active ingredients, and the one optional ingredient listed above, the composition may also include one or more of the following:-a dye, one or more surfactants, a water softener, a crystallisation suppressant, a buffer, and a thickening agent.

A non-staining dye is preferred and a suitable dye is Evron Brilliant Blue R 150% supplied by Town End (Leeds) PLC, Silver Court, Intercity Way, Stanningley, Leeds, LSI3 4LY, United Kingdom.

Various suitable surfactants have been described above.

A suitable thickening agent is a styrene poly(acrylate) based thickening agent such as CARBOPOL (RTM) Ultrez 21 supplied by Lubrizol Advanced Materials, Inc, 9911 Brecksville Road, Cleveland, Ohio 44141 -3247, USA.

Suitable water softeners include tetrasodium iminodisuccinate or tetrasodium glutamate diacetate, or mixtures thereof, and a suitable crystallisation suppressant is sodium poly(aspartate). These are preferably present in a ratio of water softener to crystallisation suppressant of 1.5:1.

This combination is both effective and environmentally friendly.

A suitable composition for controlling malodours can be formulated according to the following Examples:-.

Example I

Amounts given are in parts by weight and the mixture is made up to 100 parts with water, preferably purified water.

2 -5 parts of a mixture of disodium succinate and sodium poly(aspartate); -10 parts of a biodegradable non-ionic detergent; 2 -5 parts of an amphoteric detergent; 5-10 parts Forest Fresh 273 perfume/olfactory receptor inhibitor; -10 parts of a bacterial suspension such as GENZYME MU 20X; I -5 parts of a metal salt of ricinoleic acid (TEGO (RTM) Sorb Conc 50); 0.004 parts blue dye.

Method A mixing vessel is charged with the requisite amount of water. A thickening agent, such as Carbopol U21 is added, if required, and the mixture stirred until the desired thickness is obtained. The remaining components are added to the thickened aqueous mixture. The order of addition is not critical. Further water is added to bring to IOU parts as necessary. The resulting mixture is stirred for a further 15 minutes to ensure thorough mixing and the mixture dispensed into appropriately sized dosing bottles, sachets, or other suitable containers.

In use, typically 200 to 250 mIs of the above mixture is added to a holding tank through a toilet. An amount of 200 to 250 ml is sufficient for a holding tank having a capacity of 300 to 400 litres. It will be appreciated that the amount of composition required for a particular application will be dependent on the size of the installation and may be determined by experimentation.

Example 2

Soft Water 72.845% w.w Carbopol U21 (ETD200I) 0.4% w.w Dissolvine GL-47-S 1.5% w.w Tego Sorb Conc. 50 1.5% w.w Caflon NE0 600 9% w.w Mackam DP -122 (Albion APC30) 2.5% w.w Perfume: Fresh Concentrate 290978 or Forest Fresh 273 2.25% w.w Genzyme MU 20 10% w.w Dye: Blue Evron R 150% 0.005% w.w Total 100.00% A mixing vessel is charged with the requisite amount of water. A thickening agent, such as Carbopol U21 is added and the mixture stirred until the desired thickness is obtained. The remaining components are added to the thickened aqueous mixture.

The order of addition is not critical. Further water is added to bring to 100 parts as necessary. The resulting mixture is stirred for a further 15 minutes to ensure thorough mixing and the mixture dispensed into appropriately sized dosing bottles, sachets, or other suitable containers.

Formulations according to the present invention also include dry powder formulations. A suitable dry powder formulation is given in Example 3.

Examole 3 Sodium Bicarbonate 45.00% w.w Perfume: Forest Fresh 273 25.00% w.w Aerosil 200 (fumed silica) 12.50% w.w Tego Sorb Conc. 50 7.50% w.w IDS Powder 5.00% w.w NANSA HS85/S 2.00% w.w Genzyme P200 Powder 2.00% w.w Dowanol DPM 1.00% w.w Total 100.00% The liquid components and the perfume are sprayed onto the Aerosil 200 and the resulting solid is mixed with the other solid ingredients. Mixing is continued until the mixture is homogeneous and the mixture dispensed into appropriately sized dosing bottles, sachets, or other suitable containers.

Examrde 4 Amounts given are in parts by weight and the mixture is made up to 100 parts with water, preferably purified water.

2 -5 parts of a mixture of disodium succinate and sodium poly(aspartate); -10 parts of a biodegradable non-ionic detergent; 2 -5 parts of an amphoteric detergent; -10 parts Forest Fresh 273 or Fresh Concentrate 290978 olfactory receptor inhibitor; 5 -10 parts fresh perfume containing ODOU RAZE (RTM); -10 parts of a bacterial suspension such as GENZYME MU 20X; I -5 parts of a metal salt of ricinoleic acid (TEGO (RTM) Sorb Conc 50); 0.004 parts blue dye.

Method A mixing vessel is charged with the requisite amount of water. A thickening agent, such as Carbopol U21 is added, if required, and the mixture stirred until the desired thickness is obtained. The remaining components are added to the thickened aqueous mixture. The order of addition is not critical. Further water is added to bring to 100 parts as necessary. The resulting mixture is stirred for a further 15 minutes to ensure thorough mixing and the mixture dispensed into appropriately sized dosing bottles, sachets, or other suitable containers.

Claims

Claims 1. A composition for controlling malodours, said composition comprising:- (i) a bacteria producing one or more of the enzymes selected from the group of enzymes comprising:-protease esterase cellulase lipase amylase urease xylanase; and mixtures thereof; (ii) an olfactory receptor inhibitor; (iii) a malodour masking composition adapted to absorb malodours; (iv) a fragrance.
2. A composition for controlling malodours according to Claim I wherein the bacteria comprises one or more stains of bacillus.
3. A composition for controlling malodours according to Claim I or Claim 2 wherein the olfactory receptor inhibitor comprises a mixture of 1-cyclohexyl-1-ethyl-n-butyrate and 1-cyclohexyl-ethanol.
4. A composition for controlling malodours according to any preceding claim wherein the malodour masking composition comprises a salt or other derivative of ricinoleic acid.
5. A composition for controlling malodours according to Claim 4 wherein the malodour masking composition comprises a zinc salt or a sodium salt of ricinoleic acid.
6. A composition for controlling malodours according to any preceding claim further comprising a surfactant.
7. A composition according to Claim 6 wherein the surfactant comprises a non-ionic surfactant
8. A composition according to Claim 7 wherein the non-ionic surfactant comprises polyoxyethylene (6) C9-C11 alcohol
9. A composition according to Ciaim 6 wherein the surfactant comprises an amphoteric surfactant.
10. A composition according to Claim 9 wherein the amphoteric surfactant comprises a disodium salt of an alkylamine dicarboxylic acid such as CAFLON (RTM) AA30.
11. A composition according to any preceding claim wherein the composition further comprises a malodour neutralising composition that interacts with malodour molecules to trap the malodour molecules.
12. A composition for controlling malodours according to Claim 11 wherein the malodour neutralising composition comprises Odouraze (RTM).
13. A composition for controlling malodours according to any preceding claim further including a dye.
14. A composition for controlling malodours according to any preceding claim wherein the composition further comprises a thickening agent, such as CARBOPOL (RTM) Ultrez 21.
15. A composition for controlling malodours according to any preceding claim wherein the composition further comprises an isolates enzyme extract selected from the group comprising:-Protease; Esterase; Cellulase; Lipase; and mixtures thereof.
16. A composition for controlling malodours substantially as herein described.
17. A method of preparing a composition for controlling malodours according to any preceding claim comprising the steps of:- (a) adding a thickening agent, such as Carbopol U21 to the requisite amount of water and stirring for a period; (b) adding the following ingredients with stirring to the aqueous mixture from step (a):- 2 -5 parts of a mixture of disodium succinate and sodium poly(aspartate); -10 parts of a biodegradable non-ionic detergent; 2 -5 parts of an amphoteric detergent; 5-10 parts Forest Fresh 273 perfume/olfactory receptor inhibitor; 5 -10 parts of a bacterial suspension such as GENZYME MU 20X; I -5 parts of a metal salt of ricinoleic acid (TEGO (RTM) Sorb Conc 50); 0.004 parts blue dye; (c) stirring the resulting mixture from step (b) for a further 15 minutes to ensure thorough mixing; (d) dispensing the mixture into appropriately sized dosing bottles, sachets, or other suitable containers.
18. A method of preparing a composition for controlling malodours according to any of claims I to 16 inclusive comprising the steps of:- (a) adding a thickening agent, such as Carbopol U21 to the requisite amount of water and stirring for a period; (b) adding the following ingredients with stirring to the aqueous mixture from step (a):-Dissolvine GL-47-S 1.5% w.w Tego Sorb Conc. 50 1.5% w.w Caflon NEO 600 9% w.w Mackam DP -122 (Albion APC3O) 2.5% w.w Perfume: Fresh Concentrate 290978 or Forest Fresh 273 2.25% w.w Genzyme MU 20 10% w.w Dye: Blue Evron R 150% 0.005% w.w And making the volume up to 100 with water; (c) stirring the resulting mixture from step (b) for a further 15 minutes to ensure thorough mixing; (d) dispensing the mixture into appropriately sized dosing bottles, sachets, or other suitable containers.
19. A method of preparing a composition for controlling malodours according to any of claims Ito 16 inclusive comprising the steps of:- (a) adding a thickening agent, such as Carbopol U21 to the requisite amount of water and stirring for a period; (b) adding the following ingredients with stirring to the aqueous mixture from step (a):- 2 -5 parts of a mixture of disodium succinate and sodium poly(aspartate); -10 parts of a biodegradable non-ionic detergent; 2 -5 parts of an amphoteric detergent; -10 parts Forest Fresh 273 or Fresh Concentrate 290978 olfactory receptor inhibitor; -10 parts fresh perfume containing ODOURAZE (RTM); 5-10 parts of a bacterial suspension such as GENZYME MU 20X; I -5 parts of a metal salt of ricinoleic acid (TEGO (RTM) Sorb Conc 50); 0.004 parts blue dye; and making the volume up to 100 with water; (c) stirring the resulting mixture from step (b) for a further 15 minutes to ensure thorough mixing; (d) dispensing the mixture into appropriately sized dosing bottles, sachets, or other suitable containers.
20. A method of preparing a substantially dry powder composition for controlling malodours according to any of claims I to 16 inclusive comprising the steps of:- (a) providing Aerosil 200 (fumed silica) 12.50% w.w; (b) spraying onto the Aerosil 200 the liquid components from Example 3; (c) mixing the solid from step (b) with the other solid ingredients from Example 3 until the components are intimately mixed; (d) dispensing the mixture into appropriately sized dosing bottles, sachets, or other suitable containers.
21. A method of preparing a composition for controlling malodours including an olfactory receptor inhibitor substantially as herein described.
22. A method of reducing or eliminating malodours in chemical retention type toilets, said method comprising introducing into the toilet flushing system an effective amount of a composition according to any of Claims I to 16 inclusive.
23. A method of reducing or eliminating malodours in chemical retention type toilets, said method comprising the steps of:- (a) introducing into the toilet flushing system an effective amount of a composition according to any of Claims I to 16 inclusive; (b) introducing into the air space of the toilet cubicle a sustained release fragrance designed to mask any malodours in the air within the toilet cubicle.
24. A method of reducing or eliminating malodours in chemical retention type toilets substantially as herein described,