AU691134B2

AU691134B2 - Sanitising composition

Info

Publication number: AU691134B2
Application number: AU76133/96A
Authority: AU
Inventors: Jimmy Paltidis
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-11-27
Filing date: 1996-11-27
Publication date: 1998-05-07
Anticipated expiration: 2016-11-27
Also published as: AU7613396A

Description

SANITISING COMPOSITION

The invention relates to a sanitising and cleaning composition and in particular to a sanitising and cleaning composition containing a chlorine releasing agent.

Sanitising compositions based on chlorine releasing bactericides have been used in a number of applications where it is necessary to substantially reduce the level of potentially harmful microorganisms. One such application is in the preparation of infant feeding utensils such as baby bottles, plastic teats and the like. The cleaning and sanitising procedures currently in use require two distinct operations. Mechanical cleaning is used as a pretreatment to remove food residues and requires the use of conventional detergents. The sanitising composition is used once food residue has been removed to significantly reduce the level of potentially harmful microorganisms remaining on the utensil. It would be advantageous to use a composition which provides both detergency for cleaning and high bactericidal activity for sanitising however the components required for good detergency tend to significantly reduce bactericidal effectiveness particularly after the periods of storage necessary for the composition to reach the consumer. It is an object of the present invention to provide a sanitising composition containing a chlorine releasing agent which provides good detergency and cleaning and also provides a high level of sanitising even after prolonged storage.

Accordingly we provide a sanitising composition containing an anionic detergent surfactant, particularly an anionic surfactant containing an alkyl chain of at least eight carbon atoms; a phosphate detergency builder preferably sodium tripolyphosphate; sodium tetraborate preferably borax; an alkali metal chloride or alkali metal sulfate particularly sodium chloride or sodium sulfate; and a chlorine releasing agent preferably selected from either chlorinated trisodium phosphate or alkali metal chlorinated isocyanurate; and wherein the composition preferably has a solubility of at least 95% by weight in water at a concentration of 1g/L at 25°C. The invention uses an anionic detergent surfactant which we have found to provide superior stability in the compositions of the invention when compared with non-ionic or cationic surfactants. Generally the preferred surfactants are selected from the group consisting of alkali metal salts of one or more of alkyl sulfates, olefin sulfonates, alkyl sulfonates and alkylaryl sulfonates wherein the surfactants contains at least eight carbon atoms in the alkyl portion and most preferably in the range of from 10 to 14 carbon atoms in the alkyl portion. Sodium alkylaryl sulfonates, particularly sodium alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, are the most preferred. The anionic surfactant compound is generally present in a detergency effective amount such as at least 1% by weight of the composition and an excess may be used if desired. Typically the anionic surfactant will be present in an amount of from 1 to 20% by weight.

The composition of the invention contains a phosphate detergency builder which is most preferably sodium tripolyphosphate. For optimum stability of the composition sodium tripolyphosphate is in the anhydrous form. The amount of phosphate detergency builder is typically in the range of from 10-70% by weight of the composition.

The presence of borax (sodium tetraborate decahydrate) in the composition of the invention has been found to improve significantly the composition stability and also enhance its cleaning effectiveness. In order to provide the advantageous cleaning and stability borax is typically present in an amount of at least 5% by weight with the range of from 5 to 20% by weight being particularly preferred. The composition of the invention contains a chloride or sulfate ion containing component which is generally an alkali metal chloride or alkali metal sulfate such as sodium chloride or sodium sulfate. An alkali metal chloride is more preferred and has been found, together with the borax, to improve significantly long term stability of the chlorine releasing agent. The alkali metal chloride or alkali metal sulfate is generally present in an amount of from 2 to 30% by weight of the total composition. The chlorine releasing agent component of the invention is generally chlorinated trisodium phosphate or alkali metal salt of chlorinated isocyanurate. Typically the chlorine releasing agent will provide from 1 to 20% by weight of the composition of available chlorine and preferably from 4 to 10% by weight. The composition of the invention is typically in a dry form, being substantially free of moisture and is adapted to be dissolved in water prior to use. The dry composition will generally contain less than about 2% by weight of free water. Preferably the composition is dissolved in water at a rate of from 1 to 20g per litre and most preferably from 1 to 4g per litre of water. The prior art regimes for sanitising feeding equipment such as baby bottles have involved the use of particulate scourers or mechanical devices such as bottle brushes. We have found that the use of mechanical cleaning is unnecessary when using the composition of the invention. Indeed we have found such agents tend to decrease sanitising preformance. The decrease in sanitising performance is due to the formation of scratches and imperfections which harbour bacteria and therefore exacerbate bacterial contamination. This is particularly a problem for feeding equipment made of plastics materials. Accordingly it is particularly preferred that the composition of the invention is essentially completely soluble in water at 25°C at a rate of at least 1g per litre water so that no abrasive particles are present.

In a further embodiment, the invention provides an aqueous sanitizing composition comprising a solution of the above descπbed composition in water. The aqueous composition will generally contain from 1 to 20g of the composition per litre of water. When using the composition of the invention mechanical abrasives such as bottle brushes and scourers should generally be avoided.

The composition of the invention preferably contains at least one alkaline salt as defined by the Standard for the Uniform Scheduling of Drugs and Provisions (SUSDP). The alkaline salt is a carbonate, silicate or phosphate salt of sodium or potassium alone or in combination and is used in addition to the phosphate detergency builder (typically sodium tripolyphosphate) referred to above. The alkaline salt may also be, or be provided by, the chlorine releasing agent. For example, when the chlorine releasing agent is chlorinated trisodium phosphate additional alkaline salt is not generally necessary although it may be used if desired. The most preferred alkaline salt is trisodium phosphate which is generally used in the anhydrous form. The total amount of alkaline salt including chlorinated alkaline salts (when present), is preferably in the range of from 20 to 70% by weight of the composition.

One example of the most preferred compositions of the invention contains sodium alkylbenzene sulfonate in a detergent effective amount (generally from 1 to 15%); sodium tripolyphosphate in an amount of from 10 to 70%; borax in an amount of from 5 to 20%; sodium chloride or sodium sulfate in an amount of from 2 to 30%; and chlorinated trisodium phosphate in an amount sufficient to provide from 1 to 10% available chlorine, (typically from 10-70% chlorinated trisodium phosphate).

In a further example the most preferred compositions of the invention contains sodium alkylbenzene sulfonate in a detergent effective amount (generally from 1 to 15%); sodium tripolyphosphate in an amount of from 20 to 70%; borax in an amount of from 5 to 20%; sodium chloride or sodium sulfate in an amount of from 2 to 30%; trisodium phosphate (anhydrous) in an amount of from 10 to 70%; and sodium chlorinated isocyanurate (anhydrous) in an amount sufficient to provide from 1 to 20% of available chlorine (typically about 5 to 15% of sodium chlorinated isocyanurate).

The composition of the invention is typically a water soluble solid and may be in the form of a powder, granules, pills or a tablet. The composition may contain further additives such as colorants, perfumes, lubricant, tableting aids or solubility aids. In one embodiment the composition contains an appropriate acid such as citric or tartaric acid and an alkaline salt such as an alkali metal bicarbonate to provide effervescence in water.

The composition of the invention may be prepared by a number of methods however methods involving treatment of the components with water, such as spray drying should generally be avoided. Preferably the composition is prepared by dry blending the components in finely divided form and optionally forming the composition into granules, pills or tablets by compression.

The composition of the invention may be formed into a soluble tablet, granules pill or the like using a suitable lubricant. Suitable lubricants include alkaline earth metal stearates, stearic acid, soaps and the like and mixtures thereof.

The invention further provides a method of cleaning and sanitising articles such as infant feeding equipment and the like the method including immersing the surfaces to be cleaned in an aqueous solution, of composition containing a chlorine releasing agent in an amount sufficient to provide from 1 to 20% (preferably 1 to 10%) by weight of the composition of available chlorine and present in the solution in an amount sufficient to provide an available chlorine concentration of from 100 to 500 ppm and preferably from 130 to 350 ppm and most preferably from 250 to 350ppm; a detergent effective amount of a surface active agent and a detergency builder. The composition is preferably as hereinabove described. The composition is typically used at a rate of 1 to 20g/litre and preferably from 1 to 4g per litre of water

The method aspect of the invention may involve two steps including a first step in which the aqueous solution of the composition is agitated without the use of mechanical abrasives, such as bottle brushes or solid particulate abrasive, to remove food residues and a second step in which a further aqueous solution of the composition is allowed to remain in contact with the surfaces to be cleaned for at least five minutes. In many instances, however, good cleaning and sanitising is obtained in a single step. Where two steps are used the further aqueous solution is generally left in contact with the surface to be sanitised for at least 30 seconds and preferably at least five minutes.

The method may be carried out at any temperature however generally water no hotter than hot tap water (about 40-50°C) is necessary to achieve excellent sanitising. Boiling water and abrasives are not necessary. This is particularly advantageous in the cleaning of equipment formed of plastics materials as such equipment is generally susceptible to scratching by abrasives or is weakened by repeated treatment at high temperature. As described above we have found that the use of mechanical abrasives although effective in removing food residues reduces the effectiveness of the sanitising step. The compositions of the invention allow cleaning and sanitising to be carried out using a single composition and achieve an extremely high efficacy against microorganisms and exhibit surprisingly good storage stability.

The compositions of the invention have been found to provide a significantly improved sanitising efficiency when compared with commercial products presently used for sanitising infant feeding utensils. For example, we have found that the composition of the invention provides a higher level of sanitation than available composition even when less available chlorine is present. The composition of the invention may therefore be used to achieve significant saving on chlorine releasing agents and/or to provide a consistently higher sanitation level. Furthermore the composition of the invention allows the user to dispense with the preparation steps which use detergents and mechanical cleaning. As a result equipment has a longer useful life and the likelihood of contamination is drastically reduced.

The composition of the invention is very stable in the dry form and may be stored for many months without significant deterioration.

Although the invention is described with reference to sanitising of infant feeding utensils it has application in sanitising a wide range of other articles such as dentures, mouth guards, food processing equipment, food containers, dairy equipment, hair dressing utensils such as combs and scissors and implements used in oral or other cavities of the human or animal body.

The invention will be demonstrated by but is in no way limited to the following examples.

Examples 1-5

These examples demonstrate compositions of the invention and their preparation. The formulations of examples 1 to 5 shown in Table below were prepared by dry mixing finely divided solid components to provide a powder. The powder may be compressed into a tablet. TABLE 1

Compositions of Examples 1 to 3 and 5 were subject to the following product stability trial. The composition of Example 1 was prepared three months prior to testing and this should be taken into account in considering stability results. The other formulations were prepared for the trials.

The product was subdivided into samples which were packed into plastic vials with close fitting screw caps. Each formulation had one sample each confined at ambient (room temperature), 37°C and 45°C for the duration of the trial. At each time interval, the sample was thoroughly mixed within its container before a portion was removed for analysis. The results are shown in Table 2.

Tablet Preparation Lubricants were added to different samples (a to f) of the composition of Example 2 in accordance with Table 1a and were found to provide tablets of good water solubility using medium tableting pressures. In each case stearic acid (0.3% by weight) was also inside as a die lubricant.

TABLE 1a

Practical advantages will generally be provided by using two or more of the lubricant compounds.

TABLE 2

STABILITY OF PRODUCT with respect to AVAILABLE CHLORINE CONTENT (%m/m)

Example 6

A study was undertaken to demonstrate the antibacterial efficacy of the composition of Example 2 and method of the present invention. The composition was evaluated on artificially contaminated baby bottles and teats. The trials represent a simulated use of the products as would be suitable for use by a consumer.

The cleaning and sanitising of baby milk bottles consists of two distinct functions which in the present invention occur concurrently. These are the mechanical cleaning phase designed to remove milk and feed residues and the sanitising phase designed to remove or kill potentially harmful microorganisms. The method of the invention which was utilised was a two step cleaning and sanitising procedure each step incorporating these two distinct elements to achieve adequate sanitation of baby milk bottles. The methods of microbiological analysis of the bottles and teats are as follows. METHOD Artificial Contamination of Bottles

Full cream UHT milk was inoculated with Escherichia coli NCTC 8196 and Staphyloccocus aureus NCTC 4163 to a level exceeding 1 ,000,000 organisms per mL.

A 1 mL aliquot of artificially contaminated milk was introduced into the test bottle fitted with a teat. The milk was spread over all internal surfaces by a shaking/rolling action. The bottle was then placed in a drying oven at 50°C for two hours until all milk residues were completely dry. Cleaning and Sanitation of Bottles and Teats

The test bottles were subjected to each of the cleaning and sanitation systems as shown below. Method of Invention

Cleaning and Sanitising Procedure

Step I.

The operator washed their hands thoroughly before commencing cleaning and sanitising process. The baby bottle was dismantled removing the cap and teat and rinsing all parts with cold water immediately after use.

The teat was inserted into the body of the bottle, half filled with warm-hot tap water (40-50°C), 1 g of compound was added and the bottle sealed using cap-seal inserted into the cap. The bottle was shaken vigorously for 30 seconds, emptied and all components thoroughly rinsed with warm-hot tap water.

Step 2:

The teat was inserted into the body of the bottle, filled completely with warm-hot tap water and 1 g of compound and allowed to soak for minimum 5 minutes. Approximately half of the water in bottle was emptied into a bowl and the cap, cap-seal and teat placed into bowl ensuring that some solution was squeezed through teat holes. A clean paper napkin was then taken and saturated in solution, using the napkin to thoroughly clean the outside of bottle and cap. Particular attention was paid to the threads on the bottle and cap making sure all milk deposits were removed. The bottle was resealed and shaken vigorously for 30 seconds. Solution was discarded from bottle, all components thoroughly rinsed with warm-hot tap water and the bottle filled immediately with feed.

Note: In the method of the invention Step 1 of the washing procedure may be repeated if milk residues are not removed by the first wash. In all the trials reported this repeat step was not necessary.

Recovery of Test Microorganisms

Following sanitation the bottle teats were removed aseptically and immersed in 20 mL of neutralising recovery media (Modified Letheen Broth). The teat was mechanically shaken and rinsed in the recovery media.

Following sanitation a 20 mL aliquot of a neutralising recovery media was introduced into the bottle. Mechanical shaking and swabbing was utilised to suspend surviving bacteria in the recovery media.

Bacteria counts were performed on the recovery media utilising a surface plate technique in Modified Letheen Agar. Test Controls

With every set of test bottles control bottles were prepared which were not subjected to any cleaning and sanitation process.

The control bottles and teats were evaluated and represent the initial number of organisms present in the test and recovered by the recovery media. Measurement of Efficacy

The mean of the control counts were utilised as the initial count and the kill factor of each process was calculated based on the recovery achieved for each test bottle.

Three bottles and five teats were utilised for each trial.

The bottles utilised were Nuk (trade mark), plastic 250 mL (9 fl oz) fitted with silicone teats. Results

Method and Composition of Invention Organism: Escherichia coli NCTC 8196

No. Control Count per Bottle 1 2.2 x 10*

2. 5.0 x 10^b Geometric Mean 3.3 x 10^s

Test Counts per Bottle

Organism: Staphylococcus aureus NCTC 4163 No. Control Count per Bottle

1 6.0 x 10⁶ 2. 7.8 x 10⁶

Geometric Mean 6.8 x 10-

Test Counts per Bottle

Organism: Escherichia coli NCTC 8196 Control Count per Teat 1.3 x 10⁶ Surviving Organisms per Teat

Organism: Staphyloccoccus aureus NCTC 4163 Control Count per Teat 6.7 x 10⁶ Surviving Organisms per Teat

Example 7

The procedure of Example 6 was repeated with the exception that 0.5g of the composition of Example 2 was used in 250ml of warm water.

Results

Foolproof Method: 0.5o Formula 2D2

Organism: Escherichia coli NCTC 8196 No. Control Count per Bottle Control Count per Teat

1 5.8 x10⁶ 3.0 x10⁴

2 1.5 x10⁶ 5.0 x10⁴

Geometric Geometric

Mean 2.9x10° Mean 3.9 x10⁴

Test Counts per Bottle

Test Counts per Teat

Organism: Staphylococcus aureus NCTC 4163

No. Control Count per Bottle Control Count per Teat 1 3.1 x10⁷ 2.5x10* 2 2.1 x10⁷ 2.5x10* Geometric Geometric Mean 2.6 x10⁷ Mean 2.5x10*

Test Counts per Bottle

Notes: '>' indicates greater then. '<' indicates less than. Example 8

The tests described in Example 6 were carried out in parallel with corresponding microbiological testing of a commercially available antibacterial tablet promoted for use in sanitising baby bottles. The commercially available sanitising product relies on the consumer to pre-clean bottles and teats. The pre-cleaning step required and detailed in the commercial product uses mechanical brushing of bottles. The commercial product was used on contaminated bottles prepared in accordance with Example 6 and the procedure was in accordance with the manufacturers recommendations and was as follows.

Prior Art Method

Step 1

Components of the bottle and teats were separated and rinsed with cold water. The bottle was then washed with detergent and warm water, using a brush to clean inside and out. The bottle was then rinsed again to remove milk deposits and teats and flanges were rubbed with salt and rinsed thoroughly with water.

Step 2 One antibacterial tablet from a packet of tablets sold through retail outlets was dissolved in 2 litres of water and the made up solution squeezed through treat holes.

Step 3

The bottle was immersed in the solution making sure no air bubbles were trapped inside and teats and dummies were kept submerged. Bottles were left immersed for at least one hour before removing them. The bottles were drained and filled immediately without rinsing as per the manufacturers instructions.

Comparison of the bottles treated in accordance with the invention as described in Example 6 with bottles treated as described above showed the composition of the invention to provide antibacterial activity which was at least as good as and in many cases better than the commercially available composition.

The composition used in accordance with the method of the invention on the same bottles over a period of time was found to be superior to the above prior art method.

The composition of the invention eliminates the need for a separate cleaning composition and a separate cleaning process and provides a level of sanitising which is at least equivalent after only five minutes immersion to the commercial composition after one hour immersion. In avoiding the need to use mechanical cleaning the invention also substantially eliminates the occurrence of cross contamination which may arise with the compositions and procedures required with prior art compositions.

Example 9

This Example demonstrates the use of the composition of Example 2 in cleaning and sanitising latex teats.

1. Full cream UHT milk was inoculated with Escherichia coli NCTC 8196 and Staphylococcus aureus NCTC 4163 to a level exceeding 1 ,000,000 organisms per mL.

2. 0.2 mL of artificially contaminated milk was introduced into a series of ten latex teats. The milk was spread over all internal surfaces by a rolling action. The teats were then dried in an oven at 50°C for two hours until all milk residues were completely dry.

3. Five teats (Set A) were inverted aseptically to expose contaminated surfaces prior to subjecting them to the cleaning and sanitising method detailed in part 5.

4. Five teats (Set B) were subjected to a rinse and the milk deposits removed by thoroughly rubbing the teats and flanges with salt on both inside and outside surfaces.

5. Test teats were subjected to the following parts of the cleaning and sanitising method using the composition of Example 2. 5.1 Step 1

Insert teat into body of bottle, half fill with warm-hot water (40-50°C) and 1g. of compound and seal bottle using cap seal inserted into cap. Shake vigorously for 30 seconds. Remove teat and wipe internal and external surfaces using a sponge provided and solution from the bottle. Empty bottle and thoroughly rinse all components with warm-hot tap water.

5.2 Step 2

Insert teat into body of bottle, fill completely with warm-hot tap water and add Ig of compound and allow to soak for a minimum of 5 minutes. Empty approximately half of solution from bottle. Re-seal bottle and shake vigorously for 30 seconds. Discard solution from bottle, thoroughly rinse all components with warm-hot tap water.

6. The teats were removed and tested for bacterial survivors in accordance with the procedure for recovery to test microorganisms specified in Example 6.

7. With every set of teats a control teat was prepared which was not subjected to the process. This control represents the initial number of organisms present in the test and recovered by the test.

The results of the tests are shown below.

A. Test: Teats Inverted

Organisms: Escherichia coli NCTC 8196

Organism: Staphylococcus aureus NCTC 4163 Control Count per Teat 2.7 x 10°

Surviving Organisms per Teat

Results B. Test: Salt Pre-treatment Wash Organisms: Escherichia coli NCTC 8196

Control Count per Teat 1.7 x 10

Control Count per Teat 2.7 x 10°

Surviving Organisms per Teat

Data Summary

Teat Type: Latex Teats

Note: All means are Geometric means of replicate counts.

Comparison of results A and B show excellent sanitising and cleaning even when salt is not used. The method of the invention may therefore be used without the salt pre-treatment step generally required by prior art compositions. Example 10

The detergency of the composition was tested on milk residues according to Australian standard 1803 and found to comply with the standard at a concentration of 1g/L. Example 11

The prior art method requires bottle brushes to be used in the washing process prior to subjecting bottles to the sanitation step. Trials were undertaken to examine the level of residual bacteria on used brushes and access the potential for cross-contamination by these utensils when used under normal consumer conditions. METHOD:

Brushes utilised for the washing of artificially contaminated bottles were tested in accordance with prior art method detailed above. PROTOCOL:

For new bottles three individual and new brushes were used for each bottle. These were tested at the completion of the washing process.

For used bottles one new brush was utilised to wash all three used bottles. This brush was tested at the completion of all three washes. RESULTS:

In all cases trialled above the brushes were found to contain significant levels of contaminating bacteria. This highlights the significant problem of cross contamination inherent in the prior art methods.

Safety

Despite the extremely high bacteriocidal activity of the compositions of the invention the compositions are safe to use. For example the composition of Example 2 of Table 1 was found to have an LD50 in Sprague Dawley Rat of greater than 2000 mg/kg.

Example 12

This example demonstrates the use of the prior art method and composition described in Example 8 in cleaning bottles which have been subject to four months use under normal consumer conditions.

The bottles were artifically contaminated, cleaned and sanitized according to the procedure of Example 8.

A. Organism: Escherichia coli NCTC 8196

No. Control Count per Bottle Control Count per Teat

1 6.8 x 10" 1.0 x 10' Test Counts per Bottle

B. Organism: Staphylococcus aureus NCTC 4163

No. Control Count per Bottle Control Count per Teat

3.6 x 10^fc 1.1 x 10-

Test Counts per Bottle

Scouring of the surfaces acquired by the prior art method was found to significantly reduce effectiveness of the composition and method.

Claims

CLAIMS:

1. A sanitising composition containing an anionic detergent surfactant, containing an alkyl chain of at least eight carbon atoms; a phosphate detergency builder; borax (sodium tetraborate decahydrate); an alkali metal chloride or alkali metal sulfate particularly sodium chloride or sodium sulfate; and a chlorine releasing agent preferably selected from either chlorinated trisodium phosphate or alkali metal chlorinated isocyanurate.

2. A composition according to claim 1 wherein the composition has a solubility of at least 95% by weight in water at a concentration of 1g/L at 25°C.

3. A sanitising composition including an anionic detergent surfactant containing an alkyl chain of at least eight carbon atoms; sodium tripolyphosphate; borax; sodium chloride and/or sodium sulphate; and a chlorine releasing agent selected from either chlorinated trisodium phosphate or alkali metal chlorinated isocyanurate and wherein the composition has a solubility of at least 95% by weight in water at a concentration of 1g/L at 25°C.

4. A composition according to claim 3 wherein the anionic detergent surfacant is selected from the group consisting of alkali metal salts of one or more of alkyl sulfates, olefin sulfonates, alkyl sulfonates and alkylaryl sulfonates wherein the surfactants contains at least eight carbon atoms in the alkyl portion.

5. A composition according to claim 3 wherein the anionic detergent is a sodium alkylaryl sulfonate.

6. A composition according to claim 3 wherein the anionic detergent is present in an amount of at least 1% by weight; sodium tripolyphosphate is present in an amount of 10 to 70% by weight; borax is present in an amount of from 5 to 20% by weight; either sodium chloride and/or sodium sulphate is present in an amount of from 2 to 30% by weight; and the chlorine releasing agent is present in an amount sufficient to provide from 1 to 20% by weight of available chlorine.

7. A composition according to claim 3 wherein the chlorine releasing agent is present in an amount sufficient to provide 4 to 10% by weight of the composition of available chlorine.

8. A composition according to claim 3 including at least one alkaline salt in addition to the phosphate detergency builder in an amount of from 20 to 70% by weight of the composition.

9. A composition according to claim 3 including from 20 to 70% by weight of the total composition of trisodium phosphate.

10. A composition according to claim 3 wherein: the anionic detergent surfactant is sodium alkylbenzene sulfonate present in a detergent effective amount; the sodium tripolyphosphate is present in an amount of from 10 to 70%; the borax is present in an amount of from 5 to 20%; the sodium chloride or sodium sulfate is present in an amount of from 2 to 30%; and the chlorinated trisodium phosphate is present in an amount sufficient to provide from 1 to 10% by weight of the total composition of available chlorine.

11. A composition according to claim 3 wherein the anionic detergent surfacant is sodium alkylbenzene sulfonate present in a detergent effective amount; the sodium tripolyphosphate is present in an amount of from 20 to 70%; the borax is present in an amount of from 5 to 20%; the sodium chloride or sodium sulfate is present in an amount of from 2 to 30%; the trisodium phosphate is anhydrous and is present in an amount of from 10 to 70%; and the sodium chlorinated isocyanurate is anhydrous and is present in an amount sufficient to provide from 1 to 10% by weight of the total composition of available chlorine.

12. A composition according to any one of claims 3 to 11 which is substantially free of water.

13. A composition according to claim 3 in the form of a powder, granules, pills or tablets.

14. A composition according to claim 3 including an appropriate acid and alkaline salt to provide effervescence in water.

15. A composition according to claim 3 prepared by dry blending the components in finely divided form.

16. An aqueous sanitizing composition including an aqueous solution containing from 1 to 20g of the composition of claim 6 per litre of water.

17. A method of cleaning and sanitising including immersing the surfaces to be cleaned in an aqueous solution, of a composition according to claim 3 said composition being present in an amount sufficient to provide an available chlorine concentration of from 100 to 500 ppm.

18. A method according to claim 17 wherein the composition is present in an amount sufficient to provide an available chlorine concentration of from 130 to

350 ppm.

19. A method according to claim 17 wherein the composition is used in an amount of from 1 to 4g per litre of water.

20. A method according to claim 17 involving two steps including a first step in which the aqueous solution of the composition is agitated without the use of mechanical abrasives, such as bottle brushes or solid particulate abrasive, to remove food residues and a second step in which a further aqueous solution of the composition is allowed to remain in contact with the surfaces to be cleaned for at least 30 seconds.

21. A method according to claim 17 when used to clean and sanitise articles selected from the group consisting of infant feeding utensils, dentures, mouth guards, food processing equipment, food containers, dairy equipment, hair dressing utensils such as combs and scissors and implements used in oral or other cavities of the human or animal body.

22. A method according to claim 17 when used to clean infant feeding utensils.