WO1995017977A1

WO1995017977A1 - Cleaning method for beverage dispense lines and kit

Info

Publication number: WO1995017977A1
Application number: PCT/GB1994/002804
Authority: WO
Inventors: Geoffrey Alan Gee
Original assignee: G.W. Chemicals Limited
Priority date: 1993-12-24
Filing date: 1994-12-22
Publication date: 1995-07-06
Also published as: JPH09507134A; GB9326409D0; CZ183796A3; AU1321095A; CA2179732A1; GB2277028A; GB2277028B; EP0804296A1

Abstract

A method of cleaning beverage dispensing equipment, especially beer dispense lines, is disclosed, involving the use of peracetic acid as an active cleaning ingredient. Also described is a kit for such use. Peracetic acid has been found to be unexpectedly advantageous in cleaning beer dispense lines.

Description

CLEANING METHOD FOR BEVERAGE DISPENSE LINES AND KIT

This invention relates to a method of cleaning equipment which dispenses beverages to consumers. The invention further relates to a kit for cleaning such equipment, using the method. The invention has particular but not exclusive application to the cleaning of equipment for dispensing beer at points of sale.

The term "beer" will be used in this specification to denote various brewed products of the same type, including those known by the name beer, lager, pilsner, bitter, ale, porter mild and stout.

The problems of cleaning beer dispensing equipment, especially the plastics lines which deliver beer to the dispensing head, are well known. The problem is essentially one of microbiological contamination. Such microbiological contamination is a problem which has attracted considerable attention within the industry and it is not a simple problem. This is evidenced, for example, by an article entitled "Beer Dispense Lines" by D. Casson, published in "The Brewer" in November 1982. Among other things this article discusses the many sources of possible microbiological contamination.

As shown by the article by D. Casson, much attention has been focused on the materials used in beer lines. In Great Britain the most common material is medium density polythene (MDPE) . In Ulster and Eire the most commonly used material is nylon. This is considerably more expensive, but more robust and, it is thought, less prone to microbiological contamination because of a smoother internal surface. However, this analysis is complicated by the fact that beer dispensing equipment in Ulster and Eire is generally considerably simpler than that in Great Britain. It is generally accepted that complicated beer dispensing apparatus employing, for example, pumps, meters, restrictors, fogging checkers, refrigeration means and the like, increases the propensity to microbiological contamination.

Good landlord practice in the United Kingdom, where MDPE is the main material used for beer lines, requires the cleaning of beer lines once every seven days. In a public house with a typical number of beers, it is a time- consuming operation, typically taking a whole morning. It also requires a considerable quantity of beer to be thrown away. The cleaning operation in fact entails disconnecting the beer dispense lines from barrels; flushing beer out of the beer lines with water; making up a cleaning solution in a reservoir and pulling this into

, the beer lines; waiting for a dwell time, typically about ten minutes; pulling a fresh supply of the cleaning liquid into the beer lines; allowing a further dwell time; repeating this operation one or two further times; thoroughly flushing out the cleaning fluid with water; reconnection; and pulling beer through the lines until the beer is no longer diluted by the water.

Typically this operation, on a single beer line, requires about eight pints of beer to be thrown away. A typical public house may have ten or eleven beer lines.

Because of the disadvantages described above, many landlords clean their beer lines less frequently than every seven days. The result is poor beer quality. The beer may be cloudy, and may even have visible particles in it. It may taste acidic and cause stomach upsets. In Ulster and Eire good landlord practice requires this cleaning operation to be carried out only once a month, probably because of the use of simpler dispensing equipment and the use of nylon beer lines which have inside surfaces which are relatively smooth, on the microscopic scale. However, it would not be economical to adopt these features in Great Britain.

In terms of making improvements which would enable the interval between cleaning operations within licences premises within Great Britain to be extended, the focus has been on the beer dispense lines. As for the chemicals involved in the cleaning operation, there has been less focus. The most commonly used product is sodium hypochlorite, in conjunction with sodium or potassium hydroxide, but other sources of active chlorine, for example calcium hypochlorite, have been used. Generally a sequestrant is also present.

We have now discovered, surprisingly, that the interval between the cleaning operations can be significantly extended by use of a cleaning liquid comprising peracetic acid. Although peracetic acid has been proposed for cleaning and disinfection operations previously, it has not been proposed, to our knowledge, for use in beer dispensing equipment; and we do not believe it could have been predicted that it would so extend the interval necessary between cleaning operations.

Therefore, in accordance with a first aspect of the present invention there is provided a method of cleaning equipment which dispenses beverages to consumers, which comprises the use of an aqueous composition comprising peracetic acid as an active ingredient. Typically the method involves the cleaning of beverage dispense lines, and entails passing the said aqueous composition into and through the dispense lines; although in certain embodiments a simple soaking operation may be all that is required.

Peracetic acid exists in equilibrium with acetic acid, hydrogen peroxide and water. Typically a peracetic acid composition also contains a stabiliser. Where concentrations are quoted in this specification they are quoted in terms of peracetic acid content only, in parts per million (ppm) , rather than concentrations of the sum of all of the equilibrium products.

Suitably the concentration of the active peracetic acid component in the equilibrium mixture, used in the method of the present invention, may be in the range 100- 4,000 ppm, preferably 300-3,000 ppm, most preferably 500- 2,000 ppm. In other embodiments the concentration may suitably be in the range 20-2,000 ppm, preferably 50-500 ppm, most preferably 75-400 ppm. In preliminary tests good results have been obtained at 500 ppm, 1,000 ppm and 2,000 ppm.

Suitably the method is carried out at ambient temperature.

From time to time, for example at intervals of several weeks, it may be desirable to pass a caustic rinse (for example a 0.2-0.5 wt% solution of sodium hydroxide in water) through beverage dispense lines to remove proteins and acid residues, commonly known in beer lines as "beer stone". However such residues should not form if beer is supplied in good condition. In accordance with a second aspect of the present invention there is provided a kit for cleaning equipment which dispenses beverages to consumers, which kit comprises: - a concentrate composition for dilution with water, said concentrate composition comprising peracetic acid; a sterilising cloth for sterilising fittings by wiping; and - a sterilising material in concentrate form for addition to water, to provide soak-sterilisation of removable fittings.

Preferably the sterilising material in concentrate form is a tablet.

The sterilising material in concentrate form may be of a type to provide release of active chlorine. The material may for example be sodium hypochlorite.

Suitably the kit comprises a plurality of said sterilising materials in concentrate form, for example in tablet form. Suitably the number provided substantially corresponds to or exceeds the number of days in the recommended interval between the cleaning operations which require the use of peracetic acid.

In other embodiments the said sterilising material may be aqueous peracetic acid, suitably diluted for use to a concentration in the range defined above in relation to the cleaning of the dispense lines.

Preferably the sterilizing cloth is impregnated with a sterilising material. The cloth may suitably be supplied damp, within an enclosed plastics container or bag. Again, the sterilising material of the sterilizing cloth could be of a type to release active chlorine, or could comprise peracetic acid, or could comprise a guanidine-based solution.

Suitably the kit comprises a plurality of wiping cloths contained in a single container or bag. Suitably the number provided substantially corresponds to or exceeds the number of days in the recommended interval between the cleaning operations which require the use of peracetic acid.

Suitably the kit comprises instructions for the dilution of the concentrate composition comprising peracetic acid. Suitably the concentrate composition provides a concentration of peracetic acid species in the range 0.1-3.0 wt%, preferably 0.5-2.0 wt% Suitably the instructions also comprise information as to the manner in which the cleaning operations are to be undertaken.

Suitably the kit further comprises a receptacle into which removable parts of the beer dispensing equipment can be placed, and covered with water, and to which said sterilising material can be added, to effect sterilising, for example overnight.

The invention will now be further described, by way of example, with reference to a confidential trial.

Beer lines used to supply three types of beer were cleaned and monitored. These beer lines were of the standard MDPE material most commonly used in Great Britain. The beer types were a keg mild, sold under the Trade Mark TOBY, an extra strength lager sold under the Trade Mark TENNANTS PILSNER, and cask bitter, sold under the Trade Mark WORTHINGTON. The latter was a "live" beer containing a large population of microorganisms.

Initially, the beer lines were cleaned using the standard procedure, but employing a dilute peracetic acid solution, the peracetic acid being of concentration 500 ppm. This standard procedure employed flushing beer out of the lines with water until the water is clear; making up the sterilising solution and feeding this into the dispense lines; waiting approximately ten minutes; passing a fresh supply of the cleaning liquid into the beer lines; waiting a further ten minutes; repeating this operation twice more; flushing the cleaning fluid out with fresh water until clean; flushing the water out with beer until the beer is at full strength.

Each day thereafter beer samples were taken and assessed for cloudiness, pH and taste. Samples were examined for various microorganisms including yeasts, moulds, acetobacter and lactics. Swabs were taken daily at the delivery taps.

Overnight cleaning of delivery taps took place, the taps being sterilised by a sodium hypochlorite/sodium hydroxide solution.

On reconnection of the beer lines to the barrels, initially and each time thereafter that a barrel was changed, the parts being reconnected were carefully wiped with a wipe impregnated with a sterilising solution. The wipe was taken from a pack available under the Trade Mark STERIWIPES, from GW Products, of Elland, West Yorkshire.

The test period was 36 days. The beer was analysed by diluting it and growing colonies from a diluted aliquot in agar, under standard conditions. The swabs were immersed in sterile diluent.

This was then similarly diluted with sterile water and colonies were grown in agar.

Cloudiness was assessed by a standard colorimeter.

The results are presented in the tables and graphs which follow. In these "TVC" denotes Total Viable Count of microorganisms. "CFU/G" stands for Colony Forming Units per gram. A reading given as 3.4E+03 means 3.4 x 10³ CFU/g. "OD" or "%T at 650 nm" denotes cloudiness against a reference scale of 100.

At the end of the test the lines were examined. They were not thought to have been degraded in any way by the peracetic acid composition. It was also believed that other materials used for beer lines, including nylon, would also be unaffected by peracetic acid cleaning compositions.

pH did not change significantly during any of the tests and there were no perceived problems with beer taste. There were no customer complaints during the test period.

The results are very promising. Cloudiness was low throughout. The microorganism concentrations are very low. There are occasional increases, but from a very low level, to a level which is still acceptable. These increases may have various causes. It seems likely that some increases are associated with changing the barrel. Despite the careful hygiene procedures it is almost inevitable that this will introduce some microorganisms. It is possible that other increases are associated with spoilage because of microorganisms already in the beer, and are not associated with icrobial contamination in the beer dispense equipment. This is particularly the case with the WORTHINGTON live cask beer. It should be noted however that such increases are temporary and seem not to have a long-term effect on the beer quality.

A kit for use in the method described comprises: - a concentrate solution comprising 1 wt% aqueous peracetic acid sufficient for a single sterilising operation on up to 15 beer dispense lines;

36 wipe cloths impregnated with a sterilizing guanidine-based solution in a resealable sterile pack; - 36 tablets containing sodium hypochlorite/sodium hydroxide; a receptacle for overnight sterilisation of tap head equipment using one tablet a night; instructions giving dilution information for the concentrate solution and cleaning instructions.

Similar results have been obtained using 1,000 and 2,000 ppm aqueous peracetic acid solutions.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification

(including any accompanying claims, abstract and drawings) , and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) , may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s) . The invention extends to any novel one, or any novel combination, of the features disclosed in this specifica ion (including any accompanying claims, abstract and drawings) , or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A method of cleaning equipment which dispenses beverages to consumers, which method comprises the use of an aqueous composition comprising peracetic acid as an active ingredient.

2. A method as claimed in Claim 1, wherein the method involves the cleaning of beverage dispense lines, and entails passing the said aqueous composition through the dispense lines.

3. A method as claimed in Claim 1, wherein the peracetic acid species in the said aqueous composition used in the said method, is in the range 100-4,000 ppm.

4. A method as claimed in Claim 3, wherein :he concentration of the peracetic acid species is 300- 3,000 ppm.

5. A method as claimed in Claim 4, wherein the concentration of the peracetic acid species is 500- 2,000 ppm.

6. A method as claimed in Claim 1, wherein the method is carried out at ambient temperature.

7. A kit for cleaning equipment which dispenses beverages to consumers, which kit comprises: - a concentrate composition for dilution with water, said concentrate composition comprising peracetic acid; a sterilising cloth for sterilising fittings by wiping; and a sterilising material in concentrate form for addition to water, to provide soak-sterilisation of removable fittings.

8. A kit as claimed in Claim 7, wherein the said sterilising material in concentrate form is a tablet.

9. A kit as claimed in Claim 7, comprising a plurality of said individual doses of sterilising materials in concentrate form, the number provided substantially corresponding to or exceeding the number of days in the recommended interval between the cleaning operations which require the use of peracetic acid.

10. A kit as claimed in any of Claims 7, comprising a plurality of sterilising cloths contained in a single container or bag, suitably the number provided substantially corresponding to or exceeding the number of days in the recommended interval between the cleaning operations which require the use of peracetic acid.