METHOD FOR SIMULTANEOUS CONTROL OF CLEANING AND HYGIENE AND AGENT FOR USE WHEN CARRYING OUT THE METHOD

Abstract: For simultaneous control of cleaning and hygiene, in particular in the food industry and hospitals, an aqueous solution of an optionally fluorescent dye or a combination of such dyes which bind on organic material, including microorganisms, and colour them in the process is applied onto the surfaces which are to be cleaned. An organic contamination, if any, of the surfaces will then show itself by colouring thereof. Among the usable dyes the disodium salt of 2,4,5,7-tetraiodofluorescein is preferred. Hereby the disadvantages attached to the known methods of controlling the hygiene level at work sites and in institutions are avoided, in particular the time delay of as much as 4 days caused by the fact that samples taken out must first be incubated. By the method of the present invention immediate information about the state of the hygiene is obtained.

Description: Method for simultaneous control of cleaning and hygiene and agent for use when carrying out the method The present invention relates to a method for simultaneous control of cleaning and hygiene, so-called prophylactic cleaning, in particular for use in the food industry, hospitals and other places where hygiene requirements are high. The invention further relates to an agent for use when carrying out the method. Any production of food and any other processing or hand¬ ling of materials containing organic matter of animal or vegetable origin entail contamination of production rooms and equipment. It is desired to remove such contamination by daily cleaning for the obvious reason that precisely this kind of matter is fertile soil for the existence and growth of bacteria, fungi and other microorganisms, the presence of which is undesired because of their damaging influence on the quality of the processed raw and finished products. In the extreme case such microorganisms may be directly hazardous to health. The cleaning technology used today (irrespective of the kind of cleaning performed) does not ensure complete removal of the above organic contaminations for the simple reason that many of such contaminations are difficult or impossible to detect with the human eye. This is due partly to their physical extension and partly to their chemical nature. Until now control of the hygiene on cleaned surfaces has solely been performed by bacteriological methods, such as culturing. Such methods for controlling the hygiene level are however inappropriate and often inadequate, in particular for determining the quality of the cleaning and controlling the hygiene level at places where hygiene requirements are particularly high, e.g. in the food industry, in hospitals and the like. The bacteriological methods involve very significant dis¬ advantages, of which in particular the following should be mentioned: 1- Bacteriological methods can only be used for determining live microorganisms (e.g. bacteria and fungi), but not for determining the total amount of organic contaminations which may give rise to bacteria growth. This entails that by bacteriological methods only the bacteriological hygiene state is determined, whereas no impression of the overall hygiene is obtained. 2. Bacteriological methods involve a considerable time delay which in the extreme case may entail as much as 4 days insufficient bacteriological hygiene. E.g. in slaughterhouses cleaning is performed in the evening when the day's production has been ended. The next day (not earlier than 8-12 h after ended disinfection) bacteriological samples are taken out which then must be incubated for 24-72 h before the result is available. Bacteriological methods for control of hygiene are thus always delayed 1-4 days relative to the time of sampling at the risk of undetected dissatisfactory hygiene in the inter¬ mediate period. 3. Bacteriological methods as an expression of the over¬ all hygiene state further entail that inadequate hygiene can be masked as a result of efficient disinfection. This entails the risk that a build-up of organic contaminations which have not been measured or detected may give rise to growth of microorganisms, in particular microorganisms of resistant or pathogenic nature. 4. Finally, bacteriological methods are in practice only usable as a sort of test sampling or spot check of the hygiene, as samples or scrapes are taken at selected places and compared with the total surface. This involves a serious risk of "standardization", meaning that the samples are constantly taken out at the same places, which are thus currently checked whereas the overall hygiene may be poor. Consequently, there is a need for new methods with which is is possible unambigously to determine the quality of the cleaning during the cleaning process proper and control the hygiene level immedialy upon completed cleaning. By the method according to the present invention there is provided a surprisingly simple and reliable method capable of fulfilling these objects. If an otherwise non-colouring cleaning agent contains a dye or a combination of such dyes which react chemically with organic matter - only organic matter of vegetable or animal origin - and dyes the organic matter with a visible colour shade, such organic matter is made visible during the cleaning process proper. Hereby organic contaminations of any kind, including hard to see or even invisible contaminations, are made visible and markedly distinguishable form the background as such, whereby places at which the required cleaning has been inadequate are immediately revealed. The invention thus relates to a method for simultaneous control of cleaning and hygiene, so-called prophylactic cleaning, in particular for use in the food industry and hospitals, and the method of the present invention is characterized in that an aqueous solution of a cleaning agent containing a dye or a combination of such dyes which bind on and colour organic matter of animal origin is applied onto the surfaces to be cleaned when performing the cleaning, whereby contamination, if any, of the surfaces shows itself by colouring thereof. In this way it is possible during the cleaning proper objectively to determine the quality of the cleaning and immediately control the level of hygiene. As a result there is no risk - as was previously the case - that the cleaning is inadequate, and in addition there is no need to wait as much as 4 days for the result of a bacteriological control thereof which entailing risk of contamination of intermediate production. It is known that contamination of objects can be detected by applying a substance yielding a coloured reaction with the contamination. E.g. .EP published patent application No. 347494 discloses a method by which a dye solution which is bound to the impurities is first applied onto the object and secondly a developer solution. The contamina¬ tion subsequently reveals itself in colour. This is thus a two-step method which is used for labeling of petroleum or silicone based contaminations, such as coatings on turbine blades. US patent specification No. 4 745 797 discloses a method of detecting leaks by which a dye solution is applied onto the object to be detected. The organic material, in particular mineral oil fractions, seeping through the leak will subsequently evoke a colour reaction and consequently reveal the leak. The method is particularly useful for leak control of fuel tanks in aircrafts. Such a dye method may also be used for revealing unevenness or cracks in a surface, e.g. as disclosed in DE public disclosure No. 1 773 270. This is an indirect (not immediately visible) colour reaction with specific substances which call for detection with UV-light in order to be labeled. It is a common feature of the methods disclosed in the above specifications that they make use of dyes or combinations of dyes for detection or visualization of a physical state. However, none of the specifications concern utilization of a colour reaction for detecting contaminated surfaces, removal of such contamination, and removal control in one and the same work cycle, as is the case by prophylactic cleaning. By prophylactic cleaning is understood a method which in conjunction with any kind of cleaning process and any cleaning agent can visualize even the tiniest occurrence of dirt during the cleaning process proper. In addition to a general increase in the hygiene standard prophylactic cleaning involves a variety of apparent advantages, of which in particular the following should be mentioned: 1. Any person can - without special qualifications and without using any kind of aids - quickly, in a simple way and reliably evaluate the course and result of a cleaning solely based on the presence or absence of colour on the cleaned surface. 2. Any cleaning parameter, including choice of agents, equipment and method can be evaluated objectively during the cleaning proper. Hereby it is made possible to optimize all cleaning parameters in view of obtaining the desired hygiene at a minimum of economical, environmental and human costs. The dye used in the method of the present invention may be any dye or a specific combination of such dyes which can bind on organic materials of any animal and vegetable kind, such as proteins, lipids and carbohydrates, and in the process colour these materials if the dye is stable in the selected combination with the cleaning agent. A variety of dyes have this capability, and the invention is thus not limited to any particular dye or any particular cleaning agent. As the method of the invention is extremely usable in slaughterhouses and other food producing and processing industries it is in practice preferred to use dyes which are already known - and approved - in connection with food. Examples of food dyes which are approved in the EEC-countries are Ponceau 4R (E124), Carraoisine (E122), Amaranth (E123), Erythrosine BS (E127), Ponceau 6R (E126) and Scarlet GN (E125), all of which are red dyes. Yellow and orange dyes may be Orange GGN (Elll), Tartrazine (E102), Sunset Yellow FCF (E110), Acid Yellow (E105), Quinoline Yellow (E104) and Chrysoine S (E103). Green, blue, violet and black dyes are also known, e.g. Brilliant Green BS (E142), Indigo Carmine (E132), Patent Blue V (E131) and Black BN (E151). Particularly preferred as dye for use in the method according to the invention is Erythrosine BS (E127), a red dye which is well-known for use in connection with colouring of sausages. The substance which is marketed by Pointing Ltd., Northhumberland, England, under the trade name "Hexacol Erythrosine Supra" is- the disodium salt of the compound 2,4,5,7-tetraiodofluorescein, having the formula This dye is preferred because it is extremely well-suited for the use. It thus reacts very quickly and has an intensive colour effect. Further it exhibits negligent toxicity, and it is already widely used in the food industry and other areas within which the present method is usable. Besides being a well-known food dye, Erythrosine BS (E127) has been used within odontology, where it is administered in tablets for control of toothbrushing, in particular with children. Also here advantage is taken of the marked colour effect and the negligent toxicity. Finally, the substance has been used ophthalmologically in connection with adaptation of contact lenses and examination of eye diseases. In the method according to the invention the selected dye has been added to the concentrated cleaning agent, whereby the dye is applied onto the surfaces during cleaning. The method according to the invention is applicable in connection with all kinds of cleaning, such as foam cleaning, manual cleaning, circulation cleaning, in washing machines, when cleaning containers etc. When using the preferred dye E127 preferably 1 g E127 per kg cleaning agent is added. As the cleaning agent is typically used in concentrations of 0.2-2,0% (w/w), the dye concentration used will be 2-20 mg per 1 end solution. When the coloured cleaning solution has been applied measuring or evaluation of the cleaning quality and the hygiene standard can be performed in various ways: - 1. Visual determination of the presence of coloured coatings (which will be bright red if the preferred dye E127 is used) can be performed. 2. Visual determination by use of fluorescent light can be performed, some of the usable dyes including E127 being flourescent. Samples of the coloured surfaces can be taken out by scraping and a chemical/technical measurement of the dye concentration performed, e.g. spectrophotometric- ally. The advantages of the method according to the invention are obvious because they allow daily evaluation of the overall hygiene standard without time delay and extra labour efforts. By the method there is performed no conventional bacteria count but an overall evaluation of the hygiene as regards bacteria and organic matter which might give rise to growth of bacteria. Besides such a daily control which is extremely important, the method offers the possibility of teaching new staff correct cleaning performance as the method easily reveals places where cleaning is required or cleaning has been _ g _ dissatisfactory. Similarly, it is possible objectively to control the part processes of which the cleaning consists, such as mechanial processing, the efficiency of the cleaning agent and the like. The method may also be used to ensure that during flushing all traces of the cleaning agent have been removed. In the following the invention is illustrated in more detail by way of an example. EXAMPLE At Den Danske Slagteriskole (The Danish Meat Trade School) in Roskilde experiments have been performed with prophylactic cleaning by the method according to the present invention. A common cleaning agent is used for the cleaning in an end concentration of 1.5-2%. The agent had been admixed with 1 g of the dye E127 per kg cleaning agent. Cleaning was performed as ordinary foam cleaning with K.E.W. standard foam equipment (temperature: approx. 40- 60°C, pressure: 60-100 bar). After cleaning no disinfection was performed with chlorine or other disinfectants. The following results were obtained: 1. Cleaning generally The prophylactic cleaning agent has optimal technical efficiency: the product provides the desired foam formation and foam stability. - the product colours and makes visible all dirt occurences in the course of approx. 5 min. the product loosens all occurring dirt types of both organic and inorganic nature. 2. Hygiene The prophylactic cleaning agent results in optimal hygiene: according to visual determination all surfaces are shining and clean after the cleaning. - bacteriological measurements show a general hygiene which is quite as good as the hygiene after traditional cleaning with alkaline/acidic cleaning agent and subsequent disinfection with chlorine. 3. Working environment The prophylactic cleaning agent causes none of the traditional nuisances to the user: - no eye, skin or respiratory irritations have been observed, neither during the cleaning or in connection with handling the concentrated product. By introducing prophylactic cleaning at the gut section of the Meat Trade School, previously unseen control of both the daily cleaning result and the user's working environment has been obtained. It should be noted that the fine results have been obtained without changing cleaning procedures and without increasing time consumption. On the contrary, the cleaning as a whole has become considerably easier due to the nature of the agent and the fact that the dirt is made visible during the cleaning proper.

Claims: C A I S : 1. A method for simultaneous control of cleaning and hygiene, in particular for use in the food industry and hospitals, c h a r a c t e r i z e d in that an aqueous solution of a cleaning agent containing a dye or a combination of such dyes which bind on and colour organic material, including microorganisms, is applied onto the surfaces which are to be cleaned, whereby an organic contamination, if any, of the surfaces becomes visible as a result of the surfaces being coloured. 2. A method according to claim 1, c h a r a c t e r - i z e d in that the dye is the disodium salt of 2,4,5,7- tetraiodofluorescein having the formula N added to the cleaning agent used in an amount of about 1 g per kg cleaning agent. 3. A method according to claim 2, c h a r a c t e r - i z e d in that the cleaning agent is used in a con¬ centration of 0.2-2.0% (w/w), whereby the dye concen¬ tration used is 2-20 mg per 1 end solution. 4. Use of the disodium salt of 2,4, 5,7-tetraiodo- fluorescein having the formula as reactive dye in simultaneous control of cleaning and hygiene. 5. Agent for use in the method according to claim 1 for simultaneous control of cleaning and hygiene, c h a r ¬ a c t e r i z e d by being a possibly fluorescent dye or a combination of such dyes which bind on and colour organic material, including microorganisms. 6. Agent according to claim 5, c h a r a c t e r i z e d by being the disodium salt of 2,4,5,7-tetraiodofluorescein having the formula 7. Cleaning agent, in particular for foam cleaning, c h a r a c t e r i z e d in that it is admixed with an agent according to claim 5 or 6, preferably in an amount of about 1 g per kg cleaning agent.

Inventors: FAMME PER BRUUN, FAMME, PER, BRUUN
Applicants: CLEANSOLVE INTERNATIONAL APS
Application year: 1990
Main classification: G01N21
IPC codes: C09B11, C11D3, G01N21