DE102014220554A1 - Method for controlling microorganisms in a water-conducting domestic appliance and household appliance suitable therefor - Google Patents

Abstract

The invention relates to a method for controlling microorganisms on a surface of a water-conducting household appliance 1, 2 and / or microorganisms in a medium such as the wash liquor 6, which is at least temporarily introduced in the household appliance 1, 2, wherein the method comprises a treatment of the surface or the medium comprising parasitic microorganisms, and a household appliance 1, 2 suitable for carrying out this process.

Description

The invention relates to a method for controlling microorganisms on a surface of a water-conducting household appliance and / or microorganisms in a medium which is introduced at least temporarily in the household appliance and a domestic appliance suitable for this purpose. In particular, the invention relates to a method by which a biofilm on a surface in a water-conducting domestic appliance can be avoided, reduced and / or eliminated, or microorganisms in the medium, in particular an aqueous solution, can be reduced or eliminated.

Microorganisms, also called microorganisms, are understood to mean microscopically small organisms which are not recognizable to the naked eye, that is to say the organisms are preferably smaller than 50 μm, in particular smaller than 1 μm. Among the microorganisms include bacteria, archaea, fungi, microalgae, protozoa and viruses.

In water-bearing household appliances such as washing machines, washing dryers, dryers, in particular condensation dryers, or dishwashers, biofilms are often formed. The biofilms are preferably formed in the area of the components with permanently moist surfaces. "Permanently moist surfaces" are in this case those which come into contact with proper operation of the household appliance with water or aqueous liquids and in particular the contact persists for a longer period. Furthermore, permanently moist surfaces can also be surfaces on which water or an aqueous liquid precipitates, for example condensed from a moist air. Biofilms are formed predominantly in aqueous systems on an interface, for example, to a solid phase, and consist of a so-called EPS matrix, for example in the form of a thin mucus layer in which microorganisms are embedded. The microorganisms surround themselves with extracellular polymeric substances (EPS) to protect against external attacks and to improve their living conditions. The EPS form hydrogels in combination with water to form a mucous-like matrix in which nutrients and other substances are dissolved.

This often causes unpleasant odors in addition to dark deposits on the surfaces. Thus, biofilms that form, for example, in the Einspülschale and in areas of the tub of household appliances, create a hygienic, aesthetic and / or odor problem. Also storage water, which is stored in some household appliances for reuse in later process steps, becomes hygienically questionable if the total bacterial count in the water, which correlates directly with the strength of the biofilm, overreaches. In addition to odor problems, discoloration and corrosion can also be caused by the metabolism of the microorganisms in the biofilm.

It is therefore desirable to avoid the formation of biofilms on surfaces of water-bearing household appliances as much as possible and to reduce or eliminate existing biofilms. For this purpose it is for example off EP 1612317 A2 known to equip surfaces of household appliances, for example in the Einspülschale, biocide. However, biocidal surfaces do not prevent the formation of a biofilm in the long term since only the germs in direct contact with the surface absorb and kill the biocide. Other germs that settle on the dead germs can usually survive and multiply.

Also biocidal chemical substances that act on the outside of a biofilm, generally kill only the upper germ layers. The deeper layers are usually not reached, especially since they are protected by the EPS. In addition, chemical cleaners often require a high concentration and a long exposure time. In addition, biocides or chemicals or their reaction products are often harmful to the environment and / or harmful to health, for example, by causing allergies. In addition, repeated use of biocides can lead to resistance of microorganisms, which further complicates their control.

Thermal kill processes known from the prior art do not eliminate the biofilm itself, so that new germs can settle on the killed germs or the remaining biofilm. These often find an ideal nutrient situation, so that the re-colonization of microorganisms favors and is often reinforced.

In addition, biological methods are known for avoiding and / or eliminating biofilms. So revealed the DE 3841596 A1 a method of reducing slime and deposit formation in installations where water circulates. In the process, non-sessile microorganisms which compete with biofilm-forming microorganisms for nutrient competition and thus reduce the formation of a biofilm are supplied to the circulating water. However, for this purpose, a comparatively high number of microorganisms must be added, which can also have harmful effects on their own.

The US 2010/0028314 A1 discloses a method to avoid and / or reduce the formation of biofilms on surfaces wherein the surface is treated with the Bacillus amyloliquefaciens strain NRRL B-50154. These bacteria are capable of producing the enzyme amylase, which catalyzes the breakdown of polysaccharides, such as starch, and thus impairs the formation of biofilms. However, there is also a problem here with regard to the accessibility of deeper layers of an already formed biofilm.

On the other hand, for example, from the U.S. Patent No. 5,171,591 A It is known to use bacterial parasitic bacteria of the genus Bdellovibrio for the control or elimination of undesirable bacteria on certain foods or surfaces which come into contact with foodstuffs. Except for the treatment of food, it is, for example, from the Chinese patent CN 101991611 B known to use bacterial parasitic bacteria of the genus Bdellovibrio as a biological antibacterial for the treatment of bacterial diseases.

Furthermore, it may alternatively or additionally be desired to reduce or avoid the growth of the microorganisms in the medium, in particular in the treatment medium of the domestic appliance, and to eliminate the microorganisms in the medium.

Against this background, the object of the present invention was to provide an improved method for avoiding, reducing and / or eliminating a biofilm on a surface in a water-conducting domestic appliance or of microorganisms in a medium to be introduced or introduced into the household appliance. In particular, deeper layers of the biofilms should be able to be achieved by such a method. The generation of resistance in microorganisms as well as environmentally damaging and / or harmful effects should be avoided as far as possible.

The object underlying the invention is achieved by a method for controlling microorganisms on a surface of a water-conducting household appliance and a suitable for performing this method domestic appliance and / or microorganisms in a medium which is at least temporarily introduced in the household appliance, according to the respective independent Claims solved. Preferred embodiments of the invention are listed in the respective dependent claims. Preferred embodiments of the method correspond to preferred embodiments of the household appliance and vice versa, even if not separately pointed out here in each case.

The invention thus relates to a method for controlling microorganisms, in particular bacteria, on a surface of a water-conducting household appliance and / or microorganisms in a medium which is introduced at least temporarily in the household appliance, wherein the method comprises a treatment of the surface and / or of the medium with parasitic microorganisms. As parasitic microorganisms bacterial parasitic bacteria are preferably selected. Preferably, the bacterial parasitic bacteria belong to the genus Bdellovibrio.

According to the invention, the method comprises treating the surface of the domestic appliance or of a medium which can be introduced into the domestic appliance with parasitic microorganisms, preferably with bacterial parasitic bacteria, more or fewer bacteria being present on this surface and / or in the medium. If a biofilm already exists, this treatment can be considered a "biofilm treatment step". The medium which can be introduced into the domestic appliance is preferably an aqueous solution, in particular a cleaning or washing solution in the case of a laundry treatment machine or a dishwasher.

Here, the water-conducting household appliance is not particularly limited. All household appliances in which can form biofilms due to the presence of water and in which thus a disinfection, odor removal and / or hygienic refresher by avoidance, reduction and / or elimination of biofilms is desired, are suitable according to the invention. Particularly preferred according to the invention is a dishwasher, a washing machine, a washer-dryer or a dryer, in particular a condensation dryer. A condensation dryer is a dryer in which a moist, warm process air from a drying chamber, which contains wet items of laundry, is removed by condensation in the moist warm process air water containing.

In the method according to the invention, preference is given to using such water-conducting domestic appliances in which an aqueous liquid used therein is stored as storage water for further use in a water store which is preferably present in the domestic appliance. In a preferred embodiment of the method according to the invention, therefore, the parasitic microorganisms, in particular the bacterial parasitic bacteria, are added to an aqueous liquid present in a water reservoir of the household appliance, which as a rule recycled water, such as water from the last rinse, which is relatively clean.

According to the invention, a surface in a water-conducting household appliance is not particularly limited and may be any surface located in such a household appliance. Preferably, these are hard surfaces that are susceptible to biofilm formation and adhesion of microorganisms. Hard surfaces are understood to mean, for example, surfaces made of plastic, metal, rubber, etc.

Preferably, the surface is an inner surface of the household appliance, wherein the inner surface is again preferably a permanently moist inner surface. In this case, a "permanently moist inner surface" is, in particular, a surface located in the interior of the household appliance, which comes into contact with water or an aqueous liquid during normal operation of the household appliance.

It is inventively preferred that the inner surface comprises a Einspülschale, an inner tub wall, a water supply line, a heat exchanger surface and / or a condensate tray. The inner surfaces of the aforementioned components are preferably permanently moist inner surfaces.

In the method according to the invention, an aqueous solution or suspension of the parasitic microorganisms, in particular the bacterial parasitic bacteria, which is also referred to herein only as "aqueous bacterial preparation", wherein an aqueous preparation of microorganisms in principle also meant.

According to the invention, it is preferred that the parasitic microorganisms, in particular the bacterial parasitic bacteria, be added to a rinsing solution of the domestic appliance.

In a preferred first embodiment of the method according to the invention, therefore, the surface is rinsed or wetted with the aqueous solution or suspension. In an alternative second embodiment of the method according to the invention, however, the surface is sprayed with an aqueous solution or suspension, including in particular a spray device is used. In a further third embodiment of the method according to the invention, the aqueous solution or suspension is introduced into the medium in which the microorganisms are to be eliminated or reduced, wherein in this third embodiment at the same time the surfaces coming into contact with the medium are rinsed or can be wetted. In the three embodiments, the aqueous solution or suspension contains the parasitic microorganisms, in particular the bacterial parasitic bacteria.

In this way, the parasitic microorganisms, in particular the bacterial parasitic bacteria, are transported to the inner surfaces to be treated, for example, or into the medium to be treated. Such surfaces are found, for example, in the area of the dispenser tray and the tub of a washing machine or a washer-dryer. Since these regions are very susceptible to biofilm formation, it is particularly preferred that the aqueous bacterial preparation be carried over these surfaces or sprayed onto these surfaces. It can be made advantageous for distribution of the usual waterways use. For this purpose, the aqueous bacterial preparation may advantageously also be introduced into the medium which is supplied to the domestic appliance, which is then also transported via the waterways to the surfaces. Thus, the parasitic microorganisms or bacterial parasitic bacteria can be introduced in a washing machine, for example advantageous over the dispenser and / or the medium in the household appliance.

Preferably, a water-conducting household appliance is used which has a water storage tank for water used in the household appliance (storage water). Therefore, parasitic microorganisms, in particular bacteria-parasitic bacteria, are advantageously added to a medium present in a water reservoir of the domestic appliance, in particular an aqueous liquid.

In a preferred embodiment of the method according to the invention therefore the parasitic microorganisms, in particular the bacterial parasitic bacteria, the water reservoir or the medium contained in it of the household appliance, in particular the storage water of the household appliance, are added. This may, if desired, also be carried out in parallel with the addition to the rinse solution described above, but will generally be independent of this. Namely, if the bacteria are added to the storage water, they may favorably act during the standstill time of the apparatus.

Storage water is preferably water which is collected in a water reservoir. Such a water reservoir can be fed with water from various sources and, depending on the exclusive or preferred water source, for example, a condensate collector, a soft or Be hard water tank and / or a rinse water storage. In a dishwasher, a washing machine or a washer-dryer, the water reservoir is preferably a rinse water storage. In the rinse water storage usually used rinse water is cached, for example, to be reused in the subsequent wash cycle. In the case of a dryer or washer-dryer, the water reservoir is preferably a condensate collecting container for the condensate produced during the drying of moist air, for example a condensate tray arranged below a heat exchanger. In addition, the water storage can also be a soft water tank or a hard water tank, for example, if a washing machine has a desalination device.

The water reservoirs mentioned are susceptible to the formation of biofilms, and thus the addition of parasitic microorganisms, in particular bacterial parasitic bacteria, to the storage water is very advantageous. In particular, in the storage of rinse water to be reused in later process steps, so the sanitary requirements can be guaranteed.

The method according to the invention can be initiated in various ways, in particular automatically or at the instigation of a user of the household appliance. An automatic implementation of a method according to the invention can be carried out sensor-controlled or time-controlled.

In a preferred embodiment of a method according to the invention, therefore, the treatment is carried out with parasitic microorganisms, in particular bacterial parasitic bacteria, when a sensor indicates the presence of microorganisms, bacteria and / or a biofilm on the surface or in the medium of the household appliance.

Such a sensor may be, for example, an odor sensor or an optical sensor. For example, a method according to the invention can be initiated when a sensor signal reaches or exceeds a certain predetermined value for a smell or an optical property, such as scattering or absorption. For example, the sensor may also be a turbidity sensor or a sensor for the detection of the refractive index, the surface tension or the capacity. Corresponding sensors can be located, for example, in the areas of the household appliance that are particularly susceptible to biofilms.

In this case, the control device of the domestic appliance is preferably set up in such a way that it can ascertain the presence or the danger of the formation of a biofilm by means of the data obtained by the sensor. For this purpose, the control device generally receives signals from the sensor, which are then compared with data stored in the control device accordingly, and thus suggest a biofilm or the risk of formation of a biofilm. Then, the treatment according to the invention with parasitic microorganisms, in particular with bacterial parasitic bacteria, then initiated.

Alternatively or in addition to this, a method according to the invention or the treatment provided therein can advantageously be carried out after a predetermined operating time has been reached or exceeded.

In a further embodiment of the method according to the invention, the treatment according to the invention, e.g. a biofilm, therefore timed initiated. In this case, the addition of bacterial parasitic bacteria takes place at a specified time in the program. This can be done, for example, with any wash or rinse cycle at low temperature, since they have a beneficial effect on biofilms. In addition, after a long period of inactivity or frequent use of low temperature washing or rinsing, a biofilm treatment step may be automatically performed after certain time intervals.

Alternatively, it is also preferred according to the invention that the method according to the invention, for example as a biofilm treatment, is initiated manually by a user of the household appliance. Preferably, therefore, the water-bearing household appliance has an operating device with manually operable input elements, wherein the operating device is coupled to the device for performing the treatment and the treatment can be initiated by actuation of an input element. Thus, for example, before a planned longer standstill of the household appliance, a treatment with parasitic microorganisms, in particular with bacterial parasitic bacteria, take place, so that already the formation of the biofilm is prevented. In this case, the addition of the parasitic microorganisms caused by the user takes place advantageously in a washing machine, for example by being flushed out of the dispensing dish, for example from a special chamber, or by being released from a storage container.

In addition, the initiation of the inventively provided treatment by the user can also be combined with corresponding sensors, for example, by the user via display means, such as visually on a scoreboard, the presence or the risk of Training a biofilm is communicated. This can, as described in connection with the sensor-controlled introduction, be determined via corresponding sensors and a correspondingly set program control. However, in this embodiment, the method of the present invention, eg, a biofilm treatment step, is not automatically initiated, but the user is merely presented with a suggestion so that the user can manually initiate the step as desired.

If the program control detects a state of biofilm existence or risk of formation due to the signals from the sensor, this can preferably be indicated to the user. This happens, for example, by optical and / or acoustic signals.

However, such an indication of a state of existence or danger of formation of a biofilm to the user is also advantageous in an embodiment of the household appliance according to the invention in which the method according to the invention is initiated manually by the user.

The method according to the invention can be carried out in the case of water-conducting domestic appliances such as dishwashers, washing machines, washer dryers or dryers during an ordinary program sequence, in particular during a rinsing, washing and / or drying process, by using parasitic microorganisms according to the invention, in particular bacteria parasitic bacteria. In this case, a separate treatment, for example a separate biofilm treatment step in the rinsing, washing and / or drying program or, for example, a separate biofilm treatment program is unnecessary. However, the treatment according to the invention can also be carried out as a separate step in the usual rinsing, washing and / or drying program or as a completely separate treatment program. In this case, the control device of the water-conducting household appliance is preferably designed accordingly, so that a special treatment step or a special treatment program is provided.

In particular, it is preferred that the treatment or, in the case of biofilm already present, the biofilm treatment step is carried out before and / or after longer periods of inactivity of the household appliance. During longer periods of inactivity, biofilms may form in particular, which according to the invention can be avoided and / or removed again. Particularly preferred is the implementation of the method according to the invention before longer downtime of the household appliance, since so already the formation of the biofilm can be avoided and unpleasant odors, corrosion, etc. do not arise.

According to the invention, bacterial parasitic bacteria are understood as bacteria which attack other bacteria. These are in particular obligatory parasitic bacteria belonging to the "Bdellovibrio-and-like organisms" (BALOs), such as the genera Bdellovibrio, Bacteriovorax and Peredibacter ( Davidov Y and Jurkevitch E, International Journal of Systematic and Evolutionary Microbiology (2004), 54, 1439-1452 ). In addition, the genus Micavibrio is one of the bacteria parasitic bacteria with obligatory parasitic life cycle. Accordingly, according to the invention, parasitic microorganisms are understood as meaning microorganisms which attack other microorganisms.

Within the mentioned genera of bacterial parasitic bacteria, there are bacterial strains with a high degree of prey specificity, which thus selectively affect only very specific bacterial species, whereas other bacterial strains have only low prey specificity. Thus, depending on the field of application, a suitable bacterial strain can be selected. For the present invention, those bacterial strains which have the lowest possible specificity of bees are preferred in order to attack as many bacteria as possible of the biofilm. However, the use of comparatively prey specific bacterial parasitic bacteria is possible because the selective attack of only certain microorganisms in the biofilm, the balance of the biofilm can be disturbed sensitive, which can then lead to avoidance, reduction and / or elimination of the biofilm.

In a method preferred according to the invention, the bacterial parasitic bacteria belong to the genus Bdellovibrio. Bdellovibrio is a genus of bacteria that includes very small, very fast-swimming, gram-negative, aerobic, bacterial parasitic species. Bdellovibrions attach themselves to the cell wall of their prey bacteria, penetrate them and thus penetrate into the periplasmic space of the prey cell and digest the cytoplasm there. They multiply by cell division in the prey cell and the offspring reach the wild through dissolution of the cell wall of the prey cell. This life cycle has the advantage that prey bacteria are not only killed - and their remains then remain as a source of food for new microorganisms in the biofilm - but that the prey bacteria are lysed and thus eliminated.

Advantageously, Bdellovibrions are able to swim very fast because they are very small and have a "thicker" flagellum compared to normal bacterial flagella Thrust during locomotion leads. Thus Bdellovibrions are excellent hunters. In particular, Bdellovibrions can also hunt within biofilms and thus provide an effective biofilm attack agent.

Preferably, the parasitic microorganisms, in particular the bacteria parasitic bacteria, during the process according to the invention, e.g. a biofilm treatment step, in contact with the one surface in a water-conducting household appliance on which a biofilm is to be avoided, reduced and / or eliminated brought. This can be done, for example, by adding the parasitic microorganisms, in particular the bacterial parasitic bacteria, to a medium, such as a rinsing solution or the storage water of the domestic appliance. Since the parasitic microorganisms, in particular the bacterial parasitic bacteria, actively move in liquids, they can also reach surfaces in the biofilm treatment step which are not in direct contact with the rinsing solution or the storage water, ie are, for example, bathed directly. Instead, moisture bridges are sufficient to bring the surface into contact with the parasitic microorganisms or the bacterial parasitic bacteria, since the microorganisms or the bacteria can float from the aqueous bacterial preparation via moisture bridges to the target surfaces.

In a further preferred embodiment of the method according to the invention, measures are carried out which promote the growth of the parasitic microorganisms or bacteria-parasitic bacteria. In accordance with the invention, for example, this is an additional introduction of air and / or a targeted addition of nutrient. Since bacteria are parasitic bacteria in the case of aerobic bacteria, the introduction of air by oxygen contained promotes the growth of bacteria. Likewise, the growth is promoted by targeted nutrient addition, for example, the preferred prey bacteria. Such nutrient addition may preferably be carried out together with the bacterial parasitic bacteria, for example in an aqueous bacterial preparation provided in embodiments of the invention. The growth-promoting measures have the advantage that even an addition of very small amounts of bacterial parasitic bacteria or of parasitic microorganisms is sufficient to achieve the desired effect of avoiding, reducing and / or eliminating a biofilm.

Furthermore, it is preferred that the treatment provided according to the invention with parasitic microorganisms, in particular with bacterial parasitic bacteria, is coupled with other chemical or mechanical purification processes. For example, the use of a hypochlorite, such as sodium hypochlorite, can result in accelerated biofilm removal, especially when flushed rapidly. Such a treatment step is preferably carried out after treatment with the parasitic microorganisms or bacteria-parasitic bacteria, since all microorganisms can be killed by the use of hypochlorite.

The invention further relates to a water-conducting household appliance with a water supply and a treatment container, beisspielsweise a drum, for receiving objects to be treated, such as laundry or dishes, and at least one inner surface and / or a component for at least temporarily receiving a medium, in particular a liquid, wherein the household appliance comprises a device for performing a treatment of the surface and / or the medium with parasitic microorganisms, in particular with bacterial parasitic bacteria. The device preferably comprises a bacteria depot, i. a depot with bacterial parasitic bacteria or other parasitic microorganisms, a reservoir for an aqueous bacterial preparation and / or bacterial supply lines. Finally, this includes a spray device for the aqueous bacterial preparation.

In a preferred embodiment of the inventive water-conducting household appliance, the parasitic microorganisms or bacterial parasitic bacteria are stored in solid form in a storage container, ie a bacterial depot, or can be introduced as such into the domestic appliance, for example in the form of microcapsules, powders or as tabs. Because of the ease of dosage, tabs and microcapsules are preferred. Freeze-dried parasitic microorganisms or bacterial parasitic bacteria are particularly preferably used. A freeze-dried preparation of parasitic microorganisms or bacterial parasitic bacteria may be prepared according to methods known in the art and then introduced into a household appliance carrying water in order to carry out a method according to the invention. For example, because bacterial parasitic bacteria do not form spores, they can not be easily stored. It is therefore advantageous if they are stored freeze-dried. When a freeze-dried preparation of bacterial parasitic bacteria has been introduced into a domestic water-conducting appliance, it will generally be used to carry out the present invention Method brought into contact with water, whereby the bacteria are activated again.

In this case, the storage container in the domestic appliance according to the invention is preferably arranged such that the parasitic microorganisms or bacteria-parasitic bacteria are stored therein without water contact. For carrying out the method according to the invention, a single dose of the parasitic microorganisms or bacteria-parasitic bacteria is then generally metered in via the control device of the household appliance in such a way that this individual dose is at least temporarily supplied to the domestic appliance or introduced into the domestic appliance, for example as a medium. is brought into contact and is activated. In general, the activated single dose parasitic microorganisms or bacterial parasitic bacteria then passes through the medium and the water flow in the household appliance to the surfaces to be treated.

Alternatively, the parasitic microorganisms or bacteria-parasitic bacteria are present in the water-bearing household appliance as an aqueous bacterial preparation. This also includes gelatinous preparations. In this case, it is particularly preferred that the liquid is well ventilated and / or contains additional nutrients of the parasitic microorganisms or bacterial parasitic bacteria, such as prey bacteria. Advantageously, such an aqueous bacterial preparation is present as a liquid or in microcapsules, with microcapsules being preferred because of their simple dosage.

In one embodiment of the method according to the invention, the parasitic microorganisms or bacteria-parasitic bacteria are used together with a detergent or as a component of a detergent. This can have the advantage in embodiments of the invention that a separate dosing of the parasitic microorganisms or the bacterial parasitic bacteria is eliminated. Detergents are also understood to be detergents, wherein the detergents or cleaners should preferably not be biocidal.

In a particularly preferred embodiment, the household appliance according to the invention is a washing machine with a tub, a drum, a water inlet system and a lye drain system with a drain pump and a control device and with a container for storing the parasitic microorganisms or bacteria-parasitic bacteria, ie a bacteria depot. In this case, the bacteria depot is arranged in particular so that after contacting the single dose with water and their activation, this is rinsed through the water supply both on the dispenser tray as well as through the tub. This way, the areas that are particularly susceptible to biofilms are also reached.

In a further preferred embodiment, the household appliance comprises a control device that is set up so that the biofilm treatment step is automatically initiated. The addition of the parasitic microorganisms or bacterial parasitic bacteria preferably takes place by being flushed in via the dispensing dish, for example from a special chamber, or by release from a storage container.

In one exemplary embodiment of the method according to the invention, in a bacterial depot in a domestic appliance, for example a washing machine, tabs of a biofilm treatment agent comprising freeze-dried parasitic microorganisms, in particular freeze-dried bacterial parasitic bacteria, are stored. The biofilm treatment step is initiated by the contact of water with these tabs by dosing an appropriate amount, for example a tab, from the bacteria depot into the water conduit. This can be triggered automatically by time or sensor control or on command of the user via the control device. Thus, the required amount of parasitic microorganisms or bacterial parasitic bacteria is activated with the water and rinsed in the household appliance. This rinsing takes place in a washing machine in such a way that the tub and possibly also the dispensing bowl are brought into contact with the parasitic microorganisms or bacterial parasitic bacteria over a large area. Preferably, this is done at a water temperature in the range of 30 to 40 ° C. Due to their good buoyancy, the parasitic microorganisms or bacterial parasitic bacteria also reach inaccessible areas during the biofilm treatment step which are not directly wetted by the rinse water but in contact with it via moisture bridges. The method according to the invention terminates autonomously, since the bacterial parasitic bacteria die off after removal of the biofilm due to the lack of food.

Inventive method and household appliance according to the invention have several advantages. In particular, they enable prevention, reduction and / or elimination of a biofilm on a surface in a water-conducting domestic appliance. The invention also has the advantage that parasitic microorganisms such as the bacterial parasitic bacteria represent a living "biocide" and thus no resistance of the microorganisms are produced in the biofilm. In addition, the use of bacterial parasitic bacteria in particular has no environmentally harmful Side effects. Bacterial parasitic bacteria such as Bdellovibrio are widely distributed in the environment, for example in soils, aquatic environments and mammalian intestines. In addition, infection of mammalian cells, for example, with Bdellovibrio has never been observed. Human and other eukaryotic cells are not targets for Bdellovibrio, which is why their use as an antibiotic in the human field is currently of great interest.

In particular, the germ killing and degradation process does not produce harmful products. When the source of prey has dried up, Bdellovibrios divide into a multitude of Bdellovibrio precursors, which lyse the remnants of the prey, so that the biofilm is degraded and not merely killed, as in conventional methods.

In addition, the use of bacterial parasitic bacteria only when needed. The effect of bacterial parasitic bacteria stops automatically, as the bacterial parasitic bacteria die off when all foreign germs are digested and they therefore find no more food.

Since parasitic microorganisms or bacteria-parasitic bacteria can actively move in liquids, they can also reach areas in the household appliance that do not come into direct contact with a rinsing solution, but have remained moist due to previous processes. Thus, a very thorough "cleaning" can be done. In addition, parasitic microorganisms such as bacteria parasitic bacteria are able to hunt their prey within a biofilm. In contrast to the conventional methods of preventing or eliminating biofilms which have only a superficial effect on the biofilm, parasitic microorganisms such as bacterial parasitic bacteria can also reach the deep layers of the biofilm.

Further features of the invention will become apparent from the claims, the figures and the description of the figures. All the features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively indicated combination but also in other combinations or alone. In particular, the household appliance according to the invention can comprise the device features disclosed by the method according to the invention or directly derived therefrom.

In the following, the invention will be described with reference to FIGS 1 and 2 shown exemplary embodiments explained in more detail.

1 is a schematic representation of the presently relevant parts of a first embodiment of the inventive water-conducting household appliance, which is designed here as a washing machine.

2 shows a vertical section through a water-conducting household appliance, which is designed according to a second embodiment of the invention as a tumble dryer, in which by means of an air-to-air heat exchanger, a heat recovery takes place.

In the 1 shown washing machine 1 has a tub 4 in which a drum 3 about a substantially horizontally disposed axis of rotation 35 the drum 3 is rotatably mounted and by a drive motor 14 can be operated. The long arrow shows a direction of rotation of the drum 3 at. laundry agitator 36 and scooping devices 37 for the wash liquor 6 on the inner surface of the drum shell cause an intensification of the washing of the laundry 7 with washing liquor 6 ,

The washing machine 1 has a liquor inlet system, which is a water connection fitting for the domestic water network 8th , an electrically controllable valve 9 and a supply line 10 to the tub 4 , which have a detergent dispenser ("Einspülschale") 11 is guided, from the incoming water detergent portions in the tub 4 can transport. In the supply line 10 there is a siphon 21 ,

In the 1 shown first embodiment allows several variants for carrying out the method according to the invention.

A bacteria depot 17 , which contains in this embodiment bacteria bacteria of the genus Bdellovibrio in freeze-dried form, for example in capsules, is for this purpose with a reservoir 25 for an aqueous bacterial preparation. The storage tank 25 is via a water supply 16 with an electrically controllable valve 9 connected, which connects to the domestic water network 8th represents. Thus, by mixing water and bacteria parasitic bacteria in the reservoir 25 a solution or suspension of bacterial parasitic bacteria (also referred to herein as "aqueous bacterial preparation"). The mixing and provision can be carried out promptly for use, ie for carrying out the method according to the invention. A first adjustable closure device 27 allows the controlled addition of bacteria parasitic bacteria in the reservoir 25 ,

At the washing machine 1 of the 1 is the reservoir 25 via a first bacterial supply line 20 with the induction bowl 11 connected. In addition branches from the reservoir 25 a second bacterial supply line 26 to the tub 4 or to the drum 3 which one above in the view of 1 only indicated cuff 24 at a feed opening 23 the drum 3 allows initiation of the aqueous bacterial preparation.

Finally, the washing machine points 1 of the 1 still further possibilities for carrying out a method according to the invention. For this branches of the reservoir 25 for the aqueous bacterial preparation a supply line 18 for bacterial parasitic bacteria, resulting in a spray device 31 as well as to a water reservoir 33 leads. In the supply line 18 is a second adjustable closure device 28 arranged, which can control the supply of aqueous bacterial preparation. Further closure devices may be present in a household appliance according to the invention.

About the spray device 31 , which at a rear exit of the tub 4 is arranged, the aqueous bacterial preparation, for example, in the rear, a feed opening not shown here in detail 23 opposite, part of the tub 4 be sprayed. The inner tub wall and in particular its rear, the feed opening 23 remote part is a permanently moist surface, which are particularly vulnerable to the formation of a biofilm.

Finally, also a water storage 33 be mixed with an aqueous bacterial preparation to the water reservoir 33 free of harmful bacteria and a possible biofilm and / or to clean the storage water located therein and thus to realize a longer storage time of the storage water under hygienic conditions. In 1 is the connection of the water reservoir 33 with the tub 4 not shown in detail for reasons of clarity.

For acoustic and / or visual indication of the implementation of the method according to the invention and / or a treatment that does not function properly with bacteria-parasitic bacteria, a display device is located on the washing machine of the embodiment shown here 29 ,

In the 1 described washing machine 1 illustrates how an aqueous bacterial preparation is in contact with an interior surface of the laundry treating appliance and optionally with laundry to be treated 7 is brought. At the in 1 shown first embodiment, there is also a sensor 5 in the dispenser tray. sensor 5 is, for example, an odor sensor or an optical sensor, which can indicate the occurrence of bacterial accumulations or even a biofilm. The sensor 5 is with the control device 12 of the washing machine 1 connected and can cause the execution of a method according to the invention upon reaching or exceeding a predetermined sensor signal.

They are also in the tub 4 this embodiment, a heater 13 , a pump 22 for pumping out aqueous liquid from the tub 4 as well as a sensor 15 for measuring the concentration of detergent and / or washing aid. These components as well as the valve 9 , the drive motor 14 , the adjustable closure devices 27 and 28 and the sensor 5 are with the control device 12 connected to the washing machine 1 depending on a schedule which is responsive to a schedule and / or to the achievement of certain measurements of parameters such as liquor level, liquor temperature, drum speed, presence of bacteria or biofilm, concentration of detergent and / or detergency aid, etc inside the washing machine 1 can be bound.

2 shows a vertical section through a water-conducting household appliance, which according to a second embodiment of the invention as a tumble dryer ("dryer") 2 is configured, in which by means of an air-to-air heat exchanger 40 a heat recovery happens.

The in 2 illustrated dryer 2 According to a second embodiment of the invention comprises a drum rotatable about a horizontal axis 3 for receiving, not shown here, in particular to be dried, laundry, within which driver 36 for moving laundry - not shown here - are mounted during a drum rotation. Process air is achieved by means of a blower 19 over a heater 13 through the drum 3 in a supply air duct 38 guided. In the supply air duct 38 Room air is blown through the fan 19 from a Zulufteingang 39 sucked. The of the heater 13 heated air is from behind, ie from a drying door 42 opposite side of the drum 3 through whose perforated bottom into the drum 3 passed, comes there with the laundry to be dried in contact and flows through the filling opening of the drum 3 to a lattice grate 43 inside the drying door closing the filling opening 42 , After passing through the drum 3 is the process air flow in the dryer door 42 deflected downwards. The moist, warm process air gets into one exhaust duct 33 in which is an air-to-air heat exchanger 40 which cools the warm, moisture-laden process air (here: exhaust air) and after condensation of the moisture contained in it to the exhaust air outlet 17 leads. The separated moisture is in a condensate tray 41 collected from where it can be removed for example by pumping.

For cooling, the air-to-air heat exchanger 40 the dryer 2 over the supply air duct 38 supplied room air used. This supply air is due to the warm, moisture-laden process air and then before entering the drum 3 still by heating 13 heated.

At the in 2 shown second embodiment is a bacteria depot 17 with a storage container 25 for an aqueous bacterial preparation. For reasons of clarity is not specified here, as the water supply to the reservoir 25 he follows. The storage tank 25 is again via a third bacterial supply line 30 with the air-air heat exchanger 40 and finally the condensate tray 41 connected. In this way, for carrying out a method according to the invention, an aqueous bacterial preparation through the air-air heat exchanger 40 and into the condensate tray 41 be directed. A sensor 5 for a biofilm is present, whereby an inventive method can be initiated by the evaluation of a sensor signal.

The removal of the aqueous bacterial preparation from the condensate tray 41 is not shown here for reasons of clarity.

The drum 3 will be at the in 2 shown embodiments on the rear floor by means of a pivot bearing and front by means of a bearing plate 44 stored, with the drum 3 with a brim on a sliding strip 45 on the bearing plate 44 rests and is held at the front end. The control of the condensation dryer via a control device 12 by the user via a control unit 34 can be regulated.

For acoustic and / or visual indication of the implementation of the method according to the invention and / or a treatment which does not function properly with the aqueous bacterial preparation, a display device is located on the dryer 29 ,

The exemplary embodiments have been explained in more detail using the example of bacterial parasitic bacteria. This is only an example of the parasitic microorganisms usable in the invention. The invention can also be applied to other parasitic microorganisms in a corresponding manner.

LIST OF REFERENCE NUMBERS

1

 Washing machine

2

dryer

3

 drum

4

 tub

5

 Sensor (a) for biofilm, e.g. Odor sensor, optical sensor

6

 suds

7

 Laundry

8th

 Domestic water supply

9

 electrically controllable valve

10

 Supply line to the tub

11

 Detergent dispenser, dispenser tray

12

 control device

13

 heater

14

 drive motor

15

 Sensor for determining properties of an aqueous liquid

16

 Water supply for storage tank (for aqueous bacteria preparation)

17

 Storage container, in particular bacteria depot, e.g. for freeze-dried bacterial parasitic bacteria of the genus Bdellovibrio

18

 Supply line (for aqueous bacteria preparation to the spray device and to the water reservoir)

19

 fan

20

 First bacteria feed line to the dispenser tray

21

 siphon

22

 pump

23

 loading port

24

 cuff

25

 Storage container for aqueous bacteria preparation (preparation of bacteria parasitic bacteria)

26

 Second bacterial supply line for tub / laundry drum

27

 First adjustable closure device

28

 Second adjustable closure device

29

 display device

30

 Third bacteria supply line for heat exchanger and condensate tray

31

 Spray device for aqueous bacterial preparation

32

 rear exit of the tub

33

 Water storage (for recycled water)

34

 operating unit

35

 axis of rotation

36

takeaway

37

 scoop device

38

 supply air duct

39

inlet air

40

 Air-air heat exchanger

41

 Drain pan

42

 dryer door

43

 fluff

44

 end shield

45

 lubricating strip

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1612317 A2 [0005]
• DE 3841596 A1 [0008]
• US 2010/0028314 A1 [0009]
• US 5171591 A [0010]
• CN 101991611 B [0010]

Cited non-patent literature

• Davidov Y and Jurkevitch E, International Journal of Systematic and Evolutionary Microbiology (2004), 54, 1439-1452 [0041]

Claims (18)

Method for controlling microorganisms on a surface of a water-conducting domestic appliance ( 1 . 2 ) and / or microorganisms in a medium ( 6 ) Which is at least temporarily inserted in the domestic appliance, characterized in that the method (a treatment of the surface and / or the medium 6 ) with parasitic microorganisms. A method according to claim 1, characterized in that the parasitic microorganisms are bacterial parasitic bacteria and in particular of the genus Bdellovibrio belong. Method according to one of claims 1 or 2, characterized in that the surface of an inner, especially permanently moist, surface of the household appliance ( 1 . 2 ). Method according to one of claims 1 or 2, characterized in that the medium ( 6 ) is a liquid, in particular water or an aqueous solution. A method according to claim 3, characterized in that the inner, especially permanently moist surface is a surface or wall of a component comprising (a flushing-in tray from the group of components, 11 ), a storage container for liquids, in particular a tub ( 4 ) or a water reservoir ( 33 ), a water supply line ( 10 ) a heat exchanger ( 40 ) and / or a condensate tray ( 41 ), is selected. Method according to one of claims 1 to 5, characterized in that for the treatment of the surface and / or the medium ( 6 ) an aqueous solution or suspension of the parasitic microorganisms, in particular the bacterial parasitic bacteria, is used. A method according to claim 6, characterized in that the surface is rinsed with the aqueous solution or suspension, sprayed or wetted. A method according to claim 6, characterized in that the aqueous solution or suspension in the medium ( 6 ) is introduced. Method according to one of claims 6 to 8, characterized in that for the treatment of the surface and / or the medium ( 6 ) the aqueous solution or suspension is used together with a detergent or as a component of a detergent. Method according to one of claims 1 to 9, characterized in that the parasitic microorganisms, in particular the bacterial parasitic bacteria, one in a container, in particular a water reservoir ( 33 ), of the household appliance ( 1 . 2 ), in particular an aqueous liquid, are added. Method according to one of claims 1 to 10, characterized in that the treatment takes place when a sensor ( 5 ) the presence of microorganisms, in particular bacteria, and / or a biofilm on the surface and / or in the medium ( 6 ). Method according to one of claims 1 to 11, characterized in that the treatment takes place after a predetermined period of operation of the household appliance ( 1 . 2 ) is reached or exceeded. Method according to one of claims 1 to 10, characterized in that the treatment is carried out when it is manually initiated by a user of the household appliance. Method according to one of claims 1 to 13, characterized in that the treatment is coupled with the growth of the parasitic microorganisms, in particular the bacterial parasitic bacteria, promoting measures. Water-conducting household appliance ( 1 . 2 ) with a water supply ( 8th . 9 ) and a treatment container ( 2 ) for receiving objects to be treated ( 7 ) and at least one inner surface and / or a component for at least temporarily receiving a medium, in particular a liquid, characterized in that the domestic appliance ( 1 . 2 ) a device ( 17 . 18 . 20 . 25 . 26 . 27 . 28 . 30 . 31 ), which is adapted to carry out a treatment of the surface and / or the medium with parasitic microorganisms, in particular with bacterial parasitic bacteria. Water-conducting household appliance ( 1 . 2 ) according to claim 15, characterized in that the parasitic microorganisms, in particular the bacterial parasitic bacteria, in solid form in a reservoir ( 17 ) are held. Water-conducting household appliance ( 1 . 2 ) according to claim 16, characterized in that freeze-dried parasitic microorganisms, in particular bacteria parasitic bacteria, are used. Water-conducting household appliance ( 1 . 2 ) according to one of claims 15 to 17, characterized in that the one operating device with includes manually operable input elements is included and the operating device is coupled to the device for performing the treatment, wherein the actuation of an input element, the treatment can be initiated.

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