WO2020254557A1

WO2020254557A1 - Method, device and ventilation system for reducing the microbial pressure in an animal farm production facility

Info

Publication number: WO2020254557A1
Application number: PCT/EP2020/067069
Authority: WO
Inventors: Povl Kaas
Original assignee: Farmer-Light Holding A/S
Priority date: 2019-06-19
Filing date: 2020-06-19
Publication date: 2020-12-24

Abstract

The present disclosure concerns a method of reducing the microbial pressure in an animal farm production facility, said method including the steps of arranging at least one animal in the animal farm production facility; spraying a disinfection liquid for a predetermined time period; exposing said at least one animal with polychromatic light from at least one lamp, said polychromatic light comprising both visible light and UVB light; said exposure being of a predetermined time period; and controlling the spraying and the light exposure by managing the predetermined spraying time and the predetermined light exposure time. The present disclosure also concerns a device for the performance of said method and an animal farm production facility with such device. The present disclosure further relates to ventilation system for an animal farm production facility, wherein the system comprises at least one compartment configured for disinfecting the ventilated air.

Description

Method, device and ventilation system for reducing the microbial pressure in an animal farm production facility

The present disclosure relates to methods, a device and a ventilation system for reducing the microbial pressure in an animal farm production facility.

Background

In animal farming, animals such as pigs, piglets, cattle or other domesticated animals are kept inside in animal housing facilities. The conditions in animal housing facilities may promote the growth of a wide diversity of microorganisms including bacteria and virus. Presence of airborne microorganisms in animal housing facilities affects the quality of air in those facilities. The quality of air directly affects animals, workers and people in neighbouring areas. The intensive farming may result in an unsatisfactory increased level of microbial pressure inside the animal farm production facilities.

There are taken a variety of measures to control the microbial pressure inside the animal housing facilities in order to ensure a good air quality and the well-being of the animals kept in the animal housing as well as the well-being of the workers in the farm, such as for instance, in order to avoid contamination admission to the animals is controlled and restricted.

It is known to expose in particular cows in an animal housing facility with UV light for a limited period of time daily to promote a high content of native vitamin D content in the milk of the animals. The UV light emitted is UV-B and optionally UV-A. An example thereof is known from WO 2013/041389.

It is also known from CN206821666U to use ozone and UVB light in hen laying houses to improve the immunity of laying hens.

Animals or humans who have been infected by a bacterial disease can be treated with antibiotics. Although, for most diseases this cures the animal or human, it is

nevertheless unsatisfactory not only from a health point of view but because such antibiotic treatment is expensive and causes economic losses for the farmers.

Furthermore, over the years some types of bacteria have become resistant to such antibiotic treatment, which further increases the health risk of the animals and people exposed to the animal housing environment and may lead to an increased number of deaths for instance among piglets and other small animals in animal farming as no effective medical cure is available.

Summary

To minimize the human and animal risk of developing potential health problems as a result of microbial exposure, it is a purpose of the present disclosure to provide a method and a device for reducing the microbial pressure in an animal farm production facility.

One embodiment of the present disclosure therefore relates to a method of reducing the microbial pressure in an animal farm production facility, said method including the steps of:

- arranging at least one mammal in the animal farm production facility;

- spraying a disinfection liquid for a predetermined spraying time period;

- exposing said at least one mammal with polychromatic light comprising both visible light and UVB light; said exposure being of a predetermined light exposure time period; and

- controlling the spraying and the light exposure by managing the predetermined spraying time period and the predetermined light exposure time period.

A further embodiment of the present disclosure relates to a device for reducing the microbial pressure in an animal farm production facility, said device comprising at least one first lamp emitting polychromatic light with both visible light and UV light in the category UV-B, and optionally also UV-A, and a spray system adapted for spraying a disinfection liquid. The at least one first lamp is preferably configured for exposing at least part of the animals in the production facility to the emitted light. Furthermore, the spray system is preferably configured for spraying the disinfection liquid onto at least a part of the animals in the farm.

Animal farm production facilities are typically ventilated, and typically incoming air is mixed with ventilated air. Another embodiment of the present disclosure relates to disinfection of the incoming air and/or the recirculated air, i.e. the ventilated air that enters the production facility is disinfected. The disinfection can be provided by means of exposure of the air to UV light, in particular VUV, such as FUV, and/or UVC light, mixing with ozone and/or mixing with a disinfection liquid, or any combination thereof. With efficient disinfection of the ventilated air, the steps of spraying the animals with disinfection liquid and exposing the animals to UVB and optionally UVA light may become optional features.

The present disclosure also relates to the ventilation system for reducing the microbial pressure in an animal farm production facility. The ventilation system comprises at least one compartment configured for disinfecting ventilated air by mixing with ozone and/or chemicals, and subsequently illuminating the air with UV light.

However, the combination of both disinfecting the ventilated air, as described herein, and spraying the animals with disinfection liquid and exposing the animals to UVB and optionally UVA light, as also described herein, can be an advantageous combination, because the microbial pressure in the animal farm production facility can be reduced extremely efficiently.

Description of Drawings

Fig. 1 is a schematic illustration of an animal farm production facility with a device according to the present disclosure installed;

Fig. 2 is a schematic drawing of a lamp device according to the present disclosure;

Fig. 3 is a picture of test sample in the first experiment; and

Fig. 4 is a picture of test sample in the second experiment.

Fig. 5 is a schematic illustration of a ventilation system for disinfecting the ventilated air of an animal farm production facility. Detailed description

By the present disclosure it is realised that by reducing the microbial pressure in the animal housing, significant reductions in the amount of antibiotics and other medicines can be achieved whereby both the animal health is improved and cost-savings for the farmer are achieved. A further advantage realised by the present disclosure, in particular in relation to farms with pigs and piglets, is that Methicillin resistant

Staphylococcus aureus (MRSA) bacteria as well as other aerosol carried injections, such as virus infections, e.g. African swine fever virus, can be removed significantly and thereby the health and well-being for both animals and farm workers is improved. A reduction in the microbial pressure can be achieved by disinfection with methods of the present disclosure. Such disinfection can be inside the animal farm production facilities, in the ventilation system of the animal farm production facility or in

combination.

It is found advantageous to perform a light spray of fluid on the animals before exposing the animals to the light with visible light and UV light in the wavelengths of UV-B and optionally UV-A. This enhances the inactivation of the bacteria on the skin of the animals and the inactivation of the airborne microorganisms resulting in a reduction of the microbial pressure in an animal farm production facility and resulting in a more healthy stock of animals in the farm facility. Thus, by the present disclosure it is surprisingly found that there is a synergetic effect of combining spraying with disinfection liquid and the light emission. The spray system comprising hoses or tubes may advantageously be provided as mounting means for the lamps in the animal housing. The spraying system may also be used to cool the animals and reduce the amount of dust inside the animal housing. Besides this, the spraying system may also be used as a sprinkler system in the fire protection system of the animal housing. Thus, besides being connected to a reservoir from which disinfecting liquid is supplied, the spraying system may also be connected to a water source.

The animal farm production facility can be ventilated, wherein the air of the ventilation system, i.e. the ventilated air, is disinfected to reduce the microbial pressure. The disinfected air is ventilated into the animal farm production facility, resulting in an animal farm production facility with no airborne contamination from the milieu outside of the facility. Incoming air can furthermore be filtered through a coarse filter and/or a microfilter. In an embodiment, the at least one first lamp is preferably a high-pressure lamp emitting light with wavelengths in the ranges of 285-315 nm with a maximum intensity of 297-303 nm, preferably comprising light of 296 nm, 297 nm, 302 nm and 303 nm; 400-430 nm with a maximum intensity of approx. 405 nm, preferably comprising light of 404 nm, 405 nm and 406 nm; and visible working light with a colour temperature of 4500°-6500° K, such as 380-750 nm with a colour temperature of 4500°-6500° K. The benefits achieved by these wavelengths are that the immune system of the exposed at least one animal is enhanced, the inactivation of bacteria and virus is achieved and in respect of the later of the listed ranges of wavelengths, a visible working light is achieved so that farm workers can carry out their work in the animal farm facility.

In order to ensure that no harmful UV-C light is emitted so the animals are being exposed, the at least one first lamp is preferably provided with a sharp edge filter glass where wavelengths below 285 nm are filtered from the light emitted from the lamp. The UV-C wavelengths are thereby prevented from passing through the sharp edge filter glass.

The at least one first lamp may have an effect of 50 W, 80 W, 125 W, 250 W, 400 W, 700 W, 1000 W or more. In relation to pigs it is found sufficient to provide one lamp of 50 watt per adult pig. In relation to stable areas where a plurality of pigs are kept together one or more lamps with 50 watts or higher capacity may be provided in order to achieve an emission effect of approx. 50 watts per animal. In relation to other animals similar calculations may be performed, but the lamp effect may differ depending on the type of animal, the size of the animal or animals and the like. As a guidance, it is found advantageous to use:

50 W - 125 W per sow in a Farrowing house;

250 W - 400 W per Weaner unit for piglets;

400 W - 700 W per Finisher housing for pigs; and

400 W - 800 W for Gestation unit for pigs.

1.000 W for mating section

It is by the present disclosure realised that the animals exposed to the method may include pigs, such as piglets, weaners, and finishers, poultry, cattle or other domesticated animals.

The device may comprise a control system adapted for managing a predetermined spraying time and a predetermined light exposure time, such as ensuring the predetermined light exposure time period is up to 16 hours per day, and preferably the predetermined spraying time period is approx one minute per day, or such that the predetermined spraying time period is divided into intervals during the predetermined light exposure time period.

It is found that the step of UV light exposing preferably comprises that the

predetermined light exposure time period is up to 16 hours per day, when the UV light is outside of the ventilation system, preferably approx. 16 hours/day. This emulates daylight and then 8 hours of no light corresponding to night time. Hereby, there is achieved a reduction of microorganisms and aerosols of more than 90 %. In the preferred embodiment, it is found that the dosage for farm workers is less than 300 mJ/cm² and for the animals it is at least 500 mJ/cm², over a period of 16 hours, i.e. a typical daily light exposure time period. This daily dosage of 500 mJ/cm² has been measured over a period of 3 months without any measured damages to the animals. Furthermore, it is found that by the above-mentioned preferred intervals and exposure times, the standards concerning incoherent optical radiation of humans are met, such as DS/EN 14255-4.

The disinfection liquid is advantageously selected from a group consisting of peracetic acid (C2H4O₃), chloride (Cl), chloridedioxide (CIO2), hydrogenperoxide (H2O2), ozone (O₃) and Quaternary ammonium compounds (NFV). The spraying comprises that the disinfection liquid is provided in an aqueous solution, such as in a concentration of 5-50 %, in particular approx. 10 %. In a currently preferred embodiment, peracetic acid is found advantageous as this liquid minimizes any corrosion on any steel components in the animal housing. The step of spraying includes in one embodiment that the predetermined spray time period is approx one minute per day. Alternatively or additionally, the step of spraying may include that the predetermined spray time period is divided into a multiple of spraying time intervals of for instance 30-120 seconds during the predetermined light exposure time period of for instance up to 16 hours.

In one embodiment of the present disclosure, a ventilation system for an animal farm production facility is provided. Such ventilation system comprises a least one compartment configured for disinfecting ventilated air by mixing with ozone and/or chemicals and subsequently illuminating the air with UV light. The illumination may be provided by at least one second lamp. The ventilation system may further comprise at least one inlet for providing air from the milieu outside of the animal farm production facility. In a further embodiment, the ventilation system comprises at least one second inlet located inside the animal farm production facility for recirculating air into the ventilation system. The ventilation system may further comprise at least one outlet for ventilating the disinfected air into the animal farm production facility.

In one embodiment the ventilation system also comprises at least one filtering device for removing particles from the air. The filtering device for removing particles from the air can be in the form of filters, such as coarse and/or microfilters.

In one embodiment the ventilation comprises at least one generator for providing ozone. In another embodiment the ventilation system comprises at least one container for providing the disinfection liquid.

In one embodiment of the present disclosure the ventilated air can be disinfected in an air mixing compartment with ozone and/or disinfection liquid. In another embodiment the ventilated air can be disinfected in a UV compartment where the air is exposed to UV light, such as FUV. In one embodiment the mixing compartment and UV

compartment are separated from each other. In a preferred embodiment, the mixing- and UV compartments are in the same compartment, preferably with a divider, to separate the two compartments from each other. In a preferred embodiment the air can be mixed with ozone and/or disinfection liquid before the mixed air is disinfected in the UV compartment.

In one embodiment the incoming air (from the outside) can be combined with recirculated air from the animal farm production facility.

In one embodiment a higher pressure can be created inside the animal farm production facility, when comparing to the outside, which further aids to reduce airborne contamination from the milieu outside of the facility.

In the ventilation system the UV light used can be any UV light, as there is no risk of harming animals or humans. In a further embodiment, the at least one second lamp used for disinfecting the ventilated air is therefore located such that light from the second lamp is not emitted towards the animals, e.g. in or near the ventilation system. One advantage of placing the a least one second lamp in the ventilation system is the use of FUV and/or UVC light, giving a higher disinfection, without the risk of damaging individuals in the animal farm production facility. The at least one second lamp is preferably capable of emitting light with wavelengths in the ranges of 160-360 nm, most preferably around 315 nm. This allows for an even higher photochemical reaction as described herein. When the bacteria is inside the ventilation system, there is a high risk of dark repair (described below). Therefore it is an object of the present disclosure to perform a disinfection of the air, such that the bacteria cannot perform dark repair.

Such disinfection can be achieved by a combination of ozone and/or disinfection liquid along with the FUV and/or UVC light described above.

Ventilation systems capable of disinfection can be mounted on existing ventilation systems (retrofitting) as well as in installations of new ventilation systems.

The at least one second lamp is preferably capable of emitting up to 50 kW in the FUV and/or UVC range, allowing for a high amount of photochemical reactions.

The at least one second lamp can also be a lamp emitting both FUV and/or UVC light, and/or light in the range 160-360 nm, most preferably around 315 nm.

The at least one second lamp may have an effect of 400 W, 800 W, 5kW, 10 kW, 30 kW or more.

Lamps of the kind used in the present disclosure are of the types: low pressure, medium pressure and high pressure. Fligh-pressure lamps emit a broader spectrum of light than the low-pressure lamps. Low-pressure lamps typically only give

monochromatic light.

Alternatively or additionally, the lamps used in the present disclosure can be light emitting diodes (LED). Low-pressure lamps have working pressure much less than atmospheric pressure. For example, common fluorescent lamps operate at a pressure of about 0.3% of atmospheric pressure.

High-pressure lamps have a discharge that takes place in gas under slightly less to greater than atmospheric pressure. High-pressure lamps produce a broader light spectrum than the low pressure sodium lamps, i.e. polychromatic light.

High pressure or low pressure lamps are often also referred to as high pressure discharge lamps or low pressure discharge lamps.

The term colour temperature in relation to a light source, such as a discharge lamp, is the temperature of an ideal black-body radiator that radiates light of a colour comparable to that of the light source. The colour temperature is a characteristic of visible light.

The present disclosure also relates to an animal farm production facility with a device for reducing the microbial pressure in an animal farm production facility and/or a ventilation system according to present disclosure and optionally configured for carrying out the present disclosed method(s).

In the present disclosure the term UVA refers to the range from 315 to 400 nm, UVB refers to the range of 280-315 nm, and UVC refers to the range of 100-280 nm. The term Far UV (FUV) refers to the wavelength range 122-200 nm.

UV light can perform many reactions one of such reactions can be with genetic material through interaction between photons and nucleic acids in a reaction that polymerizes nucleic acids, often forming pyrimidine dimers, such as thymidine dimers. Polymerized bases are harmful to the cell as these cannot be replicated and transcribed. UV light also reacts with proteins by crosslinking amino acids and are thus capable of disabling the function of proteins.

DNA damage is repaired by several mechanisms in organisms. One mechanism is the photoreactivation reaction where the enzyme responsible for the reaction, cleaves the damaged DNA in a reaction with light in the 350-500 nm range. Visible light can in this way salvage damaged bacteria. The photoreactivation of the bacteria will depend on the light and the exposure time.

UV damage alone can sometimes result in sterile bacteria. For bacteria to be pathogenic, they have to be able to replicate themselves.

Another repair mechanism is the dark repair mechanism. In the dark repair mechanism enzymes can repair damaged DNA without light energy. Such an enzyme is the N- glycosylase enzymes that is capable of cleaving N-glycosidic bonds, such that for example deaminated cytosines can be replaced. As organisms can repair DNA damages in multiple ways it is an object of the present disclosure to damage the organisms in such a way, that the bacteria is not reactivated upon reaction with light. This can for example be by a combination of DNA damages and oxidation reactions.

Disinfection to the presently disclosed approach can be done by UV light or chemical treatment of air or in preferred embodiments in combination. As described below, UV light can react with certain chemicals and form highly reactive compounds. Thereby achieving an even higher reduction in microbial pressure, when the chemicals and UV light react in close proximity to the particles in the air, such as in a ventilation system

Chemical compounds of the present disclosure, such as ozone and peracetic acid disinfects by performing oxidation reactions with vital components of the cell. The chemical compounds are comprised in the disinfection liquid. Ozone functions both as a gas and a chemical compound and can as such both be in the disinfection liquid and in the air. In some embodiments of the present disclosure ozone is only provided as a gas. In other embodiments of the present disclosure there is only provided a disinfection liquid. In further embodiments of the present disclosure ozone and disinfection liquids are provided in combination.

By using high pressure lamps with a high energy in the FUV and/or UVC range O3 also splits into the two highly reactive CV and 0^3P. Both species have a very high oxidation potential. 0^3P has the highest known oxidation potential. These species will only exist for a few nanoseconds before they react with other oxygen molecules and results in higher O2 contents of the air, for the benefit of the animals. If the species react with a microorganism they will add to the disinfection of the air by this reaction. Formation of free radicals (OH·) can be advantageous for disinfection as they have a high standard potential of 2.8 eV. Free radicals reacts with cells and inactivates these for example by interaction with proteins and fatty acids of the cellular membrane thereby disrupting the membrane.

In one embodiment of the present disclosure ozone is used as an oxidizing agent. Ozone is a very strong oxidizing agent with a standard potential of 2.07 eV and can react with other compounds independently or through the formation of free radicals

0₃ + OH- 0₃- + OH·

Hydrogenperoxide is an oxidizing agent with a standard potential of 1.78 eV.

Hydrogenperoxide is unstable in suspension and will either decompose into water and oxygen or can, by reaction with UV light, form free radicals.

H2O2 + UV light 20H^*

When hydrogenperoxide reacts with acetic acid, peracetic acid is formed. Peracetic acid can advantageously be used in the disinfection liquid as peracetic acid is more stable and can be transported. Peracetic acid is also a disinfectant and forms free radicals when it reacts with water under UV light.

CHsCOOOH + H2O + UV light CH₃COO- + 20H^* + H+

Examples

In the following the present disclosure is described with reference to preferred embodiments and the accompanying drawings.

Example 1

In fig. 1 , a principal illustration of an animal farm production facility is shown. The animals 1 are provided in booths divided by stall dividers 2. Above the animals 1 below the animal housing ceiling 3, a device for reducing the microbial pressure in an animal farm production facility according to an embodiment of the present disclosure is provided. This device comprises a number of lamps 4 and a distribution hose 5 for forwarding an aqueous disinfection liquid 7 to a series of sparing nozzles 6 along the hose 5. A control system (not shown) is also provided by which the opening and closing for the spraying nozzles 6 either individually or collectively and/or a combination thereof is performed so that a predetermined spraying time period is achieved. An example of the spraying time period could be approx such that one minute per day is achieved. Alternatively, the predetermined spraying time period may be divided into a multiple of spraying time intervals of for instance 30-120 seconds during the

predetermined light exposure time period of for instance 16 hours. The predetermined spraying time may depend on the type of animal, the amount of liquid released per time unit per nozzle and/or other factors such as the size of the farm facility.

The aqueous disinfection liquid 7 is preferably selected from a group consisting of peracetic acid (C2H4O3), chloride (Cl), chloridedioxide (CIO2), hydrogenperoxide (H2O2), ozone (O3) and Quaternary ammonium compounds (NFV). In particular, peracetic acid (C2H4O3) is found advantageous due to the non-corrosive as well as non-toxic properties. Peracetic acid also has the advantage that the peracetic acid binds ammonia and therefore reduces the amount in the air. This is realised to be

advantageous in relation to chicken farms where the presence of ammonia may cause blisters and other damages to the chickens, in particular their feet. The peracetic acid binds the ammonia and is converted to ammonium, which is harmless to the chickens.

The liquid distribution hose 5, the nozzles 6 and the lamps 4 are preferably provided at a suitable distance from the floor of the animal housing and thereby in a suitable distance from the animals and the farm workers in the building. This distance could suitably be 1 -10 meters depending on the type of animal. The hoses 5 may

advantageously be provided as mounting means for the lamps 4 in the animal housing. By the present disclosure it is realised that the spraying system may also be used to cool the animals and reduce the amount of dust inside the animal housing. Besides this, the spraying system may also be used as a sprinkler system in the fire protection system of the animal housing. Thus, besides being connected to a reservoir from which disinfecting liquid 7 is supplied, the spraying system may also be connected to a water source.

With reference to fig. 2, each lamp 4 is preferably an assembly provided with a polychromatic high-pressure lamp 43. The lamp 43 is dosed such that predetermined wavelengths are emitted. This lamp 43 is arranged in a housing 44 which is open to the bottom. In the lower opening of the housing 44 the light 41 is emitted from the lamp housing 44. To ensure that no harmful UVC light is emitted a sharp edge filter glass 42 is provided in the lower opening of the housing 44, whereby wavelengths below 285 nm are filtered from the light 41 emitted from the lamp 43.

Example 2

In fig. 5 a principal illustration of a ventilation system for reducing the microbial pressure of an animal farm production facility is shown. Incoming air is filtered through a coarse filter and/or a microfilter. The incoming air is combined with recirculated air from the animal farm production facility, wherein the recirculated air may be at least a part of an outlet air from the animal farm production facility. The air is then mixed in an air mixing compartment, where ozone (produced in the ozone generator) and/or aqueous liquid is mixed into the air. The mixed air is then disinfected in the UV compartment where the air is treated with UVC light and/or FUV.

The disinfected air is then ventilated into the animal farm production facility, resulting in an animal farm production facility with no airborne contamination from the milieu outside of the facility. A higher pressure is created inside the animal farm production facility, when comparing to the outside, which further aids to reduce airborne contamination from the milieu outside of the facility.

In the ventilation system the UV light used can be any UV light, as there is no risk of harming animals or humans. The at least one second lamp can be capable of emitting up to 50 kW in the FUV and/or UVC range, allowing for a high amount of photo- chemical reactions. One advantage of placing the at least one second lamp in the ventilation system is the use of FUV and/or UVC light, giving a higher disinfection, without the risk of damaging individuals in the animal farm production facility. Another advantage of performing a disinfection in the ventilation system is that disinfection can be carried out throughout day and night, and is not limited to a daylight schedule. It should be noted that it is a preference that the second lamp is active (i.e. emitting light) when the ventilation system is active. Example 3

Two series of experiments have been performed to identify the effectiveness of the method of reducing the microbial pressure in an animal farm production facility according to the present disclosure.

In each of the first and second series of experiments, three comparative experiments were carried out with the object of identifying the difference in the reduction of microorganisms in a test sample by radiating the test sample with light only, with disinfecting liquid spray only, and with light radiation plus a spray of disinfecting liquid. The light was emitted from a high-pressure lamp emitting light with wavelengths in the ranges of:

285-315 nm with a maximum intensity at 297-303 nm;

400-430 nm with a maximum intensity at approx. 405 nm; and

380-750 nm with a colour temperature of 4500°-6500° K.

For both series experiments peracetic acid (C2H4O3) was used as disinfecting liquid.

The test sample is in the first series of experiments a piece of textile cloth, fig. 3, and in the second series of experiments a number of glass balls, fig. 4. This simulates the farm worker’s clothes and the skin surface of an animal, in particular a pig,

respectively. In both series of experiments, the bacteria used is MRS A because this bacteria needs a high amount of UV energy to achieve a germ killing rate of above log 4. It is believed that if MRS A can be inactivated then all other disease causing bacteria and viruses can be inactivated.

It should be noted that the disinfecting liquid was provided only at the start of the measurement, while the light was continuously emitted.

In the first series of experiments, a test sample in the form of a piece of cloth with MRSA bacteria thereon was placed in a petri dish posed with MRSA and the three experiments were carried out.

The light was emitted with a certain intensity (31.25 mJ/cm²/h, corresponding to a typical daily dose of 500 mJ/cm²) for different amounts of times and the number of bacteria (cfu/mL) was determined on the test sample. The recorded values are listed in the first three columns of table 1 . It is apparent that the germs are being reduced as the UV radiation time is increased. In the second experiment of the first series of experiments, the test sample was sprayed for 60 seconds with peracetic acid in a 10% solution. The test results are recorded in the fourth to sixth columns of table 1 . From the data it is apparent that the sparing itself does not have any significant influence on the amount of bacteria in the test sample.

In the third experiment, the test sample was sprayed for 60 seconds and then also exposed to light emitted with a certain intensity for a different amount of time, at an intensity of 31 .25 mJ/cm²/h, corresponding to a daily dosage (during 16 h) of 500 mJ/cm². The number of bacteria (cfu/mL) was determined on the test sample and the results are recorded in columns seven to nine of table 1 . From these results it becomes apparent that a significant reduction of bacteria is achieved and that the reduction is faster than if the test sample was only emitted with light (columns one to three of table 1 )·

Table 1 : Measurements of microorganisms in the first series of experiments.

In the second series of experiments, the test sample are glass balls placed in a petri and posed with MRSA bacteria on the surfaces and the three experiments were carried out.

The light was emitted with a certain intensity for different amounts of times, 31 .25 mJ/cm²/h, corresponding to a daily dosage (during 16 h) of 500 mJ/cm². The number of bacteria (cfu/mL) was determined on the test sample. The recorded values are listed in the first three columns of table 2. It is apparent that the germs are being reduced as the UV radiation time is increased. In the second experiment of the second series of experiments, the test sample was sprayed for 60 seconds with peracetic acid in a 10% solution. The test results are recorded in the fourth to sixth columns of table 2. From the data it is apparent that the sparing itself does not have any significant influence on the amount of bacteria in the test sample. It should be noted that the disinfecting liquid was provided only at the start of the measurement, while the light was continuously emitted.

In the third experiment, the test sample was sprayed for 60 seconds and then also exposed to light emitted with a certain intensity for different amounts of times, 31.25 mJ/cm²/h, corresponding to a daily dosage (during 16 h) of 500 mJ/cm². The number of bacteria (cfu/mL) was determined on the test sample and the results are recorded in columns seven to nine of table 2. From these results it becomes apparent that a significant reduction of bacteria is achieved and that the reduction is faster than if the test sample was only emitted with light (columns one to three of table 2).

Table 2: Measurements of microorganisms in the second series of experiments.

With reference to table 3, see below, as an example a“5-log reduction” means lowering the number of microorganisms by 100,000-fold, that is if a surface has 100,000 pathogenic microbes on it, a 5-log reduction would reduce the number of microorganisms to one. A 1 log reduction means the number of germs is 10 times smaller.

Table 3: Log reduction chart

Above, the present disclosure is described with reference to some currently preferred embodiments. However, by the present disclosure it is realised that variants may be provided without departing from the scope of the invention as defined in the accompanying claims.

Example 4

A further experiment has been performed to identify the effectiveness of the method of reducing the microbial pressure in an animal farm production facility according to the present disclosure.

For testing the method, multiple Petri dishes were prepared with Staphylococcus aureus and Salmonella bacterium. A 100 Watt high-intensity discharge (HID) lamp was positioned at a distance of 2 m from the Petri dishes. A light radiation of 31.25 mJ/cm²/h, was provided during a total time of 200 minutes, i.e. 104 mJ/cm².

The number of active bacteria (cfu/mL) was thereafter quantified on each of the test samples.

It could be concluded that >99% Salmonella and 90% of Staphylococcus aureus 90 % were inactivated by the emitted light.

Claims

1. A method of reducing the microbial pressure in an animal farm production

facility, said method including the steps of:

- arranging at least one mammal in the animal farm production facility;

- spraying a disinfection liquid for a predetermined spraying time period;

- exposing said at least one mammal with polychromatic light comprising visible light, UVB light and optionally UVA light; said exposure being of a predetermined light exposure time period; and

2. The method according to claim 1 , whereby the polychromatic light is provided by at least one first lamp, preferably in the form of a high-pressure lamp emitting light with wavelengths in the ranges of:

285-315 nm with a maximum intensity of 297-303 nm, preferably comprising light of 296 nm, 297 nm, 302 nm and 303 nm;

400-430 nm with a maximum intensity of approx. 405 nm; and

- 380-750 nm with a colour temperature of 4500°-6500° K.

3. The method according to any one of the preceding claims, whereby the

polychromatic light is provided by a plurality of Light Emitting Diodes (LED).

4. The method according to any one of the preceding claims, wherein the

predetermined light exposure time period is up to 16 hours per day, preferably approx. 16 hours/day.

5. The method according to any one of the preceding claims, wherein the

predetermined spraying time period is approx one minute per day.

6. The method according to any one of the preceding claims, wherein the

predetermined spraying time period is divided into a multiple of spraying time intervals of for instance 30-120 seconds during the predetermined light exposure time period.

7. The method according to any one of the preceding claims, wherein the at least one mammal is pigs, piglets, cattle or other domesticated animals.

8. The method according to any one of the preceding claims, further comprising the step of ventilating the animal farm production facility and that said ventilation comprises the step of disinfecting the ventilated air.

9. A method of reducing the microbial pressure in an animal farm production

facility, said method including the steps of:

- ventilating an animal farm production facility; and

- disinfecting the ventilated air

10. The method according to claim 9, wherein disinfecting the ventilated air

comprises mixing the air with ozone and/or a disinfection liquid and/or exposing the air to FUV and/or UVC light.

1 1 . The method of reducing the microbial pressure in an animal farm production facility according to any of claims 1 -8 including the method of any of claims 9- 10.

12. The method according to any one of the preceding claims, wherein the

disinfection liquid is selected from a group consisting of peracetic acid (C2H4O3), chloride (Cl), chloridedioxide (CIO2), hydrogenperoxide (H2O2), ozone (O3) and Quaternary ammonium compounds (NFV) or combinations thereof.

13. The method according to any one of the preceding claims, whereby the

disinfection liquid is provided in an aqueous solution, such as in a concentration of 5-50%, in particular approx. 10%.

14. The method according to any one of the preceding claims, further comprising a step of filtering the incoming air, such as through a coarse filter and/or a micro filter.

15. The method according to any one of the preceding claims, further comprising a step of recirculating the air from the animal farm production facility into the incoming air 16. The method according to any one of the preceding claims, whereby FUV and/or

UVC light is provided by at least one second lamp, preferably in the form of a high-pressure lamp also capable of emitting light with wavelengths in the ranges of:

a. 122-200 nm (FUV), and/or

b. 100-280 nm (UVC).

17. The method according to any one of the preceding claims, where the at least one second lamp is located in the ventilation system.

18. A device for reducing the microbial pressure in an animal farm production

facility, said device comprising

- at least one first lamp emitting polychromatic light with both visible light and UV light in the categories UV-B and optionally UVA, and

- a spray system adapted for spraying a disinfection liquid.

19. A device according to claim 18, wherein the at least one first lamp is a high- pressure lamp emitting light with wavelengths in the ranges of

285-315 nm with a maximum intensity of 297-303 nm, such as 296-297 nm and 302-303 nm, preferably comprising light of 296 nm, 297 nm, 302 nm and 303 nm;

400-430 nm with a maximum intensity of approx. 405 nm; and

- 380-750 nm with a colour temperature of 4500°-6500° K.

20. A device according to claim 18 or 19, wherein the at least one first lamp is

provided with a sharp edge filter glass where wavelengths below 285 nm are filtered from the light emitted from the lamp.

21. A device according to any one of claims 18 to 20, wherein the at least one first lamp has an effect of 50 W, 80 W, 125 W, 250 W, 400 W, 700 W, 1000 W or more.

22. A device according to any one of claims 18 to 21 , wherein the device further comprises a control system adapted for managing a predetermined spraying time and a predetermined light exposure time, such as ensuring the

predetermined light exposure time period is up to 16 hours per day, and preferably the predetermined spraying time period is approx one minute per day, or such that the predetermined spraying time period is divided into intervals during the predetermined light exposure time period.

23. A device according to any one of claims 18-22, the device further comprises at least one second lamp emitting FUV and/or UVC light.

24. A device according to any one of claims 18-23, wherein the at least one second lamp emits light with wavelengths in the ranges of

- 122-200 nm (FUV); and/or

- 100-280 nm (UVC).

25. A device according to any one of claims 18-24, wherein the at least one second lamp has an effect of 400 W, 800 W, 5kW, 10 kW, 30 kW or more.

26. A device according to any one of claims 18-25, wherein the device is configured to mix incoming air with the disinfection liquid and/or ozone and expose the mixed air to FUV and/or UVC light.

27. A device according to any one of claims 18-26, the device further comprises a coarse filter and/or a microfilter.

28. A device according to any one of claims 18-27, the device further capable of recirculating the air from the animal farm production facility into the incoming air

29. A ventilating system for an animal farm production facility, wherein the system comprises at least one compartment configured for disinfecting ventilated air by mixing with ozone and/or chemicals and subsequently illuminating said air with UV light.

30. The ventilation system according to claim 29, wherein the illumination of the air is provided by at least one second lamp .

31 . The ventilation system according to any one of claims 29-30, wherein the at least one second lamp emits light with wavelengths in the ranges of

- 100-122 nm (FUV); and

- 100-280 nm (UVC).

32. The ventilation system according to any one of claims 29-31 , wherein the

system further comprises

- at least one generator for providing ozone.

33. The ventilation system according to any one of claims 29-32, wherein the

system further comprises

- at least one container for providing a disinfection liquid.

34. The ventilation system according to any one of claims 29-33, wherein the

system further comprises

at least one inlet for providing air from the milieu outside of the animal farm production facility

- at least one filtering device for removing particles from the air.

- at least one outlet for ventilating the disinfected air into the animal farm production facility

- at least one second inlet for recirculating air from the animal farm

production facility

35. The ventilation system according to any one of claims 29-34, wherein the at least one filtering device for removing particles from the air comprises a coarse filter and/or a microfilter.

36. A system for reducing the microbial pressure in an animal farm production facility comprising the device of any of claims 18-29 and the ventilation system according to any of claims 29-35.

37. An animal farm production facility comprising a device for reducing the microbial pressure in the animal farm production facility according to any one of the claims 18-29 and/or a ventilation system according to any of claims 29-35 and optionally configured for carrying out the method according to any one of claims

1 to 17.

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FIG. 2

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