WO2004080190A1

WO2004080190A1 - Method and device for hygiene treatment of eggs

Info

Publication number: WO2004080190A1
Application number: PCT/SE2004/000241
Authority: WO
Inventors: Håkan ANDERSSON
Original assignee: Andersson Hakan
Priority date: 2003-03-10
Filing date: 2004-02-24
Publication date: 2004-09-23
Also published as: SE0300661D0; SE0300661L

Abstract

The invention relates to a method and device for treating eggs with shells to remove contaminants from a surface of the eggs and to reduce microorganisms of the eggs before packaging thereof, comprising a washing device (10) for cleaning the exterior of the eggs and for exposing microorganisms on the shell of the eggs by means of a cleaning solution, and an illumination device (12) illuminating the surface of the eggs and the exposed microorganisms present on said surface with UV light.

Description

METHOD AND DEVICE FOR HYGIENE TREATMENT OF EGGS

TECHNICAL FIELD OF THE INVENTION The present invention relates to a device and method for treating food.

In particular the present invention relates to a device and method for treating eggs to reduce microorganisms on the eggs and remove other contaminants from the shell of the eggs. This type of devices and methods are used in food industry to clean the shell of eggs, such as hen's eggs, from contami- nants before packaging thereof in packages, such as egg cartons and similar.

STATE OF THE ART It is well known that contaminants can be removed from a surface or a shell of eggs through different washing methods. Further, a plurality of devices and methods for washing eggs are disclosed in the prior art. One type of such devices and methods comprise washing eggs with water, different solutions, additives or chemicals or different combinations thereof. One such type of method is disclosed in US5756139. US5756139 discloses a method for washing and disinfecting eggs by spraying the eggs with a non-ionactive surfactant, an amphoteric surfactant and a peracid solution. Further, if is disclosed that an antifoam agent can be used when the solutions are sprayed onto the eggs. JP2001045904 discloses a device and method for washing eggs, wherein washing of the eggs is performed by means of a basic solution. The basic solution is sprayed onto the eggs under pressure. Further, it is described how the eggs can be sterilized through spraying with an acidic solution after washing. US5753493 discloses a method for washing eggs by means of a solution. The solution is arranged for removing a biofilm (cuticula) of the eggs, wherein underlying microorganisms are exposed. The solution comprises triterpene saponin, or so called saponin, which also has the effect of anti- foam agent. Then, an acidic solution is used for reducing bacteria. Another type of devices for washing eggs is disclosed in US4704755 and US47750229. These documents comprise brushes for removing dirt from eggs. US4704755 discloses a device for washing eggs, comprising a plurality of rotating brushes arranged by a conveyor for transporting eggs, wherein the eggs are washed when passing the brushes. US4750229 discloses a device for washing eggs, comprising a track for transporting eggs. The track is arranged so that the eggs rotate around an axis of the eggs during transport along the track, wherein the eggs are washed when they pass the brushes. Further, a solution can be used in combination with the brushes.

Prior art also include washing eggs by lowering the eggs into stagnant or circulating water.

One problem with this type of prior art devices and methods for treating eggs is that unsufficient cleaning and reduction of microorganisms is ob- tained. This results in reduced keeping qualities of the eggs, which is a substantial drawback when handling perishables such as eggs. Additionally, washing water can penetrate into the eggs when they are lowered into the washing water.

Further one problem with this type of prior art devices and methods is that they demand a greater effort. This results in a time-consuming and costly process.

One drawback with such prior art devices and methods is that the content of the eggs can be negatively affected when treated, wherein the quality of the eggs can become impaired. At worst the eggs can be useless as food.

SUMMARY OF THE INVENTION

One object of the invention is to overcome the above mentioned drawbacks and problems with prior art devices and methods for treating eggs and lower the treatment costs. Further, different portions of the device according to the invention are not contaminated by dirty eggs. For example, contamination of clean sections in a packaging plant by dirty eggs is pre- vented. The present invention provides a simple and effective method and device for hygiene treatment of eggs with shells to remove contaminants from a surface of the eggs and to reduce microorganisms of the eggs before packaging in packages, such as egg cartons. Hence, the invention provides an efficient reduction of microorganisms, which results in a prolongation of the keeping qualities without affecting the content of the eggs and without impairing the quality thereof. In addition the invention provides a fast and cost efficient hygiene treatment, which results in sanitized eggs. This is accomplished by the invention comprising the features of claim 1 and 14. Ac- cording to one embodiment of the present invention washing water and air is prevented from penetrating into the eggs.

Production of eggs takes place in animal stables, which hygiene is far from the requirements for food. All eggs are contaminated during production in the animal stables. Most eggs appears to be clean but are contaminated with poultry urine, dust, feed remains, bacteria, virus, contaminants and infectious agents from parasites and similar and have, directly or indirectly, been into contact with manure and waste products. Infection by some invasive salmonella types can be prevented by vaccination of the hens but similar measures are not taken towards all other types of contaminants and con- taminating substances, which can be harmful as well. These elements of risk can be prevented and the quality of the eggs can be raised by means of the invention. The invention can also be advantageous in connection with breeding eggs due to that the reduction of microbiological compounds increases the incubation and reduces the mortality of the day-old chickens. The method according to the invention can comprise the step of cooling and storing the eggs at about 10-12°C from laying at an egg producing plant up to handling on an egg packaging plant. The premises on the egg packaging plant are divided into separated sections. A first section is a raw material storage where the eggs are stored at about 10-12°C and where ap- plicators for packaging machines are positioned. A second section is a cleaning and drying section where conveyors, such as conveying belts and similar, and other equipment are washed and disinfected and treated with UV light, such as UV-C light, continuously during operation. In addition, the premises are disinfected by means of UV light during the night, for example, and are cleaned daily in a conventional manner. A third section is a clean food handling section where sorting and packaging takes place and a fourth section is a finished product storage having a temperature of about 10-12°C. The eggs are preliminarily sorted on a conveyor belt immediately before cleaning or washing, wherein visibly dirty or leaking eggs are sorted out. Visibly clean eggs are continuously cleaned or washed through overspraying and rotation under pressure, for example during half a minute. The water can have a pH of about 10-11 and can comprise disinfectants. Preferably, incom- ing water is of drinking water quality and can be exchanged when required. The content of bacteria in the washing water must never exceed a predetermined highest level. After washing the eggs can be rinsed with clean running water having an alcohol based disinfectant. The process takes place under constant supervision/control of the volumes of water, temperature for wash and rinsing, times, conductivity in the water (pH value) etc. Measurements are made continuously and are registered through data processing, for example every tenth second. Drying can be performed by means of clean air under high pressure, after which the air is evacuated immediately. Then, the eggs are sorted manually by means of transillumination. Then, the eggs are illuminated with UV light during about ten seconds and a crack egg detector sorts out all fine cracked or damaged eggs. Immediately thereafter the sanitized eggs are marked to enable tracking thereof and they are automatically packaged. The transport packages are stored in a finished product storage at about 10-12°C. The chain of storing in a controlled temperature continues through transportation and distribution.

Hence, the present invention can comprise a conventional conveyor belt or similar for transporting the eggs to and/or through at least a washing device. For example, the washing device comprises a plurality of nozzles or sprinklers for washing or spraying the eggs. The nozzles can be connected with a tap water source and/or a container with a solution for cleaning or washing, such as a cleaning solution, grease and dirt solving solution or similar. Hence, the nozzles can be arranged so that the eggs can be washed or sprayed with water and/or a solution for removing dirt from a surface of the eggs or an outer surface of the shells of the eggs. Detergents can be added to the water or the solution or can be applied on the eggs in any other conventional manner to facilitate removal of contaminants from the eggs. Alter- natively, the solution comprises water and detergents. The washing device can also comprise brushes for brushing the eggs, wherein additional cleaning of the eggs is provided. The brushes can be arranged so that brushing and spraying is performed simultaneously or separately. For example, the eggs are cleaned or washed for about 20-60 seconds at a water temperature between 35 and 45°C or between 38 and 42°C. According to one embodiment of the present invention the eggs are cleaned for about 30 seconds at a water temperature of about 40°C. The detergent can be a conventional detergent, which may comprise an antifoam agent. For example, the detergent is basic, wherein washing is performed at a pH about 11. For example, cleaning is performed at a pH about 11.5. After cleaning the eggs by means of water and detergent, possibly while brushing simultaneously, the eggs can be rinsed with water through the nozzles of the washing device to remove detergent remains. The eggs can be rinsed for about 2-7 seconds at a water temperature of about 50°C. For example, the eggs are rinsed for about 5 seconds at a water temperature of about 50°C. Hence, the temperature is raised during the treatment, wherein penetration of water and air into the eggs is prevented due to that air present inside the eggs expands and forms an overpressure in the eggs. Consequently, contaminating material is prevented from penetrating the eggs. The device can comprise means for rais- ing the temperature along at least one portion of the device to reduce penetration of water and air into the eggs during cleaning and rinsing. For example, the temperature is raised about 10°C between cleaning and rinsing of the eggs. Alternatively, the eggs can be washed or sprayed in a first washing device, brushed in a second washing device and rinsed in a third washing device. The washing device or devices can further comprise rotating means for rotating the eggs during the cleaning process and the rinsing process. For example, the rotating means are arranged on the conveyor belt. In addition, the invention can comprise a drying device for drying the eggs after the cleaning process. For example, the drying device is arranged in the washing device, wherein drying can be performed after washing and rinsing of the eggs. Alternatively, the drying device is arranged after the washing device and is connected therewith by means of a conveyor belt. For example, the drying device comprises an air-knife or similar for drying the eggs. For example, the eggs are dried for about 5 seconds, after which they can be transported onward by means of conveyor belts or similar.

The present invention also comprises an illumination device, to which the eggs are transported after the cleaning process and the drying process by means of the conveyor belt. The illumination device is arranged to reduce the quantity of microorganisms on the eggs and, in consequence thereof, improve their quality and prolong their keeping qualities. The illumination device can be arranged for illuminating the eggs with ultraviolet light, UV light, such as UV-C light, wherein the light somewhat penetrates the eggs to reduce microorganisms. The UV-C light results in a destruction of microorganisms and eggs from bacteria by breaking down DNA. Due to the cleaning process according to the invention contaminants have been removed from the outer surface of the shell. Hence, the eggs are exposed for additional treatment with light, which penetrates into the eggs a short distance and efficiently reduces microorganisms without affecting the interior of the eggs negatively. Illuminating the eggs with UV-C light is very efficient when it is performed immediately after the cleaning process. For example, the eggs are illuminated in the illumination device for about 10 seconds, after which the eggs are transported onwards for packaging. The cleaning device, conveyor belts and other parts of the invention in contact with the eggs are washed when the eggs are washed or are illuminated when the eggs are illuminated.

Further characteristics of and advantages with the present invention are made clear by the description below, attached drawings and dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with the aid of embodiment examples and with reference to the accompanying drawings, in which

Fig. 1 is a schematic figure illustrating different portions of the device according to the invention, and

Fig. 2 is a schematic diagram illustrating the method according to the invention.

DESCRIPTION

In reference to Fig. 1 and Fig. 2 the device and method according to the invention is schematically illustrated. According to the embodiment shown the device for treating eggs having shells according to the invention comprises at least one washing device 10 for cleaning an outer surface of the shells of the eggs, a drying device 11 for drying the eggs and an illumination device 12 for additional reduction of microorganisms on the eggs. The washing device 10 is connected to at least one conveyor belt 13 or similar for conveying eggs to the washing device 10. For example, the washing device 10, the drying device 11 and the illumination device 12 are interconnected through the conveyor belt 13, wherein eggs also can be conveyed through the washing device 10 and onwards to the drying device 11 , through the dry- ing device 11 and onwards to the illumination device 12 and through the illumination device 12 and onwards for packaging or similar. Hence, the conveyor belt 12 runs through the washing device 10, the drying device 11 and the illumination device 12. Alternatively, a plurality of conveyor belts are interconnected for conveying eggs between and through the washing device 10, drying device 11 and illumination device, respectively. For example, the conveyor belt 13 is arranged conventionally.

For example, visibly dirty eggs are sorted out before cleaning to avoid fouling of the device. Also cracked or leaking eggs and eggs having visible cracks are sorted out before cleaning. Consequently, a more clean device is obtained, wherein contamination and fouling by eggs inside the device is reduced.

The washing device 10 comprises a nozzle 14 or similar connected to a tap water source and/or a container so that the eggs can be sprayed or showered with water and/or a cleaning solution for removing contaminants from the shells and reduce microorganisms on the eggs. Alternatively, the washing device 10 comprises a plurality of nozzles 14. For example, the nozzles 14 are arranged conventionally and are connected to the tap water source or the container by means of pipes or similar so that water and solu- tion can be sprayed onto the eggs for cleaning or washing. Detergent and other chemicals can be added to the water or solution or can be applied onto the eggs in any other conventional way to facilitate removal of contaminants from the eggs. Alternatively, the solution comprises water and detergent, wherein the detergent can be added to the water conventionally. For exam- pie, the detergent is a conventional detergent comprising an antifoam agent. For example, the detergent is basic or the cleaning solution is basic, wherein cleaning is performed at a pH of about 11.

For example, the washing device 10 comprises brushes 15 for brushing the eggs, wherein additional cleaning of the eggs is provided. The brushes 15 are, for example, arranged conventionally. The brushes 15 are arranged so that brushing is obtained simultaneously with spraying or separately, wherein the eggs are sprayed and brushed intermittently. For example, the eggs are cleaned for about 20-45 seconds at a water temperature of about 40°C. For example, the eggs are cleaned for about 30 seconds at a water temperature of about 38-42°C. After washing the eggs by means of water and chemicals, such as a detergent, possibly in combination with brushing, the eggs are rinsed with water by means of the nozzles 14 of the washing device 10 to remove detergent remains, for example. The rinsing is, for example, performed at a higher temperature than the cleaning so that the temperature is increasing through at least a portion of the device, wherein air present inside the eggs expand and an overpressure inside the eggs is obtained to prevent water, air and other contaminating materials to penetrate into the egg. The eggs are, for example, rinsed for about 2-7 seconds at a water temperature of about 50°C. For example, the eggs are rinsed for about 5 seconds at a water temperature of about 48-52°C. Alternatively, the eggs are showered or sprayed in a first washing device, brushed in a second washing device and rinsed in a third washing device. The washing device 10 or the washing devices also comprise one or more rotating means 16 for rotating the eggs during the cleaning process and the rinsing process. The rotating means 16 is arranged to enable cleaning and rinsing around the entirety of each egg. For example, the rotating means 16 is arranged conventionally and is not described any further. Alter- natively, the conveyor belt comprises rotating means, wherein the eggs are rotated during transport.

The device according to the present invention also comprises the drying device 11 for drying the eggs after the cleaning process. For example, the drying device 11 is arranged inside the washing device 10, wherein dry- ing can be performed after cleaning and rinsing the eggs. Alternatively, the drying device 11 is arranged after the washing device 10 and is connected therewith by means of the conveyor belt 13. For example, the drying device 11 comprises an air-knife 17 or similar for drying the eggs. For example, the eggs are dried for about 5 seconds, after which they can be conveyed on- wards by means of the conveyor belt 13 or similar transporting devices. For example, also the drying device 11 comprises rotating means to rotate the eggs so that drying can be performed around the whole of each egg. Alternatively, drying is performed by clean air under high pressure, wherein the eggs dry in a few seconds. For example, the eggs are dried so that they are dry for subsequent illumination in the illumination device 12.

The present invention comprises the illumination device 12, to which the eggs are conveyed after the cleaning process and the drying process by means of the conveyor belt 13. The illumination device 12 is arranged for reducing the quantity of microorganisms on the eggs and, consequently, pro- long their keeping qualities and avoid the risk of cross contamination with other food. The illumination device 12 is arranged for illuminating the eggs with ultraviolet light, UV light, such as UV-C light, wherein the light somewhat penetrates the egg to reduce microorganisms. For example, the illumination device comprises lamp tubes or lamps producing UV light, such as UV lamps 18 or UV lamp tubes. Due to the cleaning process according to the invention contaminats have been removed from the outer surface of the shell. Hence, the light penetrates into the egg a short distance to reduce microorganisms efficiently without affecting the interior of the eggs negatively. For example, the eggs are illuminated with UV light having a wavelength and intensity so that the UV light at least partially penetrates into the shell of the eggs without passing the shell. Hence, remaining microorganisms on the surface of the eggs are exposed due to the removal of contaminants by the cleaning proc- ess, wherein additional reduction of microorganisms can be performed. Additional reduction of microorganisms is performed by illuminating the eggs with UV light after the cleaning process, wherein the UV light is brought to penetrate the eggs a short distance for reduction of microorganisms without affecting the interior of the eggs. For example, the eggs are illuminated in the illumination device 12 for about 10 seconds or between 5 and 15 seconds, after which the eggs sanitized due to cleaning and illumination are conveyed onwards for packaging, for example.

Additionally, the illumination device 12 comprises one or more rotating means, which are described in reference to the the washing device 10, to rotate the eggs during the illumination process. The rotating means are arranged so that illumination can be performed around the entirety of each egg. As described above the conveying belt, for example, comprises the rotating means.

The washing device, conveying belts and other parts of the device contacting the eggs are washed when the eggs are cleaned or are illuminated when the eggs are illuminated, wherein contamination of the eggs is avoided.

Claims

1. A method for treating eggs with shells to remove contaminants from a surface of the eggs and to reduce microorganisms on the eggs before packaging thereof, c h a ra c t e ris e d by cleaning the exterior of the eggs with a cleaning solution in a device to expose microorganisms on the shell of the eggs and thereafter illuminating the surface of the eggs and the exposed microorganisms present on said surface with UV light in said device.

2. A method according to claim 1 , wherein the device continuously is cleaned by washing and illumination with UV light.

3. A method according to claim 1, wherein the eggs are washed with water and a detergent is applied on the eggs while the eggs simultaneously are brushed to remove contaminants on the surface of the eggs.

4. A method according to claim 1 , wherein the eggs are cleaned at a temperature of about 40°C.

5. A method according to claim 1 , wherein cleaning is performed at a pH of about 11.

6. A method according to claim 1 , wherein the eggs are rinsed with water after cleaning to remove detergent remains.

7. A method according to claim 6, wherein the eggs are rinsed at a temperature of about 50°C.

8. A method according to claim 1 , wherein the eggs are dried in a drying device by means of air before illumination with UV light.

9. A method according to claim 1 , wherein the eggs are illuminated with UV- C light

10. A method according to claim 9, wherein the eggs are illuminated for 5-15 seconds.

11 . A method according to claim 1 , wherein the eggs are transported through the device by means of a conveyor.

1? . A method according to claim 1 , wherein the temperature is increased during the treatment to prevent contaminating material from penetrating into the eggs.

13.^' A device for treating eggs with shells to remove contaminants from a surface of the eggs and to reduce microorganisms of the eggs before packaging thereof, c h a ra c t e ri s e d by that the device comprises a washing device (10) for cleaning the exterior of the eggs and for exposing microorganisms on the shell of the eggs by means of a cleaning solution, and that the device comprises an illumination device (12) illuminating the surface of the eggs and the exposed microorganisms present on said surface with UV light.

^ A device according to claim 14, wherein the washing device (10) comprises nozzles (14) for washing the eggs with the cleaning solution.

15. A device according to claim 14, wherein the washing device (10) comprises brushes (15) for brushing the eggs.

16. A device according to claim 14, wherein the device comprises rotating means (16) for rotating the eggs so that cleaning around the entire of each egg can be performed.

17. A device according to claim 14, wherein the device comprises a drying device (11) for drying the eggs before illumination.

18. A device according to claim 14, wherein the illumination device (12) comprises UV lamps for illuminating the eggs by means of UV-C light.