WO1999038384A1

WO1999038384A1 - Device and method for extirpation of the neuroskeletal complex with little risk of infection at animal slaughter

Info

Publication number: WO1999038384A1
Application number: PCT/SE1999/000059
Authority: WO
Inventors: Ivan Stefanov; Alexander Stefanov
Original assignee: Ais Medical Research, Inc.
Priority date: 1998-01-16
Filing date: 1999-01-18
Publication date: 1999-08-05
Also published as: SE9800098D0; AU2304599A; SE9800098L; SE509911C2

Abstract

The invention relates to a device for extirpation of the neuroskeleton complex in animal slaughter, which reduces the risk of contamination from the tissue of the central nervous system. The device comprises a cutting unit (10), which has two symmetrical knives (13, 14), each one comprising a mainly semicircular segment (15) and a straight segment (16). Said knives (13, 14) are guided through a rotating contact device (19) to trace the front part from the tail to the upper neck. The distance from the knives (13, 14) is regulated via a sensor system (20) so that they trace the protuberance of the dorsal vertebrae. The knives are in contact (22) with a power generator having a stroke impact (21) and the complete cutting unit (10) is arranged on a carriage which may be driven along the spinal column. The carcass can be arranged on a support unit comprising two plates arranged at an angle at a ditance from each other. A protective sleeve is drawn after the knives and isolates the spinal column from the meat.

Description

DEVICE AND METHOD FOR EXΗRPATION OF THE NEUROSKELETAL COMPLEX WITH LITTLE RISK OF INFECTION AT ANIMAL SLAUGHTER

TECHNICAL FIELD

The present invention relates to a device and method for extirpation in animal slaughter and more specifically to an extirpation device and method, which reduces the risk of infection from the neuroskeleton complex.

STATE OF THE ART

During the cutting up of larger animals, a symmetrical division of the carcass is made by sawing the spinal column in half. This is a convenient solution, which further optimises subsequent technical procedures, because lesser amounts of meat need to be handled while at the same time the meat bulk surface is exposed better. This method has, however, serious drawbacks. Among other things, the opening of the spinal column entails risks for spreading potential infections from tissue from the central nervous system to other tissue in the animal carcass. Such sawing also often involves time consuming manual work in order to separate the meat around the spinal column from the bones.

The Danish patent specifications DK 167044 Bl and DK 168554 Bl, describe devices used in slaughter where parts of the meat tissue are released from the spinal column by mechanical means. Thus, these devices may be of assistance for facilitating this step during the butchering process. In these descriptions, however, it is stated that the step shown should be followed by a partition of the spinal column and sawing off of the ribs, i.e. according to the traditional principle, with risk for infection. Thus, these devices do not solve the most serious problems connected with current butchering technique.

To avoid the risk of infection from the neuroskeleton complex, a sound knowledge of anatomy is required. Since the average slaughterhouse worker cannot be expected to have such knowledge, the consequences of the human factor must be reduced. Furthermore, a demand from the meat industry is that meat losses must not increase. One aspect of the present invention is a device and method which separates the spinal column and the head from the body with minimal risk of contamination from the brain tissue to other parts of the body, and at the same time minimises meat losses. Another aspect of the invention is to achieve a standardising of the procedure, reduce the human factor and achieve a higher level of efficiency than what currently can be achieved with known technique. One further aspect of the invention is that it may be included in existing butchering routines, both technically and with regard to time consumption.

DESCRIPTION OF THE INVENTION

The aspects stated above are achieved by means of a device and method according to the independent claims. The complete neuroskeleton complex, i.e. the spinal column and head containing the central nerve tissue, is removed intact from the animal carcass by means of a knife arrangement, formed according to the transversal profile of the spinal column, which is driven along the whole length of the spinal column, from the join of the spinal column at the tail up to the head. The front parts of the knives are preferably driven along the frontal area of the vertebrae with the aid of a contact-device, and the distance between the back parts of the knives are regulated so as to follow the dorsal protuberance of the vertebrae. A preferred embodiment comprises an impact generator and a protective sleeve, which encases the neuroskeleton complex after it is cut out. Preferably, a supporting means is employed, consisting of two long, narrow plates, to secure the carcass during the cutting out process.

DESCRIPTION OF THE DRAWINGS

One preferred and exemplifying embodiment of the present invention will now be described below in detail with reference to the accompanying drawings, which illustrate:

Figure 1 a drawing of the shape of the spinal column;

Figure 2 an embodiment of a cutting unit according to the present invention;

Figure 3 an embodiment of a support unit according to the present invention; and

Figure 4 a carcass immobilised on a support unit according to the present invention. ILLUSTRATIVE EMBODIMENTS

Potential risk of transferring infectious matter from the tissue from the central nervous system (i.e. spinal marrow and brain) during the cutting up of a carcass would be reduced if the spinal column and the head could be separated from the body without the nerve tissue coming into contact with the meat. The central nervous system is encased in three membranes. Furthermore, the brain and the spinal marrow are protected by substantial bone protection, i.e. the vertebrae and the head. If the complete neuroskeleton complex could be removed intact from the body of the animal this would mean reduced risk of transferring infectious matter from the brain tissue to the meat.

Among diseases that can be transmitted via the central nervous system, and here mainly from cattle, the now well known BSE can be mentioned. Currently, researchers have been successful in experimentally infecting animals solely by injection of infected brain tissue. The logical conclusion for reducing risk to the consumer is to introduce a method of slaughter where the meat, predestined for human consumption, never comes into contact with the tissue from the central nervous system and fluid from the spinal marrow. This is true especially during the present epidemic situation. The components from the central nervous system thus, should be removed during the slaughtering procedure without any risk of contact with the remaining meat bulk.

The development of such a method is, to a large degree, based on the fact that the central nervous system, see Figure 1, anatomically has clearly defined limits. The tissue of the brain and the spinal marrow 5, 6, 7 are very well demarcated from the surroundings by the so-called soft brain membrane (pia mater) 1. The spinal marrow's fluid (liquor) 2 comes in direct contact with pia mater 1. The liquor 2 is well demarcated from the surroundings by means of the so-called spider net membrane (arachnoidea) 3, which has a well encased "package", for both the liquor 2 and the brain tissue. The arachnoidea 3 comes into contact with the hard brain membrane (dura mater) 4, which consists of a compact "package" for the brain and spinal marrow with pia mater 1, liquor 2 and arachnoidea 3. All the cranial and spinal nerves and the central nervous system lie inside the extremely strong connective tissue package. Dura mater 4 defines the outer limits of the central nervous system and at the same time forms the anatomical line between the central nervous system and the peripheral nervous system.

Outside dura mater 4, bone and connective tissue structures 9 are situated (the spinal column and the head), which mechanically protect the central nervous system. The central nervous system communicates with the remaining body systems by means of a large number of bone openings 8 in the brain and the spinal column, respectively, where nerves and blood vessels pass. The communicating openings 8 are situated outside the boundaries of the central nervous system, marked by dura mater 4. The conclusion is that external boundaries of the central nervous system are anatomically well defined, and this is the basis of the present concept for reducing risk of infection by means of separating the central nervous system together with the protective structures belonging thereto - the so called neuroskeleton complex - from the carcass. The physiological boundaries of the central nervous system are also well defined. Through said so-called blood liquor barrier, only fairly low molecular substances pass through, as compared with the prion protein (PrP), which causes BSE.

The principle of optimal separation of the musculoskeletal complex from the body is a compromised solution, whereby the separating shall take place outside the boundaries of the central nervous system, but not too far away, since this would mean larger and unnecessary meat losses. Furthermore, the importance of the human factor must be taken into account and minimised, i.e. the method shall not be dependent upon the skill of the butcher. The spinal column has a relatively complicated shape, see Figure 1, as well as firm connections with other body parts (ribs and pelvic arch, for example). This means that the knife arrangement that is used must be sufficiently powerful to also separate such parts.

Other anatomical properties can instead render ways for solving problems. The bilateral symmetry of the spinal column and the well defined dorsal and inner contours, the proportions between the spinal bone-mass and the para-spinal meat bulk and their connection are applicable aspects. (By the term - the front contour - the area turned in towards the intestines is meant). Other interesting aspects are the meat connections to the tail and the head, which have anatomical continuity. The spinal column's bilateral symmetry has implied that the cutting tool, which shall separate the meat, according to the present invention, also is built up symmetrically. The front contour of the spinal column is formed by the vertebrae and has a crooked line. This complicates the separating process. On the other hand, the back contour of the spinal column is easily accessible during the slaughter procedure and does not have one external bone connection along its entire extension. This contour is employed in the present invention to guide the cutting tool. The spinal column's dorsal contour is formed by the dorsal protrusion of the vertebrae, which forms a straight line. This protrusion is used in the present invention as points for defining the centre line. The centre line is important for a tool which functions symmetrically.

The straight shape of the spinal column is also used as a support for the cutting tool. The proportion between the spinal column's volume and the para- vertebral meat bulk, shows a much larger meat volume than that of the bone structures, i.e. on a successful separation of the mus- culoskeletal complex, the meat losses should be minimal.

The connection of the spinal column with the tail is used in the present invention as a convenient starting point for the separation, because the tail has the same construction as the spinal column and the cutting tool can be orientated in relation to the spinal column when the separation begins.

The connection to the pelvic arch, which is substantial and requires considerable power to cut through, is clearly defined both on the inside and the outside of the carcass. The connections to the sternum through the ribs also require considerable power to cut through, but at the same time they are anatomically quite visible. The connection to the head is substantial, but this is without consequence for the present invention, since the head shall be removed together with the spinal column.

In the following description it is assumed that one starts with an animal hanging by the back hoofs without hide, and which has already been eviscerated (i.e. the inner organs have already been removed). Figure 2 illustrates an exemplifying embodiment of a knife arrangement according to the present invention. A cutting unit 10 comprises a main body 11 and a knife arrangement 12, which in its turn comprises symmetrically arranged cutting elements or knives 13, 14. The shape of these knives are adapted to form a half-contour of a cross section of the carcass's spinal column, i.e. having a convex segment 15 and a mainly a straight segment 16. In the simplified form, illustrated in Figure 1, the front segment of the knives is in the shape of a semicircle 15. The knife arrangement 12, thereby can easily be adapted to the transversal pro file of the spinal column. The knives, and particularly the straight segment 16, is longer than the maximum distance between the front and back contours of the spinal column.

The front ends 17, 18, of the knives, which are adapted to the front area of the vertebrae, are connected by means of a contact device 19, which preferably comprises a wheel. The contact device 19 may, thus, easily be guided along the front area of the vertebrae, whereby the knives 13, 14, follow the contact device 19, and in this way regulate the distance of the curving shapes of the vertebrae, i.e. regulate the distance between the contact device 19 and the cutting unit's main body, 11. The position of the knives on the front part of the spinal column can be guided by a worker by means of a remote control system (not shown) and during visual control from the open forward part of the animal. Alternatively, the contact device can continuously be pressed backwards against the spinal column by means of a spring member secured on the main body of the cutting unit.

The distance between the straight segments 16 of the two symmetrical knives may be controlled. A mechanical sensor (not shown), which follows the vertebrae's dorsal protrusion, senses the variation in distance, and via a regulator 20, controls the distance between the straight segment 16 of the knives, so that the knives move as near as possible to the protrusion. This means minimal meat losses. Suitable mechanical sensors are generally currently available, and may be of any type, and the detailed shape of such sensor or distance controller 20 for the knives is not included in the idea of the present invention, therefore this is not described in more detail.

Since the cutting unit 10 should be able to cut through substantial bone parts, a powerful cutting power must be transferred to the knives. Figure 2 illustrates a power generator 21, which starts a powerful impact. This power generator 21 is arranged jointly with the cutting unit's main body and performs its impact to the knife arrangement by means of a connection 22. These impacts drive the knife arrangement 12 through the bone structures which appear along the length of the spinal column, such as the pelvic arch or the ribs. To allow the striking power to function effectively, it is necessary for the cutting unit 10 and the carcass to be arranged in relation to each other, which in the preferred embodiment is provided with the aid of a support system, which is described more in detail below.

In a preferred embodiment there is furthermore a protective sleeve arranged on the knife arrangement. The protective sleeve comprises mainly of a tube-shaped flexible plastic film, which suitably can be arranged at the back edges 23, 24 of the knives in the direction of cutting, and which is drawn along over the separated parts simultaneously as the knives are moved along the spinal column. The neuroskeleton complex thereby can be encased immediately, which further reduces the risks of spreading infection.

As has been mentioned above, the carcass of the animal must be immobilised before the separation of the neuroskeleton complex. With the aim of saving time and reducing the human factor risk, which can lead to mistakes and be a hazard to safety, the carcass is applied to a standardised support system. Such a support system 50 is illustrated in Figure 3. The support comprises two elongated plates 30, 31, arranged parallel in the longitudinal direction. The surfaces of the plates 30, 31, are arranged at an angle to each other, and are symmetrical in relation to the vertical line. Said angle is adjustable by means of hydraulic cylinders or a screw system arranged on the support system (not shown). The plates 30, 31 are longer than the animal's spinal column. The edges 32, 33, of the plates turned towards each other are not in contact with each other, but are placed at a distance from each other and thereby form a gap 34. The width of this gap 34 is also adjustable, with the aid of hydraulic cylinders or a screw system arranged on the support system, and is preferably 10 to 20 cm. The regulating system is easily implemented by state of the art technology and is not described in detail.

In the longitudinal direction, the plates are angled in relation to the vertical line, preferably at about 45°. Even this angle may be adjusted with the aid of a mechanical adjusting device arranged on the support system. When a carcass is applied on its back onto the support plates its 8

body weight will guarantee an immobilisation in relation to the support construction. At the same time, the body is pressed against the plates, and thus the spinal column's back protuberance sticks out through the gap, which is formed between the support plates at the same time as the back is straightened out.

On the front area of the support plates, an immobilising system is arranged (cf Figure 4 at 41), the purpose of which is to fix the carcass against the support in an aim to avoid the local distortions which would counteract the effect of the knives.

Mounted near to and parallel with the edges of the plates facing each other there are two rails 35, 36. These rails guide a carriage system 37, on which the cutting unit 10 is arranged. The idea is that the cutting unit 10 shall move with the carriage and rails 35, 36, from the tail to the head. The carriage is driven by a drive unit, which, for example, may make use of a cog rack system to drive the carriage forward. Other drive mechanisms, such as hydraulic systems or the like may also be used.

At the highest level on the support system a powerful pressing device 38 is provided, by means of which the tail of the animal is secured and drawn upwards, to create tension, which subsequently acts in opposite direction to the impact power of the knives thereby making the cutting more effective, and otherwise would be reduced by local tissue distortions.

The entire support system is mounted on powerful supports 39 on a moveable platform 40.

The use of the device according to the present invention is as follows, with reference to Figure, 4. First, the hide and intestines are removed from an animal 42. This means that the front area of the spinal column in the belly, the pelvic arch, the thoracic area and the neck are visible for inspection. The animal is hung by the back hooves, and the support system, that is securely mounted on a platform 40, approaches the hanging creature 42 from the rear. The two support plates 30, 31, are adjusted from the back of the head to the tail and the platform 40 is pushed forward until the animal 42 is half-lying on its back on the angled plates 30, 31, (preferably at 45°). The moveable carriage 37, on which the cutting unit shall be arranged, and which moves along the rails 35, 36, abutting the edges of the plates, is placed at the highest level possible, a good distance above the transition between the back and the tail. The cutting unit 10, comprising contact device and knife arrangement, is mounted on the mobile carriage so that the knife arrangement surrounds the tail at the transition to the sacrum. The protective sleeve is fastened to the tail at a distance from the start of the tail, and to the cutting unit 10, which then shall drag the protective sleeve after itself, so the separated part of the spinal column is covered continuously by said protection. The tail is secured immediately above the protective plastic in the pressing device of the support system.

The drive unit starts to advance from the tail towards the head, during which the power generator transfers powerful impacts to the knife arrangement. The close contact necessary between the contact device and the front side (i.e. the surface facing the belly) of the spinal column can be guided by a worker, who has visual contact with the front part of the back by the already opened belly, pelvic area and thoracic area. Said guidance allows the cutting means to follow the curving form by continuously adjusting the length of the knives between the curving front part and the straight dorsal contour.

The mechanical sensor, that is placed on the straight segment of the knives, guides the distance between the two symmetrical cutting parts and keeps these as close as possible to the dorsal protuberance.

The cutting unit moves progressively from the tail up to the transition between the neck ridge and the cranium. The cutting unit reaches the transition between the upper cervical vertebra and the head. At said point the neck muscles, which are attached to the head, are the only connection to the already separated neuroskeleton complex. This connection is chopped with a knife, which is inserted alongside the cutting means, with the cutting edge outwardly directed, so as not to damage the integrity of the neuroskeleton complex.

The two symmetrical cutting knives are dismounted from the carriage and pulled forward. By said procedure, the device may be separated from the body halves, and hang freely on the 10

support plates. The neuroskeleton complex now lies on the angled plates and is transported by the device out from the slaughter-line to be demolished.

The above description is intended to be an exemplifying description of the present invention, and shall not limit the scope of protection, which is determined exclusively by the following claims.

Claims

11CLAIMS

1. An extirpation device, comprising a mobile cutting unit (10) comprising two symmetrical, in relation to the centre line, mobile knives (13, 14), each of which is shaped like a cross section of a half-contour of a spinal column of a carcass, characterized by a support unit (50), in that the cutting unit (10) is mounted mobile in relation to the support unit (50), and in that the cutting unit (10) further comprises a contact device (19) arranged between the front edges (17, 18) of the knives, whereby the contact device (19) is brought to follow in close contact the part of the spinal column directed towards the belly, whereby the neuroskeleton complex can be isolated to reduce the risk of infection.

2. Extirpation device according to claim 1, characterized in that each of the knives (13, 14) comprises a semicircular segment (15) and a straight segment (16).

3. Extirpation device according to claims 1 or 2, characterized in that the cutting unit (10) further comprises a spring distance-guiding means (20) and a mechanical sensor, which senses the distance from the knife to the protuberance of the spinal column, whereby the distance between the straight segment of the knife (16) is regulated, depending upon information from the mechanical sensor.

4. Extirpation device according to any of the preceding claims, characterized in that the cutting unit (10) further comprises a protective sleeve for isolating the spinal column, said protective sleeve being fixed to the knives, seen in the direction of cutting, at the back edges (23, 24).

5. Extirpation device according to any of the preceding claims, characterized in that the support unit (50) comprises two elongated plates (30, 31) arranged with their long sides (32, 33) facing each other at a distance, which plates (30, 31) are angled in relation to each other.

6. Extirpation device according to claim 5, characterized in that the plates of the support unit (30, 31) in the longitudinal direction, are angled in relation to the vertical line. 12

7. Extirpation device according to claims 5 or 6, characterized in that a rail system (35, 36) is mounted on the support unit (50) adjacent to and parallel with the edges facing each other (32, 33) of the plates (30, 31) of the support unit, along which rail system (35, 36) the cutting unit (10) is mounted in a transportable manner on a carriage (37).

8. Extirpation device according to claim 7, characterized in that the support unit (50), at the upper segment of the rail system's (35, 36), comprises a fixing device (38) for stretching the tail of the carcass.

9. Method for extirpation comprising eviscerating, flaying and hanging a carcass (42) by the back hoofs, characterized in that it further comprises; immobilising the carcass (42) against a support unit (50); separating the neuroskeleton complex from the tail to the head by means of driving a knife arrangement (12), which is shaped like the transverse section of the spinal column and arranged round the spinal column, along the spinal column by means of a contact device (19) along the front side of the vertebrae; simultaneously with the separation, encasing the neuroskeleton complex in a protective sleeve; and removal of the neuroskeleton complex.

10. Method for extirpation according to claim 9, characterized in that the immobilisation comprises securing the tail of the carcass to the support unit (50).

11. Method for extirpation according to claims 9 or 10, characterized in that the separation further comprises the separation of the pelvis and the ribs.