Patents Form # 5
531
NEW ZEALAND
Patents Act 1953
COMPLETE SPECIFICATION
AFTER PROVISIONAL # DATED:
TITLE:
: 531729/535831
12 March 2004 ANIMAL CLEANING
We, F J RAMSEY LIMITED
Address: Pakatoa Island, Auckland, New Zealand Nationality: A New Zealand company do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement :
1 -
INTELLECTUAL WOPWTY OFFICE OF HI
1 k MAR 2005 ■CE1VED
190094NZ_Cap_20050314J 206JON
FEE CODE 1050
2
Animal cleaning
FIELD OF THE INVENTION
This invention relates to animal cleaning, and in particular but not exclusively, to animal cleaning in preparation for dressing the carcass of the animal.
BACKGROUND
A continual problem in the meat processing industry is the contamination of the meat with contaminants, particularly microbiological contaminants, from the exterior of the animal. The contaminants that are typically present on the exterior of the animals can be harmful to humans, or cause deterioration of the meat.
The problem is of growing significance since there is a trend towards transporting meat from the meat processing plants to distant markets, in a chilled state rather than in a frozen state. For this reason it is increasingly important to keep the meat free from microbiological contaminants.
Contamination is often transferred from the exterior of an animal and on to the meat during 15 the operation of removing the skin from the animal. The transfer can be carried out by a number of means, for example by the knife used to put the cut lines in the skin, by wool/hair "roll-over" into the knife cuts, by contaminants or particles which come off the skin or wool/hair, or via the hands of the knife operator.
The problem of the contamination of meat in a meat processing plant is not unlike the 20 problems experienced in a hospital operating theatre. And in some ways the problem in a meat processing plant is worse, since the animals are dead and their natural immune systems are no longer available to fight off contaminants. Any contaminants that remain on a piece of cut meat are able to grow and reproduce until such time as the meat is consumed. And if this period of time is many weeks, the problem can become severe.
Traditionally the attempts to reduce the contaminants on the exterior of the animals have involved bulk washing systems, for example swim washes. Such methods can spread contaminants rather than reduce them. In recent years a great deal of research and many l90094NZ-CS.0305.doc
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trials have been carried out to try and find a better solution to the problem. These efforts have often been very costly, but the results have not been significantly better than the earlier methods.
The research and trials have attempted to not only improve the hygiene of the meat but also 5 to consider animal welfare issues. It is considered that too much handling of animals, and cleaning by such methods as swim washes can cause significant stress to the animals. Long drying periods after some of these washing processes can cause the animals to get very cold, and at the same time allow further cross contamination between animals. In addition the moist skin of an animal during a prolonged drying period of say 6 to 12 hours can stimulate 10 microbiological growth and the populations of these contaminants can become greater than before the animals were cleaned.
Prolonged holding periods can also result in animal weight loss which can lead to a loss of potential earnings for both the animal growers and the meat processing plants.
The inventor has himself invested heavily in the development of new animal cleaning 15 methods and apparatus, over many years. The inventor has experienced difficulty in gaining approval from the meat industry regulatory authorities for some of these methods, sometimes due to animal welfare concerns, and at least once due to concerns that the new cleaning practices were introducing new methods by which contaminants were being spread.
Specifically, the practice of high pressure water washing of animals immediately after 20 slaughter was considered unsatisfactory' as it had the potential to spread contaminants from one carcass to another via airborne water droplets, and to spread contaminants from one part of a carcass to another due to the action of water draining down the carcass. Attempts were made to enclose these activities within air-lock chambers, and to supplement the process with additional post-washing sterilisation steps, but the whole process, and the plant to 25 support the process became too cumbersome and not at all cost effective.
It was clear to the inventor that a completely new strategy was required, that is, one that would take into account animal welfare concerns, that would satisfy the meat industry regulatory authorities, and also provide animal cleaning of a high standard, without the need for extensive plant alterations and significant capital expenditure.
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OBJECT
It is therefore an object of the present invention to provide a method of animal cleaning which will at least go some way towards overcoming the above mentioned problems, or at least provide the public with a useful choice.
STATEMENTS OF THE INVENTION
Accordingly, in a first aspect, the invention may broadly be said to consist in a meat processing industry method of animal cleaning, comprising the following steps;
a water wash of at least selected areas of the exterior of an animal,
allowing a substantial portion of the water on the exterior of the animal to drain,
stunning, or exsanguination of, the animal, and the application of a vacuum cleaning process to at least selected areas of the exterior of the animal to remove a substantial part of any remaining water from the exterior of the animal in the selected areas.
Such a method of animal cleaning presents a number of advantages. Firstly, the water 15 washing is carried out while the animal's pelt is completely intact, meaning that water is not forced onto any exposed meat. Secondly, it is not necessary for the animal to be thoroughly dried after washing since the application of a vacuum cleaning process to selected areas of the animal can be used to remove the bulk of any remaining water from the areas where cuts will be made later during the carcass dressing process. The elimination of a long drying 20 period significantly reduces the stress on an animal and the possibility of animals dying of exposure. It also reduces the time available for microbiological re-population or cross contamination between animals which can often occur during long drying periods on animals that have been cleaned with water. The shorter period of time for draining as opposed to thorough drying also shortens the flow time of the animals through a meat processing plant 25 meaning that the time from leaving the farm to carcass dressing is minimised which keeps the carcass weight loss to a minimum.
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Thirdly, no water is applied to the animal while it is suspended from the conveyor chain of a meat works. This keeps flowing water well away from the carcass dressing process or any equipment or conveyor parts which subsequently travel to the carcass dressing process. Flowing water can carry contaminants from one part of a carcass to another, or from 5 equipment to a carcass. And fourthly, the use of a vacuum cleaning process is advantageous over the use of a blow drying process sincc water droplets are not expelled from the pelt of the animal. Any expelled water droplets would generally carry contaminants and can result in the spread of contaminants around the meat processing plant and to other animals.
Preferably the selected areas of the animal include the areas on the pelt of the animal 10 adjacent to the lines along which knife cuts will be made during a subsequent pelt removal process. It is particularly advantageous to have these areas of the pelt relatively clean and dry sincc it is contamination on these areas that is most likely to be transferred onto the meat of the carcass of the animal during the pelt removal process.
Preferably the method of animal cleaning also includes a further step of wool or hair 15 trimming or removal over at least selected areas of the exterior of the animal. Wool or hair trimming or removal is advantageous in that it is easier to thoroughly clean and dry areas of the exterior of the animal where the wool or hair has been removed or trimmed. Also, a portion of the contamination on the exterior of an animal is often removed along with the removed wool or hair.
Preferably the method of animal cleaning also includes a further step of suspending the animal by its back legs from a meat processing plant conveyor chain after the animal is stunned or exsanguinated.
While the step of wool or hair trimming or removal can be carried out before the water washing step, preferably the wool or hair trimming or removal step is carried out after the 25 animal is stunned or exsanguinated and when the animal is suspended on a conveyor chain. This is advantageous because it is possible to bruise an animal while removing wool or hair while it is alive and the animal may be struggling. In contrast, when the animal has been stunned or exsanguinated and is suspended on a conveyor chain by its back legs, the areas on the pelt where the knife cuts will be made during the subsequent pelt removal process are
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clearly exposed and the animal is unlikely to struggle making the wool or hair trimming or removal simpler and less likely to bruise the underlying meat.
While wool or hair removal can be carried out by a number of methods, for example chemical hair removal, preferably the step of wool or hair trimming or removal is carried out 5 using shearing apparatus.
Preferably the water washing step is carried out by high pressure spraying. High pressure spraying is considered advantageous over swim washes since the process can penetrate and clean the hair or wool of the animal better and can be less stressful to the animals.
Preferably the high pressure spraying is directed about the entire animal, for example by the 10 use of a ring wash spraying apparatus.
Optionally the high pressure spraying is directed to selected areas of the animal only, for example to the lower surfaces including the brisket, the belly and the legs. Depending on the level of contamination and the type of contamination on an animal it is sometimes advantageous to wash only the lower surfaces. For example, sheep that are grown in a drier 15 climate may have very little contamination on their backs and sides, or may be covered in dust, and it can be advantageous to keep water away from these areas and concentrate only on cleaning the areas where the knife cuts will be made during the subsequent pelt removal process.
Optionally the water washing step includes the use of detergents and/or anti-microbiological 20 agents.
Preferably the step of allowing the exterior of the animal to drain is for a period of between 10 minutes to 1 hour, in which the animal can shake, drain, and/or naturally dry. A period of this length is advantageous in that it allows relatively rapid progress of an animal through a meat processing works, that is, there is a reduced need to move animals to large holding pens 25 for many hours to dry before continuing through the process. Such a draining period provides a suitable compromise between the need to remove running water from the animal, and the need to process the animal quickly.
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Optionally a forced airflow is used to aid the drying process while the animal is allowed to drain.
Preferably the step of applying the vacuum cleaning process to selected areas of the animal includes applying the vacuum cleaning process to at least the lower sections of the forelegs 5 of the animal. It is particularly advantageous to remove most of the water from each foreleg because when the pelt is subsequently removed from the animal, typically a small section of the pelt remains on the lower sections of the forelegs of the animal, and if this is wet, contaminants can be readily transferred from the wet pelt to the meat workers hands and/or directly to the meat of the animal. And, if the animal is suspended from its back legs it is 10 typical for a quantity of water to accumulate on the forelegs.
Preferably the step of applying the vacuum cleaning process to at least the lower sections of the front legs of the animal involves the application of a vacuum system nozzle about each front leg of the animal, for example by placing each front leg into a nozzle which is sized to accommodate the leg. Such a method is particularly effective in extracting moisture from 15 the entire circumference of the forelegs.
The combination of a shearing or trimming step followed by a vacuum cleaning step is very advantageous since the majority of any wool or hair that remains about the animal after shearing or trimming can be removed from the animal during the vacuuming step, further reducing the possibility of contamination being spread by wool or hair fragments.
Preferably the wool or hair removal or trimming step is substantially limited to an area within 50 millimetres of the proposed cut lines which will be subsequently made for pelt removal.
Preferably the wool or hair removal or trimming step is limited to a substantially "Y" shaped area on exterior of the animal, the "Y" shape extending along the belly of the animal to the 25 brisket, and from the brisket to the inside of each front leg.
Preferably each arm of the "Y" shaped area is less than 120 millimetres wide along the greater part of its length, and more preferably still the width is limited to 80 millimetres. If the shearing can be limited to a strip that is less than 80 to 120 millimetres wide the removed pelt can have a higher value since the pelt can still be sold as a full wool pelt.
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Optionally the trimming or shearing step leaves the remaining wool/hair on the pelt at least 12 millimetres long. Prevailing market prices can from time to time mean that the value of a pelt from an animal is increased if the wool/hair is at least 12 millimetres long.
Optionally the method of animal cleaning also includes the step of transporting the animal to 5 the meat works after a period of at least five hours has elapsed sincc the animal has eaten.
The method of animal cleaning can be applied to a range of animals, for example, sheep, cows, deer and goats, however preferably the method of animal cleaning is applied to sheep.
In a second aspect, the invention may broadly be said to consist in a meat processing industry animal cleaning plant comprising a water washing station adapted to clean at least 10 selected areas of the exterior of an animal, a stunning or exsanguination station, and a vacuum cleaning station wherein the vacuum cleaning station is equipped with vacuum cleaning apparatus which is adapted to remove water and contaminants from at least selected areas of the exterior of an animal.
Preferably the meat processing industry animal cleaning plant further includes a holding pen 15 or pens adapted to hold the animals after they have passed through the water washing station.
Preferably the holding pen or pens are sized to hold a quantity of animals which represents the quantity of animals which can be processed in 10 to 60 minutes in a meat processing plant associated with the cleaning plant, for example, a meat processing plant which can process 8 sheep per minute would require a cleaning plant having a holding pen or pens 20 which can hold between 80 and 480 sheep.
Preferably the meat processing industry animal cleaning plant includes a conveyor means which is adapted to convey stunned or exsanguinated animals through the vacuum cleaning station.
Preferably the meat processing industry animal cleaning plant includes a wool or hair 25 removal or trimming station.
Preferably the wool or hair removal or trimming station is equipped with shearing apparatus.
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Preferably the conveyor means is adapted to convey stunned or exsanguinated animals through the wool or hair removal or trimming station.
Preferably the meat processing industry animal cleaning plant is configured such that animals can pass through the wool or hair removal or trimming station prior to passing 5 though the vacuum cleaning station.
Preferably the meat processing industry animal cleaning plant includes an air lock door which separates the meat processing industry animal cleaning plant from the rest of a meat processing plant. Such a door can be advantageous in keeping any airborne contaminants, for example dust, hairs, or water droplets that can be generated by the meat processing 10 industry animal cleaning plant, out of the carcass dressing room of a meat processing plant.
In a third aspect, the invention may broadly be said to consist in a meat processing industry method of animal cleaning, comprising the following steps;
the application of water and/or steam to at least selected areas of the exterior of an animal, and
simultaneous or subsequent application of an air extraction or a vacuuming means to the areas of the animal that are experiencing or have experienced the application of the water and/or steam,
after the animal is first stunned or exsanguinated.
Such a method of animal cleaning presents a number of advantages. The water or steam is 20 relatively effective at dislodging and removing the types of contamination found on the exterior of animals. And if the water is hot, preferably above 82 degrees Celsius, the water and/or steam can aid in sterilising the areas of the skin and wool/hair to which it is applied. When the water and/or steam is applied in conjunction with a vacuuming means, the majority of the dislodged contaminants and the applied water and/or steam and any 25 condensed water can be collected and removed from parts of the exterior of the animal. Since the method effectively collects and removes the contaminants as they are dislodged from the animal, the method is effective in preventing both the cross contamination of other l90094NZ-CS.0305.doc
nearby animals by airborne contaminants, and the spreading of contamination over the same animal by the action of water flow.
Preferably the selected areas of the animal include the areas on the pelt of the animal adjacent to the lines along which knife cuts will be made during a subsequent pelt removal 5 process. It is particularly advantageous to have these areas of the pelt relatively clean and dry since it is contamination on these areas that is most likely to be transferred onto the meat of the carcass of the animal during the pelt removal process.
While the use of steam is effcctivc in this application, trials with the method have shown that hot water is preferable to steam. It appears that the hot water carries a higher quantity of 10 thermal energy and therefore does not tend to cool as quickly as the steam when it contacts the wool or skin of the animal.
Preferably any hot water and/or steam arc at or above 80 degrees Celsius when it reaches the exterior of the animal, and yet more preferably the hot water and/or steam are above 82 degrees Celsius.
Preferably the step of applying the water and/or steam and the step of air extraction are carricd out using a single device which has been adapted to carry out both actions simultaneously.
Preferably the meat processing industry method of animal cleaning also includes a further step of suspending the animal by its back legs from a meat processing plant conveyor chain 20 after the animal is stunned or exsanguinated.
Preferably the meat processing industry method of animal cleaning includes a step of at least partially drying the wool/hair about the lower sections of the forelegs of the animal. It is particularly advantageous to dry each foreleg because when the pelt is subsequently removed from the animal, typically a section of skin and wool/hair remains on the lower sections of 25 the forelegs of the animal, and if this is wet, contaminants can be readily transferred trom the wet wool/hair to the meat workers hands and/or directly to the meat of the animal.
Preferably the step of drying the wool/hair about the lower sections of the front legs of the animal involves the application of a vacuum system nozzle about each front leg of the
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animal, for example by placing each front leg into a nozzle which is sized to accommodate the leg. Such a method is particularly effective in extracting moisture from the entire circumference of the forelegs.
Optionally the meat processing industry method of animal cleaning includes a further step of 5 trimming heavily contaminated wool/hair from the animal prior to the application of steam. This method could for example be carried out by shearing the heavily contaminated areas of the animal. Depending on the prevailing market prices, the pelts of the animals can have a higher value if the wool is not shorn. For this reason it can be desirable to limit the use of this step to those situations in which it is absolutely necessary, that is when the 10 contamination is so heavy that the steam and vacuum steps would not clean the animal efficiently.
The combination of a shearing or trimming step followed by a vacuuming step is very advantageous since the majority of any wool or hair that remains about the animal after shearing or trimming can be removed from the animal during the vacuuming step, further 15 reducing the possibility of contamination being spread by wool or hair fragments.
Preferably the trimming or shearing step is substantially limited to an area within 50 mill imetres of the proposed cut lines which will be subsequently made for pelt removal.
Preferably the trimming or shearing step is limited to a substantially "Y" shaped area, the "Y" shape extending along the belly of the animal to the brisket, and from the brisket to the 20 inside of each front leg.
Preferably each arm of the "Y" shaped area is less than 120 millimetres wide along the greater part of its length, and more preferably still the width is limited to 80 millimetres. If the shearing can be limited to a strip that is less than 80 to 120 millimetres wide the removed pelt can have a higher value since the pelt can still be sold as a full wool pelt.
Optionally the trimming or shearing step leaves the remaining wool/hair on the pelt at least 12 millimetres long. Prevailing market prices can from time to time mean that the value of a pelt from an animal is increased if the wool/hair is at least 12 millimetres long.
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Optionally the meat processing industry method of animal cleaning includes a further step of pre-rinsing or pre-washing the animal using water prior to the animal being killed or stunned. In situations where the animal has arrived at the meat processing works in a heavily contaminated state, that is having a significant amount of dirt or faecal contamination about 5 its exterior, it can be expedient to remove the bulk of this prior to the animal moving into the slaughter room.
Optionally the pre-rinsing or pre-washing step includes the use of detergents and/or anti-microbiological agents.
Preferably the pre-rinsing or pre-washing step is carried out using jets of water which are 10 sprayed onto the animal, for example using a ring-wash apparatus. A ring-wash apparatus being one in which water is sprayed onto the animal simultaneously from below, from each side and from above. Depending on the level of contamination, the animal could require more than one pre-rinsing or pre-washing step.
Preferably the pre-rinsing or pre-washing step is followed by an at least partial drying step. 15 This partial drying step could for example be a period of time, say 10 minutes to 1 hour, in which the animal can shake, drain, and/or naturally dry. The step can optionally include the use of a forced airflow to aid the drying process.
Optionally the meat processing industry method of animal cleaning also includes the step of transporting the animal to the meat works after a period of at least five hours has elapsed 20 since the animal has eaten.
In a fourth aspect, the invention may broadly be said to consist in a meat processing plant adapted to clean an animal using either of the meat processing industry methods of animal cleaning substantially as described herein.
In a fifth aspect, the invention may broadly be said to consist in apparatus adapted to clean 25 an animal using either of the methods substantially as described herein.
In a sixth aspect, the invention may broadly be said to consist in meat from an animal that has been cleaned using either of the methods substantially as described herein.
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DESCRIPTION
The invention may also broadly be said to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of the parts, elements or features, and where specific integers are mentioned herein which have known equivalents, such equivalents are incorporated herein as if they were individually set forth.
Two preferred forms of the invention will now be described, by way of example only, with reference to the accompanying figures in which,
FIGURE 1 is a flow chart showing a meat processing industry method of animal cleaning which primarily utilises a combination of water and/or steam and vacuum cleaning post stunning or exsanguination,
FIGURE 2 is a flow chart showing the method of animal cleaning of Figure 1 and including a number of optional additional steps,
FIGURE 3 is a flow chart showing a further method of animal cleaning which primarily utilises pre-slaughter washing and post-slaughter shearing and vacuum drying, and
FIGURE 4 is a. plant layout diagram for a plant adapted for the method described with reference to figure 3, and
FIGURE 5 is a plant layout diagram for a plant adapted for the method described with reference to figures 1 and 2.
Note: The method described with reference to figure 3 below is presently considered by the inventor to be the preferred method. The method described with reference to figures 1 and 2 was a step along the way to developing the method described with reference to figure 3.
With reference to Figure 1, a method of animal cleaning is shown comprising at least a step 2, in which hot water and/or steam, and air extraction or a vacuum cleaning process are applied to selected areas of the exterior of an animal. This step is carried out after a step 1 in which the animal is stunned or killed, and before a step 3 in which the animal carcass is
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dressed. This process can be applied to an animal essentially in the condition that it is received from the farm.
The hot water and/or steam, and the vacuum cleaning process can be applied to the animal using a vacuum cleaning nozzle which is adapted to include an internal spray nozzle. The 5 spray nozzle is configured to spray hot water and/or steam towards the inlet of the vacuum cleaning nozzle, that is substantially in the opposite direction to the airflow within the vacuum cleaning nozzle. The hot water and/or steam is sprayed at sufficient velocity to ensure that it can reach the area adjacent to the inlet of the vacuum cleaning nozzle allowing the hot water and/or steam to make contact with the wool, hair or skin of the animal to which 10 the vacuum cleaning nozzle is applied.
Typically the animal is suspended from its back legs on a conveyor system during this cleaning process, exposing the belly and front legs of the animal to the cleaning process.
The hot water and/or steam can be used to clean and to sanitise the selected areas. The vacuum is used to rapidly and efficiently extract the water and/or steam, and any dislodged 15 contaminants and/or condensed water from the selected areas, leaving the selected areas of the exterior of the animal and the associated wool/hair in a relatively dry, clean and sanitised condition.
Clearly the objective is to get those areas of the exterior of the animal which are going to be cut during the skin removal process, as close to "surgically clean" as possible. As indicated 20 above, the need to keep contaminants off the meat cuts in a meat processing plant is not unlike the need to keep a patient's skin clean during surgery in a hospital operating theatre. Hot water and/or steam above 82 degrees Celsius has the advantage that it will help significantly to sanitise or sterilise the skin of the animal and the wool/hair.
While it is possible to clean and vacuum the entire exterior of the animal, it is considered 25 only necessary to apply the hot water and/or steam, and the vacuum to selected areas. These selected areas are most commonly the areas in which the cut lines will be made during the subsequent pelt removal process, these typically being a cut along the centreline of the brisket and belly, and cuts from the brisket extending along the inside of each front leg.
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Depending on the pelt removal method used it may also be necessary to make connecting cuts along the inside of each back leg.
It is preferable that the cleaning extends at least 40 to 75 millimetres each side of the proposed cut lines. Sufficient width of the cleaned area is required to prevent contamination 5 from "roll-over" of wool/hair into the cuts. Sufficient width is also required to give the knife operator, and/or the person carrying out skin removal, sufficient clean wool/hair or skin to grip while making the cuts or removing the skin. While these meat plant personnel arc required to wash their equipment and hands on a very frequent basis, there is always the possibility that their equipment or hands will inadvertently transport any contaminants that 10 they pick up, onto the meat.
While the cleaning using hot water and/or steam, and vacuuming can be carried out by hand, the step is preferably carried out using automated machinery. And it is envisaged that the process can be earned out within a module or capsule which surrounds the animal while it is cleaned. Such an enclosure would further contain any airborne contaminants and prevent 15 cross contamination between carcasses.
Such a method of cleaning animals has a number of significant advantages;
• The animal is cleaned and sanitised only moments before the carcass dressing process begins. This gives an extremely low chance of cross contamination from other animals or of microbiological population re-growth.
• The vacuum or air extraction helps to almost completely eliminate the possibility of cross contamination between animals on a conveyor chain from aerosol contaminants. The inventor experienced significant problems with aerosol contaminants when using an earlier cleaning method using high pressure water on a conveyor chain.
• The use of vacuum or air extraction will significantly reduce the possibility that 25 running water will carry contaminants from one part of the animal to another, e.g. from the anal region to the belly. The inventor experienced this problem also when using the high pressure water washing method.
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• The vacuuming process will remove loose dirt particles and wool/hair fragments that may be present in the wool/hair.
• If airflows within the meat processing plant are adequately controlled, the requirement for an air lock door between this cleaning process and the dressing area can be
eliminated. It is common for a carcass dressing area to be maintained at a slight positive pressure relative to its surroundings. If the killing/cleaning area were maintained at a slightly lower pressure, a positive airflow from the carcass dressing room towards the killing/cleaning area would result. This could be sufficient to keep the small amounts of aerosol contaminants that may be produced during the cleaning process described herein 10 away from the carcass dressing area. Clearly each plant would have to evaluate the effectiveness of such an arrangement to be sure that an air lock door was not required.
With reference to Figure 2, a second flow chart is shown, describing optional additional steps which can be used to supplement the method described with reference to figure 1 above. These additional steps can add additional cost to the cleaning process, so it is 15 preferred that these steps are only used when required, for example when the level of contamination, or the type of contamination, warrants it. For example, dirt and fresh faecal contamination could be removed using a pre-rinse step, while "dried on" faecal contamination could be best removed by shearing, or an equivalent wool/hair removal process.
Step 1 is an optional preventative measure which involves preventing the animals from feeding for at least 5 hours prior to being transported to the meat processing plant. This step can reduce the likelihood of an animal being dirtied by the excrement of another animal during transportation from a farm to the meat processing plant, or while held in holding pens. This can reduce the need for the use of a pre-wash or pre-rinse step as described below.
This step could be carried out in a number of ways, for example the animals can be removed from the pasture early in the morning before the animals begin to feed that day, or the animals can be removed from their pasture at least 5 hours before being transported to the meat works. The advantage of this step is the reduction in defecation during transportation and during subsequent handling at the meat works. Reduced defecation during these times 30 significantly reduces cross contamination between animals and therefore minimises the
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cleaning requirements, i.e. minimises the likelihood that a pre-rinsing or pre-washing step is required.
Step 2 is an optional pre-rinse or pre-wash. It is intended that a pre-rinse or pre-wash is only carried out on heavily contaminated or very dirty animals. Preferably such a rinse or wash is 5 carried out using a spray wash system and using water only. Detergents or anti-microbiological agents can be used, but these should not be required due to the 82 decree Celsius hot water or steaming step carried out later in the cleaning method. Detergents and anti-microbiological agents are often relatively costly, and can contain chemicals that are undesirable to get onto the meal. Water that contains such agents is also more costly to 10 dispose of, as it can be more harmful to the environment than water that is simply dirty.
In this step warm or cold water could be used.
Step 3 is optional and is only carried out if step 2 is carried out, and involves at least partially drying the animal. This drying step can be carried out by simply allowing the animal to shake and to drain, and to naturally dry over a period of time. It is preferable that the period 15 of time, or dwell period, is limited to between 10 minutes and 1 hour.
It is not considered necessary to dry the animal completely, as partially damp wool/hair can be advantageous in reducing the spread of contaminants in the form of dust, during subsequent handling.
Optionally this drying step could include drying of the animal using a forced airflow, for 20 example a large fan could be used to speed up the drying process.
It is considered beneficial to keep the drying step as short as possible for three reasons;
• for animal welfare reasons, to reduce the likelihood of the animal becoming uncomfortably cold.
• to minimise the likelihood of the animal being cross contaminated from other 25 animals, and l90094NZ-CS.0305.doc
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• to minimise the time that the animal is left with a damp skin, since it is considered that such warm damp conditions are ideal for the growth of populations of microbiological contaminants.
Step 4 is the killing or stunning process. The animal can be stunned, and have its throat cut, 5 for example if Halal meat is required. Alternatively the animal can be stunned and have some of its blood removed via a catheter if the blood is to be collected hygienically.
As an option, if hygienic blood collection is to be carried out, the blood removal part of this process could be carried out after either of the following cleaning steps.
After step 4 the animal is typically suspended on a conveyor system by its back legs prior to 10 the following steps.
Step 5 is optional wool/hair trimming. As with step 2 above, this step is only carried out when necessary. The wool/hair can be trimmed, by shearing for example, in situations where the wool/hair is too long, or is too heavily contaminated to be effectively cleaned by the subsequent steam/vacuum process. Such a situation would be when the animal has a 15 build up of dried faecal matter or dung in the form of dags about its anal region and hind legs.
The wool/hair trimming need only be carried out over the heavily contaminated regions of the animal, and/or over the areas selected for cleaning per step 6 below. However the wool/hair trimming can be carried out routinely to aid in the effectiveness of the cleaning per 20 step 6.
If wool/hair trimming is carried out, it can be advantageous to leave the trimmed wool/hair at least 12 millimetres long, as this can at times aid in achieving a good value for the removed pelt.
If wool/hair trimming is carried out, it can also be advantageous to minimise the trimming to 25 strips that are less than 80 to 120 millimetres wide, the strips being along the lines where the cuts will be made in the pelt during the subsequent pelt removal.
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It can be advantageous to minimise the use or the degree of the wool/hair trimming step for the following reasons;
• labour costs to carry out the step can increase total animal processing costs,
• from time to time, full wool/hair pelts can have a higher value than pelts that have 5 been fully or partially trimmed, and
• wool/hair trimming can produce contaminants in the form of short wool/hair fragments, or airborne dust. Such wool/hair fragments can find their way onto the meat during the subsequent carcass dressing process.
Preferably an air extraction or vacuum system accompanies any wool/hair trimming process 10 so that the majority of the trimmed wool/hair and any dust particles liberated can be collected and removed immediately as they are liberated from the animal.
Step 6 is the same hot water and/or steam, and vacuum process as described with reference to figure 1 above.
As discussed in step 4 above, an option is to remove the blood of the animal after at least part 15 of the exterior of the animal has been cleaned. There are two advantages in doing this;
• firstly there arc no punctures or cuts made to the animal's skin prior to the hot water and/or steam, and vacuum cleaning step and therefore the meat of the animal is not likely to be contaminated by this cleaning step, as there is no pathway in to the meat.
• and secondly, if a catheter is inserting through a cleaned and sanitised area of the 20 animal skin it is less likely to any contaminants will enter the catheter or be carried by the catheter into the meat of the animal.
Step 7 is an optional cleaning and/or partial drying of the forelegs of the animal.
Sometimes the forelegs of the animal can be wet and or dirty, especially if the animal has been pre-washed while alive and/or if the animal has recently been taken from wet or dirty 25 fields or holding pens. Wet forelegs can be a particular problem later during the carcass dressing process. It is common for the pelts to be removed in such a way that the skin
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remains on the lower part of the forelegs. Moisture and dirt can be transferred from the wool/hair on this skin prior to the lower part of the forelegs being removed from the carcass. For this reason it is advantageous to clean and/or dry at least the lower part of the forelegs.
The cleaning and/or drying of the forelegs, or at least the lower section of the forelegs, can 5 be carried out by inserting each foreleg into a vacuum nozzle which is large enough to accommodate at least part of the leg. Optionally a water and/or steam spray can be used to improve the efficiency of this vacuum cleaning step.
After the animal has been cleaned as described above it is likely that it is in a good condition to proceed to Step 8, the carcass dressing process. If the animal has been cleaned carefully 10 and thoroughly, it should be possible to remove the skin from the animal without unduly spreading contaminants from the exterior of the animal to the meat of the animal. This is likely to reduce the occurrences of meat rejection due to contamination, and can help to ensure that the meat has a long storage life, even when stored or transported in a chilled rather than frozen state.
The methods described with reference to figures 1 and 2 provide cleaning processes that allow quicker processing of animals from the time that the animals are first unloaded at the meat works. This is advantageous to both the farmers and to the meat industry, since this aspect can help to minimise weight loss from the animals' carcass. In some cases a sheep can lose 0.8 Kilograms of carcass weight in a 24 hour period when held without food waiting 20 to be slaughtered. Even a weight loss of a quarter of this amount, when multiplied by the millions of sheep slaughtered each year in New Zealand alone, and multiplied by the value of the meat, can mean a loss of 10's or even 100's of millions of dollars of potential export earnings.
With reference to Figure 3 a flow chart shows the preferred meat processing industry 25 method of animal cleaning. This method primarily utilises pre-slaughter water washing, a short drain/dry dwell period and post-slaughter vacuum drying step.
Step 1 is an optional 5 hour minimum holding period in which the animals are not fed prior to transportation to a meat works. The purpose is to reduce the defecation during l90094NZ-CS.0305.doc
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transportation and the resulting contamination of the exterior of the animals, but clearly this step is not always possible or practical.
Step 2 is a water wash of at least selected areas of the exterior of an animal. For animals which are heavily contaminated with faecal matter over a significant part of their exterior an 5 all over wash can be appropriate. However, where the contamination levels are low, for example with animals that have been grown in dry conditions, a more selective wash can be advantageous. The selective wash can for example be restricted to just the lower parts of the animal or the areas of the pelt of the animal in which cuts will be made subsequently during pelt removal.
While many washing options can be used it is considered preferable to use a spray wash system. The nozzles of the spray wash system can be configured in a number of ways, for example they can be directed to focus on particular areas of the exterior of the animal that need to be well cleaned or the animal can be passed through a spray ring system to spray the entire animal. Heated water or water containing anti-microbial agents or detergents can be 15 used, and similarly the washing process can be done in stages, for example an initial wash with a detergent followed by a water rinse.
Washing the animal while the pelt of the animal is intact is advantageous since the water is prevented from reaching any of the meat of the animal. And secondly it is good to keep running water away from the subsequent stages of the meat processing plant as water can 20 carry contaminants, for example dirty water can flow from a dirty part of an animal to a clean part or dirty water can get onto the conveyor chain of a plant and can later drip onto clean meat.
Step 3 is a relatively short draining or initial drying period after the water wash, and the period is preferably between 10 minutes to one hour. It is considered "relatively short" in 25 comparison to the present drying periods used in sheep meat processing plants which typically range between 4 to 20 hours depending on weather conditions, wool lengths and type, etc.
The shorter period between washing and further processing of the animals can be used because of the subsequent vacuum cleaning process which is used when the animal has been l90094NZ-CS.0305.doc
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stunned or exsanguinated. The subsequent vacuum cleaning process can remove any exccss remaining water from the pelt of the animal, or at least selected areas of the pelt, before the pelt removal process.
The shorter period between washing and further processing of the animals has range of 5 advantages. It significantly reduces the stress on an animal which often results from long drying periods, and it reduces the time available for microbiological re-population or cross contamination between animals which typically occurs during long drying periods on animals that have been cleaned with water.
The shorter period allows relatively rapid progress of an animal through a meat processing 10 works, that is, there is a reduced need to move animals to large holding pens for many hours to dry before continuing through the process. Such a draining period provides a suitable compromise between the need to remove running water from the animal, and the advantages gained by processing the animal quickly.
Optionally a forced airflow is used to aid the drying process while the animal is allowed to 15 drain.
Step 4 is a typical animal stunning and/or exsanguination process. Typically the process will involve a stun followed by a sticking process which will typically bleed the animal from the neck. Many sheep processing plants adopt a Halal cut at this stage in accordance with Muslim requirements.
As with the method described with reference to figures 1 and 2 clearly a range of options can be used for the stunning and/or exsanguinations steps, for example the blood could be removed from the animal via a catheter at a later stage, for example after either of the steps 5 or 6 described below.
Preferably the animal is suspended from a conveyor system after it is first stunned or 25 exsanguinated. If the animal is suspended from its back legs, the belly and forelegs of the animal are exposed and are accessible for subsequent cleaning prior to making the cuts for pelt removal.
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Step 5 is an optional wool or hair trimming or removal process. For animals which have little or short wool or hair this step is less likely to be required. However in many cases, particularly with sheep which can have thick wool on their bellies and about their legs, it can be advantageous to at least trim the wool or hair.
While a range of wool or hair removal options are available, including chemical hair removal, it is considered most convenient to trim the wool or hair using shearing equipment.
If wool/hair trimming is carried out, it can be advantageous to leave the trimmed wool/'hair at least 12 millimetres long, as this can at times aid in achieving a good value for the removed pelt.
Preferably the wool or hair removal or trimming step is limited to a substantially "Y" shaped area on exterior of the animal where cuts will be made during the subsequent pelt removal, the "Y" shape extending along the belly of the animal to the brisket, and from the brisket to the inside of each front leg.
If wool/hair trimming is carried out, it can also be advantageous to minimise the trimming to 15 strips that are less than 80 to 120 millimetres wide, the strips being along the lines where the cuts will be made in the pelt during the subsequent pelt removal.
It can be advantageous to minimise the use or the degree of the wool/hair trimming step for the following reasons;
• labour costs to carry out the step can increase total animal processing costs,
• from time to time, full wool/'hair pelts can have a higher value than pelts that have been fully or partially trimmed, and
• wool/hair trimming can produce contaminants in the form of short wool/hair fragments, or airborne dust. Such wool/hair fragments can find their way onto the meat during the subsequent carcass dressing process.
Preferably an air extraction or vacuum system accompanies any wool/hair trimming process so that the majority of the trimmed wool/hair and any dust particles liberated can be collected and removed immediately as they are liberated from the animal.
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While it is possible to carry out the wool or hair removal or trimming prior to the water washing step it is considered advantageous to do it while the animal is suspended on a conveyor system. Access to the parts of the animal which are most in need of wool or hair removal or trimming is made simpler while suspended on a conveyor system and the 5 possibility of causing bruising or other damage can be minimised or eliminated.
Step 6 is the use of a vacuum cleaning process to further clean and dry at least selected areas of the exterior of the animal. The vacuum cleaning process can be carried out by moving an industrial sized vacuum cleaning nozzle over the areas of the animal that it is desired to clean. Typically these areas will be those in which cuts will be made during the subsequent 10 pelt removal proccss. If wool or hair trimming or removal has been carried out per step 5, the areas to be vacuum cleaned will typically be carried out over the same areas and the areas adjacent to any wool or hair trimming or removal.
The vacuum cleaning not only removes water and contaminants but can also remove any wool or hair fragments that arc lying on the exterior of the animal.
Preferably the vacuum cleaning nozzle has a diameter of between 75 and 125 millimetres. And, optionally the vacuum cleaning nozzle can have comb-like protrusions on the end of the nozzle to assist with penetration into, and ruffling of, the wool or hair of the animal to further assist with the penetration of the vacuum cleaning action into the skin and roots of the wool or hair.
Preferably the step of applying the vacuum cleaning process involves vacuum cleaning the front legs of the animal. This can be carried out for example by allowing each front leg in turn to be drawn into a vacuum cleaning nozzle. In this way a substantial portion of the water that collects on the front legs when the animal is suspended from its hind legs can be removed. It is particularly important to do this because a small area of pelt usually remains 25 on the front legs just above the hooves when the pelt is later removed. If this small section of pelt contains dirty water, subsequent contamination of the carcass can occur
The combination of a water wash, followed by a short drain period and then a vacuum cleaning proccss after stunning provides a relatively fast and efficient cleaning process which can adequately clean at least the areas on the pelt of the animal where the knife cuts will be l90094NZ-CS.0305.doc
made during the subsequent pelt removal process. This allows a high standard of carcass cleanliness to be achieved while keeping cleaning costs within acceptable levels.
Step 7 is the continuation of the animal into the carcass dressing process. Preferably the animal passes through an air lock door into the carcass dressing process to ensure that the 5 carcass dressing process is fully protected form any airborne contaminants that may be released during the cleaning steps.
Preferably the plant is adapted for the cleaning of sheep.
With reference to Figure 4 a plant layout diagram is shown for a plant adapted to carry out the method described with reference to figure 3 above. The plant comprises a washing 10 station (41), a stunning and exsanguination station (43), an optional shearing station (45) and a vacuum cleaning station (47).
The washing station (41) is adapted to water wash animals while they are still alive. This washing station preferably uses pressure washing systems, for example, a ring wash spraying systems or a spraying system adapted to spray only the undersides and legs of the animals.
The washing station (41) can comprise a single washing unit or a number of washing units in series, for example, a first unit adapted to spray a detergent wash and a second unit adapted to perform a clean water rinse.
The animals are then held, within holding pens if required, for a period of preferably between 10 and 60 minutes before they progress to the stunning and exsanguination station 20 (43). Within the stunning and exsanguination station (43) the animals are typically stunned using an electrical stunner or a bolt gun, and are then stuck to bleed them and to complete the slaughter of the animals. Alternatively the animals can be stunned only at this station (43) and the blood of the animals can be removed at a later stage, for example immediately after the vacuum cleaning process.
Preferably the animals are then suspended from their hind legs on a conveyor system which then transports the animals to the shearing station (45). The shearing station (45) is provided with shearing apparatus which can be used to trim the wool or hair on all or preferably just l90094NZ-CS.0305.doc
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selected areas of the animal. The selected areas primarily being those in which cuts will later be made during pelt removal.
The animal then moves to the vacuum cleaning station (47) preferably while still suspended from the conveyor system. Within the vacuum cleaning station (47) an industrially sized 5 vacuum pump is used to draw air through a vacuum nozzle, the vacuum nozzle being attached to a flexible duct. Preferably the flexible duct and the nozzle are at least 75 to 125 millimetres in diameter. The nozzle is moved over selected areas of the animal to remove water, dirt and any loose wool or hair. The selected areas being primarily those in which cuts will later be made during pelt removal and the forelegs.
The animals are then able to be presented in a cleaned state to the carcass dressing part of a meat works. Preferably the animals pass through an air lock door on their way to the carcass dressing part of the meat works.
With reference to Figure 5 a plant layout diagram is shown for a plant adapted to carry out the method described with reference to figures 1 and 2 above. The plant comprises an 15 optional washing station (51), a stunning and exsanguination station (53), an optional shearing station (55) and a vacuum cleaning station (57).
The washing station (51) can be used for animals that are heavily soiled and is adapted to water wash the animals while they are still alive. This washing station preferably uses pressure washing systems, for example, a ring wash spraying systems or a spraying system 20 adapted to spray only the undersides and legs of the animals.
The washing station (51) can comprise a single washing unit or a number of washing units in series, for example, a first unit adapted to spray a detergent wash and a second unit adapted to perform a clean water rinse.
The animals are then held, within holding pens if required, for a period of preferably 25 between 10 and 60 minutes before they progress to the stunning and exsanguination station (53). Within the stunning and exsanguination station (53) the animals arc typically stunned using an electrical stunner or a bolt gun, and are then stuck to bleed them and to complete the slaughter of the animals. Alternatively the animals can be stunned only at this station (53)
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and the blood of the animals can be removed at a later stage, for example immediately after the vacuum cleaning process.
Preferably the animals are then suspended from their hind legs on a conveyor system which then transports the animals to the shearing station (55 ). The shearing station (55) is provided 5 with shearing apparatus which can be used to trim the wool or hair on all or preferably just selected areas of the animal. The selected areas primarily being those in which cuts will later be made during pelt removal.
The animal then moves to the vacuum cleaning station (57) preferably while still suspended from the conveyor system. Within the vacuum cleaning station (57) an industrially sized 10 vacuum pump is used to draw air through a vacuum nozzle, the vacuum nozzle being attached to a flexible duct. Preferably the flexible duct and the vacuum nozzle are at leasi 75 to 125 millimetres in diameter.
A supply of hot water or steam is supplied to a second nozzle which is integral with the vacuum nozzle. The steam or hot water is directed onto the pelt of the animal and is 15 extracted by the vacuum within the vacuum nozzle. Using such an apparatus the exterior of the animal can be cleaned and kept substantially dry.
The nozzle assembly which comprises both the vacuum nozzle and the second nozzle can be moved over selected areas of the animal to remove dirt and any loose wool or hair, and to remove any water which can remain on the animal if it has been water washed prior to 20 stunning. The selected areas being primarily those in which cuts will later be made during pelt removal and the forelegs.
The animals are then able to be presented in a cleaned state to the carcass dressing part of a meat works. Preferably the animals pass through an air lock door on their way to the carcass dressing part of the meat works.
DEFINITIONS
Throughout this specification the word "comprise" and variations of that word, such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps.
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