AU2015249176B2 - A bunging mixture and apparatus for delivering same to an animal carcass - Google Patents

Abstract

This invention relates to a mixture for use as a bung in the processing of animal carcass, wherein the mixture includes at least 30% render meal, at least 25% of a setting agent, wherein the setting agent is a fat or wax which is a solid at temperatures of 400C and below, and at least 5% water. The invention is particularly advantageous as it uses constituents that are produced as a byproduct of the processing of animal carcasses so potential reduces wastage and costs.

Description

A BUNGING MIXTURE AND APPARATUS FOR DELIVERING SAME TO AN ANIMAL CARCASS

TECHNICAL FIELD

The invention relates to a mixture that is suitable for bunging an animal carcass prior to being processed for its meat. The invention also relates to an apparatus and method for delivering the bunging mixture to the animal carcass.

BACKGROUND ART

The processing of the carcasses of ovine and bovine species is a significant industry in many countries. For food safety and hygiene reasons, a common initial step in the processing of the carcass is the sealing of the rectum, referred to herein as bunging.

This helps prevent leakage of fecal matter which may otherwise contaminate the meat of the carcass due to its bacterial content. Furthermore, feces can create an unpleasant working environment for workers processing the carcasses. A few different techniques are employed when sealing the rectum; patches, plugs and settable plugs. A typical example of a patch is disclosed in United States Patent No. 5,588,905. This describes an adhesive patch that is fixed to the anus region of the carcass. The sealing properties of such patches can be variable due to the pelt that surrounds the anus. Furthermore, because of the adhesive used, it can be difficult to remove the patch when it is no longer required.

Additionally, the material from which the patch is manufactured, as well as the adhesive, is not usually biocompatible. There is a risk it may enter the food chain for humans and/or animals, for example pets, if accidently left in place or not fully removed.

Another method of bunging commonly used is to insert paper plugs into the rectums of the carcasses. However, these plugs, usually conical in shape, do not always provide a good seal particularly with scouring animals.

The other main technique employed to seal the rectum of the carcass is to inject a settable plug into the rectum. Once it sets, this seals the anus thereby preventing leakage of fecal matter. An example of this method is described in United States Patent No. 5494481. This document describes a mixture of water, gum, modified food starch, together with a preservative. A further example of a bunging mixture is described in United States Patent No. 5120267, although this is in a liquid form and relies on cyanoacrylate-based adhesive.

However neither of these exemplar mixtures is ideal because of cost and the use of non-food grade materials (such as the cyanoacrylate-based adhesive) or at least preservatives and other materials that are not sourced from animals.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention there is provided a mixture for use as a settable bung in the processing of animal carcass, wherein the mixture includes: at least 30% render meal; at least 25% of a setting agent, wherein the setting agent is a fat or wax which is a solid at temperatures of 40°C and below; and at least 5% water.

According to another aspect of the present invention there is provided a mixture for use as a settable bung in the processing of animal carcass, wherein the mixture includes: at least 30% render meal; at least 25% of a setting agent, wherein the setting agent is a fat or wax which is a solid at a temperature of 40°C and below; at least 5% water; and at least one inert core.

According to another aspect of the present invention, there is provided a method of delivering a bunging mixture for a settable bung to an animal carcass, wherein the mixture includes at least 30% render meal, at least 25% of a setting agent, wherein the setting agent is a fat or wax which is a solid at temperatures of 40°C and below; and at least 5% water, the method including the steps of: a) filling a delivery device with the bunging mixture; b) inserting the delivery device into the anus and rectum of the carcass; and c) extruding at least a portion of the contents of the delivery device into the rectum; the method characterised by the additional step of: d) heating the bunging mixture to between 50°C and 70°C prior to its extrusion.

According to another aspect of the present invention, there is provided a method of delivering a bunging mixture to an animal carcass substantially as described above, wherein the mixture also includes at least one inert core.

The term “bunging”, and its derivatives, should be understood to relate to the general process of sealing the anus and/or rectum of a freshly slaughtered animal with a bung in order to prevent or minimise leakage of fecal matter from the rectum.

The term “extruding”, and its derivatives, should be understood to mean the process by which the bunging mixture is delivered to the carcass after the mixture has been prepared.

In preferred embodiments of the present invention, the bunging mixture is used with the carcasses of ovine species (sheep). However, this should not be seen as limiting as the bunging mixture and method may be used with other species of animal, such as bovine species, that are valued for their meat.

The bunging mixture and method described herein provides a means by which the rectum of a freshly slaughtered animal carcass is sealed with a settable formulation to prevent or minimise leakage of fecal matter. It utilises constituents which are safe for consumption by animals as pet food (for example). The amounts in which the respective components are present in the mixture contribute towards the ease of its use; it has a relatively low melting point at which it is flowable but is still settable at the internal temperature of the animal carcass.

The bunging mixture includes at least 30% render meal.

The term “render meal” should be understood to be the ground and rendered byproduct stream from an animal carcass processing chain. Render meal consists of processed animal components. As render meal is derived from animal by-products, it is suitable for animal consumption.

The render meal effectively functions as a filling or bulking agent for the bunging mixture. It is an ideal component for a bunging mixture as it is readily sourced and furthermore, the carcasses to which the bung is being delivered may ultimately be a source of further render meal.

An example of a suitable render meal is a dry, normal grind, meal which is supplied by PVL Proteins Limited (a subsidiary of Wilson Hellaby). However, this is not meant to be limiting and any commercially available render meal may be readily employed with this mixture.

The percentage of 30% should be understood to mean the minimum amount of render meal present in the bunging mixture. A greater percentage of render meal may be included in the bunging mixture.

For example, in some embodiments, the mixture could include a maximum of 70% render meal. This may mean that the relative proportions of the other constituents of the bunging mixture, and the temperature at which it is delivered to the carcass, will need to be adjusted accordingly to maintain the desired properties for the bung. However, it should be noted that the inventors found that when render meal is present in the mixture at high amounts, the structural integrity of the resulting bung deteriorates.

In preferred embodiments, the bunging mixture includes at least 45% render meal.

The mixture also includes at least 25% of a setting agent, wherein the setting agent is a fat, wax, or mixture thereof, wherein the fat or wax is a solid at temperatures of 40°C and below. The fat or wax effectively acts as a setting agent and binds the mixture together.

Persons skilled in the art will readily appreciate suitable fats or waxes that meet the specified criteria of being a solid at 40°C. For example the fat may be derived from plants and be in the form of palm, soybean or sunflower oil, which are all readily sourced. These are just examples of suitable plant-derived fats that may be used and should not be construed to be limiting. Alternatively, a wax such as beeswax may be used.

However, in preferred embodiments of the present invention, the fat or wax is an animal-derived fat. This form of fat is usually more economic to source and use. Furthermore, it may be a by-product of the animal being processed at the time the invention is being used.

The term “animal-derived fat” should, as the term suggests, be understood to mean any fat derived from the carcasses of animals. Reference shall now be made throughout the remainder of the specification to the setting agent being a fat or an animal-derived fat.

In preferred embodiments of the present invention, the animal-derived fat may be sourced from bovine species, i.e. the animal-derived fat is derived from beef. It will be appreciated that beef-derived fat will be safe for consumption by animals (in for example, pet food). However, this is not meant to be limiting, and the use of fat from other animal species is envisaged; for example, the fat may be derived from ovine species.

The percentage should be understood to mean the minimum amount of fat present in the mixture. In some embodiments, the mixture could include a maximum of 45% fat. An amount higher than this may not only be uneconomic, due to the cost of the animal-derived fat, but also affect the setting time of the resulting bung. The structural integrity of the bung, once set, may also be compromised.

In preferred embodiments of the present invention, the fat is stearin. Stearin is a triglyceride known for its hardening properties.

Even more preferably, the animal-derived fat is beef tallow stearin. This form of fat is produced from the byproducts from the processing of beef, and is very stable.

White stearin has been found particularly useful in the present mixture. It is highly refined, bleached and deodorised. However, with minor variances in quantity, brown stearin may also be used in the bunging mixture depending on availability and cost.

This example of the animal-derived fat that may be employed in the present invention is not meant to be limiting. For example, beef tallow, which is used as a cooking fat, may also be used. Other alternatives may be ovine stearin or ovine tallow. Persons skilled in the art will readily appreciate other alternatives of animal-derived fats that may be used as the fat component of the present bunging mixture.

It will be appreciated that during the preparation of the bunging mixture, the setting agent at least needs to be heated in excess of 45°C in order for it to reach its melting point so that it may be mixed with the other components of the bunging mixture.

Both stearin and beef tallow have melting points which are between 60 to 65°C (white stearin has been found to have a slightly lower melting point than brown stearin) and start solidifying at about 41 to 43°C (white stearin starts solidifying at a slightly higher temperature than brown stearin).

The mixture also includes at least 5% water. The amount of water present is important to the dispersal of the render meal through the fat or wax as the case may be, resulting in a more homogenous mixture. However, as the percentage of water increases, mechanical hardness of the resulting bung may be affected.

The amount of water stipulated also has the benefit of reducing the fat that needs to be present in the mixture. This is advantageous for cost reasons, as the fat component of the mixture has been found to be the most expensive to source.

The preferred ratio of render meal to water to fat is 4:1:3.25 to 4:1:3.5 when the mixture is delivered to the carcass at 50°C to 60°C.

In some embodiments of the invention, the bunging mixture may include an inert core, the remaining portion of the mixture effectively acting as a coating for the core.

This inert core may be formed from any suitable material and used as a means to reduce the amount of the remaining constituents of the bunging mixture. The use of an inert core has the potential to affect setting times and may be particularly suitable for use in the bunging of larger animal species.

The inert core may be biocompatible plastics material, starch or other pet food suitable materials that will be recognised by the skilled addressee as being suitable for use as a core for the bung.

The inert core may take a variety of forms but preferably is substantially cylindrical with rounded ends, similar to a tablet. However this is not meant to be limiting and it may take a spherical or other shape, depending on the method of delivery to the carcass. A single, large inert core may present problems when attempting to deliver the bunging mixture to the carcass. Therefore, in some embodiments, the bunging mixture may include a plurality of inert cores as small spherical beads or the like. This may have the effect of replicating the overall effect of a single larger core but allows the bunging mixture to flow better for the purposes of delivery.

The mixture may also include additional components in an amount of up to 15% of the bunging mixture. For example, the mixture may include a preservative that is recognised as being safe for consumption by animals at least. Another possibility may be gum or other agents that may assist in solidifying of the bunging mixture. A delivery device is used to extrude a shot of the bunging mixture into the rectum of the carcass.

For mixing, preferably the bunging mixture is heated in excess of 65°C. If left to cool, the mixture will begin to set from 41 °C to 45°C but latent heat from the phase change to a solid will increase the temperature to around 55°C.

Preferably, the bunging mixture should be at a temperature of between 50°C and 70° when is extruded from the delivery device into the anus of the carcass that requires bunging.

Even more preferably, the bunging mixture is at a temperature of between 50°C to 60°C when it is extruded from the delivery device. This temperature is sufficient to ensure that the bunging mixture sets and forms a bung in a timely manner such that further processing of the carcass is not unduly disrupted while also reducing the possibility that the mixture does not block the delivery device.

It will be appreciated that the present invention offers a number of advantages over existing bunging mixtures and methods, including: • use of animal food-grade constituents; • use of constituents that are produced as part of the subsequent byproduct processing, thereby potentially reducing costs and allowing for recycling; • settable at carcass temperatures; • relatively viscous, and therefore extrudable, at temperatures only a few degrees higher than body temperature; or • at the very least, offers the public a useful choice.

BEST MODES FOR CARRYING OUT THE INVENTION

The development of the present invention came about through extensive trial and experimentation. It is important that the bunging mixture be easily extruded but is also settable at temperatures of around 40°C and below within a limited timeframe. A bung which takes a long time to set may not be retained within the rectum and may disrupt further processing of the carcass. Ideally, setting should occur within four minutes of extrusion. Factors that affect setting time include the amount of stearin present in the mixture and the temperatures at which the bunging mixture is delivered to the carcass.

Preparation

For use, the bunging mixture may be prepared in a mixing vessel such as a hopper or the like. It will be appreciated that the mixing may be automatically controlled by integrating dosage meters regulating the delivery for each of the constituents of the bunging mixture into the hopper. Persons skilled in the art will readily appreciate how to automate the mixing process.

As noted above, the preferred ratio of render meal to water to fat is 4:1:3.25 to 4:1:3.5 when delivered to the carcass at 50°C to 60°C.

Preferably, the render meal and water are mixed prior to introduction of the beef-derived fat. This has been found to reduce the amount of fat that is absorbed by the meal, with a subsequent reduction in costs. It was found that as the percentage of water increased, the mechanical hardness of the bung also increased.

Preferably, the render meal/water mixture is allowed to stand for a period of time to ensure adequate absorption prior to the introduction of the beef-derived fat.

It has been found that setting of the bunging mixture is improved when the mixture is substantially homogenous. To ensure this, the animal-derived fat is heated until it melts at which stage it is introduced to the render meal/water mixture.

Preferably, the animal-derived fat is heated to at least 65°C. However, this is not meant to be limiting as some animal-derived fats have differing melting points.

For example, white stearin, the preferred beef fat derivative of the Applicant, has a melting point of 61 °C while brown stearin, a possible alternative, has a melting point of 65°C.

The melting of the beef-derived fat may be performed in a separate vessel, the contents of which are then transferred to the vessel containing the meal/water mixture. However, this is not meant to be limiting and it may be performed in batches or even continuously depending on the user’s equipment.

Delivery

Reference shall now be made to the carcass being bunged as being a sheep carcass. However, this should be understood to not be limiting and with minimal adaptations, the invention may be used with bovine and other animal species.

In use, the bunging mixture can be provided to the sheep carcass using a delivery device.

The delivery device should be understood to include a reservoir, or at least be connected to a reservoir, for the bunging mixture. The delivery device also includes a nozzle or outlet through which the contents of the reservoir may be delivered to the carcass and an activation and metering means. A means to monitor and regulate temperature may also be provided.

In some embodiments of the invention, the delivery device may be a syringe or the like.

Persons skilled in the art will appreciate that a syringe includes a reservoir through which a plunger may pass to expel some or all of the contents of the reservoir out the nozzle of the syringe.

However, in preferred embodiments of the invention, the delivery device is a gun attached to a continuous, or near continuous, supply of bunging mixture. Reference shall now be made to the delivery device being a “bunging gun” but this should not be construed as being limiting; the delivery device may take a variety of forms which will be readily apparent to a skilled addressee.

Preferably, the nozzle includes a guard structure. This helps to guide the nozzle and prevent damage to the rectum and/or anal cavity of the carcass. It may also reduce the potential for any fecal matter blocking the nozzle during delivery of the bunging mixture.

When the bunging gun has been inserted into the anus of the carcass, the shot of bunging mixture may then be delivered. It will be appreciated that the bunging gun will include a means of regulating the appropriate amount of bunging mixture. The Applicant has found that an amount of about 60 grams is sufficient for the formation of an adequate bung for a sheep carcass.

However, it will be recognised that bung size is species dependent; a bung for a cow carcass is likely to be larger due to the size of the animal.

In preferred embodiments, the hopper in which the bunging mixture is prepared is provided with piping or hoses to link it to the delivery device. This allows for a continuous supply of bunging mixture if the constituents of the mixture are fed to the hopper while the delivery device is in operation. This will be convenient when dealing with multiple carcasses such as in a commercial carcass processing facility, in which parts of the processing line are fully or semi-automated.

Preferably, the piping or hoses includes means to control the temperature of the bunging mixture as it is transferred to the bunging gun. For example, the piping or hoses may pass through a water jacket. Alternatively, the bunging gun itself may include a temperature control means. This helps ensure that the bunging mixture is delivered to the bung gun at an appropriate temperature for delivery to the carcass.

However, in some embodiments of the invention, the bunging gun may not have a continuous supply of bunging mixture. In these embodiments, the bunging mixture may be allowed to cool down in the hopper before being transferred to the reservoir of the bunging gun. The bunging gun may also include a means to heat or maintain the bunging mixture at the appropriate temperature for delivery.

The bunging gun may be operable by a user, such as a meat worker, or by an industrial robot.

Preferably, the nozzle of the bunging gun is inserted into the anus of the carcass to a depth of up to 160 millimetres. During trials with carcasses, it was found that a lesser depth was found to result in inadequate retention of the bung as the sheep carcass was subsequently dressed (the process by which the pelt, hocks and so forth are separated from the carcass).

Results

Best results were achieved with a bunging mixture having a ratio of between 3.25 to 3.5 of fat relative to four parts meal and one part water.

This allowed the use of a temperature of between 50°C to 60°C for delivery of the bunging mixture. The use of this temperature range for extrusion of the bunging mixtures means that the delivery device only needs to have minimal heating requirements.

It also means that the bunging mixture will set more quickly than if it were delivered at higher temperatures. It is preferable to not unduly prolong the setting of the bung as this may disrupt flow of a commercial carcass processing facility.

In trials, the carcass was suspended from hooks by its rear hocks. Thus, the bunging gun was orientated downwards as the bunging mixture was extruded.

The bunged carcasses were monitored until eviscerated at which time the bungs were inspected.

In initial trials, a sound bung had been formed in up to 80% of the carcasses. Subsequent trials found 90% to 100% of carcasses had a sound bung which provided a good barrier to fecal matter. Importantly, the bung was retained even during dressing of the carcass.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

Claims (12)

1. WHAT WE CLAIM IS:

   1. A mixture when used as a bung in the processing of animal carcass, wherein the mixture includes: at least 30% render meal; at least 25% of a setting agent, wherein the setting agent is a fat or wax which is a solid at temperatures of 40°C and below; and at least 5% water.
2. 2. The mixture as claimed in claim 1 wherein the mixture includes between 45 to 55% render meal.
3. 3. The mixture as claimed in claim 1 wherein the mixture includes between 25 to 35% of the setting agent.
4. 4. The mixture as claimed in any one of claims 1 to 3 wherein the setting agent is an animal-derived fat
5. 5. The mixture as claimed in any one of claims 1 to 3 wherein the animal-derived fat is stearin.
6. 6. The mixture as claimed in claim 5 wherein the stearin is white stearin.
7. 7. The mixture as claimed in any one of claims 1 to 3 wherein the setting agent is a fat or wax derived from plants.
8. 8. The mixture as claimed in any one of claims 1 to 3 wherein the setting agent is a wax.
9. 9. The mixture as claimed in claim 8 wherein the setting agent is beeswax.
10. 10. A method of delivering a bunging mixture to an animal carcass, wherein the mixture includes at least 35% render meal, at least 25% of a setting agent, wherein the setting agent is a fat or wax which is a solid at temperatures of 40°C and below; and at least 5% water, the method including the steps of: a) filling a delivery device with the bunging mixture; b) inserting the delivery device into the anus and rectum of the carcass; and c) extruding at least a portion of the contents of the delivery device into the rectum; the method characterised by the additional step of: d) maintaining the bunging mixture at a temperature between 50°C and 70°C prior to its extrusion from the delivery device.
11. 11. The method as claimed in claim 10, wherein the bunging mixture includes an inert core.
12. 12. The method as claimed in either claim 10 or claim 11, wherein the bunging mixture is heated to between 50°C and 60° prior to its extrusion from the delivery device.