IE20020494A1 - Animal by-products rendering - Google Patents

Abstract

There is provided an animal by-product rendering process comprising the steps of gathering slaughter hall fat products and sending them directly from the slaughterhouse at a temperature between 5 to 30 C to a rendering plant, then heating and agitating the contents at a temperature between 101 and 110 C in an initial heating step, then fractionating the dry material at between 120 to 150 into a liquid tallow phase and a proteinaceous solid phase, namely greaves. Subsequently, sterilising the materials at 120 C, then stopping the agitation and removing some of the fat from the greaves, then further sending the tallow and greaves liquid mixture through a screen, then separating the greaves in the bin while maintaining the greaves at between 45 and 55 C. Subsequently, centrifuging and storing the greaves. <Figure 1>

Description

Introduction "Animal By-products Rendering" The present invention relates to an animal by-products rendering processes.

Many of the by-products from a slaughtering plant are effectively low grade or low value animal by-products such as beef, adipose and intestine fats, which heretofore have been io of little use commercially and indeed, in many cases, have been a cost to the slaughtering plants in that they have to spend considerable money in having them disposed of.

Essentially, the problem is that good quality tallow is an exceedingly useful by-product and is used extensively for cosmetics and for human consumption. However, if it is to be used for human consumption or indeed, to be used, for example, for cosmetics, it is vital that the tallow does not deteriorate. Unfortunately, if exposed to air under normal ambient conditions, fat deteriorates rapidy and gradually becomes rancid and is thus of relatively Sttte value. A further problem w©i rendering fats and the by-products cf stau^Wering. is that increasingly, government regulations are making it difficult for slaughter houses to dispose of animal waste in a cost effective way. The environmental regulations being imposed on the operators slaughter houses make it very important to render, as far as possible, such animal by-products and at least dispose of them in an environmentally friendly manner. Unfortunately, this is a costly process and therefore anything that can be done to reduce the cost of such rendering is to be encouraged. Further, anything which increases the value of such products is doubly advantageous.

The problem of rancidity in abattoir waste materials and the recovery of edible proteins therefrom has been, for example, discussed in UK Patent Specification No. 974154 (Separator AG). However, the rendering of the fat earned out, as described in this specification, is earned out at relatively low temperatures.

It is well known and described in many patent specifications to provide a rendering process to separate the fat phase from the proteinaceous solid phase by using the steps of heating and separating by means of a settling tank or centrifuge. Unfortunately, none of these prior art methods are sufficiently successful. A typical example of such a process IE02 04 9 4 -2is, for example, the method described in GB Patent Specification No. 2258239 (Marrow Research & Development Limited).

Essentially, dry rendering of these low animal by-products, namely, beef adipose and intestinal fats, allows the production of two products, namely, tallow and greaves which are basically protein.

The present invention is directed towards providing an improved process for rendering animal by-products.

Statements of Invention According to the invention, there is provided an animal by-products rendering process comprising:gathering slaughter haO fat products; sending the fat products directly from the slaughterhouse at a temperature of between 5°C and 30°C to a rendering plant; heating the fat products in a cooking vessel while agitating the contents at atmospheric pressure and at a temperature between 101 °C and 110°C in an initial heating step; collecting moisture driven off in the initial heating step to leave a moisture free dry material in the cooking vessel; further heating and agitating the dry material at between 120° to 150°C to fractionate the dry material into a liquid tallow phase and a proteinaceous solids phase, namely, greaves; holding and agitating the fractionate materials at at least 120°C for between 10 and 20 minutes to sterilise the materials; IE 0 2 04 9 4 -3stopping the agitation for between 5 and 15 minutes to allow the greaves to settle in the cooking vessel; removing the liquid tallow from approximately half way up the cooking vessel and sending it to a storage tank; delivering the rest of the material comprising tallow and greaves liquid mixture through a screen in a percolating bin to separate large sized greaves from the liquid mixture; delivering the liquid mixture to a settling tank to separate tallow from the remainder of the greaves while maintaining the liquid mixture at between 45°Cand55°C; delivering at least the greaves from the percolating bin to a centrifuge to dry the greaves; storing the greaves; and removing the tallow from the settling tank to storage.

The advantage of sending the fat products directly from the slaughterhouse at an elevated temperature is that it ensures that firstly, the fat products do not deteriorate due to storage and secondly, there is a reduction in the energy requirements.

In one process according to the invention, the intestinal fats are removed from the carcass by:directing a pressurised jet of air and water into the intestinal cavities to flush out the intestines; cutting up the flushed intestines; allowing the intestines to drain for between 10 and 30 minutes; and IE 0 2 04 9 4 -4sending the drained intestines with the other fat products from the slaughterhouse.

In any of the latter two processes, the initial heating step the initial heating step is carried out at between 101°C and 104°C, the extracted water vapour is condensed and the condensed water is sent to an activated sludge treatment plant.

Ideally, the products are drained for approximately 20 minutes.

Ideally, the heating to carry out the fractionation of the dry material is carried out at approximately 130°C. Ideally, the fractionate materials are held at the same pressure for approximately 15 minutes.

It is envisaged that in accordance with the invention, one or more of the following optional steps may be performed:(a) the greaves and some of the taiiow are removed from the bottom of the setting tank and delivered to the cooking vessel for further processing; (b) the greaves and some of the tallow are removed from the bottom of the settling tank and delivered to the centrifuge; (c) the greaves and some of the tallow are removed from the bottom of the settling tank and delivered to waste disposal; (d) the step of removing the tallow from the settling tank comprises lowering an extraction pipe, while using a sight glass on the tank wall, into the settling tank: the tallow is removed from the top of the settling, tank ancl delivered to an additional settling tank; (e) the tallow recovered in the centrifuge is delivered to the tallow storage tank.

The invention thus provides a tallow and greaves material which is produced very efficiently.

IE 0 2 04 9 4 -5Detailed Description ofthe Invention The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:Fig. 1 is a simplified layout of an animal by-products rendering plant according to the invention, I Fig. 2 is a more detailed plan view, Fig. 3 is a view along the lines A-A of Fig. 2, Fig. 4 is a vertical section along the lines B-B of Fig. 2, Fig. 5 is a cSagrammaticaJ side view of a setting tank according to the invention, Fig. 6 is a stylised view showing another operation in accordance with the invention, and Fig. 7 is a graph ofthe temperature profile in a cooking vessel used in the invention.

Referring to the drawings and initially to Fig. 1 thereof, there is illustrated a rendering plant, indicated generally by the reference numeral 1 which comprises a pair of cooking vessels or cookers 2, each feeding a percolation bin 3, each of which in turn feeds, by a conveyor 4, a basket centrifuge 5. The cookers 2 are steamed jacketed vessels which have rotating steam heated agitators mounted therein which can operate under pressures from 0 to 6 bar, normally about 5 bar. There is also illustrated a greaves bagging store 6, a liquid tallow storage area 7, an infeed hopper 8, a blow gun 9 and settlement tanks 10.

Referring now in more detail to Figs. 2, 3 and 4, it will be noted that the intake bin 8 houses an inclined screw conveyor 20 and that the blow gun 9 is connected by piping 21 to the two cookers 2. Each cooker 2 has an output hopper 23 and is driven by a motor 24 through a gear box 25. A pump 27 connects the two cooking vessels 2 to the settlement IE 0 2 04 9 4 -6tanks 10 through piping, shown by interrupted lines. For ease of understanding, not all the piping used in the rendering plant 1 is illustrated.

Referring now to Fig. 5, each settlement tank 10 has a frusto conical base 30 surrounded by steam carrying coils 31 and has an outlet valve 32 mounted above a solids bin 33. An outlet pipe 35 is pivotally mounted at 36 and can be pivoted within the tank 10 by a chain 37. The pipe 35 has an inlet 38 which therefore can be raised within the settlement tank 10. Various other pipe connections are provided but are not shown.

Referring to Fig. 6, there is illustrated a work station, indicated generally by the reference numeral 40, comprising a table 41 having a mesh drain area 42 mounted above a liquid take-off tank, not shown. There is also illustrated a water air nozzle 45 and an operator, identified by the reference numeral 46, working on a carcass 47.

In operation, slaughter hall products such as kidney fat, channel fat, dug fat and neck fat are recovered during the dressing process and transported via cyclone compressed air blowers to the rendering plant 1, namely, to the infeed hopper 8 and are delivered by the screw conveyor 20 into the blow gun 9 where they are deiwered trough the pipes 21 to the cookers 2. Further, intestinal fats are deaned and harvested at te work station 40 try an operator inserting the water air nozzle 45 into the intestinal cavities of a carcass, flushing out all intestinal contents, while at the same time, coupling up the tissue contents with a butcher’s knife. After flushing, products are placed on the mesh drain 42 for a predetermined time, generally between 10 and 30 minutes before being again transported to the processing facility, namely, the rendering plant 1 by a blower.

It has been found that the use of compressed air in the water nozzle improves the production process by speeding up the operation, reducing water consumption and improving the cleaning effect. Thus, a considerable amount of fat and intestines are transmitted, very rapidly, at temperatures in the order of 5 to 30°C to the infeed hopper 8, where they are quickly delivered to the cooking vessels 2.

When a batch of the product is delivered to a cooking vessel or cooker 2, initially the products are heated and agitated so as to boil off moisture and any entrained gases. This is generally done at a temperature of about 101 to 104°C and at atmospheric pressure. Generally, about 40% of the weight of the products is liberated as moisture, which ecu z U4 9 4 -7moisture is extracted as vapour and then condensed in an evaporative cooling tower before being cleaned in an activated sludge treatment plant. The dry product remaining in the cooling vessel 2 is then further heated to between 120 to 150°C, normally about 130°C to liberate lipids through tissue cell walls. This fractionates the raw material into two phases, namely a liquid tallow phase and a proteinaceous solid phases which, in the industry, is called greaves. The greave fe essentially protein. Once approximately 130°C has been achieved, then the batch is held at 130°C for a period of about 15 minutes to sterilise the product. This is done to destroy bacterial pathogens such as salmonella species. Table 1 shows the time temperature profile in a cooking vessel 2 while Fig. 7 shows it as a graph. Elapsed Time (Mins) Table 1 Cooking Vessel Temperature (°C) 0 40 35 88 30 91 45 96 60 98 75 100.2 90 101.5 105 102.3 120 108.1 135 128.4 150 119.9 165 107.8 180 110.3 When sufficient heating has been carried out, which is done by steaming, the agitation is stopped. The usual consumption rate is of the order of 0.4 to 0.5 Kg of steam which is somewhat less than heretofore because instead of using cold fat or indeed frozen products, the products are arriving into the cooking vessel at relatively elevated IE 0 2 04 g 4 -8temperatures. After agitation in the cooking vessel is stopped, the mixture is allowed to settle under gravity for approximately 10 minutes. Then, tallow is drained from the top half of the cooking vessel and delivered directly to the in-storage area 7 where it is loaded immediately into bins or containers which are sealed.

The mixture, which is essentially a slurry of tallow and greaves, is delivered into the percolation bins 3, each of which contains a mesh which captures most of the larger greaves so that what is left are smaller particulate matter, namely, greaves in tallow which is then pumped to the settlement tanks 10, where sufficient time is allowed for the particles to settle out of the tallow. The pipe 35 can be raised or lowered within the settlement tank 10 with the use of a sight glass (not shown) within the tank 10, the distance to which the pipe 35 can be lowered so as not to remove any particulate matter with the tallow. Liquid tallow can be easily seen. Thus, liquid tallow can be removed from the top of the settlement tank 10. The greaves and liquid tallow in the bottom of the settlement tank 10 can be either delivered out through the outlet pipe 35, manually fed back into the cooking vessel 2 as raw material, fed to the centrifuge 5 or removed as waste product, dependtog on the quality of tallow or greaves required. It wiB be appreciated that the heating coils 31 can maintain the tallow at a defined temperature, usuafiy less than 50°C. This temperature is sufficiently lower so that the tallow density is sufficient for liquidity. This temperature does not damage the tallow properties such as free fatty acid content, pH and peroxide value.

The centrifuge 5 is used to centrifuge the greaves. The dried greaves from the centrifuge 5 are removed to the greaves cooling and bagging area 6, while the liquid tallow again can be either stored directed or sent back, for example, to either the settlement tanks 10 or to one of the cooking vessels 2.

The initial heating step may be at any temperature from between 101 to 110°C, however, generally speaking, there is no need to exceed 104°C. While the ideal temperature to heat the subsequent dry material to is 130°C, this can be easily exceeded and any temperature between 120 and 150°C will allow the fat to fractionise the dry material. The sterilisation can take place by holding the fractionated materials at at least 120°C and ideally at 130°C for anything between 10 and 20 minutes. Again, while in the embodiment described above, the agitation which was said to be stopped for 10 minutes to allow 10 minutes settling within the cooking vessel, this settling time can be less than this such as, 1EΟ 2 04 g 4 -9for example, 5 minutes or could be substantially more, such as 15 or 20 minutes. What is required is to ensure that there is reasonable settlement of the greaves. The temperature in the settling tanks should be normally less than 50°C and may be anything between 45°C and 55°C.

It will be appreciated that there are many ways in which the greaves and some of the tallow can be handled, for example, the greaves and some of the tallow can be removed from the bottom of the settling tank and delivered to the cooking vessel for further processing or delivered to the centrifuge directly or delivered for waste disposal. It will be io appreciated that the tallow recovered from the centrifuge may be delivered to the tallow storage tanks back to the settling tanks or to the cooking vessel.

In the specification the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms "include, includes, included and including" or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

The invention is not United to the embodiment hereinbefore described, but may be varied in both construction and detai withm toe scope of the appended claims.

Claims (12)

1. An animal by-products rendering process comprising:gathering slaughter hall fat products; sending the fat products directly from the slaughterhouse at a temperature of between 5°C and 30°C to a rendering plant; heating the fat products in a cooking vessel while agitating the contents at atmospheric pressure and at a temperature between 101°C and 110°C in an initial heating step; collecting moisture driven off in the initial heating step to leave a moisture free dry material in the cooking vessel; further heating and agitating the dry material at between 120° to 150°C to fractionate the dry matenai into a iquid taflow phase and a proteinaceous sofids phase, namely, greaves; holding and agitating the fractionate materials at at least 120°C for between 10 and 20 minutes to sterilise the materials; stopping the agitation for between 5 and 15 minutes to allow the greaves to settle in the cooking vessel; removing the liquid tallow from approximately half way up the cooking vessel and sending it to a storage tank; delivering the rest of the material comprising tallow and greaves liquid mixture through a screen in a percolating bin to separate large sized greaves from the liquid mixture; IE02 049 4

2. A process as claimed in claim 1 in which intestinal fats are removed from the carcass by:directing a pressurised jet of air and water into the intestinal cavities to flush out the intestines; cutting up the flushed intestines; allowing the intestines to drain for between 10 and 30 minutes; and sending the drained intestines with the other fat products from the slaughterhouse.

3. A process as claimed in claim 2, in which the products are drained for approximately 20 minutes.

4. A process as claimed in any preceding claim, in which:the initial heating step is carried out at between 101 °C and 104°C; the extracted water vapour is condensed; and the condensed water is sent to an activated sludge treatment plant. IE Ο 2 04 9 4 - 125. A process as claimed in any preceding claim, in which the heating to carry out the fractionation of the dry material is carried out at approximately 130°C.

5. Are held at approximately 130°C for approximately 15 minutes.

6. A process as claimed in any preceding claim in which the fractionated materials

7. A process as claimed in any preceding claim, in which one or more of the following optional steps are performed of:10 (a) the greaves and some of the tallow are removed from the bottom of the settling tank and delivered to the cooking vessel for further processing; (b) the greaves and some of the tallow are removed from the bottom of the settling tank and delivered to the centrifuge; and (c) the greaves and some of the tallow are removed from the bottom of the setting tank and oowered to waste disposal.

8. A process as claimed in any procedng dam n whach tie step of removng the 20 tallow from Ihe settling tank comprises lowering an extraction pipe, while using a sight glass on the tank wall, into the settling tank to a position above which the greaves and particulate matter have settled and then removing the tallow from the top of the settling tank and delivering it to an additional settling tank. 25

9. A process as claimed in any preceding claim, in which the tallow recovered in the centrifuge is delivered to the tallow storage tank.

10. An animal by-products rendering process substantially as hereinbefore described with reference to the accompanying drawings.

11. Tallow produced in accordance with the method of any preceding claim. -11 delivering the liquid mixture to a settling tank to separate tallow from the remainder of the greaves while maintaining the liquid mixture at between 45°C and 55°C; delivering at least the greaves from the percolating bin to a centrifuge to dry the greaves; storing the greaves; and removing the tallow from the settling tank to storage.

12. Dried greaves produced in accordance with the method of any of claims 1 to 10.