MEASURING MEAT TENDERNESS

Abstract: A device (1) to aid in determining tenderness of meat. The device (1) includes a body (2) which supports a load cell (6) and an elongated probe (4). The probe (4) has a leading tip (5) provided with four tip pins (16) which engage the meat and provide resistance to movement of the probe (4) through the meat sample. The four supplied to the probe (4) is registered by the load cell (6) that produces a signal indicative of the force. Surrounding the probe (4) and slidably mounted in the body (2) is a piston (3) wich is movable from a forward position to a tracted position exposing a greater length of the probe (4). The forward end of the piston (3) is provided with prongs (8) which aid in locating and securing the device (1) in the correct position with respect to the meat sample.

Description: - 1 - MEASURING MEAT TENDERNESS FIELD OF THE INVENTION The. present Invention relates to the meat Industry and more particularly to a probe to aid in classifying meat in respect of tenderness and exterior fat layer thickness. BACKGROUND OF THE INVENTION Traditionally, meat, Including beef, lamb, and pork, has generally been classified by means of inspection carried out preferably by a trained inspector. However, it is a disadvantage of this method that the classification is generally unreliable due to varying standards between Inspectors, and that inspection is generally merely visual. Various devices have been proposed to determine the tenderness of meat. These devices have generally been unsuccessful. It is the object of the present invention to overcome or substantially ameliorate the above disadvantages. SUMMARY OF THE INVENTION There 1s disclosed herein a device to aid in determining the tenderness of meat, said device comprising: a body to be gripped by a user; an elongated probe member fixed with respect to said body and extending fowardly therefrom in the direction of intended movement of the device, said probe having a forward extremity adapted to penetrate the meat sample; a piston sUdably mounted in said body for longitudinal movement along said probe, said piston being movable relative to said probe from an Initial start position spaced towards said extremity, and a retracted position displaced rearwardly from said start position exposing a greater length of said probe; and a load cell in communication with said probe member to provide a signal indicative of the force applied to said extremity as it penetrates a meat sample. There is further disclosed herein a tip for a device to aid in determining tenderness of meat, said tip comprising a tip body to be attached to the forward end of a probe, and a plurality of forwardly extending tip pins attached to said body. The present invention also comprises methods for determining meat tenderness and fat thickness. BRIEF DESCRIPTION OF THE DRAWINGS A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein; Figure 1 is a schematic sectional view of a device to aid 1n determining tenderness of meat; Figure 2 is a schematic sectional view of a second embodiment of a device to aid in determining tenderness of meat; Figure 3 is a schematic sectional view of an end of the probe of the devices of Figures 1 and 2; Figure 4 1s a perspective view of the device of Figure 2, with slight modifications, performing a fat measurement; Figure 5 is a schematic sectional view of a modification of the device of Figure 2; Figure 6 is a schematic part sectioned side elevation of the probe employed in the device of Figure 5, with an N-cap removed; Figure 7 1s a schematic end elevation of the probe of Figure 6; and Figure 8 1s a schematic sectioned side view of a leading portion of the device of Figure 5. BEST MODE AND OTHER EMBODIMENTS OF THE INVENTION In the accompanying drawings there is schematically depicted a device 1 to aid in the classification of meat (in the form of whole carcasses) in respect of eating quality. That is, to rank carcasses in order of their toughness. The device 1 of Figure 1 performs two tests. The first of these tests determines the force required to have the tip 5 of probe member 4 penetrate the connective tissue (not shown) extending between a pair of ribs of a carcass. Preferably, the connective tissue tested would be that extending between the twelfth and thirteenth rib. The second test determines the force exerted while penetrating the probe 4 a predetermined distance into the eye (not shown) behind the connective tissue. The device 1 includes a body 2 of generally cylindrical configuration, having an internal bore 18. Slidably mounted within the bore 18 is piston 3. The probe 4 is rigidly affixed to the body through its attachment to a load cell 6. Piston 3 terminates at its forw?"d end with cap member 17 through which the probe 4 extends. The extremity 117 extending forward of the cap member 17 is tapered to a diameter which is smaller than the tip 5 diameter. Formed integrally with, or attached to cap member 17 are prongs 8. The forward end of probe 4 Includes four pins 16 which extend forward and are covered by pin cover 24 (Figure 3 ) . Pin cover 25 may be fixed to 4, so as to completely cover pins 16, or leave pins 16 partially projecting outwardly therefrom. Alternatively pin cover 24 could be slidable so as to selectively cover or uncover the pins. The cover 25 also serves to clean the pins 16 when urged forward over the pins. In the embodiment of Figure 1, the body 2 is provided with a pivoting catch member 7, the purpose of which is to selectively engage and detach the piston 3 from body 2. Piston 3 is provided with an annular groove 15 into which catch member 7 normally extends to axially fix the body 2 to the piston 3. Fixed within the body 2 is guide member 11, having radial tip projections 111, through which a rear extension 4' of probe 4 extends. Extension 4' is attached to the load cell 6 which in turn is attached to body 2 by means of a rigid attachment member 19, secured in position by a screw 19. Fixed to the inside of piston 3 is retaining ring 10 onto which abuts one end of the spring 20. The other end of the spring 20 abuts a terminal recess 21 of guide 11. Within the piston 3, there are grooves or tracks 9 in which the projections 111 formed on the guide member 11 ride. Tracks 9 are provided with an optional helical portion 9' and angularly offset portion 9" whereby guide member 11 and hence body 2 must rotate with respect to piston 3 as the projections 111 traverse the helical portion 9'. The need for the helical portion 9' and offset portion 9" depend entirely on the characteristics of the load cell, as will be explained. At the rear end of body 2 is attached a threaded adjustment cap 13, the purpose of which is to adjust the force on and position of the load cell 6 and thus establish a datum. A computer or other recording means is connected to load cell 6 to record the force readings. In use, catch 7 is initially engaged with the annular groove 15. The device is then grasped by body 2 and the prongs 8 are pierced into the carcass to locate and avoid ribs. Once a rib-free area is lonted and face 23 of piston cap 17 is flush with the carcass, catch 7 is pressed so as to render body 2 and piston 3 axially relatively movable. With pins 16 now extending from the retractable pin cover 25, the body 2 and probe 4 are pushed forward relative to the piston 3. At the same time, the load cell 6 experiences the force exerted on the probe tip pins 16. As the probe moves into the carcass, pins 16 surround at least one strand of connective tissue to ensure that the strands are not spread apart or radially displaced as probe 4 is advanced. The body 2 is advanced until slots 22 encounter the helical portion 9' of track 9, by which point the connective tissue has been punctured or torn. Body 2 is then rotated while still being advanced so that slots 22 are now riding on track portions 9". As force is still being applied, probe member 4 continues further into the eye of the meat. As this occurs the reading transmitted from the load cell 6 to the computer conveys the tenderness of the meat being tested. It should be noted that 1t Is envisaged that pins 16 may optionally be retracted into cover 5 during the meat tenderness reading (i.e. after the connective tissue 1s punctured). It is also envisaged that this two step procedure may be replaced by a one step procedure whereby helical portion 9' and offset portion 9" of track 9 may not be necessary, i.e. track 9 could be a continuous straight section or done away with altogether. Conventional, present load cell and computer technology require a pause between the puncture of the connective tissue and the tenderness reading primarily to allow the load cell to reset. It 1s for this reason that helical portion 9' forms part of this preferred embodiment. Upon completion of the above procedure, probe 4 is extracted from the meat and spring 20 acts to return piston 3 to the position depicted in Figure 1. As shown in Figure 2 an alternate embodiment of the device includes a coil or double wound coil 21' located within and retained by the bore 18. When energized, the coil produces a magnetic field. As the spring 20 Is compressed by the retracting piston 3, the variation in the coil voltage is observed, because the amount of metal in the coil's field increases as the spring 20 compresses. This allows a distance or penetration measurement to be made with the combination of coil 21' and spring 20. To take a tenderness measurement with the device shown in Figure 2, a user would typically enter a personal I.D. number and other relevant information including carcass I.D. number into a keypad which is associated with the computer which monitors the load cell output and coil voltage. The operator then locates a bone free area of meat using the - 5 - prongs 8, then pushes the probe tip 5 and cap tip 117 into the meat until the cap 23 is flush with the sample area. The release mechanism 7 is then released, whereupon further advancement of the body 2 drives the probe 4, but not the piston 3, into the sample. As the probe tip pins 16 enter the carcass or sample, frictional resistance against the tip 5 allows the pins 16 to become unsheathed as the cap 25 retracts. Simultaneously, the spring 20 begins to compress, which results in a coil voltage change. The instant the forward movement of the pins 16 is detected by the coll arrangement 2V , a force reading is obtained from the load cell 6. A force reading is then obtained at regular pre-set intervals (e.g. every 0.5 mm) until a maximum penetration is detected or the device is withdrawn. By measuring the force on the load cell 6 at fixed intervals, the CPU of the computer (through programmed instructions) can calculate the mean of the total force curve over distance curve. As an alternative the CPU could be programmed to calculate the mean of the force peaks. Once the mean of the force curve or peak has been stored, preferably in nonvolatile memory, the CPU may then calculate the tenderness of the sample using a linear equation. The result of the interpretation of the force curve or peak mean is preferably expressed as a value on a scale of 1 to 5, with 1 being very tender and 5 being very tough. Stored data may be easily transferred to a storage device, printer or personal computer, either for further analysis or printing labels etc. As shown by Figure 4, the device described with reference to Figure 2 can measure the amount of fat on a dressed carcass. The device 1 must first be modified by locating tubes 40 over the prongs 8. The tubes may be retained by set screws 41. In the alternative, the prongs 8 may be provided with an enlarged diameter rear portion. Either variant forms a step 42 in the effective prong diameter which resists penetration into a layer of connective tissue. To perform the fat depth measurement, the operator pushes the prongs 8 through the layer of external fat 43 of a sample, until the step or tube ends 42 contact the layer of connective tissue 44 under the fat layer 43. The operator can sense the resistance offered by the connective tissue 44. The operator then depresses the release or catch 7 and advances the body 2 and probe. When the probe tip 5 comes into contact with the external fat 43, the load cell 6 registers a rise in the applied force. At this moment, the force reading causes the CPU to take a reading from the coil position sensor 21'. This position of the probe relative to the piston 3 is referred to as the start distance. As the pins and tip of the probe penetrate the fat layer 43, the force over distance curve remains relatively flat. When the probe reaches the connective tissue 44 the force over distance curve rises sharply. This is interpreted by the CPU as a cue to take a reading from the position sensor 21'. This distance measurement is referred to as the end distance. The difference between the start and end distance measurements represents the depth or thickness of the fat. While the device and method of the present invention have been described with reference to particular construction details and operations, these should be understood as having been provided by way of example and not as limitations to the scope or spirit of the invention. In particular, a range or probes 4 and tips 5 may be provided being suitable for various different quality and types of meat. Further a wide array of signal processing devices and computational tools such as CPU's, input devices and output devices may be employed for the purpose of accomplishing the beneficial results of the Instant apparatus and method. In Figure 5, there is schematically depicted a modification of the device 1 of Figure 2. In this embodiment, the load cell 6 is supported by the rigid member 19 by two or more bolts 19'. The bolts 19 extend through passages in the body 2 and are covered by means of a cap 13. At the leading portion of the device 1, the extremity 117 is modified so as to consist of a body 118 which threadably engages an end wall 119 of the body 1, and a nut 120. This arrangement of the extremity 117 allows for adjustment of the start load to be applied to the cell 16 and to provide a datum. In Figure 6, the tip 5 of the above discussed embodiments is shown. The tip 5 includes a cap consisting of a cap body (not shown) and a cap body retainer 26. The cap body retainer 26 threadably engages the cap body to retain it in position. The total assembly of cap body and cap retaining member 26 are slidable along the body of the probe 4 to expose the pins 16.

Claims: AMENDED CLAIMS [received by the International Bureau on 17 October 1991 (17.10.91); new claim 11 added (1 page)] 10. The tip of claim 9, wherein there are four of said tip pins. 11. The device of claim 3 further including a position sensor for determining the distance of penetration of the device, said position sensor comprising a coll through which an electric current may flow, the coll being wound around at least a portion of the body of the device, and means for sensing the voltage across the coll.

Inventors: JOHNSTON GEOFFREY, JOHNSTON, GEOFFREY
Applicants: JOHNSTON GEOFFREY, JOHNSTON, GEOFFREY
Application year: 1991
Main classification: G01N33
IPC codes: G01N3, G01N33