Removing Bone and Hard Particles from Ground Meat
With increased consumption of ground meat, especially ground beef, quality issues for these products have become more important to industry and consumers alike.
Ground meats are usually obtained from relatively low-value cuts and trimmings, and may on occasion contain undesirable hard particles. Hard particles in coarse-ground meat products may include bone chips or fragments, cartilage and dense connective tissue; all of which are considered undesirable and can be reduced by utilising hard-particle removal systems during grinding operations, these systems are commonly known as BES (bone elimination system).
BES fitted to TSMI 1000-200
BES fitted to C250 Grinder on an
existing BES mount
BES fitted to C250 Grinder on a
retrofit BES mount
There are two commercial systems available; they are classified as central removal and periphery removal systems, the latter of which Wolf-Tech Engineering promotes.
It is important to highlight the principles of hard-particle separation from ground meat, and the factors which influence performance of particle separation. Any hard particles within a relatively fluid medium will migrate to an area of minimal movement, in the case of meat within the cutting sets of a grinder, to the outer edge within the knife housing. Any soft material in this area will be forced back into the product stream by the higher density material. This area will become a solid mass of compressed hard material, if a port is introduced within this area the hard material will discharge via this port.
Product and processing parameters such as initial bone and connective tissue content, temperature, pre-grinding size and grinder knife design are considered important for removing hard particles effectively.
The most important factor in removing hard particles is to know that any device will only remove particles larger than the Holeplate hole diameter, obviously anything smaller will pass through the holeplate.
Temperature is a key issue relating to colder products, BES units will only work effectively above -4 degrees C, below this temperature frozen product become indistinguishable from hard particles.
Pre-grinding size is important because if the product is pre-ground to a size close to the final grind size any hard particles will have been reduced in size and may pass through the final holeplate. Any pre-grinding size should be at least twice the final holeplate size, but better at three times. Also if the product is pre-ground too small it will result in reduction of product compression pressure at the cutting sets it will result in fat separation and product smearing due to lower product transient speed through the cutting sets.
Knife design should be considered, for the central removal system a straight knife with the rake of the knife facing forward of the perpendicular will encourage any hard particles to be moved to the centre area of the hole plate. With the periphery removal systems the knife should have the rake facing backwards of the perpendicular to move any hard particles, unable to pass through the holeplate, to the outside of the holeplate again with a strait edged knife being preferable, ideally with a centre “V” design knife blade profile.
At no time would we recommend a semi-circular or Sycle knife-blade for use in BES operations as these tend to hold the product within the concaved area of the knife forcing the product and any hard particles through the holeplate. This type of knife is ideal for pre-cutting.
Wolf-Tech Engineering offers a BES for all sizes of grinders and from many differing manufacturers. The standard rotary BES can be adapted for many types of machines with adapter plates and/or modification of the grinder knife housing.
Wolf-Tech Engineering offers a bone elimination system for grinding fresh meats (i.e. without ice crystals) and the Wolf-Tech Bone Elimination System has a peripheral discharge with a variable timing sequence and a controlled volume discharge quantity.
This set-up enables the user to adjust the rate of elimination to specific products, thus cutting way back on yield losses from taking out good product.
The Wolf-Tech BES has a single moving part so enhances the reliability of the unit. It is completely operated by pneumatics externally and controlled by low voltage electrical timers within the main control panel. This allows a totally safe wash-down with the unit quickly removed by screw clamp and quick release air fittings.
BES fitted to Combigrind 1500-200.
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