Equipments Needed for Processing Organic/Natural Pork Products
The demand by consumers for organic and natural meat-based foods, including that of pork products, has grown tremendously over the past decade. Numerous food manufacturers have developed and are marketing organic processed pork products and several retail markets specialize in the sale of organic meat products to today’s consumers. For the growth of organic processed pork products and ensuing their trade, one needs to have clear understanding about the various equipments required for processing of different categories of value-added pork products. Details of some of the relevant equipments are mentioned hereunder.
Meat grinder/ Meat mincer
A meat grinder is a machine used to force meat or meat trimmings by means of a feeding worm (auger) under pressure through a horizontally mounted cylinder (barrel). At the end of the barrel there is a cutting system consisting of star-shaped knives rotating with the feeding worm and stationary perforated discs (grinding plates). The perforations of the grinding plates normally range from 1 to 13mm. The meat is compressed by the rotating feeding auger, pushed through the cutting system and extrudes through the holes in the grinding plates after being cut by the revolving star knives. Simple equipment has only one star knife and grinder plate, but normally a series of plates and rotary knives is used. The degree of mincing is determined by the size of the holes in the last grinding plate. If frozen meat and meat rich in connective tissue is to be minced to small particles, it should be minced first through a coarse disc followed by a second operation to the desired size. Two different types of cutting systems are available, the “Enterprise System” and the “Unger System”:
- The “Enterprise System” is mainly used in smaller meat grinders with orifice diameters up to 98 mm and consists of one star knife, sharpened only on the side facing the disc, and one grinder plate. Hole diameters can vary from 13 to 5 mm.
- The “Unger System” is used in meat grinders with orifice diameters up to 440 mm and consists of the kidney plate, one- or two-star knives sharpened on both edges and one or two grinder plates. For a final particle size above 8 mm the recommended setting is kidney plate – star knife – grinder plate. For a final particle size <8 mm the recommended setting is kidney plate – star knife – grinder plate (13 mm) – star knife – grinder plate (6 to 1 mm).
The smallest type of meat grinder is the manual grinder designed as a simple stuffing grinder, i.e. meat material is manually stuffed into the feeder. For all these small machines the Enterprise cutting system is used with one star knife and one grinder plate. These machines are very common everywhere in food processing but their throughput and production capacity is limited due to the small size and manual operation. The intermediate size meat grinder, also designed as a stuffing grinder, has orifice diameters up to 98 mm. It is driven by a built-in single-phase electrical motor (250 V) and available as both a table and floor model. The meat is put onto the tray and continuously fed by hand into a vertical cylindrical hole leading to the feed auger. The meat or fat is forced by its own weight into the barrel with the rotating feed auger. This type of meat grinder is the most suitable for commercial small-scale operations. Some brands use the Enterprise cutting system, others the Unger system. Large industrial meat grinders are driven by a three-phase electrical motor (400 V) and equipped with the Unger cutting system. The orifice cylinder diameter of this type of grinder ranges from 114 – 400 mm. Most of the industrial meat grinders are also equipped with a device for separating tendons, bone particles and cartilage.
Manual grinder
Grinder as table model
Grinder as floor model
Installation
Care must be taken that grinders are positioned properly. Most grinders have adjustable rubber feet. This allows the horizontal levelling and avoids transfer of vibration from the machine to the table (small models) and floor (industrial grinders). The initial electrical connection to the power supply line should be done with an empty housing (auger / feeding worm and cutting set removed) for safety reasons. Industrial size meat grinders are usually driven by three-phase motors and the direction of rotation must be checked. When viewed from the front, the feeding worm must rotate counter-clockwise. The cutting set is attached to the feeding worm with the cutting edges of the star knives facing counter-clockwise. Before starting the machine for the first time, all parts must be thoroughly cleaned and dried. A useful option often used by meat processors, is to run some clean fat through the system to make sure that remains of grease are removed from the housing and the cutting set.
Operations
Apart from the need for frequent cleaning, the cutting system of grinders has to be assembled and dismantled at various times per shift or day to be adjusted to the desired particle size. Care must be taken of the following:
- The grinder plates must be frequently checked for any damage to the surface, as a clear cut is only possible when the grinder plates are kept smooth. If damage such as grooves or scratches appear, the grinder plates must be planed (reground) immediately.
The star-knives (cutters) must also be kept sharp. Cutters are usually sharpened at the cutting edges. In systems with replaceable blades these blades are not sharpened but replaced regularly.
- Grooved grinder plates and blunt star-knives result in poor cutting (mashed ground meats).
- Parts from different cutting sets must not be mounted together, as they might be made of materials of different hardness. This can result in grooved grinder plates or damaged star-knives.
- The cutting assembly must never be over-tightened to avoid excessive friction heat and undesirable heat transfer to the meat.
- A grinder should never run empty as this will damage the knives and blades.
In industrial-size grinders, the electrical motor and driveshaft are connected via V-shaped belts. These belts usually require little servicing. Care must only be taken that the belts are kept at the correct tension. If the belts are not sufficiently tightened they show increased wear, excessively tightened belts lead to increased power consumption and could cause damage to the motor or driveshaft.
Cleaning
Ginders are normally used for mincing raw fresh meat and other animal tissue. Meat grinders and their cutting parts must therefore be cleaned and disinfected frequently – during or at the end of each production cycle in order to maintain a good hygienic status. The most critical spots for cleaning are inside the barrel (feed auger housing). Any meat materials or fats left in the grooves of the thread must be removed by hand, followed by thorough flushing and brushing until all residues are washed out. The driveshaft pin, where the feeding auger is interlocked, must also be brushed and flushed with plenty of water. The use of a high-pressure water cleaner is discouraged here, as this could damage the rubber seal in which the driveshaft pin rotates. After cleaning, the barrel should be dried properly, also to avoid metal corrosion. Cleaning of grinder plates provides a special challenge for responsible staff as care must be taken that the many holes are totally free of impurities. This is very difficult in discs with tiny holes for smaller particle sizes. If a high-pressure water cleaner is available, it should be used.
Bowl cutter/ Bowl chopper
The bowl cutter is the commonly used meat chopping equipment designed to produce small or very small (“finely comminuted”) lean meat and fat particles. Bowl cutters consist of a horizontally revolving bowl and a set of curved knives rotating vertically on a horizontal axle at high speeds of up to 5,000 rpm. Many types and sizes exist with bowl volumes ranging from 10 to 2000 litres. The most useful size for small- to medium-size processing is 20 to 60 litres. Bowl cutters should be equipped with a thermometer displaying the temperature of the meat mixture in the bowl during chopping. Modern large scale bowl cutters may have devices to operate under a vacuum, which helps to improve colour and texture of the meat products by keeping oxygen out of the meat mixes and avoid air pockets. Cutter knives should be adjusted to a distance of 1-2 mm from the bowl for optimal cutting (check the manufacturers recommendations for each model). Most of the large and high-speed bowl cutters are equipped with mechanical discharger devices for emptying the cutter. The process of chopping in a bowl cutter is used for producing fine comminuted products such as frankfurters, bologna, liver sausage etc., and enables processors to offer a much wider range of products.
Small 15 litre bowl cutter, single-phase motor
Large 50 litre bowl cutter, three-phase motor
Bowl cutter filled with meat for chopping
LBowl cutter with meat emulsion
Installation
Small table models operate on single-phase electrical power. The equipment is usually positioned on a suitable working table. The operator has to make sure that the knives are installed in the right position and securely tightened. Upon connection to the power supply, the bowl cutter is operational. Other details are similar to bigger models and are explained in the following paragraphs. Bigger bowl cutters (floor models) need to be positioned with the rim of the bowl levelled horizontally, using the adjustable rubber-feet. The rubber feet should not be replaced by metal bolts, as they facilitate the smooth running of the bowl cutter. The knives (blades) are inserted following the recommended scheme and must be tightened firmly. Care must be taken that the knife head (Fig. 18.10d) rotates freely in the bowl and cover (always rotate one initial round by hand) and all knives have a sufficient but not too wide clearance (1-2 mm) from the bowl. After a few rounds at slow speed, the knives must be tightened again firmly. To avoid unnecessary vibrations from the knife head, bowl cutter knives should be balanced (equilibrated). In bigger bowl cutters with large knives, special balancing sets are used.
Operation
Care must be taken that no metal or other hard materials accidentally find their way into the bowl cutter. It is advisable to frequently check all bolts, nuts and screws, especially around the cover. The cut-out safety switch must be checked regularly to ensure that the knife shaft brake stops the machine immediately if the cover is erroneously opened during operations. The built-in thermometer should also be frequently checked as it could get damaged by vibrations. All lubrication points (grease nipples) have to be greased following the instructions given by the equipment manufacturer and oil changing intervals must be observed. As a rule of the thumb, the knife shaft is usually greased monthly and the motor shaft six-monthly. The oil in the gear assembly (gear box) should be changed yearly.
Cleaning
Special care must be taken during cleaning. The spaces between the knives must be properly cleaned to remove all residues of batter mixes. A brush with long handle should be used to avoid injuries. A critical spot for cleaning is the narrow gap between the rotating bowl and the housing of the knife shaft as well as the paddle on the bowl cover. The knife head should be dismantled regularly for proper cleaning (once a week) and reassembled following the instructions given before. Moisture and defective seals in switches have a significant negative effect on the functioning of a bowl cutter. When high pressure cleaners are used, direct contact of the water jet with the switches must be avoided. The noise protection lids and front parts of vacuum covers are often made of transparent plastic and must be cleaned with mild cleaning agents to maintain their see-through appearance.
Sausage filler/ Sausage stuffer
These machines are used for filling all types of meat batter in containers such as casings, glass jars, cans etc. The most common type of filling machine in small and medium size operations is the piston type. A piston is moved inside a cylinder forcing the meat material through the filling nozzle (funnel, stuffing horn) into the containers. Piston stuffers are either attached to the filling table or designed as floor models. Modern filling machines for larger operations are designed as continuous vacuum stuffers. During the filling process a substantial part of the enclosed air is removed from the product, which helps to improve colour and texture of the finished products. These models are usually equipped with a portioning and twisting devise and have a casing grip devise attached for filling of “shirred” (folded) uncut collagen and plastic casings. This type of continuous filling equipment is relatively expensive and is thus not used in small- to medium-size operations.
Manual sausage stuffer (5 Litre)
Hydraulic sausage stuffer (10 litre)
Piston stuffer (20 litres)
Installation
Hydraulic sausage stuffers must be placed on an even floor. Before the machine is connected, the power supply with correct voltage (V), frequency (Hz) and power (kVA) must be confirmed. The oil level in the hydraulic tank should be controlled to avoid dry-running of the oil pump and ensure sufficient oil pressure development. In 3-phase (380 V) powered stuffers, it must be confirmed that the piston shaft is moving in the right direction. The piston must be mounted straight to allow smooth vertical movements in both an upward and downward direction.
Operation
Before the start of each operation, care must be taken that the rubber gaskets are inserted in the piston and lid and funnels of the correct size are firmly attached. The hydraulic oil must be checked regularly and topped up to maintain the required level. If the oil shows signs of wear (white emulsion-type content or water at the bottom of the tank) it must be replaced to avoid damage to the pump. Strictly avoided should be dropping the funnels on the floor to ensure that they fit neatly onto the outlet opening and maintain their smooth surface as scratches can lead to damaged casings.
Cleaning
During cleaning the piston must always be removed to allow for thorough cleaning of the whole cylinder. The rubber gaskets must also be removed from the piston and cleaned as remains of sausage mixes could settle in the groove. An opening at the bottom of the cylinder allows the cleaning water to drain out. The funnels must be cleaned with a special brush. A simple method for cleaning the funnels is to first push a compacted wet piece of paper towel through the funnel to remove meat materials or sausage batter from inside. As this is a clean operation, such recovered meat materials can be recycled in the production. Wet cleaning is then carried out by using the funnel brush.
Clipping machine
Clipping machines place small aluminium sealing clips on the sausage ends and replace the manual tying of sausages. They can be used for artificial or natural casings. Clipping machines can also be connected to filling machines. Such machines work with so called casing brakes, which are devices for slow release of the shirred casings from the filling horns ensuring tight filling. Then the filled casing segments are clipped in portions. So called double clipping machines place two clips next to each other, which ensures that the individual sausage portions remain clipped on both ends and easy separation of the sausage portions is possible. When using shirred casings, the time consuming loading of pre-cut casings is no longer necessary. Wastage of casings can be reduced to a minimum by tight filling and leaving only as much casing for the sausage end as needed for the placing of the clips. Clipping machines are mainly used in larger operations and in most cases operated by compressed air. For medium-scale operations manually operated hand clippers are available.
Manually operated sausage clipping machine with clip rails
Brine injector
This equipment serves for the injection of brine into meat. Brine is water containing dissolved salt and curing substances (nitrite) as well as additives such as phosphates, spices, sugar, carrageenan and/or soy proteins. The injection is done by introducing pointed needles into the muscle tissue. Brine injection is mainly used for the various types of ham, bacon and other whole muscle products. Brine injectors are available in different sizes from manually operated single-needle devices for small-scale operations to semi-automated brine injectors with up to 32 needles and more. In large machines the quantity of brine injected into the fresh meat can be determined by pre-setting of pressure and speed. It is very important that all parts of the brine injectors are thoroughly cleaned after every working session and disinfected regularly. Before the injector is used again all hoses and needles should be rinsed with warm water as particles left in the system can block the needles. Absolute cleanliness is necessary as microorganisms remaining in the system would be injected deep into the meat pieces during the operation.
Brine injector, pump driven with multi needle device (for small pieces)
Brine injector, pump driven with multi needle device (for large cuts)
Tumbler or Massager
Tumblers are used for the processing of meat products such as whole-muscle or reconstituted hams. Such machines resemble in principle a drum concrete mixer. A rotating drum with steel paddles inside slowly moves the meat pieces thus causing a mechanical massaging effect. This mechanical process is assisted by the addition of salt and phosphates to achieve equal brine distribution and liberates muscular protein from the meat tissue (protein extraction). The semi-liquid protein substances join the meat pieces firmly together during later heat treatment. For hygienic reasons it is important to place the tumbler below 10°C to avoid excessive microbial growth during lengthy tumbling times (more then 4 hours or even over night). In specific cases it is recommended that the tumbler should be operated refrigerated or inside a cold room below -1°C, as these temperatures are best to extract as much soluble protein as possible from the muscle meat.
Vacuum tumbler
Creating vacuum inside the tumbler
Vacuum packaging machine
For vacuum packaging the meat product has to be placed into a vacuum bag (multi-layer synthetic bag). Air is removed from the bag by means of the vacuum packaging machine and the bag then sealed. Special vacuum packaging machines can operate with so called gas-flushing, where a mixture of gas is injected after evacuating the air. Such protective gas atmospheres inside the product package inhibit bacterial growth and stabilize the meat colour. The gas mixtures usually contain CO2 and N2.
Vacuum packaging machine
Products after vacuum packaging
Ice flaking machine
In these machines ice flakes are continuously produced from potable water. Ice is needed in meat processing for some types of meat products. Water, added in the form of ice, is an important ingredient in order to enhance protein solution and to keep the temperature of the meat batter low. Ice flakers with in-built UV-water-disinfection device are available for areas with unsafe water supply.
Ice flaking machine
Ice-flaking machine with ice
Smoke oven
Products after smoking
Band saw / Bone saw
In most meat shops and meat cutting operations, band saws are used to facilitate the breaking of carcasses. In meat processing operations, band saws can also be helpful for cutting of frozen meats. Band saws are available as table and floor models and are made of stainless steel. The band saw blade moves mainly inside the body by rolling over two large wheels. Only a small portion of the rotating blade is exposed just above the band saw table on which the material to be cut is moved.
Band saw/ Bone saw – closed
Band saw/ Bone saw – opened
Installation
After being positioned at its designated place and levelled, the band saw must be assembled carefully. The body door is opened and the band saw blade is pushed over the two wheels with the cutting teeth facing the door opening and fitted into the guide. By adjusting the upper wheel with the tensioning knob, the tension of the blade is corrected to allow for a firm grip between wheels and blade. The band saw must be connected properly to the electrical power supply line. Care must be taken that the band saw blade rotates in the right direction, with the blade moving downwards at the exposed portion. The materials to be cut will be kept firmly on the table in this direction only.
During cutting operations, the material to be cut must always be moved on the table by using the safety cutting handle. The band saw must be cleaned frequently and disinfected at the end of daily operations. First the door is opened and the tensioner of the band saw blade released. The blade is taken out of the machine and cleaned separately and must be stored in a dry and safe place. All meat, bone and fat particles which have accumulated inside the space where the blade circulates must be removed and the machine cleaned thoroughly. The door should be kept open to avoid corrosion due to moisture.
Cooking utensils
- Cooking vat
Cooking vat is a double jacketed chamber with heating coils. It can be used both for immersion cooking (e.g. sausages) and steam cooking (e.g. formed ham). Modern cooking vats are equipped with thermo regulators and cut off mechanism once it attained the required temperature. Cooking vats are used to pre-cook raw materials and pasteurize meat products (sausages, hams). In small scale facilities without piped hot water supply, cooking vats are also used to heat up the cleaning water. When cooking vats are not used, stagnant water must be avoided by keeping the water outlet open. In gas and oil fired vats, burner elements and ignition flames must be frequently checked and cleaned. Most cooking vats are equipped with a thermostat, which needs to be monitored to confirm its readings. During cooking the sensor of the thermostat must be completely covered by water to avoid damage and wrong temperature reading. Cooking vats should never be heated up without a sufficiently high water level to avoid damage to the stainless steel shell.
Cooking vat
With frankfurters for cooking
- Hot air oven
A hot air oven can be used for those products which need to cooked under dry heat e.g. patties/ burgers, kababs etc.
Hot air oven
Patties are loaded for cooking
Equipment for personnel
The provision of hygienic equipment and personal protective equipments essential to prevent contamination of meat and meat products through contact with clothes, shoes or direct contact with hands or breath. Some appliances and protective clothes, boots etc. also serve to protect workers from accidents.
- Hygienic equipment and materials
Protective clothing: To avoid contamination of workplaces, materials and products from street clothes, workers have to wear clean protective clothing. Either one-piece overalls or two piece sets are recommended as they cover the complete body. In some workplaces only overcoats are used with the disadvantage that the trousers/skirt is not covered.
Head gear: Human hair on equipment, materials and products must be avoided. Caps and/or hairnets are used to cover and contain hair.
Gloves: In meat processing, staff are encouraged to wear latex gloves to avoid direct contact of materials and products with hands. This is of special importance during packaging, when also mouth protection is recommended to avoid contamination of fresh and processed products.
Gum (rubber) or plastic boots: These boots are used to protect staff in meat operations from moisture. The sole design facilitates a firm grip on slippery surfaces. For easy detection of dirt, boots are usually white.
Plastic aprons: This type of apron is used to protect workers and their working clothes from moisture, meat and fat. Plastic aprons should be long enough to overlap the boots, thus allowing splash water to rinse off.
- Appliances for safety reasons
Safety aprons: Almost 50% of all injuries in meat operations are caused by knives. Most of these occur during deboning when the knife is moved towards the body. To avoid such injuries, special safety aprons should be used, covering the front of the body. Safety aprons can consist of a tight mesh of stainless steel rings or overlapping aluminium chips. To avoid unnecessary meat and fat settlements in the mesh, the safety apron is worn under a plastic apron.
Safety gloves: To avoid injuries to the hand handling the meat material during deboning and cutting, a safety glove is highly recommended for this hand. These gloves are made of a tight mesh of small stainless steel rings and should be chosen long enough to also cover the wrist. To avoid unnecessary meat and fat residues in the mesh, the glove can be covered with a latex glove.
Safety helmets: In workplaces where there is a risk of objects falling, staff are encouraged to wear safety helmets made of firm plastic. Helmets are strongly recommended are slaughter lines, below overhead rails and in storerooms with high shelves.
Hygienic and protective materials
Metallic gloves
Knives
Due to the multiple operations in the meat sector different types of knives are used for different purposes. There are knives for bleeding, flaying and evisceration of animals as well as for deboning of carcasses, cutting of meat and slicing of choice cuts and processed products. All these knives have very specific design features to support the operations they are made for. Knives are also used for cutting of other raw materials and casings. Knives used in meat operations should have basic safety features. The handle should be made of plastic material with non-slip surface and designed to allow a firm and safe grip. Plastic handles are also a hygienic requirement. The end of the handle is often slightly enlarged (handle knob) to prevent the knife from slipping out of the hand and the portion close to the blade should have a similar enlarged design to avoid the hand from slipping over onto the blade.
It is of utmost importance that knives are handled with care to avoid injuries to workers and damages to the knife itself. When working with meat, knives must be cleaned frequently to eliminate the risk of cross-contamination. Knives must also be sharpened in a proper way to avoid unnecessary wear and kept sharp to reduce the potential for injuries. Working with a blunt knife requires more force and results in a higher risk of slipping off the meat or bone. It also leads to early fatigue and slower work speed. The correct shape of the blade at the cutting edge is very important to facilitate a long-lasting sharpness and allow for easy whetting during operations. The recommended shape is a slightly convex cutting-edge area as this ensures a firm structure and facilitates smooth cutting through meat and sausages. Cutting edges showing straight or even concave shapes result in very thin blade edges with an increased risk of small cracks and also require more handling force by workers.