The range of products that is placed on the market sliced or pre-cut is already much larger than many would believe. It includes not only cold- and hot-smoked fish fillets but also more and more seafood products that require slicing, from the ready-to-eat squid ring to the delicate crustacean carpaccio. In recent years, portion cutting and slicing requirements have continued to grow and have pushed ahead developments in this area. Whereas in the past one multi-purpose machine was usually enough to handle all cutting and slicing jobs the higher performance requirements of today’s markets can often only be fulfilled using special machines. There are slicers and portion cutters for fresh and frozen products that can be designed as single, double or multi-lane machines. Machines for the high-speed production of fixed weight and fixed length products stand out for their extremely high slicing speed, and multi-blade horizontal slicers cut up whole pieces into numerous equally thick slices in one go.
Pre-sliced smoked salmon sides is a common standard
Although the standard product is still the diagonal cut through the fillet, there are today also long slice machines which cut the fillet over its entire length. Linking the slicers to modern computer controls opens up further possibilities. Some slicers can vary the cutting angle within the batch from the tail to the head of the fillet, thereby enabling slices with equal surface areas. Other machines successively change slice thickness so as to produce slices of equal weight. Machine manufacturers are always coming up with new ideas for their machines so as to give them new capabilities and performance features. This in turn gives potential users from canteen kitchens to small-scale and industrial fish processors a huge number of cutting options and slicing programmes.
Sometimes it is a user’s particular need that drives forward the development of additional technical features for cutting machines. But just as often it will be the manufacturers themselves who invent new cutting variants which then open up opportunities for fish processors to save time, increase productivity or offer innovative products. For example, cutting pockets into fillets which can then be filled in various ways, or slicing very thin slices that can be used for making roulade-like products. Who would have thought a few years ago that even extremely sensitive, fragile products such as hot-smoked or poached salmon could be carefully divided into pieces of consistently good quality without notable material losses? Modern sensor and computer technology, in combination with precisely controllable rotating blades, meanwhile make it possible to use machines for even highly sensitive work steps which in the past always had to be carried out by hand… for example trimming fillets.
There are suitable machines for almost every requirement
Requests from many consumers and retailers for special product innovations drive developments forward in the cutting and slicing sector, too, and processors are faced time and again with the question as to whether a particular slicing feature is better achieved by hand or with a machine. In the artisanal sector, hand-held slicers such as those in the Whizard series produced by Bettcher Industries are often used for trimming fish fillets or slicing smoked salmon. The rotating circular blade slices the fish fillet precisely in the desired lengths. The width of the slices is limited by the inner diameter of the circular cutting unit, and an adjustable thickness template ensures constant slice thickness. The operation of these work-saving devices requires some experience and skill but can be learned by the user in a relatively short time. Particular advantages of the Whizard trimmer, claims Bettcher, include increased productivity, an improved material yield, and reduced labour costs compared to traditional hand slicing with a knife.
Flexibility and versatility or special features?
Favorable investment and operating costs as well as a wide range of applications make multi-purpose machines the ideal solution for small and medium-sized businesses when it comes to cutting and slicing fish products. Multi-purpose cutters are available in various sizes and performance grades as table models or stand-alone units. However, multi-purpose cutters have the disadvantage that they almost always have to be operated manually which of course uses up manpower. As a rule, the material for cutting has to be guided by hand on a carriage past the rotary circular knife. The machines’ construction, too, imposes certain technical and physical limits on the material that is to be cut. The size of the individual fillet slices, for example, depends decisively on the cutting angle resulting from the position of the carriage in relation to the usually vertically arranged circular knife. With a horizontal alignment of the carriage the blade cuts through the fillet at a right angle, resulting in very small slices. The closer the carriage is to a vertical position, the larger the slices will be. Theoretically, with a 90° positioning of the carriage even long slices would be possible over the entire length of the fillet. However, this will only be possible if the material for slicing is sufficiently stable and does not collapse in an upright position. For this reason, sensitive fish fillets which are to be sliced on multi-purpose cutters are usually frozen, which is sometimes a disadvantage with products which are to be sold as "fresh".
Consistently clean cuts even with a high material throughput
The automatic multi-purpose cutter Slico 700 from Dadaux is intended for the continuous cutting of meat and fish products. The carriage loaded with the cutting material always returns automatically to the initial position after the programmable cut has been carried out. Smooth, sawtoothed or micro-sawtoothed blades ensure a precise, clean result.
A kind of special case in the field of all-round solutions are multi-blade horizontal cutters which are available for manual operation as well as in fully automated designs. Originally, these machines were developed for meat processing in order to save time when cutting compact meat blocks into horizontal slices, such as roulades, steaks or schnitzels. Today, however, they are also used to cut fish products into portions, strips or nuggets. During cutting, the fish piece passes through a series of parallel, rotating circular knives, the distances between which determine the width of the slices. Some devices even allow slice widths of just a few millimeters. The cutting speed and the pressure on the cutting material are adjustable and, depending on the application, knives with different profiles are used. With the fully automatic multi-blade circular blade cutting machine from CRM Food Technology, for example, boneless fresh meat or fish can be cut reliably and precisely into slices, strips, steaks, or schnitzels. Optionally, the systems can even be equipped with ozone disinfecting units to reduce bacterial contamination during operation. Similar systems are used for cutting the annoying bones found in freshwater fish species such as carp (the lamellar fillet structure resulting from the cutting process is held together by the skin, which is not cut). The size of the bone pieces remaining in the fish depends on the distance between the individual knives.
Automation enables integration into processing lines
Applications in industry mostly make use of automatic slicers which can be equipped with a wide range of performance options. They usually combine high capacities, sometimes more than a hundred cuts per minute, with great user-friendliness and enormous flexibility. Some are intended for slicing fresh and smoked fish products, others are particularly suitable for frozen food. One of the most appreciated equipment variants is the automatic cutting angle adjustment which allows for different cutting angles in the course of one slicing process.
This technique is offered, for example, by slicers from Geba, a well-known manufacturer of slicers, now part of the Marel Group. The SC 250 MA fresh slicer has a capacity of up to 250 slices of smoked salmon per minute, with the cutting angle ranging from 10° to 68°. This machine is thus suitable for a large variety of slice variants from sushi slices to bacon cuts or raw fresh salmon portions and cold and hot smoked salmon. It is very easy to change between the slicing programmes. Optionally, the SC 250 MA can also space out the cut slices and portions in batches, which facilitates subsequent packaging. A typical feature of Marel is the combination of the machines with intelligent control and monitoring technology. Each fillet is individually weighed and scanned by a camera to measure its size. From these data the computer then calculates the section profile that is required to make optimal use of the material and meet the final product targets.
Ultra-fine chopping enables full use of raw materials
The cutting machine KUJ V from Kronen Nahrungsmitteltechnik offers comparable performance. The machine cuts slices from 2 to 12 mm, strips from 2 to 20 mm and cubes from 3 to 20 mm in a single operation. The quality of the blades enables exact and very clean cuts without crushing the product. The KUJ V can even process pressure-sensitive products gently because the cutting speed can be regulated in seven stages.
More than 50 different machine models of slicers, dicers and shredders are manufactured by the American company Urschel Laboratories. Depending on the size and design of the machines and the type of material to be cut, several hundred to one thousand kilograms can be chopped per hour. Particularly outstanding in the extensive range of products from the Urschel range are the machines from the Comitrol series which chop cooked and frozen fish parts to flakes or extra-fine particles from which pastes for spreads and fillings can be produced. "Shredded" heads, bones and skins of fish can be used as a basis for fish soups or extruded snacks.
Specific solutions for soft and cold slicing
The Hamburg company Salmco Technik claims to be the only manufacturer worldwide that produces both cold and fresh slicers for salmon and many other types of fish. The product portfolio ranges from simple table models to semi-automatic machines and fully automatic slicing lines. With this tiered range Salmco covers almost all applications of fish processing from small family-run companies to large industrial operations. Many machine solutions are manufactured by Salmco to meet specific customer requirements. For example, a specially modified cold slicer, which is combined with a vacuum packaging machine to produce 200 g packs with sliced products for the retail sector. Salmco slicers are exported to more than 60 countries worldwide.