High-speed slicers for the salmon industry

In 1976 the independent sales representative Rudolf Maass founded in co-operation with Adolf Cavier the company Rudolf Maass + Partner KG in Hamburg. His vision was the development and production of a salmon slicer for industrial use. This was the genesis of the Maass Salmon Slicer CM 176. Through constant, intensive co-operation between producer and customers, the company’s range of slicers grew rapidly.

Since the company was founded 35 years ago Maass + Partner have focused solely on cold slicing technology. With its circular knife the Salmon Slicer CM 176 produced 95 slices a minute in 1976. Today this performance has increased to 350 slices per minute. The main attraction is that due to the automatic adjustment of the cutting angle the yield of slices of a usable size is maximised.

Maass + Partner have one basic machine in their programme, but this machine offers numerous possibilities: from the Maass Salmon Slicer MP 210 which produces 210 slices per minute to the top model CM 576 -350 with 350 slices per minute.

One machine, multiple choices

Maass + Partner have one basic machine in their programme, but this machine offers numerous possibilities: from the Maass Salmon Slicer MP 210 which produces 210 slices per minute to the top model CM 576 -350 with 350 slices per minute it can cut up to 380 kilograms of frozen smoked salmon per hour with one machine, which is about three tonnes a day in a one-shift operation.

“We supply to salmon processors who are geared to high performance“, says Günter Berndt, one of the two company managers. “Due to today’s low margins in the processing industry it is the machine that has to earn the money, and only a high-speed machine can do that.” It is now 35 years since Rudolf Maass and his partner Adolf Cavier built the first slicer of this model and filed for a worldwide patent. The unique feature of Maass machines is the circular blade that rotates horizontally with up to 350 rotations and at the same time turns around itself. It operates within a similarly round stainless steel casing into which the frozen salmon sides are fed from above at an adjustable cutting angle.


Less loss with greater flexibility

Quite a lot has happened since the prototype was completed and demonstrated to potential customers in 1976. “Since then the machine has hardly changed in appearance”, explains Mr Berndt, “but we have increased slicing performance and reliability considerably and greatly reduced slicing losses. We give a written guarantee today for less than two per cent losses.” Considering that the company’s biggest customers slice up to 50 tonnes of salmon per day it is easy to imagine that every per cent less loss makes a very noticeable financial difference.

Over the years there have been notable improvements as regards cutting angle, too, which today can be varied from eight to 45 degrees. Together with the shape of the salmon side the cutting angle determines the size of the slices. The salmon’s shape is, of course, determined by nature and as such cannot be influenced. A large cutting angle produces smaller slices, a small angle large slices. By varying the cutting angle it is thus possible to achieve more or less equally large slices from different sized salmon to meet individual customer requirements.

Clever engineering for increased yields

Because fish is a natural product, it not only comes in different sizes but each individual salmon side is not in itself evenly shaped. Towards the tail end it becomes much thinner. As a result the slices towards the tail end get smaller and smaller and finally fall below the weight limit of five grams below which they are not allowed into the pack. In order to solve this problem the Maass technicians came up with a solution of which they are particularly proud. The pre-set cutting angle is automatically decreased in the final third of the salmon. This means that the slices produced towards the flat end of the fish are longer than they would be if the original cutting angle had been maintained. The result is that more slices reach the necessary minimum weight. The technology behind this clever method for increasing yield is quite simple: when a salmon is fed into the machine an automatic salmon recognition system “sees” the salmon and triggers the slicing process. When the tail end of the fish moves out of the system’s view the machine “knows” that the final third of the fish is coming, and the angle is reduced. Once the side is completely cut the angle is automatically returned to its original setting for the next salmon.


Guenter H. Berndt, Managing Director of Maass + Partner, with Petra Jensen

Cold slicing maintains the integrity of the cold chain

The product, explains Günter Berndt, is not only subject to the considerably warmer ambient air during the processing stage, but also to the heat energy that is produced during slicing, and this has to be taken into consideration, too. The main argument, however, is the packaging process itself. A lot of heat is produced when the packaging is sealed and this also impacts the product. And once the packed product is warmed up, argues Mr Berndt then it is not possible to cool it down again to the required temperature during the subsequent processes. For, as he points out, the portion packs are usually piled on top of one another and stored in large lots. Even very low temperatures in the storage depot would not penetrate through to the core of the batch where temperature would be too high.

And the temperature would also be too high to maintain the integrity of the cold chain during the product’s journey to the consumer, says Mr Berndt. Experience has shown that temperature rises at every transport stage. This means that if product temperature is traced back through all the different stages, the salmon has to be very cold when packed.

Slicing speeds like those achieved by the Maass Salmon Slicer CM 576 T are today only possible with frozen slicing technology for which the salmon is cooled down to a temperature of -8 to -14 °C. Maass + Partner with their performance-oriented industrial customers have thus concentrated solely on this method and have never had a soft slicer in their programme. Mr Berndt does not see the fact that the salmon has to be frozen for slicing as a disadvantage: “Whether the salmon fillet is sliced fresh or frozen is becoming increasingly insignificant. The double-digit growth on the frozen market shows that customers accept the frozen product.” According to Mr Berndt, the low temperatures and the smooth slicing surface additionally decrease bacterial growth. So cold slicing made sense, particularly where longer delivery paths were concerned: “If you have to cover distances to the buyer for which the salmon has to be frozen anyway it is more favourable to do this prior to slicing and thereby reduce bacterial growth.” He thus only sees soft slicing as an alternative for small local suppliers.

Retrofits always possible

Demand for Maass technology is good and Mr Berndt is very content with current business. “2010 was a good year. Our team puts together about two machines a month in our workshop, and then there’s service, spare parts supply, overhaul and repair, and retrofitting of older machines. Because slicing technology is constantly being further developed we make sure that the machines we sell can be retrofitted with the new technology. This is a binding promise he makes to every customer.

Another trust-building feature is the guarantee which Maass gives for its machines, irrespective of the buyer’s location. With an export share of 95 per cent and customers in such far-away places as Japan and Chile this is sure proof of the company’s confidence in its own products. Says Mr Berndt, “our machines are so reliable that we can afford to do this. If anything does go wrong, one of the Maass employees has to deal with it. This requires flexibility, of course, but that is one of the team’s particular strengths. “In our company no one works only at a desk or only at the workbench”, he explains. “We do everything together, we’re a real team, and that’s our strength”. This flexible attitude extends to the service offered to customers. Twenty-four hours a day, 360 days a year. Spare parts that are ordered before twelve noon are dispatched the same day.