Processed cheese slices packed on the fly
Image: adapa Group
The individual wrapping of processed cheese slices, used for example as toppings for sandwiches or burgers, is a demanding business. adapa Finland Jakobstad, part of the adapa Group (formerly Schur Flexibles), is one Europe’s flexible packaging manufacturers, and over the last two decades has become an expert in individually wrapped slices (IWS) flow-wrap films for the hot filling of processed cheese slices. Leif Elenius, TQM and R&D manager for adapa Finland discusses this application with Dairy Industries International.
Q. How should one look at the packaging process of the individually packaged processed cheese slices?
The filling and packaging process takes place in one step using a vertical flow-pack system specially designed for hot filling. The film, which was specially developed for this application, is formed into a tube into which the processed cheese mass, which has a temperature of approx. 85 °C, is continuously dosed vertically. The mass is pressed into the shape of a slice, sealed and, depending on the type of line, either hot or, after cooling down in a water bath, cut into slices and ejected from the line. The individually packaged cheese slices are then transported in stacks of usually 10 or 15 slices via a conveyor belt to further outer packaging, e.g., as consumer packaging in a flow-wrap or in a cardboard box.
Q. What makes this process so demanding?
The product is filled at around 80 to 85 °C and requires an extremely heat-resistant film. It must be possible to guide this film through the line at high speeds without any difficulties. The stability and quality of the material are of great importance here: if the film tears or has even the smallest of defects, the product contaminates the line and efficiency drops. Furthermore, it must be possible to fill the soft cheese mass precisely into the film tube and further in the process cut it into slices after it is packed in the IWS flow-wrap. Once in use, each individual slice should then be able to be easily removed from its film in a consumer-friendly manner. The art lies in developing the appropriate film recipe that fulfils all these requirements.
Q. What aspects are important here?
There are many parameters that influence the optimal choice of film. For example, our research and development is intensively involved in the application process, namely whether the cheese slices are cut and sealed in a hot or cold state. The handling and product transport within the line is most important, for instance how the cheese slices are ejected from the line and stacked at the end. This is where the
coefficient of friction of the film is a determining factor: some producers need a particularly smooth film structure to achieve a high output, for others the packed and stacked slices may stick together a little more so that the stack of slices stay in place when being transported to the final packaging.
Q. What does adapa’s solution look like?
We have been very familiar with the market and requirements in this segment for a good two decades and have developed our films specifically for this application. The ProPeel-IWS are multi-layer, co-extruded polypropylene films which, even with greatly reduced film thickness, manage the balancing act between enclosing the hot product and the shortest sealing times – also through contamination – as well as, enabling cutting through the film while it is still warm. This is due to the combination of a sealing layer with a high melting point of up to 165°C. The standard films, which we have developed for this application are adapted to individual customer requirements, such as higher film rigidity.
Q. What are helpful aspects for films?
In addition to a film’s appearance due to transparency and printability as well as their sealing and opening capabilities and properties, one of the most important characteristics is mechanical stability: the films should prove an extreme machineability and have a high puncture and tear resistance. This is essential for the efficiency of production.
In recent years, adapa has succeeded in reducing the thickness of ProPeel IWS films from approximately 35μm to as little as 20µm. Due to this approach, it has already been able to achieve material savings for many customers. Not only does this conserve resources, but in the case of IWS films, more metres of film fit onto one roll, resulting in a reduction of line downtime. In addition, the amount of product and packaging material waste that occurs when starting up the line is reduced.
Also, more metres can be transported by truck load.
Q. Do you see a further developments for hot fill in the future?
With the 20-μm films, we are approaching the technical limit. We are talking about process speeds with an output of up to 1,100 pieces per minute. That is a speed at which the cheese slices literally “fly” through the line and at which the reliability of the film is key. However, the possibilities of this application are far from exhausted. Current testing is ongoing for other hot-filled products, including pâté or chocolate.
adapa Group in Wiener Neudorf, Austria, specialises in high-barrier packaging solutions for the food, tobacco, hygiene and pharmaceutical industries. It was founded as Schur Flexibles in 2012 and renamed in 2022. It generates annual sales of around €690 million and employs around 2,200 people at 22 sites across Europe.