Steam sterilise for a natural product


Equipment developer Oystar Hassia explains how aseptic steam sterilisation can also add value to food products

Food producers are increasingly employing aseptic filling and packaging to extend product shelf-life. Equipment developer Oystar Hassia explains how aseptic steam sterilisation can also add value

Producers of milk products, puddings, creams, baby food, yoghurt and fruit juices are realising the advantages of aseptic filling and packaging. German equipment developer Hassia, a company in the Oystar Group, believes its natural aseptic steam method can sterilise and add value to such products.

Often methods that employ hydrogen peroxide are used for sterilisation of the packaging materials. However, there is another technology that physically sterilises packaging materials, ensures quality and prolongs shelf life: steam aseptic.

As the name suggests, sterilisation is carried out through the use of steam ­– a natural medium, free of pollutants and already available at most food manufacturing companies. The steam system guarantees a germ reduction of >log 4 ­–­ statistically equivalent to one non-sterile cup among 10,000 cups, at most.

The sterilising effect is based solely on the action of damp heat and since no additives are required, the value-added aspect of the products produced via this method also increases.

The system developed by Oystar Hassia operates as follows:

At the first workstation the base packaging film is sterilised at approximately 150°C for a short retention period by means of saturated steam – comparable to the direct action of a UHT unit – and then passed on in a sterile tunnel with sterile excess air pressure.

Successive preheating of the base film then takes place over several machine cycles, including deep-drawing into a water-cooled form by means of servo-driven pre-forming stamps and compressed air. This is followed by filling of the cups.

The base packaging film is sterilised and preheated over successive stages

The base packaging film is sterilised and preheated over successive stages

The cover film is likewise sterilised by means of saturated steam before the cups are hermetically sealed. Only then does the chain of cups leave the sterile tunnel. During the entire process the temperature, pressure and process times are constantly checked and stored in the control system in a manner that is reproducible.

In addition to the sterilisation of the packaging materials and the closed path through a sterile tunnel, the dosing units also fulfil all of the aseptic requirements to ensure complete sterility. For example, the machines are equipped with Cleaning-in-Place (CIP) dosing for fully automatic cleaning without disassembly. Then Sterilisation-in-Place (SIP) is used, which ties in the CIP process with general sterilisation.

For the greatest possible product flexibility, dosing systems are employed that make it possible to fill several components, for example whipped pudding of different flavours, in respective 100ml cups per work cycle.

With its TAS Thermoforming Aseptic series, Oystar Hassia set out to create a solution that would meet all efficiency requirements and maximise profit for customers. As a result, systems meeting all required capacity ranges are available.

Depending on the cup size, machines are available with between 6- and 48-fold format designs. With a machine cycle rate of up to 40 cycles per minute, a packaging output of approximately 14,000 to 115,000 cups per hour is possible

Key benefts

Oystar Hassia steam aseptic systems use only steam to sterilise the foil. The product suffers no taste change and looks appetising in its natural colours

Steam ...

    • is free of contaminants and therefore safe as a natural medium

    • is already present in most dairy or food-processing plants

    • unlike some chemicals, leaves no residue in the product

    • is safe for staff and does not cause health problems