Consumers are demanding healthier foods while at the same time have increased concerns about food safety risks, two trends that may often conflict with each other in food processing.
To address the demand for foods without synthetic or chemical preservatives manufacturers are exploring new preservation methods, such as ohmic heating, high-pressure pulsed electric field, bright light, and aseptic processing.
Aseptic cold filling (ACF) requires separate sterilisation of the product, bottles or cartons, and their closures. The sterilised product is then packaged in a sealed-off sterile environment and the container sealed under aseptic conditions.
Through the method processors can achieve a shelf life without the use of preservatives or refrigeration. Aseptic filling can also help to extend the shelf life of existing products, allowing companies to consolidate operations and extend their distribution chain.
Many of the machine makers here at Anuga FoodTec are attempting to integrate aseptic process technology in filling operations from start to finish, say the conference's organisers, Koelnmesse.
"Along with this development, the trend toward aseptic cold filling of beverage containers, which preserves a product's properties, continues unabated,? Koelnmesse stated in a press release. This is why one of the most important challenges facing many drink manufacturers today is the technical updating and conversion of their plants to aseptic production.
Some of the systems involve designing mixing and pasteurisation in one process. Heat transfer plates and pipes that make it easy to kill microorganisms come into play.
Processors must select the right heating element to ensure the quality of the products and the efficiency of the processes, Koelnmesse stated.
Modern systems for fruit juice production, for example, combine two process steps ?pasteurisation and continuous mixing ?in one unit. For fruit juices, a concentrate is heated with steam to the desired pasteurisation temperature and kept hot.
The concentrate is then mixed with sterile, cold water to the desired value and simultaneously chilled. Before it moves to the filling system, the finished, pasteurised drink product is buffered in a sterile tank.
With aseptic cold filling systems, bottles are sterilised in "dry?or "wet?sterilisation processes. Wet sterilisation uses peroxyacetic acid to sterilise the PET and HDPE containers, while dry sterilisation calls for spraying the containers inside and out with a hydrogen peroxide mist, Koelnmesse stated.
Filling machines used in the cold aseptic process are also getting smaller as the cleanrooms that are needed for this procedure have shrunk in size, and are now no larger than the housings of the production units.
Insulator technology has allowed companies to reduce by 80 per cent the cleanroom volume of two-lane rotary machines used in the filling lines.
Tetra Pak SIG Combibloc, Krones and KHS are some of the bigger names competiting for a chunk of this market.
One of Krones' main exhibits at this years' Anuga FoodTec is a complete aseptic block for filling containers of milk and mixed milk drinks. Krones designed its PET-Asept L wet sterilization process for the milk-processing industry.
The machine consists of a sterilizer, a rinser and a filler with insulator technology. A weighing filler was constructed under criteria set by the milk industry.
"The key advantage of this compact cleanroom concept is that all of the relevant parts and components that could create or transmit impurities have been strictly excluded from the cleanroom,? Koelnmesse stated.
The dairy industry is particulary interested in aseptic cold filling for "extended shelf life" (ESL) milk. ESL refers to the longer-than-average durability of foods that must be stored in cool locations.
ESL milk normally has a shelf life of about 12 to 21 days in a closed cold chain at 10 °C. The growing market for ESL milk products has pushed companies such as Tetra Pak Processing to design special aseptic processing plants for direct heating.
For example, the Tetra Therm Aseptic VTIS is a steam injector that heats the product to the desired temperature within a very short period of time. The product is then expansion cooled in a vacuum container. The expansion-cooling process, which can be regulated, removes the steam that has been injected and restores the water balance. The product is then homogenized in an aseptic process and cooled to its final temperature in a heat exchanger.
Manufacturers must also design equipment to meet the hygienic requirements demanded bz the process.
There are no longer any seams or open flutes. Instead seals are flush with the front of the unit. Smooth and slanted surfaces make the equipment easier to clean. Anuga FoodTech runs from 4 to 7 April 2006.