|The Packaging of Fruit Juice and Non-Carbonated Fruit Drinks (CDI, 1998, 87 p.)|
|III. THE DIFFERENT TYPES OF PACKAGING|
|D - LONG SHELF LIFE STERILISED PRODUCTS (ASEPTIC PACKAGING)|
Sterilised packaging treatment was developed by Tetrapak in the mid-1960s for the preservation of milk (140°C in 5 seconds).
For reasons of quality, this process has been adopted by practically the entire milk industry and is now being considered by manufacturers of fruit juices. In effect, the product is heated for a very short time - less than a minute - compared to the long heating treatment for the hot filling system. The shelf-life is also several months at room temperature.
Remark: For acidic products (pH < 4.5), a heat treatment at 90/95°C during a few seconds is enough (HTST), but for products with a higher pH (pH > 4.5) a UHT treatment is necessary.
The product (juice) is treated at a high temperature (from 95 to 140°C) for several seconds in order to destroy bacteria, yeasts and mould, and to deactivate the enzymes responsible for undesirable reactions during storage. After rapid cooling at 20/30°C, the treated product is packaged. The packaging machine must therefore include a special section in which all the procedures of filling and closing the packaging are executed in an environment free of bacteria and any other contaminants. The packaging itself must be disinfected to ensure that it is also free of any contamination (oxygen peroxide, ultraviolet, hot air, etc.).
To avoid all risk of contamination (a single bacteria can corrupt the package), sophisticated techniques must be adopted (automation, integrated cleansing, etc...) which requires production rates of at least 4000 units per hour.
· Improved preservation of natural taste due to the short sterilising treatment and subsequent rapid cooling.
· A completely natural product without chemical preservatives.
· The possibility of using packaging materials other than glass or metal, i.e. compound cardboard and multi-layer plastics.
· High investment costs (more than £ 625,000 for the combined UHT steriliser/aseptic packaging machine).
· High production rates.
· Sophisticated technology necessitates a highly trained labour force (production and maintenance).
· Steril working conditions at the packaging level.