|technology > packaging|
|Field of application|
|Techniques, methods and equipment|
|a) Type of packing materials|
|Textiles and wood|
|Rigid and semi-rigid plastic containers|
|Paper and board|
|b) Filling, bottling and canning|
Filling is the process of putting the product in the package in a proper way.
In the European Parliament and Council Directive 94/62/EC, Article 3 outlines the definition of packaging as “all products made of any materials of any nature to be used for the containment, protection, handling, delivery and presentation of goods, from raw materials to processed goods, from the producer to the user or the consumer. Non-returnable items used for the same purposes shall also be considered to constitute packaging.” It then goes on to state that “Packaging consists only of:
- sales packaging or primary packaging, i.e. packaging conceived so as to constitute a sales unit to the final user or consumer at the point of purchase
- grouped packaging or secondary packaging, i.e. packaging conceived so as to constitute at the point of purchase, a grouping or a certain number of sales units whether the latter is sold as such to the final user or consumer or whether it serves only as a means to replenish the shelves at the point of sale; it can be removed from the produce without affecting its characteristics; and finally
- transport packaging or tertiary packaging, i.e. packaging conceived so as to facilitate the handling and transport of a number of sales units or grouped packaging in order to prevent physical handling and transport damage. Transport packaging does not include road, rail, ship or air containers”.
Secondary packaging involves methods such as crates, pallets (wooden and plastic), shrinkwrap, trays, boxes and wrap-around cartons.
flour, sugar and salt. Wooden (shipping) containers have traditionally been used for a range of foods, such as fruits, vegetables, tea, wines, spirits and beer. These wooden containers were replaced a long time ago in some sectors (e.g. only plastic crates are now used for packaging beer) and are increasingly being replaced everywhere by plastic drums and crates.
soft drinks and beer. They are also used for canning, sterilised foods (fruits, vegetables, condensed milk, meat products). Metal cans are recyclable. Aluminium foil is also widely used for the packaging of several types of food.
moulding and stretch blow moulding. Typical materials used are PVC, PS (polystyrene), PP (polypropylene), XPP (expanded polypropylene – for thermoforming), HDPE (high-density polyethylene), PET (polyethylene terephthalate), polycarbonate, etc. The containers are often made on-site. Some of the containers are reusable, e.g. polycarbonate bottles for milk. Rigid and semi-rigid plastic containers are used for milk, soft drinks, dairy products, margarine, dried foods, ice-cream, etc.
milk and fruit juices. Paper and board are also extensively used for food packing, often as secondary packing.
The filling of liquids, pastes, powders and particulate foods can usually be distinguished by the packaging medium and the food product. For example, the filling of milk and other drink in glass bottles is normally called bottling, whilst filling in metal cans and subsequent heat processing is normally called canning.
The requirements for filling are:
- accuracy to ensure that the required amount of product is packed
- hygiene, i.e. ensuring that the product is hygienically filled at the correct temperature to guarantee the highest possible quality and optimum shelf-life.
- Volumetric filling, applied for liquids, but also for a range of other products like pastes and powders. Most common is the piston filler.
- Weight filling, large particulate materials (e.g. confectionery, tablets, etc) are filled into containers using a photoelectric device, similar to a sorter to count individual pieces. Also multi-head weighers are in development which aim to be able to weigh different products simultaneously, prior to filling into the same container.
The filling of liquid foods like milk and fruit/vegetable juices can be categorised by the temperature of the food at the time of filling, e.g. hot, ambient or fresh cold filling, or as aseptic filling. The temperature ranges involved in the filling process are best illustrated by the hot filling and fresh cold filling processes. Hot filling is done at temperatures of up 95°C, in order to inactivate certain relevant micro-organisms, whilst many drink products are formulated with ingredients that do not need to be heat treated in order to be microbiologically safe and these are therefore fresh cold filled at between 0 to 5°C.
For aseptic packing, pre-sterilised (by e.g. hydrogen peroxide) containers are necessary, and the filling taking place in a sterile zone.