Materials used for packing and Packaging Hazards

PACKAGING MATERIALS AND HAZARDS

Materials used for packing

The conventional methods of packing which are prevalent even now to a large extent are tin or aluminium containers, glass bottles and jars, paper and waxed paper wrappings, paper cartons, cardboard and certain plastic containers. Tin and aluminium containers have become costly and glass bottles though very good in many respects have problems associated with breakage and heavy transportation charges on account of weight. Continued use of paper in increased volume dwindles the natural resources.

Against the conventional materials there has emerged increased usage of newer materials derived synthetically. Some polymeric plastic materials are polystyrene, polyvinyls, polyvinydines and derivatives, vinyl acetate, poly ethylene, polypropylene and polyesters.

Folding cartons and paper board boxes are used extensively in the food industry. Tin plate containers-the cylindrical open-top variety are mostly used for processed foods. Aluminium is used principally as foil e.g., chocolates. It is also used as bottle caps and closures and easy open tops for cans.

Polystyrene is principally made into tubs for ice creams, packs for eggs, sausages and small packages for butter, jam and cheese. Bags made from the simplest of all plastic polymers, namely, polyethylene or ' polythene' as commonly known have relatively low preserving qualities. Material such as polyesters vinyl acetate derivatives and multilayer films made out of a combination of different materials have good preserving characteristics for food products.

Timber crates are used extensively for packing weights above 100 kg. Plastic crates are well established in the dairy industry and for the transportation of bottled beer, mineral water and soft drinks. High density polythene is used for milk crates.

Shrink wrap packaging is a system where heat shrinkable thermoplastic film is wrapped around an article or a group of articles. The film is made to shrink around it by the application of heat to achieve a skin light package. Canned food products, bottles and jars of all types can be shrink wrapped.

Now-a-days it is expected that packaging material be environment friendly or ecofriendly, that is, it should not pose many problems for mankind and hazards to the environment. For example, corrugated boxes are ecofriendly and are preferred for exporting. They can be effectively replaced for conventional wooden boxes which need to destroy the trees. Recyclability of packaging is desirable so as to preserve the resources of the packaging material for future generations.

Packaging Hazards:

Plastics such as cellulose acetate, polyamide polyethylene polypropylene and polyvinyl chloride are often used as packing materials because they are light in weight and are resistant to diffusion due to solvents and high temperatures.

However care should be taken that only food grade plastic packing materials should be used for packaging foods to prevent the following packaging hazards.

1.     Production of noxious thermal breakdown products which are injurious to health.

2.     Formation of toxic residues that result when subjected to heat treatment for sterilisation of the contents.

3.     Unfavourable reactions between acid and oil content of the food and the packaging material.