5.2 Re-use of packaging
Glass bottles are commonly re-used either by buying in second hand or selling the product in returnable bottles. In both cases the treatment of re-cycled glass is crucial for they must be inspected and properly cleaned.
The most serious risk when using second hand bottles is that they may have contained a poisonous substance such as insecticide. It is strongly recommended that a responsible worker in the plant checks each bottle visually and by smell and rejects any that are suspect. The payment of a bonus for the number of contaminated bottles, often acts as an incentive.
After examination the bottles need to be washed thoroughly. While commercial bottle washing powders are available most small producers will find it more convenient to use a 1 to 2% solution of caustic soda to which a standard 'washing-up liquid' is added. Remember that caustic soda will damage the hands. Operatives should wear protective rubber gloves. After washing the bottles must be thoroughly rinsed to remove all traces of detergents and caustic. This can be a time-consuming job, repeatedly rinsing till all traces of bubbles have gone, and the semi-automatic rinser shown below can speed up the process (Figure 5-3). If the bottles are not to be re-filled immediately after washing, but put into store, remember that they will need another rinse before filling.
If labelled returnable bottles are involved then it is worth using labels that will fall off easily in water (wet strength paper and water soluble adhesive) as described in the chapter on labelling. The actual washing operation should be carried out with bottle brushes which can usually be found in a local pharmacy.
When selling in returnable bottles the deposit charged is seldom enough to buy a new bottle. For this reason the average bottle must make a given number of trips to maintain economic production. The profitability of many small businesses depends on this average trip life of bottles so accurate records should be kept and pressure put on customers with a low return rate.
5.2.2 Drums and tins
Drums and tins are commonly re-used (Table 5-1) as they are very expensive to replace. The same warnings apply, as in glass above, regarding to their having been used for poisonous substances. They must be properly inspected and cleaned. Drums that are used for poisonous substances generally have warning markings on the outside, often a skull, and should never be used for packaging foods.
If drums or tins are to be used for packing oils they must be absolutely dry before filling since the presence of water will speed up the development of rancidity. It should also be remembered that oils packed in plain, unlined, steel drums will quickly go rancid.
Table 5-1: Most common metal containers re-used
5.2.3 Plastic barrels and drums
Large plastic containers are increasingly replacing metal drums and can often be bought second hand. Once again the food producer must be certain that they have not been used for any toxic substance. In addition the food producer should check that the type of plastic is food grade. It is recommended that plastic drums are not used for packing oils or oily foods.
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