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Transfer to foods from secondary packaging was measured by incorporating substances (surrogates) into secondary packaging so that there would be a ready source of substances whose transfer could be measured. Surrogate substances were used because substances already present in packaging materials vary between different types of material both in terms of types of substances present and quantity. The deliberate incorporation of substances maximised the information obtained from the studies and permitted trends to be identified which can be applied more widely to packaging materials other than those examined in the research.
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Corrugated board boxes and cartonboard boxes were used as secondary packaging materials. Foods packaged in primary packaging were then stored for up to 200 days in this secondary packaging. Crisps, savoury biscuits, sweet biscuits, dried fruit, breakfast cereal, chocolate coated confectionery and choc-ices were the foods stored. The foods were removed from the packaging at known time periods and analysed to determine whether the incorporated substances had transferred and, if so, how much had transferred.
Considerable attention has been paid to the transfer of substances from primary packaging materials to foods i.e. from the packaging material which is the immediate layer surrounding a packaged foodstuff. Less attention has been given to so-called secondary packaging i.e. materials used for packaging but which are separated from the food by a layer of primary packaging. Examples of secondary packaging are the outer cartonboard box of a breakfast cereal, where the cereal is packaged in a plastic wrapper (primary packaging) inside the box; or a corrugated board box used to transport packets of biscuits from the manufacturer to the retailer.
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Currently, only primary packaging materials are tested to any great extent to ensure their safety-in-use in terms of transfer of substances. The general assumption is that there will not be significant transfer of substances from secondary packaging to food and hence, that chemical testing of the type applied to primary packaging is not required. If there is a potential for transfer, those involved in the packaging chain (packaging manufacturers, importers, food producers, distributors of food, food retailers, caterers etc.) need to be made aware of this so that they can take appropriate action.
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A series of studies was carried out to evaluate the potential for transfer of substances from secondary packaging to foods, to identify the factors which are important in transfer and to develop guidelines for use by those involved in the food distribution chain to minimise transfer.
<p>Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research webpage</a>.