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Staple items of the diet (dietary staples) are packaged in a wide variety of materials and formats. All dietary staples can be purchased in a pre-packaged format, although some may also be purchased loose or packed in-store. They are also distributed, sold and stored under a wide range of environmental conditions. It is these packaging and environmental factors, in conjunction with the nature of the foodstuff itself, which determine the potential for chemical migration to occur.
For those dietary staples that are packaged, knowledge of the materials used for these items in conjunction with an assessment of consumption of these foodstuffs, provides a means of assessing the potential exposure to chemicals that may migrate into the dietary staples from the packaging materials.
Some surveys have been reported which have identified and quantified specific migration risks for individual product / pack combinations. In contrast, this study is deliberately 'broad brushed' in its approach, seeking to provide an overview of potential food migration issues that may exist for packaged dietary staples in the UK. This is achieved by combining consumption data with market information about the packaging materials and formats used for over 100 dietary staples, and evaluating this in the light of existing scientific knowledge of the known and expected migration issues associated with the packaging materials / formats identified. In making this evaluation, environmental conditions influencing the potential for chemical migration are considered, as is the potential presence of post-consumer recycled materials used in plastic and paper based packaging materials.
From the data and evaluation, general conclusions can be drawn on the use of packaging for dietary staples in the UK, and specific instances of chemical migration interest can be highlighted.
The study applied a series of progressive steps to collate and analyse existing data and information on a number of levels of detail.
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First step, existing National Food Survey data was used to quantify and rank consumption of dietary staples in the UK. Consumption data for 1998 was used for the baseline analysis and data for the period 1995-2000 was used to identify any important trends in consumption.
Then, for each dietary staple the market share by brand and by packaging material / format was determined. Brand shares were determined predominantly from available market research such as Mintel Food and Drink reports. Shares of packaging materials / formats for prepackaged products was determined predominantly through shelf-audits at supermarkets. Some dietary staples, such as fruit and vegetables, bread, and meat and meat products, may also be purchased loose or can be packaged in-store. Where appropriate, the proportion of prepackaged to loose/in-store packing was estimated on the basis of available data on sales distribution channels.
Factors which may affect migration were determined for each dietary staple / packaging material / packaging format combination. In particular, the analysis considered shelf-life, storage temperature, and the potential for recycled plastic or paper and board to be included in the structure of the primary pack.
Potential migration issues were then identified. These were drawn from Pira International's existing knowledge and expertise of food migration issues, supported by a comprehensive literature search.
The market and technical data were evaluated to identify issues of potential migration interest. This was a qualitative evaluation, and was not based upon a toxicological risk assessment.<p>
A pareto type analysis (the principle that the majority of problems (80%) are produced by a few key factors (20%)) was applied to select specific dietary staples for further consideration and clarification of the extent of potential migration issues. The dietary staples selected by the pareto analysis were subsequently grouped according to common packaging format/components which may give rise for concerns.<p>Finally, additional market information and consumption trends over time were presented in order to clarify the nature and possible extent of specific issues of migration interest.
<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>.