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Information on the types of silicone products that come into contact with food and available migration data was reviewed. Additionally, possible migrants, including reaction/breakdown substances, were predicted from available manufacturing, compositional and curing data. To check these literature-based findings, representative commercial food contact silicone products (four silicone rubbers, three silicone fluids and three silicone resins) were obtained. A range of analytical techniques (eg Gas Chromatography - Mass Spectrometry and Liquid Chromatography - Mass Spectrometry) was used to identify substances that were present with a potential to migrate. Overall and specific migration experiments were carried out on each of the silicone products using distilled water, 3% acetic acid, 10% ethanol and 95% ethanol (solvents that simulate different food types) to assess substances that did migrate. The test conditions for migration experiments reflected in-service contact conditions for the products. Substances with potential migratory behaviour were targeted and, where found, quantified. Specific migration tests on the silicone products were also carried out with foods (carbonated water, orange juice, white wine and olive oil). In addition migration testing was undertaken on examples of bakeware items coated with a heat resistant, non-stick silicone resin coating.
Silicones are used in a variety of different food contact situations and conditions. The silicone class of polymers is very versatile and the physical form of the silicone product can vary from relatively low molecular weight lubricants and oils, through high molecular weight rubbery polymers to extensively cross-linked hard resins. At present there is no specific EU harmonised legislation for food contact silicone materials. However, they are covered by Regulation (EC) No 1935/2004, which in Article 3 provides that substances should not migrate into food in quantities that would harm human health or affect the quality and characteristics of the food. Annex 1 of this Regulation includes silicones within a list of materials and articles that will be covered by specific measures. There is also a Council of Europe resolution on Silicones (Resolution AP 2004) but this is intended for guidance use by the industry and is not legally binding.
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This project was carried out to provide detailed information on the types and composition of silicone based products that are used in contact with food and identify the extent to which migration of specific constituents into food could occur. The project builds on information previously obtained on elastomeric silicone food contact materials such as seals and tubing.
<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>.