Specific migration testing plastics

Specific migration tests - Again, the plastic is contacted with a food simulant but any analytical work in targeted on a specific additive and its concentration determined using an appropriate chromatographic technique. 

Applications Radiotracer measurements, which combine high sensitivity and specificity with poor spatial resolution, have been used for migration testing. For example, studies have been made on HDPE, PP and HIPS to determine effects of manufacturing conditions on migration of AOs from plastic products into a test fat [443]. Labelled antioxidant was determined radio-analytically after 10 days at 40 °C. Acosta and Sas-tre [444] have used radioactive tracer methods for the determination of styrene ethyl acrylate in a styrene ethyl acrylate copolymer. 

Guide to test methods for the specific migration of substances from plastics... 

The completion of harmonisation of rules for plastic food contact materials and articles is within sight. The finalisation of the positive list for authorised additives is likely to happen in 2008. In 2007 the Commission will, besides the Community list of authorised additives, publish a list of additives authorised at national level for which a valid application for EU authorisation has been made to EES A. Only these substances may be used until evaluation is finalised by EES A and a decision on authorisahon is taken by the European Commission. Another project in the plastics sector is the extension of the rules to multimaterial multilayer structures where the plastic layer is in contact with the food. At this moment only plastic materials which consist entirely of plastic are covered by the plastics Directive. These materials, when they are made up from layers of plastic, constitute only about 15% of the mutilayer market. Other multilayer materials such as beverage cartons, which consist of a food contact layer of plastic and aluminium and/or paper, are not yet covered by specific legislation. Extension of the plastics mles to these materials will have to take into consideration requirements for the non-plastic layers and establish mles for migration testing of these materials. 

General information about how to determine specific migration is available in CEN document EN 13130-1 2004 Materials and articles in contact with foodstuffs - Plastics substances subject to limitation - Part 1 Guide to test methods for the specific migration of substances from plastics to foods and food simulants and the determination of substances in plastics and the selection of conditions of exposure to food simulants . CEN has also established methods for the determination of some specific migration. Table 5.4 is a list of components for which CEN methods are established. Another source of methods for the determination of specific migration can be found at http // cpf.jrc.it/smt/. At this website of the Joint Research Centre methods are collected and made public online. A summary of the methods available at the website of JRC is given in Table 5.5. 

Materials and articles in contact with foodstuffs - Plastics substances subject to limitation - Part 1 Guide to test methods for the specific migration of substances from plastics to foods and food simulants and the determination of substances in plastics and the selection of conditions of exposure to food simulants... 

For substances with proven toxic effects. Specific Migration Limits (SMLs) have been declared in food simulants or the maximum amounts in a given material for unstable compounds are stated. An example can be the SML for melamine (2,4,6-triamino-1,3,5-triazine), which is set at 30 mg/kg. On the other hand, acrylamide cannot be detected at all in the migration tests (its detection limit is 0.01 mg/kg), although it is known as a common process contaminant. The SML value for dibutyl phthalate is 0.3 mg/kg and for bis(2-ethylhexyl) phthalate 1.5 mg/kg, but plasticised plastics should not be used for fatty foods. In sealing lids for jars intended for infant and baby food, the migration of epoxidised soybean oil is often controlled (SML = 30 mg/kg). 

To support the analyst in applying such controls, CEN (the European Standardisation Commission) has in TC 194 adopted and validated analytical methods for the determination of the overall migration and the migration of some specific substances. These methods are intended to be applied for testing plashc materials and articles. At national level, e.g., in The Netherlands, the methods and simulants may also be used to demonstrate compliance with national regulation of non-plastic or multilayer materials composed of plastics and non-plastics (e.g. plastic on paper, coating on metal). 

---