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<p>A standard operating procedure and method validation report for the determination of NP in food contact materials was prepared. The methodology was provided to two additional laboratories to derive between laboratory validation data. The analysis of foodstuffs packaged in NP containing food contact materials and migrating from cling film into foods was performed. Evaluation of the food concentration data derived was used determine the relative contribution of migration compared to NP occurrence from other sources. </p>
<p>Background: Nonylphenol (NP) is a generic term used to describe a complex commercial mixture of mainly nonyl-substituted phenol. The presence of NP in certain food contact materials has been reported. Although NP itself is not authorised for use in food contact plastics it may be present as an impurity or a breakdown product of alkylphenol ethoxylates or tris(nonylphenyl)phosphite. Alkylphenol ethoxylates are used as dispersing or stabilising agents in some food packaging polymers (plastics and rubber) and papers. Tris (nonylphenyl) phosphite is an antioxidant used to stabilise some food contact plastics. To confirm the presence of NP in food contact materials the Food Standards Agency commissioned a previous project (A03047) to develop a method of analysis for NP in different types of food packaging and the subsequent analysis of a range of material types. NP was detected at parts per million levels in examples of polystyrene (PS) and polyvinyl chloride (PVC), but also in ethylene vinyl acetate, polycarbonate and rubber at much lower levels. This new project aimed to provide between laboratory validation data for the method of analysis developed in the earlier FSA funded work and to derive information on the source of NP in foods, i.e. migration from food contact materials or from environmental contamination. </p>