Determination of styrene migration from polystyrene cups into milk : FCM-24/01 proficiency test report

The implementation of the EU legislation on food contact materials (FCM) requires the EU Member States to be able to conduct testing to ensure compliance with legal requirements. These tests are performed by laboratories designated for official controls In 2023, the EURL-FCM organised a PT round (FCM-23/02) for the determination of styrene in milk. The scope of that PT was to assess the proficiency of National Reference Laboratories (NRLs) and Official Control Laboratories (OCLs) in quantifying styrene in milk at a concentration proposed to be the new specific migration limit (SML) for styrene in a future amendment to Commission Regulation (EU) No 10/2011. The analytical capability of laboratories was demonstrated, with over 80 % of satisfactory z scores. Consequently, the EURL-FCM organised in 2024 a new PT round (FCM-24/01) to assess the capability of laboratories to conduct migration experiments. This PT round focused on the determination of styrene migration from polystyrene cups into milk and was open to EU NRLs and interested OCLs. This report summarises the outcome of the PT round - test item analysed consisted of polystyrene single-use cups to be used for the migration test into commercial milk containing 1.6 % fat. Twenty-nine laboratories registered for the exercise and twenty-four submitted results, including 17 NRLs from EU Member States and Switzerland, and 7 OCLs. The performance of individual laboratories in determining styrene migration was expressed as deviation from the assigned value (D %). Out of the 24 laboratories, 15 laboratories obtained a D % lower than 50 %, and 9 higher than 50 %. The outcome of this PT exercise highlights the need for a harmonised procedure to carry out migration tests.