Current approaches and challenges of sample preparation procedures for the safety assessment of paper and cardboard food contact materials: A comprehensive review

In the European Union (EU), Regulation (EC) 1935/2004 provides a harmonized legal EU framework and sets out the general principles for safety and inertness for all Food Contact Materials (FCMs) and Food Contact Articles. From a food safety point of view, however, specific EU legislation for paper and cardboard FCMs is lacking, while at Member State level, national legislation differs among countries. More than 11,000 chemicals have been identified in all types of FCMs, most of them without any information on toxicity or migration potential from FCM to food. The present review shows a wide variability of protocols, approaches, and conditions used in scientific studies, which are difficult to compare. In this regard, procedures and conditions laid down in EU legislation for plastics and European Standards (EN protocols) may serve as a good basis for the future sample preparation procedures in the framework of paper and cardboard FCMs safety assessment. Challenges on sample preparation procedures are presented involving the interlinked steps of sample preparation, conditions used and their impact in chemical analysis and in vitro bioassay testing. Currently, there is no general consensus on the criteria for structuring, evaluating, and tuning sample preparation procedures for paper and cardboard FCMs. For this purpose, a set of modified criteria and a decision tree are proposed based on the literature. Along this, mass transfer processes occurring in paper and cardboard FCMs and parameters affecting chemical migration need to be accounted for prior to reaching general consensus on criteria for sample preparation procedures.