JRC - Guiding laboratories in migration testing of polypropylene cups
JRC scientists studied the impact of pre-heating on migration properties of polypropylene cups. It will help control laboratories that aim to achieve consistent results when testing the migration of additives from food contact materials (FCMs).
The JRC hosted in 2017 a proficiency test (PT) organised by the European Union Reference Laboratory for Food Contact Materials (EURL-FCM). It revealed that several National Reference Laboratories (NRLs) pre-heated prior to migration testing the polypropylene beverage cups used as test items.
This pre-heating was applied for obtaining rapidly the correct migration temperature at the surface of the cup and the food simulant used for migration testing. However, an increased variance of the reported data from the proficiency test was observed, leading to the study performed by the JRC in its role as EURL-FCM.
Therefore, systematic experiments were carried out to study pre-heating effects on beverage cups and to identify changes in the physical structure of the plastic material that might influence the migration of additives into a food simulant consisting of water and ethanol (50% v/v).
Results showed that heat-treated plastic cups may undergo some changes in crystallinity starting already at 40oC. Furthermore, physical changes have been observed on the surface of the material by microscopy. Such changes showed to have impact on the migrating amounts of additives under certain pre-heating conditions.
Consequently, the EURL-FCM recommends to the National Reference Laboratories and official control laboratories to avoid pre-heating FCM articles prior to migration testing and thus further harmonising the migration tests.
Read more in:
J. Alberto Lopes et al.: Influence of pre-heating of food contact polypropylene cups on its physical structure and on the migration of additives. Food Packaging and Shelf Life 20 (2019) 100305.