On January 5, 2017 the EU Reference Laboratory for food contact materials (EURL-FCM) of the European Commission’s (EC) Joint Research Centre (JRC) published a report entitled “Testing approaches for the release of metals from ceramic articles.” This study, undertaken in support of the revision of the Ceramic Directive 84/500/EEC, aimed “to investigate the release of metals from ceramics into food and simulants, and to develop adequate methodologies for testing these articles including at lower limits.”
A set of 73 samples represented a vast variety of ceramics, including hand crafted and highly decorated articles, more prone to a higher release of metals. Three types of experiments were performed, two with food simulants (acetic acid 4% for 24 hours at 22°C and citric acid 0.5% for 2 hours at 70°C) and one with benchmark food (tomato sauce for 2 hours at 70°C). For all samples except one, migration was lower in tomato sauce compared to both simulants; migration profile with acetic acid was more representative of migration into hot tomato sauce.
A high heterogeneity of samples was observed, necessitating the need to test up to four replicates per sample. Furthermore, due to the inconsistent relationship between the first and third migration values, it was concluded that “prediction of values for the third migration based on the value of a first migration may not be derivable.” Since a longer storage had no significant influence on metal release, a repeat use testing setup was considered adequate regardless of the frequency of article use.
A smaller sample set of cookware (6 articles) was also tested with slightly different conditions. The results were inconclusive since all three possible relationships for lead release were observed for food simulants and benchmark food: higher, lower, and comparable release in both media.
Philip Lightowlers (January 18, 2017). “Metal leaching test methods probed by JRC.” Chemical Watch
Beldi, G., et al. (2016). “Testing approaches for the release of metals from ceramic articles – In support of the revision of the Ceramic Directive 84/500/EEC.” JRC EURL-FCM (pdf)