Mutagenicity assessment of food contact material migrates with the Ames MPF assay

ABSTRACT

A major challenge in the safety assessment of food contact materials (FCM) is the evaluation of unknown non-intentionally added substances (NIAS). Even though consumer exposure levels may be quantitatively low, these substances are considered to be of high toxicological concern if they act as DNA reactive mutagens. From a safety assessment perspective, it is therefore important to detect their presence in FCM migrates. The present study applied the Ames MPF assay to assess the mutagenicity of migrates obtained from 30 food contact material samples out of 3 categories: plastics, composite materials and coatings. As a food simulant, 95% ethanol (EtOH) had a superior performance to less volatile simulants when evaluating recovery rates of representative model substances in different volatility categories. To monitor possible interference of the FCM matrix with Ames MPF results, migrates were spiked with reference substances and recovery rates were established. Out of 30 samples tested, two caused significant inhibition of revertant formation in the presence of the spiking control. Overall detection limits of the applied test method were estimated by determination of the lowest effective concentrations (LEC) for 10 Ames-positive substances. Even though the current limits of detection are not sufficient to entirely fulfil regulatory and safety requirements, three out of 30 FCMs showed evidence of dose-dependent effects in the Ames MPF assay. Overall, the data obtained supported the relevance of testing FCM migrates for DNA reactive contaminants and showed the value of the Ames MPF assay for the safety assessment of FCMs.

KEYWORDS:

• Food contact materials
• non-intentionally added substances
• Ames test
• Ames MPF assay
• genotoxicity
• packaging safety
• in vitro bioassays
• migrate

Acknowledgments

We would like to thank Elisabeth Pinter and Stefanie Neuner for assisting with sample preparation of FCM migrates, Veronica Osorio and Daniela Neubert for conducting chemical analysis, Bettina Esche for performing some Ames MPF assay experiments and Michael Washüttl for his contacts to industry partners providing empty packaging materials for analysis. Furthermore, we would like to thank Mary Wallis and Christopher Hartl for proof-reading the paper.

Additional information

Funding

The present study was funded by the Österreichische Forschungsförderungsgesellschaft mbH and partners from the packaging and food industry in the context of the project ‘Migratox’ (FFG project number 3014994). The funding source was not involved in the study design, collection, analysis or interpretation of data. Furthermore, this work was co-funded by Nestlé Research Center.