Tjoena Siere provides technical guidance to the firm’s attorneys in the regulatory compliance of substances used in food-contact materials, including those intended for contact with drinking water. Using her expertise in Analytic Chemistry, Tjoena frequently prepares and submits petitions to the European Food Safety Authority (EFSA) and other EU national authorities, such as the Dutch G4 Commission and the German BfR.

Tjoena prepares test protocols for overall and specific migration testing and the migration of oligomers and other non-intentionally added substances (NIAS) in support of petition dossiers and opinion letters. In addition, she evaluates the migration test results reported by clients, then advises on the reliability of the results presented, their relevance for the intended application, and, if required, she gives guidance to the test lab. Tjoena also evaluates client information and advises on data needed for petition dossiers. She is regularly invited to speak at industry conferences and events.

Prior to joining Keller and Heckman, Tjoena worked at a global research institute, focusing on food packaging. As a food-contact materials and legislation project manager, she prepared custom-made project proposals to enable her clients to meet their business goals. While in this position, she was also involved in the evaluation of the composition of food-contact materials based on national, European, and U.S. legislation. Tjoena also prepared and submitted dossiers to the relevant authorities for the authorization of new substances and supervised the migration studies required for both compliance testing and petitioning, including specific migration and screening studies on migrating oligomers and reaction products. 

Tjoena, at the request of the relevant authorities, has evaluated many dossiers that were submitted to EFSA and the Dutch G4 Commission for the authorization of new substances in food-contact materials. She was also a partner in a consultancy firm, offering advice and support on the regulatory requirements of food-contact materials, where she focused on the preparation and filing of dossiers to EU national authorities, including The Netherlands and Bundesinstitut für Risikobewertung (BfR) and the U.S. Food and Drug Administration (FDA). Tjoena was a member of the Dutch G4 Commission for many years, where she was actively involved in the evaluation of new substances to be authorized for use in food-contact materials pursuant to Dutch Regulation on Packaging and Consumer Articles.  

Tjoena’s vast knowledge of the authorization of new substances, particularly food-contact materials, benefits our partners and their clients when hands-on experience of the filings of various dossiers is needed.