The European Food Safety Authority panel on food contact materials assessed a mixture of tungsten oxides used as a reheat additive in polyethylene terephthalate (PET) at up to 75 mg/kg. Migration measured as tungsten was about 1 microgram per kg of simulant, and two in vitro genotoxicity tests were negative. The panel found no safety concern for this use and set a migration ceiling for other uses.
Key numbers
- Maximum intended use: 75 mg tungsten oxide per kg PET (Abstract; Section 3).
- Specific migration from PET plaques containing 150 mg/kg (double the maximum use) into 95% ethanol, 10 days at 60 C: about 1 microgram per kg, measured as tungsten by ICP-MS (Section 3.1).
- Similar migration (about 1 microgram per kg) from LDPE plaques at 150 mg/kg into 3% acetic acid and 95% ethanol (Section 3.1).
- Bacterial reverse mutation test negative up to 5,000 micrograms per plate; in vitro micronucleus test in human lymphocytes negative up to 20 micrograms/mL (4 h) and 40 micrograms/mL (24 h) (Section 3.2).
- Conclusion: no safety concern as a PET reheat additive; for other functions or polymers, migration should not exceed 50 micrograms per kg food, expressed as tungsten (Section 4).
- The panel noted an oral derived no-effect level (DNEL) of 0.6 mg/kg body weight per day assigned by the European Chemicals Agency (Section 3.2).
- Data tiers used by the panel: migration below 0.05 mg/kg food needs only a limited toxicity data set (Section 2.2).
Methods (brief)
Desk assessment of an applicant dossier under the EU framework regulation for food contact materials, following Scientific Committee on Food guidelines. Exposure was estimated from migration into food simulants assuming up to 1 kg of food per day in contact with the material. Genotoxicity studies followed OECD guidelines under GLP.
Evidence fitness
Supports statements about the EU safety assessment of tungsten oxide in food contact plastics, its measured migration and the migration ceiling the panel recommended. It does not provide tungsten levels in foods or a chronic oral reference value derived by EFSA; the DNEL is attributed to another agency.
Limitations
All data were supplied by the applicant (ColorMatrix Group); impurity information is confidential. Repeated-dose toxicity data were not evaluated because migration was low. Findings apply to this substance and use, not to dietary tungsten generally.
Related evidence
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