The panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) said available migration data of the substance complies with the existing SML but combined with other sources, the limit could be exceeded.
The Scientific Committee on Food established a no observed adverse effect level (NOAEL) of 50 mg/day for zinc and an upper limit of 25 mg/person per day was recommended in 2003.
CEF made the recommendation in a scientific opinion which can be found here.
Umicore Zinc Chemicals application
The safety assessment covers zinc oxide in nanoform either uncoated and coated with [3-(methacryloxy)propyl] trimethoxysilane.
It is intended to be used as a transparent ultraviolet light (UV) absorber in all types of polyolefins.
When coated with [3-(methacryloxy)propyl] trimethoxysilane, the coating is up to 2% by weight of the zinc oxide.
The additive is to be used in the polymer at a maximum content of 2% and 3% by weight for the uncoated and the coated species, respectively.
Plastics are intended to be used in contact with all foodstuffs for long-term storage at room temperature.
Zinc oxide in bulk form is authorised as an additive for plastic materials and articles in contact with food with a SML of 25mg/kg food.
The coating agent, [3-(methacryloxy)propyl]trimethoxysilane, is authorised as a monomer for plastic materials and articles in contact with food but must only be used as a surface treatment agent for inorganic fillers and with a specific migration limit (SML) of 0.05 mg/kg.
The European Food Safety Authority was asked by the Ministry of Health, Welfare and Sport, the Netherlands, to evaluate the safety after a dossier submitted by Umicore Zinc Chemicals, Belgium.
No nanoform migration
The substance is used as a powder in nanoform. In the final polymer low-density polyethylene (LDPE) with the maximum intended use level of coated and uncoated zinc oxide nanoparticles are still present but largely aggregated.
Specific migration was tested from LDPE films (thicknesses 30–40 μm), containing the maximum use level of uncoated and coated species, into 3% acetic acid and 10% and 50% ethanol for 10 days at 60 °C.
Migration of zinc into 3% acetic acid was up to 7.6 mg/kg (2% zinc oxide), and up to 17.3 mg/kg (3% coated zinc oxide).
Migration of zinc into 10% and 50% ethanol was up to 80 μg/kg for the coated and uncoated species.
CEF concluded zinc oxide nanoparticles uncoated or coated does not migrate in nanoform, so the safety evaluation should focus on the migration of soluble ionic zinc.
Available migration data for ionic zinc from the intended application comply with the current SML, but with the dietary exposure from other sources the UL of 25mg/person per day could be exceeded.
It recommended the EU Commission reconsiders the SML of 25mg/kg for zinc, taking into account consumers are exposed from sources other than food contact materials.