Mutagenicity assessment of inorganic substances permitted by the positive list for food packaging; Focusing nano sized inorganic substances

Abstract

Assessment of mutagenicity for substances permitted by the positive list (PL) for food contact materials is ongoing in Japan. To demonstrate what is necessary for decreasing uncertainty as regards risk assessment of PL for nanomaterials, here we focused on genotoxic responses of both bulk and nano-sized titanium dioxide. The results of in vitro and in vivo studies show that bulk titanium dioxide has no mutagenicity. It is suggested that oxidative stress in cells induced by nano-sized titanium dioxide can be responsible for indirect genotoxic effects. In general, further consideration will be necessary to evaluate nanomaterials under PL system.