An appraisal of the published literature on the safety and toxicity of food-related nanomaterials

Nanotechnology is poised to impact the food and food-related industries through improvements in areas as diverse as production, packaging, shelf life, and bioavailability of food and beverage components. An evalua- tion was undertaken to characterize the published literature pertaining to the safety of oral exposure to food- related nanomaterials and to identify research needs in this area. Thirty publications were identified in which a toxicological endpoint was assessed following in vivo (oral) or in vitro exposure to food-related nanomaterials. These publications were evaluated for overall quality using a two-step method that determined the reliability of the study design and the extent of nanomaterial characterization within each study. Of the 21 in vivo studies evaluated, 20 used mice or rats, 15 were lacking in some critical component of study design (e.g., oral gavage dose volume was not reported), none was longer than 90 days in duration, and only seven reported more than five physicochemical parameters for the nanomaterial(s) being evaluated. Of the nine in vitro studies evaluated, seven focused on cytotoxicity, two evaluated genotoxicity, only five reported more than five physicochemi- cal parameters for the nanomaterial(s) being evaluated, and none discussed the potential interference by the nanomaterial(s) of the experimental assays that were employed. The results of this evaluation indicate that there is currently insufficient reliable data to allow clear assessment of the safety of oral exposure to food-related nanomaterials. Significant investment must be made to generate studies of sufficient quality and duration and that report comprehensive nanomaterial characterization such that results can be judged reliable and interpretable. Failure to do so will result in the perpetuation of the publication of studies that are inadequate for use in risk characterization.