Long-term wear effects on nanosilver release from commercially available food contact materials

ABSTRACT

Potential consumer exposure to nanoparticles (NPs) from nanoenabled food contact materials (FCMs) has been a driving force for migration studies of NPs from FCMs. Although NP migration from fresh, unused FCMs was not previously observed, conditions that result in significant changes to the surface of FCMs have not been investigated for NP migration into food. Therefore, a quantitative assessment of nanoparticle release from commercially available nanosilver-enabled FCMs was performed using an abrasion protocol to simulate cleaning, cutting, scraping and other stressful use conditions. Laser scanning confocal microscopy (LSCM) analysis showed a general increase in root mean square (RMS) roughness after FCM abrasion, and particle count (for particle sizes from 80 nm to 960 nm) at the surface was 4 orders of magnitude higher for the abraded FCMs. Migration was evaluated using both water and 3% (v/v, volume fraction) acetic acid as food simulants. Low concentrations of total Ag were detected in water simulants with a small portion (<10 ng dm⁻²) in the form of silver nanoparticles (AgNPs). Median particle diameter ranged from 39 nm to 50 nm with particle number concentrations on the order of 10⁶ particles dm^{− 2}. Total Ag migration into 3% (v/v) acetic acid was significantly higher than in water; however, 3% (v/v) acetic acid was not suitable for evaluation of NP release due to dissolution of AgNPs to Ag⁺ under acidic solution chemistries.

KEYWORDS:

• Metals analysis
• ICP/MS
• food contact materials
• food simulants

Acknowledgments

This project was supported in part by an appointment to the Research Participation Program at the Centre for Food Safety and Applied Nutrition administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Consumer Product Safety Commission and the U.S. Food and Drug Administration. The authors would like to acknowledge the FDA White Oak Nanotechnology Core Facility for instrument use. The authors also thank Dr Danielle Gorka and Dr Justin Gorham at NIST for providing PVP-coated AgNPs for LSCM control images.

Disclaimer

The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the CPSC. Mention of trade names or commercial products does not constitute endorsement or recommendation for use, nor does it imply that alternative products are unavailable or unable to be substituted after appropriate evaluation. Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose.

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