Characterization of Nanoparticles in Silicon Dioxide Food Additives

S.A. Khan, M.E. Johnson, A.R. Montoro Bustos, K.E. Murphy, I.H. Strenge, T.R. Croley
US Food and Drug Administration,
United States

Keywords: nanoparticles, silicon dioxide, food additive


Food additives are added to food for their technical effect in food (e.g., emulsifier, stabilizer, thickener, anticaking agent, antioxidant, etc.). Food grade additives may have a particle size distribution that extends into the nanoscale range. Silicon dioxide, in its amorphous form, is an approved food additive (21 CFR 172.480) for use as an anticaking agent. During production, there is a possibility of the occurrence of nanosized silicon dioxide particles, however, there are limited data concerning the particle size distributions of food-grade silicon dioxide. Therefore, we conducted multi analytical techniques to characterize the particle size distribution of six commercially available silicon dioxide food additives. In this work, dynamic light scattering was used to measure particle size distribution, electron microscopy for imaging and single-particle inductively coupled mass spectrometry (sp-ICP-MS) to measure the concentration of nano-sized materials present in silicon dioxide additives. These results allow the USFDA to gain a greater understanding of the nano-sized particle occurrence in commercial food-grade silicon dioxide intended for use as food additives.