Are Nanoparticles Present in Silicon Dioxide Food Additives?

Silicon dioxide (SiO2) is a commonly used food additive in the United States, approved for direct consumption. It serves as an anticaking agent in powdered food products and contributes to the stability of beer production. However, there is limited information available regarding the particle size and size distribution of SiO2 used in food additives. In recent years, concerns have been raised about the potential presence of nanoparticles in SiO2 food additives. Therefore, it is crucial to characterize these additives and understand their physicochemical properties using advanced analytical techniques to ensure their safety.

In this study, SiO2 food additives directly obtained from manufacturers and distributors were subjected to thorough characterization using multiple analytical tools. Dynamic light scattering (DLS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and single-particle inductively coupled plasma mass spectrometry (spICP-MS) were employed to analyze the additives under different experimental conditions.

The data obtained from these analytical techniques revealed the presence of nanosized primary particles ranging from 1 to 100 nm, as well as aggregates and agglomerates exceeding 100 nm in size. The SEM images demonstrated similar morphology among SiO2 food additives obtained from different distributors. These findings lay the foundation for evaluating the nanomaterial content in regulated food additives and enable the FDA to address knowledge gaps in the analysis of nanosized particles present in commercial food additives.

The authors dedicate this work to the memory of Timothy R. Croley and Savelas A. Rabb. They acknowledge the FDA White Oak Advanced Characterization Facility (ACF) for their assistance and the use of instruments. The authors also express gratitude to Jiwen Zheng for scientific discussions and support with the ACF.

The authors disclose no conflicts of interest related to this research. The mention of specific commercial equipment, instruments, and materials in this article is solely intended to describe the experimental procedure and does not imply any endorsement or recommendation by the National Institute of Standards and Technology. It is important to note that the identified materials, instruments, or equipment may not necessarily be the best available for the intended purpose.