Dekkers et al. (2011)		Peters et al. (2012)	Heroult et al. (2014)	Contado et al. (2013)
Samples	AEROSIL 200F and AEROSIL 380F (see more information in Appendix A)	32 food products	3 food products (black coffee, soup and pancake)	1 food product (coffee creamer)	4 samples of SAS: AEROSIL300, AEROSIL380, Tixosil43 and Tixosil73 380F (see more information in Appendix A)	2 food products (a powdered ‘cappuccino’ mixture and a food integrator)
Analytical method(s) used	TEM	HDC‐ICP‐MS	HDC‐ICP‐MS (additional measurements with DLS and SEM)	FFF‐ICP‐MS	SdFFF, SEM, TEM	SdFFF, SEM
Sample preparation		Food samples were suspended in “LC” or Milli‐Q water using ultrasonic liquid processor XL 2000 for 15 min. Suspension filtrated prior measurement. Some sample resuspended by a sonic bath for 15 min		The samples were defatted with hexane prior to suspension in water and applied sonication. A suspension of the crude creamer in water using mechanical shaking was also analysed	Protocol: vortexing the suspension for 30 s, ultrasonic suspension for 10 s, and vortexing the suspension for further 30 s	The samples of powdered cappuccino mix in water were dispersed with ultrasonic probe and vigorously mixed with hexane. The aqueous phase was centrifuged. The suspension of the food integrator in water was shaken with vortex and ultrasonic probe
Results	AEROSIL 200F‐ primary particles 12 nm (no information on the % of number of particles). AEROSIL 300F‐ primary particles 7 nm (no information on the % of number of particles). Most of the primary particles seem to form larger aggregated and/IR agglomerates	Percentage of silica in nano‐form range from ‘not measured’ in 21 food products to up to 19% (coffee creamer) or 33% (instant asparagus soup. Analysis of a freshly prepared cup of coffee containing coffee creamer (sample not sonicated). The percentage of silica in nano‐form in the processed food (coffee with coffee creamer) was more than two times higher than from non‐processed food	Percentage (relative to total silica) of nano‐silica (5–200 nm) in food products in water range from 5% to 29% (higher for black coffee)	11% of total silicon within the size of 1–100 nm	A300 (TEM): primary particles (7–10 nm) with tendency for form aggregates of different sizes. A380 (SEM): structure of aggregates with clusters of 50–200 nm. T43 (SEM): primary particles (25–50 nm) are organised in clusters of different sized forming agglomerates that exceed 10 m. T73 (SEM): irregularly shaped particles (80–100 nm), some spherical particles (200–300 nm) and a majority of larger aggregates	Most of the silica particles were organised in aggregates and agglomerates > 100 nm; the food integrator (rich in silica) showed a more heterogeneous population of aggregates than the cappuccino mixture and presented only a limited number of isolated particles smaller than 100 nm

	Athinarayanan et al. (2015)		Yang et al. (2016)		Contada et al. (2016)	Barahona et al. (2016)
Samples	Commercially available E 551 (no further information available)	2 food products (a commercial brand of ‘zero calorie’ sweetener and a commercial brand of a powdered vanilla flavour)	6 samples of food‐grade SiO2 from commercial vendors in the USA and China (no further information available)	13 food products (including tablets)	4 samples of SAS (AEROSIL300, AEROSIL380, Tixosil43 and Tixosil73 380F (see more information in Appendix A). 1 food sample (instant cappuccino mix)	11 samples of SAS (Syloid Al‐1, Syloid 244, Syloid 72, Tixosil 38, Tixosil 43, Tixosil 73, AEROSIL380, Cab‐O‐Sil M‐5F, Cab‐O‐Sil EH‐5F, Tixosil 38 AB, Tixosil 38 A) (see more information in Appendix A)
Analytical method(s) used	DLS	TEM	TEM	TEM and SEM	DCS and SdFFF	DLS, AF4‐MALS‐ICP‐MS, TEM
Sample preparation		Samples were disperse using sonication 30 min. The pellet was redispersed in ethanol for TEM analysis	Suspension was sonicated (30 min) in a water bath sonicator	Suspension was sonicated (30 min) in a water bath sonicator. Then, the suspension was centrifuged. Pellet was re‐suspended in water	Suspension were mixed on a vortex (30 s) and then: stirred using magnetic bar (15 min); or sonicated 120 s; or sonicated in water bath for 15 min	Ultrasonic probe used as dispersing technique
Results	Average size 160 nm	Primary particles (20–50 nm) were aggregated	All samples contained agglomerates (0.5–2 m); the mean diameters of all primary particles below 100 nm with mean primary particle sizes of 9–26 nm (no quantification)	Nanoparticles of SAS observed in 10 out of the 13 samples (no quantification). Morphology and sizes of SAS in food samples similar to the food‐grade SiO2	The 4 samples of SAS consist of nano‐primary particles, aggregates and agglomerates to build entities of large sizes. Aggregates and agglomerates break to smaller entities, whose size and relative amount depend on the dispersion methods. Cappuccino mix contains particles and/or aggregates of sizes spanning between 30 nm to 2 m	DLS: hydrodynamic diameter range 152.3–202 nm for fumed SASs and 284.9–644.6 nm for the other samples. AF4‐ICPMS: in 7 out of the 11 samples particles < 100 nm (number of particles/L 10−11 range 0.1–11.4). TEM characterisation confirmed that all the samples contained primary particles and small aggregated below 100 nm

TEM: transmission electron microscopy; HDC: hydrodynamic chromatography; ICP‐MS: inductively coupled plasma mass spectrometry; FFF: field flow fractionation; SdFFF: sedimentation field flow fractionation; SEM: scanning electron microscopy; DLS: dynamic light scattering; AF4: asymmetric flow‐field flow fractionation; MALS: multiangle light scattering.