Study of the presence of micro- and nanoparticles in drinks and foods by multiple analytical techniques.

A variety of food and drink samples (n = 21) were analyzed to evaluate the presence of (nano-) particles in their composition. After assessment of the sample pre-treatment step, a fast screening analysis was performed for drinks by Dynamic Light Scattering showing particles from 10 to 300 nm that could correspond to organic or metallic NPs. Metallic NPs were identified in foods by Single-Particle mode Inductively Coupled Plasma Mass Spectrometry and Asymmetrical Flow Field-Flow Fractionation coupled to Multiangle Laser Light Scattering and Inductively-Coupled Plasma Mass Spectrometry. The determination of Ti, Si and Ag concentration in the initial food suspensions, after filtration and centrifugal ultrafiltration enabled to estimate the ionic and nanoparticles content. Si-containing particles can be present in cappuccino powder as large aggregates and Si- and Al-containing particles in hot chocolate. Ti-containing NPs (80-200 nm) were found in chewing gum and Ag NPs in silver pearls (50-150 nm) used for decoration pastry.