Nanoparticles have a diameter of less than 100 nm. While silver is used as a food dye, nanosilver has not been approved for use in food and the BfR says it “welcomes this in the context of the yet to be answered questions about risk assessment”.
It is used as an antimicrobial in other contexts however, such as in coatings for fridges and footwear to combat odour.
“The properties of nanoparticles differ from those of larger particles of the same substance. It is these special properties that make them interesting for various applications. However, it has still to be ascertained whether their toxic properties change and they could become a health risk for consumers,” the BfR said.
It maintains more research is needed to address points such as the scale at which consumers come into contact with nanoscale particles, and how big the danger of resistance development is.