Nanotechnologies comprise a range of technologies, processes, materials, and applications that involve manipulation of substances at sizes in the nanoscale range i.e. materials with one dimension of approximately  1–100 nanometers (nm) (1 nm = 10-9 metre or one billionth of a metre). By comparison, the bacterium E. coli is around 2,000–4,000 nm in length.

There has been some concern about the safety of nanotechnology and its use in the food industry. It is important to remember that foods are naturally composed of nanoscale materials e.g. sugars, amino acids, peptides and proteins. Many of these substances also form organised, functional nanostructures, and we have consumed these materials in foods without evidence of adverse effects for decades. Milk is an example of an emulsion of nanoscale particles, and the industry uses nano-sized structures to create emulsions (butter), foams (ice cream), solids (cheese) and gel networks (yoghurt).

The use of nanotechnology provides many opportunities for innovation in the food sector, with potential applications in primary production, food manufacturing and preservation, and packaging. For the food sector, these include:
• nanostructured food products (including emulsions)
• nanoencapsulation of food additives (colours, preservatives, flavourings and supplements)
• enhanced food packaging (improved mechanical, barrier and antimicrobial properties)
• nanocoatings on food equipment (non-stick and easier to clean).

For example, silver has a long history of use as an antimicrobial substance. So it is not surprising that silver nanoparticles have been found to be potent agents against numerous species of pathogenic bacteria. Hence its potential for incorporation as a nanoparticle into polymers to form functional antimicrobial coatings and packaging.

From a public health aspect, the main concern is to understand the pharmacokinetics of these materials and to ensure greater bioavailability does not lead to increased health risks. In the case of nanosilver, it is still unclear to what extent it passes through the intestinal lining intact, or is dissolved into silver ions in the acidic stomach environment. Little is known about whether it can pass through natural biological barriers e.g. the blood–brain barrier, the placenta, or into breast milk.

Nanotechnologies are a rapidly evolving area with potential current and future application for the food industry. The challenge is to understand the impact of nanoscale materials on human health. Therefore, FSANZ requires all new food products manufactured using nanotechnologies that may present safety concerns, to undergo a comprehensive scientific safety assessment.

For more information on nanotechnology, consult:
FSANZ (2015). Nanotechnology and food