Introduction

Nanotechnology generally deals with very small particles that sized between 1 and 100 nanometre (nm) in at least one dimension. A nanometre is one billionths of a metre. To give an impression of the small size in nanoscale, the size of a nanoparticle in relation to that of a football is roughly equivalent to that of a football relative to the size of the Earth.

Nanoparticles can occur naturally or man-made in food. Many food products contain natural particles in nanoscale range, for example globular proteins is 1-10 nm in size and the thicknesses of carbohydrates and fats polymers are less than nanometres. Traditional manufacturing processes also produce nanoparticles through homogenisation, emulsification, etc. Examples include casein micelles and whey proteins in milk and emulsified droplets in mayonnaise. Such natural nanoparticles have been eaten safely for generations and not impose risk to human health.

In recent years, man-made nanoparticles have drawn a high attention in food sector. Due to the small sizes, the chemical and physical properties of nanomaterials can be very different from their respective bulk materials. This offers considerable opportunities for the development of innovative products and applications in the food sector. However, safety issues surrounding the use of nanotechnology in food have raised public concern.

Applications of nanotechnology in the food sector

1. Nanoencapsulation is a major area of nanotechnology application in the food sector. Nanoparticles are manufactured to encapsulate food ingredients and additives to mask their unpleasant tastes and flavours, protect the encapsulated ingredients from degradation, as well as to improve dispersion of water-insoluble food ingredients.
2. Another major focus of application of nanotechnology in food processing involves the development of nanostructured food ingredients and additives, usually with claims that they offer improved taste, texture and consistency, enhanced bioavailability and permit mixing of previously "incompatible" ingredients in food matrix. Examples of nanostructured foodstuffs include spreads, ice cream, yoghurt, nano-salt, etc.
3. Other indirect applications of nanotechnology in food area include the development of nanosized agrochemicals and veterinary medicines.

Concerns over the application of nanotechnology in food

1. Nanoparticles become an indirect source of food contaminant.
2. Uptake of nanomaterials alters the absorption profile and metabolism in the body.
3. Toxicity of nanoparticles remains largely unknown.
4. Lack of effective analytical method and predictive model to evaluate the safety of nanoparticles.

Safety of food derived from nanotechnology

1. At present, there is no tenable evidence that food derived from nanotechnology is any safer or more dangerous than their conventional counterparts.
2. Despite no general conclusion has been made by international food safety authorities on the safety of nanofood incorporated with nanomaterials, there is also no evidence that ingested nanomaterials have harmed human health.
3. Different jurisdictions, such as Australia, European Union, United States and New Zealand, have established committees to monitor the development of nanotechnology and take appropriate action if necessary.

Advice to trade

1. Traders should ensure the products on sale are safe for human consumption.
2. Do not sell nanomaterials that have not undergone safety assessment.

Advice to public

1. Maintain a balanced diet.
2. Buy food from reliable suppliers.

Risk Assessment Section
Centre for Food Safety
March 2017