Nanotechnology refers to controlling matter at an atomic or molecular scale of between one and 100 nanometres (nm) - one millionth of a millimetre. Although a fairly recent phenomenon, current estimates on the value of products using nanotechnology put it currently in the range of US$7bn. In the food industry, the technology has a variety of uses including detecting bacteria in packaging, or producing stronger flavours and colourings. Public risks Friends of the Earth in Europe, the US and Australia today called for a temporary halt on using nanotechnology in the food chain, claiming that not enough it poses a number of unexamined risks to human health. According to the group, nano particles have a very large surface area which makes the particles highly 'bioactive' - i.e. they are quickly absorbed into human cells, tissues and organs. Once absorbed, some nanomaterials may prove toxic to the human body, resulting in increased oxidative stress, the group claims. Oxidative stress is generally thought to be a trigger for a wide range of chronic diseases, including cancer, cardiovascular disease, arthritis, diabetes, and neurodegenerative diseases like Alzheimer's. FOE also claims that nanotechnology entrenches a globalised, mono-cultural system of agriculture that could potentially destroy "biological diversity" and various food systems across the world. "All deliberately manufactured nanomaterials must therefore be subject to rigorous nano-specific health and environmental impact assessment and demonstrated to be safe prior to approval for commercial use in foods, food-packaging, food contact materials or agricultural applications," the report states. Public confusion Another major problem with nanotechnology is a current lack of public understanding, as "secrecy surrounds the commercial use of nanotechnology and nanomaterials by the food industry," the report states. According to FOE, food manufacturers are guilty of keeping consumers in the dark on whether use the technology or not, as they not required to label nano foods on the product. Some of the largest food companies in the world, including Kraft, Cadbury, Nestle and Unilever, explore the technology in some way, but many more could be using nanomaterials as most firms are reluctant to discuss the topic, the group claims. As well as compulsory 'nano' labelling, the FOE also calls for the food industry to involve the public in all aspects of decisions made regarding nanotechnology is food and agriculture. "People's right to say no to agriculture must be recognised explicitly," the group states. Legislation In the EU, US, and Australia, current food legislation treats all particles equally, therefore if a food ingredient is approved in bulk form it is automatically approved in nano form. However, in February 2008, the European Commission released a voluntary code of conduct for nanotechnology, acknowledging that research previously conducted into the health effects is inadequate. The EU food packaging regulation EC1935/2004 is also currently under review. The legislation covers all materials that come into contact with food, and the Institute of Food Science and Techonology (IFST) has called for it to be extended to cover nano materials.