Nanotechnology and food

No longer in the realm of science fiction, nanofoods are on their way to a supermarket near you.
 
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  • Updated:23 Feb 2009
 

01 .Nanofoods

Nanotechnology illustration

In brief

  • Nanotechnology involves structures as small as molecules, with new and unexpected properties that could make them hazardous to health.
  • Nanofoods may already be on supermarket shelves without us knowing — and without violating current Australian food regulations.
  • CHOICE wants nanofoods better regulated to ensure they are both safe and properly labelled.

Please note: this information was current as of February 2009 but is still a useful guide today.


What is nanotechnology?

Broadly speaking, nanotechnology involves manipulating matter at the nanoscale to create new materials, structures and devices. The nanoscale is usually taken to mean structures ranging in size from one to 100 nanometres, about the size of individual molecules. One nanometre (nm) is a billionth of a metre and to put this in perspective, a human hair is about 80,000nm–100,000nm thick, while a single molecule of the protein haemoglobin (which carries the oxygen in our blood) is about 4nm across.

At this tiny scale, materials can have different properties from their bulk form because of the larger relative surface area (making them potentially more reactive) and new quantum effects that can take over from the usual laws of physics.

Consumer products range from invisible sunscreens (with nanoscale titanium dioxide and zinc oxide) to shirts that don’t stain. In medicine, progress is being made in areas such as disease diagnosis and drug delivery targeted at specific sites in the body (making cancer treatment, for example, potentially more effective), and in other non-domestic situations, nanotechnology is being applied in the fields of environmental protection for water and air purification, pollution detection and harnessing solar energy.

What's the food industry doing?

”Nanofoods” refers to all foods to which manufactured nanoscale food components have been added and/or packaged in materials to which manufactured nanoparticles have been added. Nanotechnology certainly offers exciting possibilities for the future, such as safer food that can be conveniently stored for longer periods without deterioration. Other possibilities include foods fortified with healthy ingredients such as vitamins, antioxidants or omega-3 fats, encapsulated so that they are delivered exactly where they are needed in your body.

Some of the food giants, including Kraft, Nestlé and Unilever, are exploring the use of nanotechnology, but so far keeping very quiet. There are, however, plenty of potential food applications of nanotechnology being openly canvassed.

  • Food additives Ingredients are processed to form nanostructures or nanotextures to enhance taste, texture and consistency of food. One example of this might be the development of ice-cream with a lower fat content that retains a fatty texture and flavour.
  • Food processing equipment Knives and chopping boards can be coated with antibacterial silver nanoparticles. These products are already on the market, despite evidence suggesting that nanosilver may be toxic and is already of definite environmental concern. When products treated with nanosilver are washed, nanoparticles are released into waste water treatment facilities and can destroy beneficial bacteria.
  • Food quality Nanosensors (integrated with packaging) may increase the shelf life of food by detecting spoilage bacteria or the loss of food nutrients, possibly releasing antimicrobials, flavours, colours or nutritional supplements in response.
  • Food packaging Nanomaterials are already added to packaging to keep food fresher for longer; for example, blocking UV light using nanoscale zinc oxide and antibacterial films that contain silver nanoparticles.

What CHOICE wants

The main issue around regulation is not the small size of nanoparticles as such, rather their novel properties. We’ve always been exposed to naturally occurring nanoparticles, but never before to nanoparticles specifically manufactured to influence food properties. We simply do not yet know enough about how they could affect human health; no one predicted, for example, that carbon nanotubes could cause cancer (see Nanotubes — The new asbestos?).

Regulation definitely warrants a precautionary approach; lack of evidence of harm isn’t evidence of safety. CHOICE would therefore like to see all nanofoods considered as “novel” and as such trigger rigorous case-by-case safety assessments, as required for all novel foods under the Food Standards Code. Specifically, we would like to see the following safeguards:

  • A definition of “nano” incorporated into the Food Standards Code.
  • Safety assessments carried out by FSANZ to specifically address the new potential risks posed by nanomaterials.
  • All food containing manufactured nanoparticles to be specifically labelled.
  • All manufactured nanoparticles to be treated as new chemicals and subject to rigorous new safety testing – even those previously used in bulk form. For example, chocolate with nanotitanium dioxide (added to improve its appearance) should not be allowed on the market without undergoing any safety assessment simply because titanium dioxide in its bulk form is a permitted additive.

Without these changes, there’s a very real possibility that nanofoods will appear legitimately on the shelves without having undergone any safety testing — with the potential for serious consequences.

 
 

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Small particles, big risk

The very properties that make nanomaterials so attractive – their small size (that of atoms and molecules) and relatively larger surface area – can also make them potentially toxic to humans.

  • They have far greater access to our body (bioavailability) than larger particles, resulting in greater uptake into individual cells, tissues and organs. This greater access and reactivity may introduce new toxicity risks. Numerous test tube studies (in vitro) have shown that nanomaterials can cause damage to cells and tissues in a number of ways, including changing the DNA and causing mitochondrial damage.
  • There’s some evidence to suggest nanoparticles may be associated with rising levels of immune system dysfunction and inflammations of the gastrointestinal tract (GIT), including the suggestion that exposure may be associated with Crohn’s disease, a damaging and chronic inflammation of the GIT which can lead to cancer.
  • There has been some research which shows that nanoparticles can cross the blood/brain barrier. A leading European toxicologist has said we cannot rule out a link between nanoparticles and diseases such as Alzheimer’s, Huntington’s and Parkinson’s.

Graph showing relationship between surface area and particle diameter

Food risks

There’s nothing inherently unsafe about very small particles — we are exposed to them every day. The air we breathe, the food we eat and water we drink all naturally contain particles within the nanometre range. Most health concerns relate to the potential impacts of deliberately manufactured nanoparticles that are different from anything that occurs in nature (see Nanotubes — The New Asbestos?, below).

The study of the toxicity of nanomaterials, “nanotoxicology”, is in its infancy, so rigorous safety information is limited. However, experts agree there is an urgent need for research in this area:

  • We don’t know how nanoparticles in food are absorbed, transported around the body, accumulated or eliminated. Some nanoparticles may be able to transfer food components to parts of the body not normally exposed to them.
  • Worse, we don’t know how to routinely test for the presence of nanomaterials in food, which is concerning since in order to assess the risk posed by any chemical we must first be able to identify and measure it.

Nanomaterials now in commercial use by the food industry, such as nanoscale titanium dioxide (used as an ultraviolet protector and an antimicrobial in food packaging and containers) and silver (used as an antimicrobial in food packaging, chopping boards and knives), have been shown to be toxic to cells and tissues in both test tube and animal studies.

Nano moleculesAnother area of concern is the potential for nanonutritional additives (functional foods) to provide an excessive dose of some vitamins and nutrients, or to interfere with the absorption of other nutrients. Dr Qasim Chaudhry, leader of the nanotechnology research team at the UK’s Central Science Laboratory, warns that nanoparticles and nanoencapsulated food ingredients “may have unanticipated effects, far greater absorption than intended or altered uptake of other nutrients, but little, if anything, is known currently”.

Nanotubes — The new asbestos?

A recent study in mice found that some forms of carbon nanotubes may be as harmful as asbestos if inhaled in sufficient quantities.

There are many unanswered questions. It is still not clear whether carbon nanotubes will become airborne and be inhaled, or whether they still can successfully work their way to the sensitive outer lining of the lungs.

A pivotal report on nanotechnology by the Royal Society in the UK in 2004 recommended that, until there was evidence to the contrary, factories and research laboratories should treat manufactured nanoparticles and nanotubes as if they were hazardous.

Based on the results of this study, the toxicity and potential implications of long, multi-walled carbon nanotubes is an issue of priority for the Office of the Australian Safety and Compensation Council (ASCC). The ASCC has also initiated a nanotechnology occupational health and safety research program, while the NSW Department of State and Regional Development’s recent inquiry into nanotechnology recommended that a national mandatory labelling scheme be put in place for all engineered nanomaterials used in the workplace.

What are our food regulators doing?

The national regulator, Food Standards Australia New Zealand (FSANZ), seems less concerned than its equivalents in the US and UK.

FSANZ has strengthened the Application Guidelines for nanofoods, but the Food Standards Code itself remains unchanged, and CHOICE does not believe the changes made so far adequately protect consumers. Furthermore, there is no requirement for manufactured nanoparticles to be specifically labelled.

FSANZ is thus failing to provide adequate information for consumers to make an informed choice — supposedly one of its primary aims (see What CHOICE wants).

Under wraps

With no specific regulation so far, and in the absence of laws requiring manufacturers to identify nanofoods on the label, there could well be nanofoods already on the supermarket shelves that we don’t know about. Some nanotechnology analysts estimate that between 150–600 nanofoods and 400–500 nanofood packaging applications are already on the market internationally.

In Australia, confectionery packaging, bottle coatings and PET drink bottles containing nanoparticles could already be on the market, because there is no regulatory process or safety assessment.

Do we really want nanofood?

A recent poll of more than 1000 people commissioned by Friends of the Earth found nine out of ten Australians want safety checks on nanofood additives. Ninety-six percent of respondents agreed that food companies should conduct safety testing on food and food packaging ingredients that contain nanoparticles; 92% thought food companies should label food and packaging that contain nanoparticles; and 40% said they would not purchase foods containing nanoparticles at all.

Last year a phone survey of more than 1000 people, carried out on behalf of the Australian Office of Nanotechnology, found that although many respondents were hopeful, even excited, about potential uses of nanotechnology, particularly in the area of medicine, the area of food was an exception — nearly 80% of respondents were either concerned or very concerned that food labelling should provide information about nanotechnology.

Public opinion surveys in some European countries have also found that consumers are not in favour of the use of nanomaterials in food or packaging. Consumers also believe nanomaterials should be independently assessed for safety before they are placed on the market.

For more information

A number of organizations collect and disseminate information related to application of nanotechnology.

  • Australian Office of Nanotechnology (AON) was set up to coordinate the implementation of the National Nanotechnology Strategy, which was approved in early 2008. This “aims to establish the environment that allows Australia to capture benefits of nanotechnology while addressing the issues impacting on successful and responsible development of nanotechnology”. As part of the strategy the AON set up a Health, Safety and Environment Working Group to address any potential health, safety and environmental issues that nanotechnology may raise.
  • NanoSafe Australia network is a group of Australian toxicologists and risk assessors, who have formed a research network to address the issues concerning the occupational and environmental health and safety of nanomaterials. Their work includes the release of a position paper for people working with nanotechnology,Current OHS best practices for the Australian Nanotechnology Industry.
  • Friends of the Earth has been working on nanotechnology since 2005. They’re calling for a moratorium on the sale of all nanofoods until new nanoparticle risk assessment and detection methodologies are developed and validated.
  • On the international front, a number of international organisations, such as the International Standards Organisation (ISO) and the Organisation for Economic Cooperation and Development (OECD) are working to define protocols and guidelines for the responsible use of nanotechnology. Australia has representatives on these committees.
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