Today’s Sydney Morning Herald reports concerns from scientists that nanoparticles in some popular sunscreens may trigger a range of ailments from skin rashes to cancer. However the Australian Therapeutic Goods Administration have dismissed these claims, saying no specific health risk has been identified and any risks are “unproven” and “theoretical”.
There has also been recent interest in the role of nanotechnology in food. We asked the New Zealand Food Safety Authority and the Riddet Institute to comment on the use of nanotechnology in the food industry and to address concerns about the safety of nanoparticles in food. Their comments are below.
New Zealand Food Safety Authority: Nanotechnology and Food
How common is the use of nanoparticles in the food industry? How is this changing?
Nanomaterials are not new. The air we breathe, the water we drink and the food we eat, naturally contain nanoparticles. What is new is the ability of scientists to manipulate matter at the nanoscale to create new and unique materials.
Apart from foods that traditionally contain nanoparticles, New Zealand Food Safety Authority (NZFSA) is not aware of any foods being sold in New Zealand that contain manufactured nanoparticles. Food Standards Australia New Zealand (FSANZ) is the agency responsible for developing food standards that apply in both New Zealand and Australia. FSANZ has not received any applications to approve any manufactured nanoscale particles for food use.
What is the basis for concern about the safety of nanoparticles in food?
Manufactured nanoparticles can have very different physical, chemical, and biological properties compared to what they exhibit on a macro-scale. While this can enable unique applications, it could potentially have safety implications.
How might very small particles of an otherwise safe substance pose a risk when consumed?
Manufactured nanoparticles can have different properties compared with their macro-sized form. Concerns have been raised that these changes may alter toxicity.
Other concerns include the ability of manufactured nanomaterials to enter and interact with the human body. However, human exposure to nanomaterials is nothing new. Nanoscale food substances exist naturally and are able to be metabolised in the body.
The potential for manufactured nanomaterials in food packaging to migrate into food has also been raised as a potential food safety risk. However, if there is no release or migration of nanoparticles then there would be no additional concern about safety.
Can nanoparticles cross into the body’s cells and cause damage?
Food traditionally contains nano-sized particles and the human body is able to process these without any ill effects. Concerns have been raised that due to their size, there is potential for nanoparticles, both manufactured and naturally occurring, to penetrate membranes and get access to sub-cellular structures that larger particles can not.
Do nano-particles have an effect on nutrition or absorption of nutrients?
Nano-sized nutrients are likely to be absorbed quicker and more efficiently by the body.
What further research is most urgently needed to address the safety of nanoparticles in food and packaging?
While New Zealand’s food regulatory framework is well positioned to deal with any concerns about the safety of foods containing manufactured nanomaterials, there is a concerted international effort to ensure there is a co-ordinated approach to safety aspects.
The OECD Working Party for Manufactured Nanomaterials was established in 2006 and is currently working on eight projects which will provide important information on the human health and environmental safety aspects of manufactured nanomaterials.
One of the projects is testing a representative set of manufactured nanomaterials for human health and environmental safety effects. While another project is looking at whether existing test guidelines (used for “traditional chemicals”) can be successfully applied to manufactured nanomaterials.
Do we need mandatory labelling of nanomaterials in food and packaging? What else can be done to address consumer concerns?
Mandatory labelling is usually used to provide information relevant to food safety and public health (e.g. additives and preservatives, nutrition, including sugar, fat, energy content, and allergens). It is unclear whether manufactured nanomaterials pose any food safety risk, therefore it would be premature to answer this question.
It is important to note that the New Zealand Food Safety Authority is not aware of any food available in New Zealand containing manufactured nanomaterials. In addition, current regulations cover the potential uses of nanotechnology in food. Food additives, processing aids, and novel foods, for instance, are required to undergo a pre-market assessment to establish their safety before they can legally be used in food in New Zealand. This would also apply to newly manufactured nanoscale particles.
The Riddet Institute, Massey University: Nanoparticles in food and food packaging
Imagine food packed with antioxidants and omega-3 oils or packaging that keeps food fresher and kills bacteria. These and other exciting developments are just around the corner thanks to nanoparticle technology.
Biomaterial nanoparticles are made from proteins, fats and carbohydrates that are digested or excreted by the human body. These are allowed in foods in some cases, e.g. for delivering vitamins and bioactive nutrients. Inorganic nanoparticles are made from materials such as metals, metal oxides and mineral compounds. Food packaging containing inorganic nanoparticles could inhibit bacteria, control the amount of oxygen that gets into food or indicate whether foods have been transported and stored at the right temperature. At the moment, inorganic nanoparticles cannot be added to foods because there is not enough information about their safety. Further research is required to understand how they interact with the body, and how safe they are.
Biomaterial nanoparticles
Naturally digestible materials such as milk proteins are ideal ingredients for nanoparticles. Nondigestible food-safe materials such as ‘resistant starch’ or plant gums contribute to dietary fibre and pass through the body.
One example of biomaterial nanoparticles is the patented encapsulation technology developed at the Riddet Institute that ‘locks in’ the health benefits of omega-3-rich fish oils. Droplets of healthy oil are encapsulated in milk proteins to form nanoparticles. Encapsulated droplets are protected from oxidation, preserving their healthiness. Biomaterial nanoparticles could also deliver healthy bacteria to the gut, where they can out-compete disease-causing bacteria and lower cancer risk.
So far, only a handful of foods contain biomaterial nanoparticles, mainly as delivery systems for vitamins and bioactive nutrients1, 2. Many other biomaterial nanotechnologies are currently under development, and can be expected to appear in the coming 2-5 years.
Inorganic nanoparticles
Inorganic nanoparticles also have potential applications in the food industry. They are not added directly to food at present, but offer exciting new possibilities for food packaging. Silver or silicate nanoparticles embedded in plastics can inhibit the growth of bacteria3, 4. Food containers and plastic wrap made of such materials could improve the safety of foods, especially raw meat. Titanium dioxide nanoparticles embedded in food packaging could slow the ripening of fruit and vegetables by breaking down ethylene gas5.
Other developments in food manufacture and testing also use inorganic nanoparticles. Carbon nanotubes have improved the speed, accuracy and cost of testing foods for healthy bioactive compounds or unwanted pesticide residues6. Nanoparticle inks that change colour in response to heat, light or oxygen could indicate whether a food product has been stored correctly, and how much shelf life is left7.
The safety of inorganic nanoparticles is a hot topic around the world. In October 2008 the European Food Safety Authority released a draft scientific opinion on potential risks arising from the use of nanotechnologies in the food industry8. According to literature reviewed by the EFSA, the small size and large surface area of nanoparticles makes them different from anything science has encountered before. Some nanoparticles can be absorbed into the bloodstream via the gut, where larger particles of the same material cannot be absorbed.
Studies to date have not been able to determined whether nanoparticles are modified by the body, because they are very difficult to detect and characterise. It appears that the size and surface material of inorganic nanoparticles determine whether they are absorbed in the gut and how they interact with the body once absorbed. The EFSA emphasized that it is not possible to generalise about the safety of inorganic nanoparticles because their properties vary widely with size and material. As a result, safety assessment has to be on a case-by-case basis. Further research is needed on the interactions between nanoparticles and the body before any conclusions can be drawn about their safety9.
References
1. Chaudhry Q, Scotter M, Blackburn J, Ross B, Boxall A, Castle L, Aitken R and Watkins R, Applications and implications of nanotechnologies for the food sector. Food Additives & Contaminants: Part A 25:241-258 (2008).
2. The Project on Emerging Nanotechnologies, Inventories. http://www.nanotechproject.org/inventories/ [10 October 2008].
3. Quintavalla S and Vicini L, Antimicrobial food packaging in meat industry. Meat Science 62:373-380 (2002).
4. Jong-Whan R, Seok-In H, Hwan-Man P and Ng PKW, Preparation and characterization of chitosan-based nanocomposite films with antimicrobial activity. Journal of Agricultural & Food Chemistry 54:5814-5822 (2006).
5. Maneerat C and Hayata Y, Gas-phase photocatalytic oxidation of ethylene with TiO2-coated packaging film for horticultural products. Transactions of the ASABE 51:163-168 (2008).
6. Ahmed MU, Hossain MM and Tamiya E, Electrochemical biosensors for medical and food applications. Electroanal 20:616-626 (2008).
7. Mills A, Tommons C, Bailey RT, Tedford MC and Crilly PJ, UV-activated luminescence/colourimetric O-2 indicator. International Journal of Photoenergy (2008).
8. European Food Safety Authority, Draft Opinion of the Scientific Committee on the Potential Risks Arising from Nanoscience and Nanotechnologies on Food and Feed Safety. www.efsa.europa.eu [23 October 2008].
9. Maynard AD, Aitken RJ, Butz T, Colvin V, Donaldson K, Oberdorster G, Philbert MA, Ryan J, Seaton A, Stone V, Tinkle SS, Tran L, Walker NJ and Warheit DB, Safe handling of nanotechnology. Nature 444:267-269 (2006).
Further information on nanotechnology
A new report: A Hard Pill to Swallow: Barriers to Effective FDA Regulation of Nanotechnology-Based Dietary Supplements has just been published, highlighting the FDA’s regulatory challenges posed by nanomaterials.