Issues and Challenges for nanoscale science in food applications

Bernadene A. Magnuson, Ph.D. Senior Scientist and Regulatory Consultant

Cantox Health Sciences International, Mississauga, ON Canada

E-mail: bmagnuson@cantox.com Ph 905-542-2900

ABSTRACT

The growing interest in the potential use of nanomaterials in food applications is evident by the increasing number of scientific publications in food related journal, and food-specific conferences on nanotechnologies (Chaudhry et al., 2008). As the science develops and more and more potential applications of nanomaterials are being discovered, there are also issues and challenges arising regarding adoption of this new technology by the food and food-related industries. The three issues that were discussed at the 2007 IFT International Nanoscience Conference were: (1) are nanomaterials safe for food applications? (2) will the use of nanomaterials be accepted by the public? (3) what are the potential environmental and societal impacts of nanomaterials in food?

Are nanomaterials safe for food applications?

The answer to this question is not going to be a simple one. In other words, it will depend on the situation, on the type of nanomaterial used and how the nanomaterial is used. The safety of any situation or agent is assessed by determining the likelihood of the risk of harm. The risk that is posed is assessed by considering the hazard (define) and the degree of exposure. If there is either low hazard (resulting from low inherent danger or toxicity) or low exposure, the overall risk will be low. Thus when considering the safety of food applications of nanomaterials, one must assess both the inherent toxicity of the nanomaterial, and the likelihood of exposure to the nanomaterial.

There is a large body of data on the toxicity of inhaled nanomaterials, due to the presence of nanoparticles in air from industrial pollution and natural sources (Borm and others 2006). Development of nanomaterials for medical applications is also providing information on the toxicity of nanomaterials injected directly into the body or blood stream, and use of nanomaterials in sunscreens and cosmetics has provided data on dermal toxicity. There are, however, few studies that have evaluated oral exposure and the ability of nanomaterials to cross over the gastrointestinal tract. Even fewer have evaluated the bioavailability of nanomaterials from a food product.

Factors that affect the toxicity of nanomaterials include chemical composition, size and shape, and surface characteristics of the particles or materials (Oberdorster and otherz 2005). General concerns that apply to nanoscale materials as compared the same chemical composition in microscale dimensions include: greater exposure to surface of particles per unit mass; potential differences in exposure route due to small size (i.e. may aerosolize more readily); potential differences in distribution due to increased ability to cross cell membranes; and the potential for a new mode of action of the compound based on the novel properties resulting from the nanosizing of the material (Nel and others 2006). Some of the challenges in the evaluation of nanomaterials are the need to adequately characterize the nanomaterials in terms of size, shape, uniformity of size and shape, agglomeration properties, chemical purity, and stability in the test organism and in the specific test conditions. Use of standards and validated methods for the test material is highly desirable.

The potential exposure to nanomaterials will greatly depend upon their use in the food and food-related industry. Incorporation of nanomaterials into multi-composite packaging materials, in which the nanomaterial layer is coated with other materials, for example, is likely to result in minimal transfer to the food and thus present exceedingly low exposures to the nanomaterial by the food consumer. In contrast, use of nanomaterials as carriers of nutrients or bioactive compounds that will be added directly to the food product, will result in higher levels of exposure and will depend on the concentration in the food and the amount of that food consumed. In these cases, the composition of the nanomaterials is likely to be modifications of compounds found in food, such as proteins, lipids, etc.

Will the use of nanomaterials be accepted by the public?

The investment of resources by the food sector into nanotechnology is likely somewhat conservative compared to other industries as the question of public acceptance of new technologies is often slower for food applications than for other applications. Consumers readily identify the benefits of the use of nanotechnology for protection of the environment, lowering of energy costs, improved health through medical applications and improved food safety and nutrition (Anon. 2006). Their greatest concerns with regard to risk were in the applications of food and medicine. The fact that food is consumed by the entire population, including children and the elderly, is why the public has a very low level of risk acceptance for new technologies in the food supply. According to the study by Currall and colleagues (2006), nanotechnology is perceived by the public as presenting less risk than other frequently consumed products such as alcoholic beverages and genetically modified foods. Thus the future does appear to promising for the development of applications of nanomaterials in food uses. Consumer acceptance of the use of nanomaterials will greatly depend upon their perception of the benefits to them as a consumer, their perception of the safety and environmental impact of the use of nanomaterials. Education and transparency by the food industry will be critical to promote understanding and acceptance of this promising technology.

What are the potential environmental and societal impacts of nanomaterials in food?

Environmental scientists are currently evaluating the life cycle of nanomaterials to determine how long they last, how they degrade and how they move through the environment. As often more than one industry is finding uses for a particular nanomaterial, such as nanosilver, these analyses are challenging and continuing to evolve. The National Nanotechnology Initiative (NNI) is undertaking studies to assess the societal implications of nanotechnology, addressing questions such as who will benefit from nanotechnology and who will pay? Their findings will be provided on the NNI website (www.nano.gov). These issues are going to be continually evaluated as the use of nanomaterials become more widespread.

The current needs of the food industry are to undertake and support research to establish the safety of the nanomaterials that will be used in food, and to develop and understanding of the effects of oral uptake and the food matrix. Education within the food and nutrition industry is needed, as well as consumer education to ensure consumers receive accurate information. Lastly, continued vigilance of the potential environmental and societal impacts of nanomaterials is also necessary.

References

Anonymous, 2006. Research Report. Public Awareness of Nano Grows. Report to the Woodrow Wilson International Center for Scholars Project on Emerging Nanotechnologies. http://www.nanotechproject.org/file_download/files/HartReport.pdf. Accessed October, 2006.

Borm PJ, Robbins D, Haubold S, Kuhlbusch T, Fissan H, Donaldson K, Schins R, Stone V, Kreyling W, Lademann J, Krutmann J, Warheit D, Oberdorster E. 2006. The potential risks of nanomaterials: a review carried out for ECETOC. Part Fibre Toxicol. 14;3:11.

Chaudhry Q, Scotter M, Blackburn J, Ross B, Boxall A, Castle L, Aitken R, Watkins R. 2008. Applications and implications of nanotechnologies for the food sector. Food Addit Contam. 25(3):241-58.

Currall SC, King, EB, Madera J and Turner S. 2006. What drives public acceptance of nanotechnology? Nature Nanotechnology, 1:153-155.

Nel A, Xia T, Mädler L, Li N. 2006. Toxic potential of materials at the nanolevel. Science. 3;311(5761):622-7.

Oberdörster G, Maynard A, Donaldson K, Castranova V, Fitzpatrick J, Ausman K, Carter J, Karn B, Kreyling W, Lai D, Olin S, Monteiro-Riviere N, Warheit D, Yang H; 2005. ILSI Research Foundation/Risk Science Institute Nanomaterial Toxicity Screening Working Group. Principles for characterizing the potential human health effects from exposure to nanomaterials: elements of a screening strategy. Part Fibre Toxicol. 6;2:8.