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From: Food Quality & Safety magazine, December/January 2011

Is Food Nanotech Withering on the Vine?

Despite interest, negative public perceptions have companies pulling back

by Catherine Shaffer

As recently as 2005, food manufacturing giants like Kraft Foods and Nestlé were touting the food science breakthroughs they expected to make using nanotechnology. At the time, anticipated innovations included tiny chemical tongues and noses to sense spoilage, smart foods that could change composition to suit the consumer, and delicious junk foods with the nutritional profile of broccoli. Kraft even organized a consortium of government and academic institutions, called the Nanotek Consortium, to study nanotechnology applications in food.

But the Nanotek Consortium has disappeared, and references to nanotechnology have fallen out of the public communications of big food companies. “We have not nor are we currently using nanotechnology in our products or packaging. Regarding the Nanotek Consortium, we are no longer affiliated with the group,” Kraft spokesman Richard D. Buino wrote in an e-mail to Food Quality.

At the same time, nanotechnology-based innovations have been appearing on supermarket shelves. Many observers attribute the pullback to increased public resistance and concern about untested technologies. However, a lack of regulations specific to nanoparticles means that food companies have a blank check to include them in products without disclosing that information in any way. It seems that although the food industry’s interest in nanotechnology was blossoming just a few short years ago, it has now withered, or at least gone underground.

Water-Filtration Techniques
Water-Filtration Techniques. Researchers are experimenting with carbon nanotube-based membranes for water desalination and nanoscale sensors to identify contaminants in water systems. Other nanoscale materials that have great potential to filter and purify water include nanoscale titanium dioxide, which has been shown to neutralize bacteria, including E. coli, in water.

Why Nanotech?

Many nanotechnology innovations pioneered in other disciplines, such as drug delivery, have potential applications in foods. For example, single molecule detection technology for tracking enzymatic reactions could potentially be used to detect chemical contaminants or pathogens in food. Nanosized capsules developed for delivering targeted drug or biological therapy could be used to encapsulate time-released flavor enhancers or specialized sensors for food quality measurements. Nanotubes and particles could potentially be used to create desired textures, and nanofilms could be included as barriers to spoilage or oxidation.

“One of the areas where nanomaterials and nanotechnology have potential is for very rapid and sensitive detection of foodborne pathogens. There is a potential for benefit to the consumer,” said Bernadene Magnuson, PhD, a senior scientific and regulatory consultant with Cantox Health Sciences International, a scientific, toxicology, and regulatory consulting firm that offers its clients expertise in food and nutrition.

Foodborne pathogens have been an increasing problem in the food industry and in our food supply. In March 2010, the Produce Safety Project at Georgetown University estimated that the annual cost of foodborne illness in the U.S. is $152 billion. That’s obviously a massive problem for which solutions are desperately needed—and a compelling entry in the “benefit” column in any risk-benefit assessment for a nanotech-based pathogen monitoring system.

In addition to technology borrowed from pharmaceutical and materials science, the food industry is producing its own innovation. “Nestlé and Unilever are developing nanoparticle emulsion methods to help with food textures to make them more uniform. Nestlé is also exploring the delivery of nutrients and antioxidants in nanocapsules,” said Chananit Sintuu, an analyst with Lux Research, a research and advisory firm covering many industrial areas, including nanomaterials. Sintuu cited a 2008 publication in the Journal of Agricultural and Food Chemistry in which Nestlé researchers described the use of “self-assembly structures” to improve the texture of an emulsion. “Therefore,” the authors wrote, “the objective of the present study was to investigate controlled release of aroma compounds from the dispersed phase of self-assembly structures in an emulsified water solution, closer to popular food products in terms of lipid content.”1

When queried about their work with nanotechnology in emulsions, however, Nestlé spokeswoman Hilary Green responded, “Nestlé does not do research in the field of nanotechnology. Although we are not doing our own research, and we are not working with other laboratories in the field of nanotechnology, we do recognize the potential nanotechnology has in the longer term to improve the properties of food and food packaging.”

Part of the problem may be a matter of ontology. The most common definition of a nanoparticle is a particle between 1 and 100 nanometers (nm). However, some of the particles appearing in foods and packaging, and some of those being studied for toxic effects, are larger than 100 nm but still too small to be called microparticles. These particles, of 300, 400, or even 700 nms, may have different properties than the bulk materials from which they are made, and yet they do not fall under the authority of a narrow regulatory definition limited to particles smaller than 100 nm.

One area of open and active innovation in nanotechnology is the packaging of foods. The U.S. Army Natick Soldier Research, Development and Engineering Center is trying out new nanomaterials in the packaging for its Meals, Ready to Eat. The nanocomposite material offers some significant potential benefits, including lighter weight and increased shelf life for the product inside. The optimized formulation consists of melt-processed low-density polyethylene and 7.5% montmorillonite-layered silicate nanoparticles of 6 mil thickness total (six one-thousandths of an inch). Its performance as a barrier to air and heat was significantly better than the standard meal bag, which is made of 11 mil thick low-density polyethylene.

Nestlé does not do research in the field of nanotechnology. Although we are not doing our own research, and we are not working with other laboratories in the field of nanotechnology, we do recognize the potential nanotechnology has in the longer term to improve the properties of food and food packaging.

—Hilary Green, Nestlé

Risks of Nanotechnology

The risks of nanomaterials in food or food packaging are not well characterized. Some foods naturally contain nanoparticles. For example, milk contains casein protein, which falls into the nanoparticle size range. Those natural nanoparticles are not associated with any increased risk in food. However, some studies suggest that nanoparticles may be more chemically reactive and more bioavailable than larger particles because of their increased surface area.

A 2006 publication in Environmental Science and Technology by scientists from the Institute for Chemical and Bioengineering in Zurich, Switzerland, suggested a nanoparticle-specific cytotoxic mechanism of uncoated iron oxide.2 And in the same year in Nano Letters, another group of Swiss scientists studied the toxicity of carbon-based nanoparticles to lung cells and found a size-dependent toxicity.3

Other studies show relatively benign effects of nanoparticles. In a recent study published by Liu and colleagues in Biomaterials, Chinese scientists found that mesoporous hollow silica nanoparticles had very low toxicity.4

One nanomaterial that is appearing in many consumer products, including some that are food-related, is nanosilver. Ionic silver is known to be toxic to bacterial cells in culture. Nanosilver is a very potent form of ionic silver, whose attributes are likely due in part to its nanoparticle size. Nanosilver has found its way into food packaging, containers, kitchen tools like cutting boards, and even health supplements.

Nanosilver, sold as colloidal silver, is a highly sought after cure-all in the alternative medicine community, although it has been found to have high toxicity to certain rat and mouse cells in vitro. While it has not been shown to have the same toxicity to humans, it can cause an unsightly graying of the skin called argyria. Consumer advocacy groups argue that under a precautionary principle of public health, products such as nanosilver should not be used in human foods or in surfaces that contact food until in vitro toxicity studies are reconciled with thorough human health studies, including studies of the effects of long-term exposure.

The Power of Perception

It’s fair to say that the actual risks of nanotechnology in foods have yet to be defined. However, another set of risks frames the public discourse on nanotechnology: perceived risks. To some consumers, the prospects of nanotech beverages that change flavors to suit the drinker, or tiny nanotech bloodhounds to sniff out spoilage, are not so appealing. Consumer groups have challenged companies on their nanotech research and petitioned the U.S. Food and Drug Administration (FDA) and other government agencies to look more closely at nanomaterials in the food supply.

“What was going on five or six years ago, researchers in most universities and also in the private sector were jumping on the nanotechnology bandwagon. It was kind of a buzzword. They were working on projects that only a few years before they were not using the word nanotechnology to describe,” said Paul Thompson, PhD, a professor of agricultural, food, and resource economics at Michigan State University in East Lansing. Dr. Thompson is a philosopher who has dedicated his career to studying technological controversies in agriculture and food science.

According to Dr. Thompson, the use of the term nanotechnology to describe certain types of food chemistry work created a negative impression, and the industry seems to have responded by moving away from that specific terminology.

“There’s a set of real risks versus perceptual risks,” said Sintuu. According to Sintuu, the real risks of nanotechnology are comparable to any other new product that is going on the market for human use. Any novel technology that will be ingested by the public has a potential risk associated with it. The perceived risks, however, have become the larger issue in the nanotechnology industry. Because there are no nanotech-specific regulations, the perception is that any and all nanotechnology is harmful, regardless of whether or not there is scientific data to back up that assumption.

“There’s a huge knowledge gap,” said Sintuu. “Well-characterized tests need to be developed to more accurately determine what the real risks are; at the same time, a comprehensive process to educate consumers and ensure their concerns are addressed is necessary in order to keep any perceptual risks at bay.” In addition, Sintuu added, successful management of nanotechnology risks requires the cooperation of government agencies, academic institutions, non-government organizations, and technology developers to adopt an integrative “open risk management” approach to nanotechnology risk management.

The FDA established a nanotechnology task force in 2006 to address those policy gaps. The FDA told Food Quality in an email that it is preparing a food ingredient guidance document that would address some nanotechnology issues and is hoping to publish it in the near future. The agency declined to discuss any details of that document before publication.

A 2007 task force report recommended that the FDA issue guidance for the use of nanomaterials in a broad range of products, whether subject to premarket clearance or not. On the other hand, the task force also concluded that the evidence did not merit mandatory labeling. “Because the current science does not support a finding that classes of products with nanoscale materials necessarily present greater safety concerns than classes of products without nanoscale materials,” said the report, “the Task Force does not believe there is a basis for saying that, as a general matter, a product containing nanoscale materials must be labeled as such. Therefore the Task Force is not recommending that the agency require such labeling at this time.”

Across the pond, the European Commission has called for a consultation to define “nanomaterials,” which will help set the stage for new regulations pertaining to nanofoods. “The definition of the term ‘nanomaterial’ should be based on available scientific knowledge and should be used for regulatory purposes,” according to a statement on the initiative. “The definition should determine when a material should be considered as a nanomaterial for legislative and policy purposes in the European Union.”

There’s a huge knowledge gap. Well-characterized tests need to be developed to more accurately determine what the real risks are; at the same time, a comprehensive process to educate consumers and ensure their concerns are addressed is necessary in order to keep any perceptual risks at bay.

—Chananit Sintuu, Lux Research

Nanotech in the Wild

A number of nanomaterials have already made an appearance on the market in food products. The environmental advocacy group Friends of the Earth has identified 104 commercially available foods, nutritional supplements, food contact materials, and agricultural chemicals that contain manufactured nanomaterials. Some examples include Nano Tea, by Shenzhen Become Industry & Trading Co., which contains 160 nm particles; products containing 300 nm SunActive Fe iron, including “Daily Vitamin Boost” fortified fruit juice by Jamba Juice and Vanilla Oat and Chocolate Oat Nutritional Drink Mixes by Toddler Health; Canola Active oil by Shemen; and a large number of products marketed as nutritional supplements.5 Jamba Juice could not be reached for comment.

Types of food packaging that include nanomaterials include packaging by Nanocor for some Miller beers that includes a nylon/nanocomposite barrier; composite biopolymer trays by Plantic Technology used in some Cadbury products; and an adhesive made of 50 to 150 nm starch, made for McDonald’s burger containers by Ecosynthetix.5

However, because manufacturers are not required to disclose the use of nanomaterials in products, Friends of the Earth estimates there are many more instances of nanomaterials that are intentionally added to foods that are not disclosed to consumers.

A counterbalance to the curiosity that drives innovation in food technology and the use of nanoparticles in new food chemistries, whether they are labeled as such or not, is the cost of research and innovation in what is essentially a conservative field run on slim margins. “They will not likely use or develop expensive nanomaterials as ingredients or packaging materials because of the challenge of selling products that are priced too high. So [nanomaterials] will likely not be used much by the food industry until the technology develops so that is more economically viable,” said Dr. Magnuson.

As a result, an interesting dynamic could develop. On the one hand, increased oversight and regulation are needed to ensure the safety of certain new food-related nanotechnologies, and, at the same time, increased support, promotion, and even funding are required to bring promising nanoparticle technologies to the market. Whatever side of the spectrum you start from, it’s clear that progress can only be made from the middle, where openness and dialogue create an atmosphere of optimism as well as prudence.

Shaffer is a freelance writer based in Ann Arbor, Mich. Reach her at cathshaffer@gmail.com

References

  1. Phan VA, Liao YC, Antille N, et al. Delayed volatile compound release properties of self-assembly structures in emulsions. J Agric Food Chem. 2008;56(3):1072-1077.
  2. Brunner TJ, Wick P, Manser P, et al. In vitro cytotoxicity of oxide nanoparticles: comparison to asbestos, silica, and the effect of particle solubility. Environ Sci Technol. 2006;40(14):4374-4381.
  3. Magrez A, Kasas S, Salicio V, et al. Cellular toxicity of carbon-based nanomaterials. Nano Lett. 2006;6(6):1121-1125.
  4. Liu T, Li L, Teng X, et al. Single and repeated dose toxicity of mesoporous hollow silica nanoparticles in intravenously exposed mice [published online ahead of print November 18, 2010]. Biomaterials.
  5. Miller G, Senjen R. Out of the laboratory and onto our Plates: nanotechnology in food and agriculture. Friends of the Earth. March 2008. Available at: http://foe.org/healthy-people/nanofood-and-nano-agriculture. Accessed December 3, 2010.

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