Food applications of nanotechnologies: An overview of opportunities and challenges for developing countries

Trends in Food Science & Technology 22 (2011) 595e603

Food applications of nanotechnologies: An overview of opportunities and challenges for developing countries Qasim Chaudhry* and Laurence Castle The Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, United Kingdom (Tel.: D44 1904 462584; fax: D44 1904 462111; e-mail: [email protected]) Like other sectors, recent developments in nanosciences and nanotechnologies are offering lots of new opportunities for innovation to food and related sectors worldwide. Whist developing countries can potentially benefit from these developments, there are also a number of challenges ahead. This concise review provides an account of the main issues emanating from applications of nanotechnologies in food and related sectors with a particular reference to developing countries.

Introduction Rapid advancements in nanosciences and nanotechnologies in recent years have opened up new prospects for so many industrial and consumer sectors that they have been regarded as the hotbed of a new industrial revolution. The food sector, which is worth over 4 trillion US$ per annum globally (Murray, 2007), is an obvious target of these new developments. Food related applications of nanotechnologies offer a wide range of benefits to the consumer (Table 1). These include a possible reduction in the use * Corresponding author.

of preservatives, salt, fat and surfactants in food products; development of new or improved tastes, textures and mouth sensations through nano-scale processing of foodstuffs. Nano-formulations can also improve the uptake, absorption, and bioavailability of nutrients and supplements in the body compared to bulk equivalents. Nanotechnologyderived polymer composites offer new lightweight but stronger food packaging materials that can keep food products secure during transportation, fresh for longer during storage, and safe from microbial pathogens. Antibacterial nano-coatings on food preparation surfaces can help maintain hygiene during food processing, whereas the use of ‘Smart’ labels can help protect safety and authenticity of food products in the supply chain. However, despite the projected benefits, the current level of nanotechnology applications in food and related sectors is still new emergent in most countries and, despite a steady increase in the number of available products, the vast majority of new developments is still at R&D or near-market stages. Because of the scarcity of information on commercial activity in this area, estimates of the current and future market share of nanotechnology-enabled food products vary widely. The global market value for nano-enabled food and food packaging products was estimated at around US$4 million in 2006, predicted to grow to between US$6 billion by 2012 (Cientifica, 2006) and >US$20 billion by 2010 (Helmut Kaiser Consultancy, 2004). The main focus of new applications so far appears to be on food packaging and healthfood products, with only a few known examples in the mainstream food and beverage areas. According to market estimates, food packaging applications make up the largest share of the current and short-term predicted market for nano-enabled products in the food sector. The most promising growth areas identified for the near-future include ‘Active’ and ‘Smart’ packaging, health-foods, and functional food products (Cientifica, 2006). According to Helmut Kaiser Consultancy (2004) report, the nano-food sector is led by the USA, followed by Japan and China, whereas Asian countries (led by China) could be the biggest future market for nano-food products. It has been suggested that the number of companies undertaking R&D in food related applications could range between 200 and 400 (Cientifica, 2006; IFST, 2006), including some major international food and beverage companies. In view of this, more developments in this area can be expected in the coming years, and this may have a major

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Table 1. List of current and projected nanotechnology applications in the food and agriculture sectorsa Projected benefits

Potential risks

Comments

Processed nano-structured or nano-textured food products

Use of less fat and emulsifiers, stable emulsions, better tasting food products. A typical product of this type of application would be a nano-textured food (e.g. ice cream, mayonnaise, spread, etc.) which is low-fat but as “creamy” as the full-fat alternative. Such products would therefore offer ‘healthy’ but tasteful products to the consumer. Processing foodstuffs at submicron or nano-scale is also known to kill any microbial pathogens.

This application area is of least concern, as the food nanostructures are likely to be solubilised or digested in the GI tract and should not carry insoluble materials to the circulatory system.

Nano-Carrier systems for delivery of nutrients and supplements in the form of liposomes or biopolymerbased nano-encapsulated substances

Taste masking of certain ingredients/additives, such as fish oils, protection of certain ingredients during processing, improved optical appearance, improved bioavailability of nutrients and supplements, antimicrobial action, and other health benefits.

Organic nano-sized additives (many of them naturally occurring substances) for food, health-food supplements, and animal feed applications

Due to larger surface area, lesser amounts would be needed for a function or a taste attribute. Other claimed benefits include better dispersability of water-insoluble additives in food products without the need for additional fat or emulsifiers, and enhanced tastes and flavours due to greater surface areas of the nano-sized additives compared to bulk forms. Virtually all products in this category are also claimed for enhanced absorption and improved bioavailability in the body compared to conventional bulk equivalents. Essentially the same benefits as claimed for organic nano-sized additives (see above). Other projected benefits include increased food hygiene due to antimicrobial activity of nanosized metal(oxide) additives.

Increased absorption, uptake and bioavailability of certain additives and supplements may also alter tissue distribution of the substances in the body. ADME properties of some encapsulated substances may be different from conventional bulk equivalents. Nano-sizing may lead to changes in the absorption and bioavailability of the additives and may also alter tissue distribution.

Although the development of microemulsions is known to generate a range of droplet sizes e some in the nano range, there is currently no clear example of a commercially available food product which is proclaimed to have been specifically nano-structured. A number of nano-structured food ingredients and additives are understood to be in the R&D pipeline e some may be near market. One example, currently under R&D, is that of a mayonnaise which is composed of an emulsion that contains nanodroplets of water inside. The mayonnaise would offer taste and texture attributes similar to the full fat equivalent, but with a substantial reduction in the fat intake of the consumer (Clegg, Knight, Beeren, & Wilde, 2009). A number of nano-encapsulated additives and food supplements are commercially available in some countries and to consumers worldwide via the Internet.

Inorganic nano-sized additives for food, health-food and feed applications

Application area of main concern. Some inorganic additives in this category may contain insoluble, indigestible and potentially biopersistent nanoparticles.

This type of application is expected to exploit a much larger segment of the food and healthfood sectors. The materials may range from colours, preservatives, flavourings, to supplements and antimicrobials. Examples include ongoing R&D in Taiwan (Hwang & Yeh, 2010) and Japan (Tsukamoto, Wakayama, & Sugiyama, 2010) into micronised starch, cellulose, wheat and rice flour, and a range of spices and herbs for herbal medicine and food applications. A range of inorganic additives is available for supplements, nutraceuticals, and food, feed and health-food applications. Examples include silver, iron, silica, titanium dioxide, selenium, calcium, magnesium, platinum etc.

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Nature of application

Potential consumer exposure to nanoparticles through migration into foodstuffs, or ingestion of edible coatings.

Nano-coatings on food contact surfaces for barrier or antimicrobial properties

For “active” or self-cleaning surfaces in food processing facilities such as abattoirs.

Potential consumer exposure to nanoparticles through migration into foodstuffs.

Surface functionalised nanomaterials

Processing aids, additives for food preservation/ detoxification Antimicrobial and other health benefits. The 2nd generation nanomaterials that add certain functionality to the matrix, such as antimicrobial activity, or a preservative action, such as through absorption of oxygen. For food packaging materials, functionalised ENMs are used to bind with the polymer matrix to offer mechanical strength or a barrier against movement of gases or volatile components (such as flavours) or moisture.

Potential consumer exposure through migration into foodstuffs.

Nanofiltration based on porous silica, and regenerated cellulose membranes

Filtration of water, and removal of some undesired components in food e such as bitter taste in some plant extracts, and clarifying wines and beers. Colloidal silica (thought to be in agglomerated form) is known to be used in clarifying beers and wines.

Potential consumer exposure unlikely unless nanoparticles end up in the filtered products.

This area of application constitutes the largest share of the current and short-term predicted market for nanotechnology applications in the food sector. Examples include plastic polymers with nanoclay as gas barrier, nanosilver and nano-zinc oxide for antimicrobial action, nano-titanium dioxide for UV protection in transparent plastics, nano-titanium nitride for mechanical strength and as a processing aid. Another application is the deposition of metallic aluminium on plastic films. Migration tests, and modelling studies, have so far shown little evidence of any significant migration of nanoparticles from plastic polymers into food. More tests are needed on biopolymer based nano-composites. A number of nanomaterial-based coatings are available for food preparation surfaces, and for coating food preparation machinery. Examples include nano-silica coating for hydrophobic for self-cleaning surfaces; titanium dioxide or zinc oxide nanocoating for photocatalytic sterilization of food contact surfaces, and nanocoating of silver for hygienic food preparation surfaces. Also reported are nanoscale lipid structures for development of water-repellent surfaces. Main uses of surface functionalised nanomaterials are currently in food packaging. Possible uses are also emerging in animal feed. Examples include organically modified nanoclays that are currently used in food packaging to enhance gas-barrier properties. As nanotechnologies converge with other technologies (e.g. biotechnology), the use of functionalised nanomaterials in food and related applications is likely to grow in the future. Other examples are not yet available, but a number of nano-bio materials are under development e some may find use in food related applications. The use of porous silica in nanofiltration systems needs to be considered differently from the use of other nanomaterials in food products.

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“Improved” packaging in terms of flexibility, gas barrier properties and temperature/moisture stability. “Active” packaging incorporating metal/metal oxide nanoparticles for antimicrobial properties. They are claimed to prevent microbial growth on the surface of plastic packaging and hence keep the packaged food fresher over relatively longer periods.

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Food packaging applications Plastic polymers containing (or coated with) nanomaterials for improved mechanical or functional properties

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Table 1 (continued) Projected benefits

Potential risks

Comments

Nano-sized agrochemicals (fertilisers, pesticides, biocides, veterinary medicines)

Improved delivery of agrochemicals in the field, better efficacy, better control of application/dose, less use of solvents in agricultural spraying.

Potential risk of worker exposure to hazardous substances, consumer exposure through potential carryover of residues in foodstuffs.

Nanosensors for food labelling

Better food authenticity, safety and security from the use of “Smart” packaging, which incorporate nano-sized sensors that can monitor condition of the food during transportation and storage. Also under development are “Intelligent” packaging concepts that will release a food preservative only when releases preservatives only when triggered by rough handling or transport abuse, or when microbial activity initiates in the packaged food.

Through (potential) migration into foodstuffs.

Water decontamination

Breakdown of organic pollutants, oxidation of heavy metals, elimination of pathogens.

Potential consumer exposure to nanoparticles through consumption of treated drinking water, or carryover from wastewaters used in agriculture and food processing.

Animal feed applications

Reduced use of feed additives, improved bioavailability, less environmental impact, removal of toxins in feed.

Potential consumer exposure through carryover from consumption of animal products (such as meat, milk). Animal welfare can also be an issue.

Despite known R&D activity in this area, there is no product currently available on the market. Nano-encapsulated and solid lipid based nanoparticles have been explored for delivery of agrochemicals, such as slow- or controlled-release fertilisers and pesticides. Any application of this type for a pesticide or veterinary medicine will go through premarket approval. Developments include safety and quality indicators that can be applied as labels or coatings to add an intelligent function to food packaging. For example, to monitor the integrity of the packages sealed under vacuum or inert atmosphere by detecting leaks, freezeethawerefreeze scenarios by detecting variations in timeetemperature, or microbial safety by detecting the deterioration of foodstuffs. This area of application is likely to see a rapid growth in the future. R&D work also is ongoing to integrate nano(bio)sensors with Radio Frequency Identification Display (RFID) systems to enable tracking down of food products in the supply chain. Nano-iron and other photocatalysts (e.g. titanium dioxide) are also finding use in water treatment. Nano-iron is already available in industrial scale quantities. A number of companies are thought to be using the technology in developing countries where water resources are scarce. A few examples of nano-sized additives that have specifically been developed (or are under development) for animal feed are known. These include nanomaterials that can bind and remove toxins (e.g. mycotoxins), or pathogens in animal feed.

a

More details on different applications of nanotechnologies for the food sector can be found in (Chaudhry et al., 2010; 2008).

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Nature of application

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impact on the agricultural and food sectors in the medium to longer terms. Considering the fact that rapid advancements in nanotechnologies have also raised a number of technological, health and safety, regulatory and societal issues, it is likely that the developing countries will lag behind the developed world in terms of technical knowhow, production/processing capacity, quality control, safety assessment etc. Developing countries are also likely to face issues such as high costs, effective regulatory controls and certain barriers to international trade etc. It is, however, also possible that, because of the less well developed regulatory and other control systems, developing countries will offer a more open market for nano-food products in the future. Current state of nanotechnology applications Food production The emerging applications of nanotechnologies for food production include nano formulated agrochemicals (e.g. fertilisers, pesticides, biocides, veterinary medicines) for improved efficacy, less use of farm chemicals, better control of applications (e.g. slow release pesticides), safer and more nutritious animal feeds (e.g. fortified with nano-supplements, antimicrobial additives; detoxifying nanomaterials), and nano-biosensors for animal disease diagnostics. Example applications include nano-sized feed supplements and feed additives, such as nano-form of a biopolymer derived from yeast cell wall that can bind mycotoxins to protect animals against mycotoxicosis, and an aflatoxin-binding nano-additive for animal feed derived from modified nanoclay (Shi, Xu, Feng, Hu, & Xia, 2005). Another example is polystyrene nanoparticle with polyethylene glycol linker and mannose targeting biomolecule that can potentially bind and remove food-borne pathogens in animal feed (Qu et al., 2005). Nano-encapsulated and solid lipid nanoparticles have also been explored for the delivery of agrochemicals (Frederiksen, Kristensen, & Pedersen, 2003). However, despite a great deal of interest in this area, examples of available products are still very scarce at present, and most developments seem to be at R&D stage. Such applications, nevertheless, have the potential for adoption at a very large-scale by the agricultural sector worldwide. In view of this, it is important that developing countries develop and put in place adequate risk management strategies in advance, because some of the applications (e.g. nano-pesticides) may pose a greater (or different) risk to farm workers, the environment, and the consumers. Food processing Currently known example applications of nanotechnologies for food processing have been detailed by Chaudhry, Castle, and Watkins (2010) and Chaudhry et al. (2008). These include the use of nano-food ingredients/additives in the form of: e Processed food nano-structures for improved (or new) tastes, textures, and mouth-feels. Nano-structuring of

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natural food materials can potentially enable the use of less fat but still produce tasteful food products. A typical product of this technology would be a nanostructured ice cream, mayonnaise or spread, which is low-fat but is as “creamy” in texture as the full-fat equivalent. Such products would therefore offer a ‘healthy’ option to the consumer. e Nano-sized or nano-encapsulated food additives and supplements can improve dispersability of fat-soluble additives in food products, improve food tastes, enable hygienic food storage, reduction in the use of fat, salt, sugar and preservatives, and improvement in the uptake and bioavailability of nutrients and supplements. Currently available examples include vitamins, antioxidants, colours, flavours, and preservatives. Also developed for use in food products are nano-sized carrier systems for nutrients and supplements. These are based on nano-encapsulated substances in liposomes, micelles or protein based carriers. The nano-carrier systems are also used for taste masking of certain ingredients and additives, or to protect them from degradation during processing. Examples include food additives, such as a synthetic form of the tomato carotenoid lycopene, benzoic acid, citric acid, ascorbic acid, and supplements such as vitamins A and E, isoflavones, ß-carotene, lutein, omega-3 fatty acids, coenzyme-Q10. e Inorganic nanomaterials may also be potentially used in (health)food products. Example include transition metals and metal oxides (e.g. silver, iron, titanium dioxide); alkaline earth metals (e.g. calcium, magnesium); and non metals (e.g. selenium, silicates). Food packaging is currently the major area of application of metal and metal-oxide nanomaterials. Example nanomaterials finding use in packaging include plastic-polymer composites with nanoclay for gas barrier, nano-silver and nano-zinc oxide for antimicrobial action, nano-titanium dioxide for UV protection, nano-titanium nitride for mechanical strength and as a processing aid, nano-silica for hydrophobic surface coating etc. The use of nanosilver as an antimicrobial, antiodorant, and a (proclaimed) health supplement has already surpassed all other nanomaterials used in different sectors (Woodrow Wilson International Centre for Scholars, 2008). The current use of nano-silver is mainly for health-food and packaging applications, but its use as an additive in antibacterial wheat flour is the subject of a recent patent application (Park, 2005). Nano-silica is reported to be used in food contact surfaces and food packaging applications, and some reports suggest its use in clarifying beers and wines, and as a free flowing agent in powdered soups. The conventional bulk forms of silica and titanium dioxide are permitted food additives (SiO2, E551, and TiO2, E171), but there is a concern that the conventional forms may also contain a nano-sized fraction due to natural size range variation (EFSA, 2009). A patent (US Patent US5741505)

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describes nano-scale inorganic coatings applied directly on food surface to provide moisture or oxygen barrier and thus improve shelf life and/or the flavour impact of foods. The materials used for the nano-coatings, applied in a continuous process as a thin amorphous film of 50 nm or less, include titanium dioxide. Another example is that of nano-selenium, which is being marketed as an additive to a tea product in China for a number of (proclaimed) health benefits. e Surface functionalised nanomaterials are being developed that may add a certain functionality to food or packaging products. Current examples include the use of organically-modified nanoclays in food packaging applications. However, due to the possible convergence of nanotechnologies with other technologies (e.g. biotechnology), the development of new functionalised nanomaterials is likely to grow in the future.

Applications for food packaging Whilst most nanotechnology applications for food and beverages are currently at R&D or near-market stages, applications for food packaging are already becoming a commercial reality (Chaudhry et al., 2010). As mentioned before, food packaging applications form the largest share of the current and short-term predicted market for nano-enabled products in the food sector (Cientifica, 2006). It has been estimated that nanotechnology-derived packaging (including food packaging) will make up to 19% of the share of nanotechnology-enabled products and applications in the global consumer goods industry by 2015 (Nanoposts report, 2008). The incorporation of nanomaterials in plastic polymers has led to the development of improved or novel food packaging materials, for example: e Polymer nano-composites with improved properties in terms of flexibility, durability, temperature/moisture stability, gas-barrier properties e ‘Active’ packaging based on polymers incorporating nanomaterials with antimicrobial properties e ‘Active’ nano-coatings for hygienic food contact surfaces and materials, and hydrophobic nano-coatings for self-cleaning surfaces e Nano-(bio)sensors for ‘Smart’ packaging concepts Examples include plastic polymers with nanoclay as gas barrier, nano-silver and nano-zinc oxide for antimicrobial action, nano-titanium dioxide for UV protection, nano-titanium nitride for mechanical strength and as a processing aid, nano-silica for surface coating etc. The use of nano-composite with biopolymers is expected to rise because they offer possibility for carbon-neutral biodegradable materials for packaging. This will offer opportunities for developing countries to utilise their agricultural and forestry resources, by-products and wastes for development of biopolymer nano-composites. Food packaging applications are also driven at two levels:

1. Raw material manufacture, which will require a greater technical know-how, infrastructure and capacity 2. Uses/applications of the material will not require hightech or large capacity. This will suit many developing countries, where new developments can be taken up by SMEs. For further information on recent developments in this area see Smolander and Chaudhry (2010). Other applications There are a number of other emerging applications of nanotechnologies that could offer innovative solutions to the food and related sectors. Examples include the use of nano-porous materials for water filtration and for removal of undesirable tastes, flavours or allergens from food products. The use of nanomaterials such as zero valent iron is finding increasing applications in water decontamination. Other developments nearing market include nano-coatings (e.g. of titanium dioxide) for photocatalytic sterilisation of surfaces and water, nano(bio)sensors for food safety, and nano-barcodes for food authenticity (Chaudhry et al., 2010). Water treatment, filtration, desalination using nanotechnologies offers a lot of benefits to developing countries in terms of safe use/re-use of potable water; for example, possible removal of arsenic from drinking ground water in Bangladesh. Possible de-centralised water treatment will further reduce infrastructural costs in developing countries. The nano(bio)sensors are expected to enable multi-analyte detection of pathogens and food contaminants. They are also expected to be low-cost, and usable in the field by relatively little training. These features are very suitable for a user in a developing country. The potential benefits of these sensors will include microbial and chemical safety of foods to protect consumer health. This is again very relevant to the developing countries where food/water borne illnesses may be more prevalent. Opportunities and challenges for developing countries Projected benefits The new developments emanating from nanotechnologies offer a number of benefits to the food sector in developing countries, as they do in developed countries. The relative attractiveness of each depends on local circumstances. They include: e More efficient food production methods e less use of agrochemicals (e.g. pesticides, antibiotics, veterinary medicines; less harm to the environment; less carryover of harmful chemicals residues in food); e More hygienic food/feed processing (better food and feed safety and quality, reducing food-borne illnesses in developing countries); e Novel food products with improved tastes, flavours, mouth feels (healthy/nutritious/tasteful food products);

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e Longer shelf-life of food products (contributing to reducing food waste, and a more dependable food supply); e Innovative lightweight, stronger, functional packaging (reducing the cost of transportation and packaging materials in the environment); e ‘Smart’ labels to ensure food authenticity, safety, and traceability.

nano-additives (e.g. metals or metal oxides), or functionalised nanomaterials. Such applications may pose a risk of consumer exposure to ‘hard’ nanomaterials e the ADME profile (adsorption, distribution, metabolism and elimination) and toxicological properties of which are not fully known at present. Some of the projected applications in the agricultural sector (e.g. nanopesticides) will also fall in this category.

More details on different applications of nanotechnologies for the food sector can be found in (Chaudhry et al., 2010, 2008).

Any potential risk arising from nanotechnology-derived food contact materials will be dependent on the migration behaviour of nanomaterials from packaging. The few experimental and modelling studies reported so far (Avella et al., 2005; Bradley, Castle, & Chaudhry, 2010; EFSA, 2008) suggest that the likelihood of nanoparticle migration from polymer packaging to be either nil or very low. On the  basis of modelling (Simon, Chaudhry, & Bakos, 2008), it can be predicted that any detectable migration of nanoparticles from packaging to food will only take place where very small nanoparticles (in the lower nm range) have been incorporated in a polymer matrix that has a relatively low dynamic viscosity, and the particles are not bound to the polymer matrix. This provides some reassurance in the safety of nanotechnology-derived food contact materials, although further research is needed to determine migration patterns in other polymer-nanomaterial composites, especially those derived from biopolymers. In relation to risk assessment of nanotechnology applications, it is of note that acutely toxic materials are unlikely to be used knowingly in food products. Thus any concerns over consumer safety mainly relate to long term, or new/unforeseen harmful effects of exposure to nanomaterials. Nanoadditives in food are also likely to undergo various transformations in food and the GI system due to agglomeration, aggregation, binding with other food components, and reaction with stomach acid, enzymes, and other biotransformation in the body. Such transformations may lead to nanomaterials losing their ‘nano’ characteristics. However, there is currently little understanding of the nature or impact of biotransformations on the safety of nano-food products.

Potential risks Whilst nano-sizing of materials offers lots of potential benefits, it also brings the prospect of consumer exposure to some insoluble and possibly biopersistent nanoparticles (termed as ‘hard’ nanomaterials) through consumption of food and drinks. The concern is that, once in the body, nanoparticles with large reactive surfaces may cross biological barriers to reach those parts of the body which are otherwise protected from entry of (larger) particulate materials. Whilst most foods processed at nano-scale should not raise any special health concerns, there are a number of knowledge gaps in our current understanding of the properties, behaviour and effects of ‘hard’ nanomaterials which may be used in food applications. Such knowledge gaps make it difficult to assess the risk to a consumer, although a careful consideration of the nature of materials and applications can provide a basis for a conceptual risk categorisation on a case-by-case basis. For example, products containing natural food nano-structures that are likely to be digested/degraded in the GI tract (also termed as ‘soft’ nanomaterials) may not require a detailed evaluation compared to products containing insoluble and biopersistent nanomaterials. On the basis of this, the following broad application categories may be considered: e Areas of least concern: where food products contain processed (natural) food nano-structures, which are either digested or solubilised in the gastrointestinal (GI) tract, and are not biopersistent. e Areas of some concern: where food products contain encapsulated food/feed additives in nano-sized carriers which may not be biopersistent but may carry the encapsulated substances across the GI tract. In such a case, tissue distribution of the materials contained in nano-carriers may be different from that of conventional bulk equivalents. Also an increased bioavailability of vitamins and minerals may not always be beneficial for consumer health. A greater uptake of food colours or preservatives could take the application outside of the conditions under which the ADI (acceptable daily intake value) was set for the additive. e Areas of major concern: where food products contain insoluble, indigestible, and potentially biopersistent

Regulatory aspects A number of regulatory gap studies have shown that developments in nanotechnologies are not taking place in a regulatory vacuum, as the potential risks will be controlled under the existing frameworks (Gergely, 2007). The current regulatory frameworks for food and food contact materials in different jurisdictions, such as the European Union, the United States, and Australia are broad enough to ‘capture’ nanotechnology applications in the food sector. These include regulations relating to general food safety, food additives, novel foods, specific health claims, chemical safety, food contact materials, water quality, general product safety, and other specific regulations on the use of certain chemicals in food production/protection, such as biocides, pesticides, veterinary medicines etc. The

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environmental regulations are also likely to capture the use of nanotechnologies in food packaging, and agri-food production applications. For more information on regulatory aspects of nanotechnologies see (Chaudhry et al., 2008; Gergely, Bowman, & Chaudhry, 2010; Hodge, Bowman, & Ludlow, 2007). Current gaps in knowledge In view of the pros and cons of the use of nanomaterials in food products discussed here, there are a number of knowledge gaps that need further research. These include: e A clear, fit-for-purpose, definition of nanomaterials and nanotechnologies is needed. This is currently being considered under the recast of the food laws in Europe. Meanwhile, working (but not final) definitions for various terms connected with nanotechnologies have been adopted for the purposes of FAO/WHO/CODEX discussions (FAO and WHO, 2009). e Validated methods for detection and characterisation of nanomaterials in complex food matrices are not currently available. A few research projects are currently addressing this need; for example, the EU’s ‘Nanolyse’ project , and relevant projects at USDA/ NIFA. e Toxicological research on nanomaterial safety is in its infancy. Some common themes have, however, started to emerge from research projects that are underway in this area. This knowledge, however, needs to be periodically pooled and reviewed to draw conclusions and directions for future research. e ADME profiles of nanomaterials may be different from bulk equivalents, and it is not known how the ingested nanoparticles will behave in the body. Again research in this area is at an early stage. e The long term health consequences (if any) of ingestion of insoluble and biopersistent (‘hard’) nanoparticles via food are currently not known. There is also little understanding of the potential risks of functionalised nano(bio)materials that are emerging from the convergence of nano- and bio-technologies. e Guidance on risk assessment methodologies is patchy. The European Food Safety Authority has currently published a draft scientific opinion on risk assessment of nanotechnology applications for food and feed for public consultation (EFSA, 2011). e There have been some uncertainties over the adequacy of regulatory oversight of nanotechnology applications for food and related products. For example, uncertainties over responsibility/liability for relevant products and applications, appropriate permissible limits that relate to the (potential) effects of nano-substances in food/feed, an exclusive pre-market approval system for nano-enabled products etc. These uncertainties are currently being addressed by different regulatory authorities. For example, there are certain regulatory developments in the pipeline

in the EU e e.g. the recast of the key European regulatory instruments, such as Regulation 258/97 (the Novel Foods Regulation), which is expected to include an explicit reference to foods modified by new production processes ‘such as nanotechnology and nanoscience, which may have an impact on food’ http://ec.europa.eu/food/food/ biotechnology/novelfood/initiatives_en.htm. Because of the cross-cutting nature of nanotechnology applications, most of the challenges are not specific to food and related sectors, or to developing countries alone. Indeed, these challenges require efforts at an international level to realise the potential of nanotechnologies in a manner that is both beneficial and safe to the consumer. Possible ways to achieve this could be through: e Establishment of international research collaborations and networks that can address different aspects of the existing and new nanotechnology applications in agriculture and food sectors e i.e. not only the benefits but also the potential risks to the consumer and the environment (e.g. http://www.foodnano.org/). The main innovation routes to nanotechnology applications are likely to arise from small and medium enterprises (SMEs) and small spin off companies. Therefore new start-up businesses need be encouraged in developing countries to drive innovation this field. It is also of note that small start-up companies are usually taken over by larger ones through mergers etc, and this may cause a barrier to further developments. Industry sponsored research also needs to be encouraged. A number of Venture capital companies are already seeking partnerships in developing countries. Internal collaborations within a country between different R&D institutions, industry and government departments can overcome many of the current barriers. e Development of clear and consistent guidelines for risk assessment of nano-food products. e Establishment of a global body to ensure quality control (i.e. a product indeed has been derived from nanotechnologies and not just labelled for a commercial gain e or vice versa), and safety assessment of nanofood products on a case-by-case basis. e Promotion of industry best practices and self-regulation in the use of nanotechnologies for food and related applications. e A harmonised regulatory system at the global level that ensures pre-market evaluation of nano-food products, sets liabilities, and sets clear limits for any nano-additives in food and related applications. e Possible labelling of nano-food products to inform the consumer.

Conclusions An overview of the current and projected applications of nanotechnologies for the food and related sectors shows

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that they offer a variety of benefits to the whole of food chain e from innovative tastes and textures, to a potential reduction in the dietary intake of fat, salt and other food additives, improved absorption of nutrients and supplements, preservation of quality and freshness, and better traceability and security of food products (Table 1). Many of the benefits e such as improvements in food quality and hygiene, shelf life extension, water decontamination/desalination etc, offer enormous potential for improvement of public nutrition and health in developing countries. The current level of nanotechnology applications in the global food sector is, however, only small and most products and applications are still at R&D stage. There are also some major knowledge gaps in regard to our current understanding of the properties, behaviour and effects of nanomaterials. The use of nanomaterials, especially the insoluble and biopersistent nanoparticles, in food applications must, therefore, consider safety of the products to consumer health and the environment. The existence of stringent regulatory controls in many countries provides reassurance that only safe products and applications of nanotechnologies will be permitted on the market. However, there may be a need for a pragmatic regulatory oversight in some developing countries to ensure a case-by-case pre-market safety evaluation of the nanotechnology-derived products to safeguard the consumer from any potential risks. References Avella, M., De Vlieger, J. J., Errico, M. E., Fischer, S., Vacca, P., & Volpe, M. G. (2005). Biodegradable starch/clay nanocomposite films for food packaging applications. Food Chemistry, 93, 467e474. Bradley, E. L., Castle, L., & Chaudhry, Q. Nanoparticles in food contact materials and articles, in preparation. Chaudhry, Q., Castle, L., & Watkins, R. (Eds.). (2010). Nanotechnologies in food. Royal Society of Chemistry Publishers, ISBN 9780-85404-169-5. Chaudhry, Q., Scotter, M., Blackburn, J., Ross, B., Boxall, A., Castle, L., et al. (2008). Applications and implications of nanotechnologies for the food sector. Food Additives and Contaminants, 25(3), 241e258. Cientifica Report (August 2006). Nanotechnologies in the food industry. www.cientifica.com/www/details.php?id¼47 Clegg, S. M., Knight, A. I., Beeren, C. J. M., & Wilde, P. J. (2009). Fat reduction whilst maintaining the sensory characteristics of fat using multiple emulsions. In: 5th International symposium on food rheology and structure (pp. 238e241). ISFRS. EFSA (2008). 21st list of substances for food contact materials, scientific opinion of the panel on food contact materials, enzymes, flavourings and processing aids (CEF) (question No EFSA-Q-2005151, EFSA-Q-2006-324, EFSA-Q-2006-323), adopted on 27 November 2008. The EFSA Journal, 888e890, 1e14. EFSA e European Food Safety Authority (2009). Scientific opinion on ‘the potential risks arising from nanoscience and nanotechnologies on food and feed safety’, scientific opinion of the scientific committee, adopted on 10 February 2009. The EFSA Journal, 958, 1e39.

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