Nanotechnology in Food Safety - III

Applications of Nanotechnology in Food Safety

As nanotechnology opens the door to a whole new array of consumer products, what, industries, food technologists and regulators are doing to improve the safety of our food supply seems limited only by one’s imagination. Since fresh fruits, vegetables, meat and poultry products are major potential vehicles for the transmission of human pathogens leading to foodborne disease outbreaks, there is a major public attention to food safety. Hence, the need to develop new antimicrobials to ensure food safety is major concerns over researchers working on nanotechnology, because of the antimicrobial properties of nanomaterials, where nanotechnology offers great potential for novel antimicrobial agents for the food and food-related industries. Thus, use of nano-antimicrobial agents added directly to foods or through antimicrobial packaging is an effective approach. As a result, the use of nanotechnology by the food and food-related industries is expected to increase, impacting the food system at all stages from food production to processing, packaging, transportation, storage, security, safety and quality. As a matter of fact, one of the most common applications of nanomaterials in food safety is through the uses of nanoscale silver, because historically silver is used as an antimicrobial agent, which is used in a variety of applications today such as dental implants, catheters, and wound healing dressings.

Antimicrobial agents

By reducing the particle size of silver to the nanolevel that exhibits an increased efficiency in its ability to control the bacterial growth, while improving its biocompatibility in mammalian systems. Hence, applications of silver nanoparticles in food packaging has involved its embedding into biodegradable coatings that have successfully inactivated bacteria. It also acts as an anchor through the assistance of certain amino groups to common surfaces, such as glass, that has exhibited successful inhibition in the form of biofilms, and its combination with graphene oxide on these surfaces have even been found to inhibit almost 100% of bacterial attachment. Similar chemicals manipulated at the nanolevel such as titanium oxide (TiO₂), zinc oxide (ZnO), cerium oxide (CeO), and others, have been used as photocatalytic agents in order to create surface reactive oxygen species (ROS) capable of damaging organic matter, such as bacteria, from developing.

Natural antimicrobial extracts, such as nano-encapsulated cinnamaldehyde, thyme oil emulsified with soluble soybean polysaccharide, and mandarin oil nano-emulsions, have also found to be successful additions and alternatives to harsh chemicals for these surfaces as well. Food packaging products have also found the use of selenium and cellulose particles to successfully inhibit the production of ROS that can arise and degrade food quality.

One of the newest nano-enabled techniques that have risen in the fight against microbial agents in food is known as engineered water nanostructures (EWNS). These highly charged and mobile agents contain ROS, allowing for their successful interaction and inactivation of microorganisms on surfaces. By being applied to water through either electro-spraying and/or ionization processes, EWNS has a highly targeted capability to deliver their antimicrobial potential to food-related microorganisms, reaching what has been measured as up to a 99.99% reduction in organismal presence.

Food ingredients for color, texture and flavor

The food industry is beginning to use nanotechnology to develop nanoscale ingredients to improve color, texture and flavor of food, where nanoparticles TiO₂, SiO₂ and amorphous silica are used as food additives, i.e. TiO₂ is used as a coloring in the powdered sugar coating on doughnuts.

Food production and packaging

Nanomaterials used for food packaging provide many benefits such as improved mechanical barriers, detection of microbial contamination and potentially enhanced bioavailability of nutrients. This is perhaps the most common application of nanotechnology in food and food-related industries. A number of nanocomposites, polymers containing nanoparticles, are used by the food industry for food packaging and food contact materials. The use of ZnO and MgO nanoparticles for food packaging has been reported. Amorphous silica is used in food and in food containers and packaging. Nonetheless, engineered water nanostructures generated as aerosols are very effective at killing foodborne pathogens such as Escherichia coli, Listeria and Salmonella on steel food production surfaces. Such food contact substances containing nanomaterials have the potential of migrating from food packaging into food, so this technology still must demonstrate regulatory compliance before it gains wide-spread acceptance in the industry.

Nutrients and dietary supplements

Nanomaterials are used as ingredients and additives (e.g., vitamins, antimicrobials, antioxidants) in nutrients and health supplements for enhanced absorption and bioavailability.

Food storage

The antimicrobial properties of nanomaterials enable them to preserve food during storage and transport. Nanosensors can be used for a variety of applications. Commercial use of nanosensors has been reported to check storage conditions and during food transport in refrigerated trucks for temperature control.

Food nanosensors

Nanomaterials are used as sensors to detect contamination and regulate the food environment. They can detect microbial and other food contaminants. Therefore, they are used as sensors in food production and at packaging plants. They can monitor the condition of food during transport and storage. They can detect nutrient deficiency in edible plants, and dispensers containing nutrients can deliver them to plants when needed. Therefore, nanomaterials can be used as nanosensors and nanotracers with almost unlimited potential by the food industry.

Food Safety Issues in Nanotechnology

Besides a lot of advantages of nanotechnology to the food industry, safety issues associated with the nanomaterial cannot be neglected, where many researchers discussed safety concerns associated with nanomaterial giving emphasis on the possibility of nanoparticles migrate from the packaging material into the food and their impact on consumer’s health. Although a material is being generally regarded as safe (GRAS) substance, additional studies must be required to examine the risk of its nano counterparts because the physiochemical properties in nano-states are completely different from that are in macro-state. Moreover, the small size of these nanomaterials may increase the risk for bioaccumulation within body organs and tissues, i.e. silica nanoparticles which are used as anti-caking agents can be cytotoxic in human lung cells when subjected to exposure. There are a lot of factors that affect dissolution including surface morphology of the particles, concentration, surface energy, aggregation, and adsorption. A model to study the migration of particles from food packaging has been developed by Cushen et al. in 2014, where they studied the migration of silver and copper from nanocomposites and observed that the percentage of nano-filler in the nanocomposites was one of the most crucial parameters driving migration, more so than particle size, temperature, or contact time. Since every nanomaterial has its individual property, therefore, toxicity will likely be established on a case-by-case basis. Further, regulatory authorities must develop some standards for commercial products to ensure product quality, health and safety, and environmental regulations.

Safety of food derived from nanotechnology

Consumers are exposed to nanomaterials by consumption of food and beverages containing these extremely small particles of large reactive surface area of unknown safety. Once absorbed in the gastrointestinal system, they may bio-accumulate in various organs of the body, leading to potentially adverse effects. Thus, application of nanotechnology by the food industry is of public concern. Public acceptance of food and food products containing nanomaterials depends on their perceived safety. According to the journal Nature Nanotechnology, “the food industry will only reap the benefits of nanotechnology, if issues related to safety are addressed and manufacturers are more open about what they are doing.” Food safety concerns over the application of nanotechnology in food is rising due to widespread of novel applications in food industry. The major concerns over the issue are:  

Negatives

Nanoparticles become an indirect source of food contaminant.

Uptake of nanomaterials alters the absorption profile and metabolism in the body.

Toxicity of nanoparticles remains largely unknown.

Lack of effective analytical method and predictive model to evaluate the safety of nanoparticles.

           

Positives

At present, there is no tenable evidence that food derived from nanotechnology is any safer or more dangerous than their conventional counterparts.

Despite no general conclusion has been made by international food safety authorities on the safety of nanofood incorporated with nanomaterials, there is also no evidence that ingested nanomaterials have harmed human health.

Food Safety Regulations on Nanotechnology

Different jurisdictions, such as Australia, European Union, United States and New Zealand, have established committees to monitor the development of nanotechnology and take appropriate action if necessary. In March 2009, the scientific committee of the European Food Safety Agency published an opinion on nanoscience and nanotechnology regarding food and animal feed safety. A guidance document on how to assess potential risks associated with certain food-related uses of nanotechnology followed in May 2011, providing practical recommendations to regulators on how to assess applications from industry to use engineered nanomaterials in food additives, enzymes, flavorings, food contact materials, novel foods, food supplements, feed additives and pesticides.

The U.S. Food and Drug Administration (FDA) has issued a draft guidance for industry use of nanomaterials in animal feed. However, more research is required to determine the impact of nanomaterials in food on human health to ensure public safety and improve public communication of the safe use of such materials in commercial food supply. Some test methods for nanomaterial safety assessment have been reported, however, no internationally accepted standard protocols for toxicity testing of nanomaterials in food or feed are currently available. Such protocols are in the development stage by organizations such as the International Alliance for Nano Environment, Human Health and Safety Harmonization and the U.S. National Research Council. A uniform international regulatory framework for the evaluation of nanotechnology is a necessity for both human food and animal feed.