Since writing on nanotechnology over two decades ago, the science of the very small has grown to become a substantial multibillion-dollar global industry backed by more than $5 billion in annual research funding from industrialized nations like the United States, Australia and Japan, as well as the European Union. Nanoscale materials can now be found in countless consumer products including foods, food packaging, pharmaceuticals, clothing, paint, cosmetics, lubricants and automobiles.
Science of the very small
By way of a visual image, one nanometer (nm) is like a toy glass marble compared to the planet earth. For the scientifically minded, a hydrogen atom is 0.25 nm in diameter and a strand of DNA is about two nanometers in diameter.
There are two broad fields of research in nanotechnology. The first field concerns the properties that nano-size particles provide to materials in a wide array of applications. The second field concerns the assembly of atoms and molecules into functioning nanoscale devices. Currently most nanotechnology applications within the food industry come from introducing nano-size compounds into foods, packaging and food processing equipment.
As conventional materials such as metals, metal oxides, silica and clay are reduced to less than 100 nm in particle size, the laws of physics change from the conventional to what scientists call the “quantum size effect” where the mechanical, electrical, thermal, chemical and optical properties become quite different from their macro state. It is these new properties that nanoparticles provide to food ingredients, packaging materials and food contact surfaces that present countless exciting opportunities but also numerous challenges to our industry.
Nanotechnology provides solutions for our industry to overcome common ingredient problems like poor solubility, high melting point, chemical instability, poor bioavailability and undesirable ingredient interactions by “nanosizing” the delivery systems. Typically this involves forming nanoemulsions, microgels, biopolymers and liposomes that overcome the challenges of incorporating ingredients that are normally difficult, if not impossible, to incorporate into foods by traditional means.
Nanotechnology can contribute substantial benefits to food packaging. For example, metals (zinc, silver, copper, gold, platinum), metal oxides (zinc oxides, titanium oxide, magnesium oxide), organically modified clay, natural antimicrobials (carvacrol, nisin, thymol, isothiocyanate and ethanol) in nano-size forms imbedded in food packaging materials have been reported to inhibit bacterial growth to varying degrees. Ferric oxide and metal salts have been demonstrated to be effective oxygen scavengers when used in separate sachets or incorporated into packaging film. Nano-size polymers, aluminum oxide and silicone dioxide incorporated into packaging film and nano-thick metallic layers can improve film strength and have also demonstrated excellent gas barrier properties. Non-transparent materials are invisible in their nano form within food packaging materials. When incorporated into packaging film, titanium dioxide and zinc oxide provide excellent UV protection.
A number of concerns have been raised by scientists, individuals and organizations such as organic producers’ associations that nanoparticles may present significant health risks to humans. Animal-based tests have revealed that airborne and ingested nanoparticles may lead to a variety of conditions including fibrosis, premature skin aging, chromosomal damage, heart disease and neurological disease. There is also uncertainty as to what the impact of nanoparticles will be on our ecosystem when they are released into the environment.
As already noted, governments in developing countries are investing heavily in nanotechnology because they believe that the benefits to date warrant industry support. Food safety concerns are addressed differently around the globe. On the whole, governments appear to be providing basic food safety guidelines to industry and placing the onus on industry to ensure that products incorporating nanomaterials are safe for the applications for which they are designed. Labelling requirements also vary widely geographically.
Nanotechnology has demonstrated that it can enhance food safety, provide better physical protection, and extend product shelf life. This said, industry must proceed cautiously to ensure products incorporating nanomaterials are safe for their intended use and that the technology is managed carefully to minimize any impact on our environment.
Dr. R.J. (Ron) Wasik, PhD, MBA, CFS, is president of RJW Consulting Canada Ltd. Contact him at [email protected]