Engineering at a molecular level may be a future corporations' dream come true, however, nano-particles inside your body have few long-term studies especially when linked to health issues. Despite this new huge income-generating field there is a growing body of toxicological information suggesting that nanotechnology when consumed can cause brain damage (as shown in largemouth bass), and therefore should undergo a full safety assessment.
It is possible for nano-particles to slip through the skin, suggestive of a potential unnatural interaction with the immune system, or when micro particles enter the blood-stream. Some sunscreens on the shelf today, for instance, have nano-particles that might be able to penetrate the skin, move between organs, with unknown health effects. Nano-particles in cosmetics have few regulations done by FDA.
It is clear that nanotechnology is already in the in some food and cosmetics, (including anti aging products and sunscreens). 'Smart' packaging and tracking, is ubiquitous. Invisible, (to the naked eye and some microscopes), edible nano-wrappers, complete with bar codes can track not only early spoilage, but improve the taste of food, or, whatever is called food. Manufacturers are excited because the availability of food would no longer be affected by limited resources, bad crop weather, water problems, etc. A modern way to feed the world.