The development means food samples would no longer have to be sent to a laboratory for tests - a comparatively lengthy and costly procedure - but could be analyzed for safety and quality at the farm, slaughter house, during transport, or in a processing or packaging plant, the project's researchers say.
The system employs the use of nanotechnology - a science that arranges an atom's shape and size on the nanoscale so that it functions in a different way. The science holds the promise of helping manufacturers produce novel products and improve their processing and packaging.
A nanotech portable device would not only accelerate the testing procedure, but would allow more tests to be carried out on more produce samples, increasing the overall safety of the food supply. The process involves using nanowires and antibodies in such a way that a single test will be able to identify the presence and type of contamination as well as its concentration.
In developing the process, scientists manipulated individual nanowires by assigning each a recognizable pattern of silver and gold stripes. Each nanowire, while similar in composition, is identifiably different from one another in a system described by the scientists as"nanobarcoding".
Specific pathogen antibodies are then attached to the individual nanowires. For example; nanowire-one could have the antibody to Salmonella and nanowire-two the antibody to E. coli.
These strips are then placed on the meat. If a meat product has Salmonella the hazardous cells will bond with the Salmonella antibody onnanowire-one.
The results are still impossible to see with the naked eye at this point because of the microscopic nature of the technology. To overcome this hurdle, scientists developed a fluorescent solution that contains a multitude of antibodies. The nanowires are then exposed to the fluorescent antibodies. Because pathogens would have already bonded with antibodies on the nanowires, the fluorescent pathogens will also bond with these pathogens and their specificnanowires.
Scientists have dubbed this process "sandwich immunoassay" because the pathogen would be stuck between the antibody on the nanowire and the fluorescent antibody that it was later exposed to to make it visible.
Since each nanowire is recognizable by its gold and silver striped pattern, a processor will instantly be able to tell which pathogens are present and in what concentration.
The innovative technique was pioneered by Lawrence Livermore National Laboratory scientist Jeffrey Tok, who collaborated with groups at Stanford University, University of California at Davis, and Oxonica technologies.
The technology is now being fitted with nano-sized nickel stripes, which will allow the nanowires to be magnetically separated during the required washing steps--a prerequisite for any portable microbiodetector.