DNA test identifies pathogens in tainted foods
New testing device finds pathogens and toxins in produce.
Fruit or vegetable packers concerned that their produce may be contaminated with unsafe pathogens will soon have a simple screening method they can use to ease or confirm their fears. It’s a handheld tool that’s said to be easy to use on-site, gives results in about an hour, and costs about a dollar per test.
Called the X-Mark, the detection technology is being developed by nanoRETE, a Lansing, Michigan-based company formed to market the invention of a Michigan State University biosystems engineering professor, Dr. Evangelyn Alocilja.
Alocilja directs the Nano-Biosensors Laboratory at MSU, and has been working on these kinds of projects since 2000. In 2001, she developed what was called “the electronic nose” that could sniff gases produced by bacteria like E. coli 0157:H7 and identify it based on the composition of those gases. For various reasons, that technology was never commercialized.
With this new technology, she is a founder of her own company and intends to make sure the product comes to market. She’s the company’s chief scientific officer.
MSU Technologies, the office that manages technology transfer at MSU, was involved in licensing the technologies to nanoRETE. The company is backed by Michigan Accelerator Fund 1, a Grand Rapids, Michigan, investment partnership that invests in Michigan-based early-stage life science and technology companies.
X-Mark works on a different principle than the electronic nose. Instead of detecting gases emitted by a living organism, this device identifies bacteria from antibody-antigen interaction, their DNA, and other protein biomarkers.
Alocilja explained how it might work with fruit. An apple could be swished in distilled water. To this sample, a nanoparticle solution coated with a specific antibody would be added, a different antibody for each pathogen one might want to detect. It is a platform technology capable of testing for E. coli, salmonella, and any other bacteria or toxin.
The sample is placed on a chip less than a half-inch square and placed into the reader, which gives the result about 40 minutes later. Traditional laboratory testing could take two or three days.
“Our unique preparation, extraction and detection protocol enables the entire process to be conducted in the field, without significant training,” Alocilja said. “Results are generated in about an hour from receipt of sample to final readout, quickly identifying contaminants so that proper and prompt actions can be taken.”
The device, about the size of a cell phone, is very sensitive, detecting as few as five to ten cells in a milliliter sample.
X-Mark technology can be used, she said, to detect other harmful bacteria or toxins, such as anthrax or tuberculosis, and could be used in medical settings as well as in food packing operations.
For pathogens in food, testing can be as specific depending on the antibody or it can be a screening method for a broad class of bacteria.
Alocilja said the product should come to market in about two years.