Dr. Daniel Lim, a professor of Biology at the University of South Florida, has done what up until now was thought to be impossibleuse a portable device the size of a car battery to develop an assay which cuts the pathogen detection time in food samples from 72 hours to 20 minutes.
This revolutionary breakthrough in pathogen detection, known as the Analyte 2000, uses a fiber-optic biosensor to identify E. coli O157:H7, Listeria, Salmonella and Cryptosporidium. The biosensor works by attaching an antibody to an optical fiber which targets bacteria that might be present in the sample. If the antibody attaches to the bacterium, a second detection antibody with a fluorescent label is bound to the complex to form an ELISA-like or sandwich immunoassay. A fluorescent laser light is then shined on the sample through the fiber in order to identify the type of pathogen. In most cases, identification occurs within 15 to 20 minutes.
Applications for the biosensor include not only the food industry, but water quality as well. It can be used to detect E. coli and Salmonella at beaches closed due to suspected contamination. The instrument has also been used by the U.S. military to identify toxins from Iraq, and by first responders during the 1999 World Trade Organization (WTO) conference in Seattle to screen for bacteria in case of a bioterrorism event.
The Analyte 2000 is manufactured by Research International, Inc. of Woodinville, Washington.
Photo: courtesy of Research International, Inc.