New Simple, Inexpensive Test Accurately Detects E. Coli 0157

Using technology developed by a private company, a USDA biochemist has developed a rapid, easy-to-use test that detects E. coli in food products. The test uses magnetic beads coated with anti-E. coli 0157 antibodies and ruthenium-labeled antibodies. Ruthenium is a metal that, through a chemical reaction, emits light that helps detect the presence of E. coli.

C. Gerald Crawford, with USDA's Agricultural Research Service, used equipment and technology patented by IGEN International, Inc., of Gaithersburg, Maryland, to perfect the test. The test, which works on hamburger meat, is from 10 to 100 times more sensitive than other tests for E. coli. Crawford developed the assay at the ARS Eastern Regional Research Center in Wyndmoor, Pennsylvania.

No special training is necessary to conduct the inexpensive test and the equipment, including a computer, can fit on a small table. Samples can be loaded onto a tray similar to a carousel for a slide projector, and 50 samples can be tested in an hour. Total time from sample to answer: only 6-8 hours.

A large commercial meat supplier is evaluating the test. From the new assay, IGEN hopes to develop a line of fast, highly sensitive tests that will help food producers detect contaminants. IGEN develops, manufactures and markets diagnostic systems using ORIGEN, patented "electrochemiluminescence" technology, which is based on chemically generated light to detect pathogens.

Scientific contact: C. Gerald Crawford, Plant-Soil Biophysics Research Unit, Eastern Regional Research Center, Wyndmoor, PA 19038; phone (215) 233-6628, fax (215) 233-6746, e-mail cgcrawford@arserrc.gov.