E. coli

New rapid test, also to measure how many

HorticomNews30/12/2002

30 de diciembre de 2002

USDA Agricultural Research Service scientists have developed a rapid, easy-to-use test to detect and count Escherichia coli O157:H7 bacteria in natural and constructed bodies of water. A notice published by the May 2002 issue of the magazine Fresh Cut informs.

USDA Agricultural Research Service scientists have developed a rapid, easy-to-use test to detect and count Escherichia coli O157:H7 bacteria in natural and constructed bodies of water. Using proprietary technology developed by Igen International, ARS microbiologists Dan Shelton and Jeff Karns in the Animal Waste Pathogen Laboratory, Beltsville, Md., developed the test, which uses magnetic beads to detect the pathogen. The magnetic beads are coated with anti E. coli monoclonal antibodies that bind to the bacteria, making it possible to count them.

Current testing methods are designed only to detect the bacteria, but not to measure how many are present. The number of  E. coli bacteria present is crucial information since the levels that cause infection can vary from person to person, depending on thealth status.

Also, the new method makes it possible to detect E. coli in water samples in a day or less, compared with traditional testing that can take up to four days to complete. Shelton says the test could potentially have application for testing water in food processing plants and the speed for getting a reading might possibly be cut down to an hour in such applications. Currently, the time needed to assess results is five hours.