A team of food scientists has developed a sensor that can detect
the potentially deadly bacteria Listeria monocytogenes in less
than 24 hr at concentrations as low as 1,000 cells/ml of fluid.
This amount of fluid is about the size of a pencil eraser. The
sensor also is selective enough to recognize only the species
monocytogenes.  Known as an "optical biosensor," the device uses
light to detect the presence of a target organism or molecule.
The sensor is made of a small piece of optical fiber that is
coated with an antibody that specifically recognizes L.
monocytogenes, captures it, and binds it to the fiber. When the
fiber is placed in a liquid food solution, any L. monocytogenes
in the sample will stick to the fiber.  The selectivity,
sensitivity and rapidity of this sensor represent a vast
improvement over the types of test kits that are currently
available commercially, say scientists at Purdue. Collectively,
these qualities make this research an important contribution in
the field of food safety.   Liste