Look to sensors for detecting L. monocytogenes.

Researchers at Purdue University (Department of Food Science, 1160 Food Science Building, W. Lafayette, IN 47907) are developing biosensors that should be able to detect L. monocytogenes in food on processing lines. Earlier this year, President Clinton announced that the federal government would require food processors to cut the rate of Listeria illnesses in half by 2005, instead of 2010 as was previously planned.

The sensors will be an alternative to using PCR or an Elisa to detect bacteria. They'll act like a microchip to which is bound an antibody that's specific to L. monocytogenes. If bacteria are present in a sample, they will bind to the antibody. The chip will send an electronic signal indicating the existence of the bacteria.

The technology is in the early stages. A prototype is possible in about two years. Researchers probably will try to patent their technique. The U.S. Department of Agriculture is expected to propose that processors be required to test for L. monocytogenes in their plants and on equipment.

L. monocytogenes is the most deadly food pathogen. It sickens more than 2500 people each year in the United States, and one out of five of its victims dies. L. monocytogenes is a difficult pathogen to control. It is very heat-resistant. It grows even when refrigerated  and survives freezing.

In the past, we told you about researchers at the University of Arkansas (Department of Food Science, 272 Young Ave., Fayetteville, AK 72703) who've developed a detection technique that should speed the detection of L. monocytogenes on food products. The monoclonal antibody (MAb EM-7G1) reacts only with pathogenic Listeria species at very low levels. Other detection techniques require time- consuming steps to differentiate between L. monocytogenes and other, harmless species.

Further information. Arun Bhunia; phone: [phone]; fax: [phone]; email: [e-mail].