A team of food scientists has developed a sensor that can detect the potentially deadly bacteria Listeria monocytogenes in less than 24 hours at concentrations as low as 1,000 cells per milliliter of fluid - an amount about the size of a pencil eraser. The sensor also is selective enough to recognize only the species monocytogenes.

"The selectivity, sensitivity and rapidity of this sensor represent a vast improvement over the types of test kits that are currently available commercially," said Arun Bhunia, associate professor of food microbiology and one of the sensor's developers. "Taken together, those qualities make this research an important contribution in the field of food safety."

Listeriosis, the illness caused by consuming Listeria-contaminated foods like deli meats or cheese, leads to higher rates of hospitalization and mortality than any other foodborne illness, said Tao Geng, research associate in the department of food science and the sensor's co-developer.

"The mortality rate for people with listeriosis is very high, and for this reason, the FDA has a zero-tolerance rule for Listeria. There should be none at all in any ready-to-eat products," he said.

According to the Centers for Disease Control and Prevention, approximately 2,500 people develop listeriosis every year, and approximately one in every five cases is fatal. The elderly, pregnant women, newborn infants and individuals with compromised immune systems are most at risk of contracting the disease.

The bacteria classified as Listeria include six different species, but only L. monocytogenes can infect humans. This makes it especially important to develop highly selective sensors that can detect only L. monocytogenes, Bhun
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Contact: Jennifer Cutraro
jcutraro@purdue.edu
765-496-2050
Purdue University
5-Oct-2004