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Researchers have claimed to discover a substance that greatly increases the survival of listeria monocytogenes - a food-borne bacterial pathogen that contaminates processed meat and milk products, as well as fresh produce, according to a new study. 

According to researchers, the findings would lead to the development of techniques to enhance food safety. 

The discovered substance, called exopolysaccharide (EPS), that listeria secretes on its cell surface under certain condition. The substance coats bacterial cells, making them form aggregates or clumps. 

"We think that EPS plays a significant role in survival of listeria in the environment, during food storage, processing and transportation," said Mark Gomelsky, a professor in UW's Department of Molecular Biology, in the press release. 

"Listeria rarely causes serious disease in healthy individuals but, in immune-compromised people, elderly and pregnant women, it can be deadly, causing as much as 20 percent to 25 percent mortality."

"We were studying the cell signaling in listeria, by a molecule called c-di-GMP," Gomelsky added. "What we discovered, quite unexpectedly, is that a strain with a high level of this signaling molecule overproduces EPS."

Researchers are also determining the sugar composition of the discovered substance. 

"This may provide crucial information as to how to remove EPS from listeria. We also want to determine what signals make listeria produce EPS," added Kurt Miller, a UW professor of molecular biology. "The long-term strategy is to discover how to stop listeria from producing EPS and how to make EPS-coated listeria less resistant to disinfection."

The study has been published in Public Library of Science (PLoS) Pathogens.