Monday, August 18, 2014

Listeria strength revealed

A research team at the University of Wyoming  has discovered why bleach and other disinfectants are often ineffective against listeria monocytogenes.
Listeria is the food-poisoning bacteria responsible for the deaths of 22 Canadians who ate processed meats from a Maple Leaf Foods Inc. plant in Toronto two years ago.

It has also been responsible for a number of other food-poisoning outbreaks around the world, including contaminated dairy products.

Mark Gomelsky, a professor in UW’s Department of Molecular Biology, and other researchers discovered and characterized a substance, called exopolysaccharide (EPS), that listeria secretes on its cell surface under certain conditions. 
This coating keeps disinfectants from killing the bacteria.
Gomelsky is a senior writer of a paper, “Cyclic di-GMP-Dependent Signaling Pathways in the Pathogenic Firmicute Listeria monocytogenes," that has been published in Public Library of Science (PLoS) Pathogens.
“You can readily kill listerial cells with a disinfectant like bleach, but you can’t easily kill clumped cells,” says Volkan Koseoglu, a doctoral student.
The team hopes their discovery will eventually lead to improved food safety.