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.
