Listeria is a hardy bug
June 28, 2005
IFT Daily Newsletter
http://www.ift.org/cms/
Listeria monocytogenes in ready-to-eat products can do quite a bit of damage even after several months in a starved state, according to new research results. Ramakrishna Nannapaneni, a food science research associate for the Univ. of Arkansas, has been exploring the issue for the Food Safety Consortium with a research team led by Mike Johnson.
́There has been a tremendous effort to find out virulence differences within Listeria monocytogenes for risk assessment needs,-- Nannapaneni said, pointing to the bacterium's damaged cells. ́The next logical question is how long they remain virulent. That's been the focus of our work.--
The Arkansas experiments tested Listeria monocytogenes cells that had been starved for 196 days and those that had not been starved. The healthy cells were strong enough to kill 90% of a target mouse cell population within two hours of release. The starved and injured cells, after more than six months of languishing, still had enough strength to kill 60% of their target cell population within six hours, then 90% of the target after eight hours.
́It's important to understand how these starved cells are waking up and how to suppress them,-- Nannapaneni said. ́The long-term starved cells become smaller and coccoid, but they still remain viable and virulent.--
