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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR MICROBIOLOGY AND CONTROL OF ENTERIC PATHOGENS THAT CONTAMINATE FRESH PRODUCE Title: Comparison of the Stress Response of Listeria monocytogenes Strains with Sprout Colonization

Authors
item Gorski, Lisa
item Flaherty, Denise
item Duhe, Jessica - SAN FRANCISCO STATE UNIV.

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 7, 2008
Publication Date: August 1, 2008
Citation: Gorski, L.A., Flaherty, D., Duhe, J. 2008 Comparison of the Stress Response of Listeria monocytogenes Strains with Sprout Colonization. Journal of Food Protection. 71(8) 1556-1562

Interpretive Summary: Listeria monocytogenes is a bacterial human pathogen acquired through contaminated food. In nature, L. monocytogenes lives on decaying plant tissue, and uncooked produce can be a vehicle of transmission. Seventeen strains of the foodborne pathogen Listeria monocytogenes were tested for their ability to colonize alfalfa, radish, and broccoli sprouts, as well as their capacity to withstand acid and oxidative stress, two stresses common to the sprout growth environment. Whereas large variations in different strains’ abilities to colonize alfalfa sprouts were confirmed, the variations with radish and broccoli sprouts were less severe. With a few exceptions, strains that were poor colonizers of alfalfa tended to be among the low colonizers of radish and broccoli and vice versa. The strains showed variability in their resistances to both acid and oxidative stress. Statistical analysis showed that there was no correlation between acid stress and sprout colonization, but there was a positive correlation between resistance to oxidative stress and colonization of all three sprout types. While the response to oxidative stress is known to be important for L. monocytogenes virulence, it may also be important for life outside of a host.

Technical Abstract: Seventeen strains of the foodborne pathogen Listeria monocytogenes were tested for their ability to colonize alfalfa, radish, and broccoli sprouts, as well as their capacity to withstand acid and oxidative stress, two stresses common to the sprout growth environment. Whereas large variations in different strains’ abilities to colonize alfalfa sprouts were confirmed, the variations with radish and broccoli sprouts were less severe. With a few exceptions, strains that were poor colonizers of alfalfa tended to be among the low colonizers of radish and broccoli and vice versa. The strains showed variability in their resistances to both acid and oxidative stress. Statistical analysis showed that there was no correlation between acid stress and sprout colonization, but there was a positive correlation between resistance to oxidative stress and colonization of all three sprout types. While the response to oxidative stress is known to be important for L. monocytogenes virulence, it may also be important for life outside of a host.

Last Modified: 10/25/2014
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