Affiliation:
1. Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, North Dakota, USA
2. Department of Food Science, Cornell University, Ithaca, New York, USA
Abstract
ABSTRACT
Growth of
Listeria monocytogenes
on refrigerated, ready-to-eat food is a significant food safety concern. Natural antimicrobials, such as nisin, can be used to control this pathogen on food, but little is known about how other food-related stresses may impact how the pathogen responds to these compounds. Prior work demonstrated that exposure of
L. monocytogenes
to salt stress at 7°C led to increased expression of genes involved in nisin resistance, including the response regulator
liaR
. We hypothesized that exposure to salt stress would increase subsequent resistance to nisin and that LiaR would contribute to increased nisin resistance. Isogenic deletion mutations in
liaR
were constructed in 7 strains of
L. monocytogenes
, and strains were exposed to 6% NaCl in brain heart infusion broth and then tested for resistance to nisin (2 mg/ml Nisaplin) at 7°C. For the wild-type strains, exposure to salt significantly increased subsequent nisin resistance (
P
< 0.0001) over innate levels of resistance. Compared to the salt-induced nisin resistance of wild-type strains, Δ
liaR
strains were significantly more sensitive to nisin (
P
< 0.001), indicating that induction of LiaFSR led to cross-protection of
L. monocytogenes
against subsequent inactivation by nisin. Transcript levels of LiaR-regulated genes were induced by salt stress, and lmo1746 and
telA
were found to contribute to LiaR-mediated salt-induced nisin resistance. These data suggest that environmental stresses similar to those on foods can influence the resistance of
L. monocytogenes
to antimicrobials such as nisin, and potential cross-protective effects should be considered when selecting and applying control measures for this pathogen on ready-to-eat foods.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Reference37 articles.
1. SwaminathanBCabanesDZhangWCossartP. 2007. Listeria monocytogenes. In DoyleMPBeuchatLR (ed), Food microbiology: fundamentals and frontiers, 3rd ed. ASM Press, Washington, DC.
2. FDA. 2003. Quantitative assessment of relative risk to public health from foodborne Listeria monocytogenes among selected categories of ready-to-eat foods. FDA, Silver Spring, MD.
3. Quantitative risk assessment for Listeria monocytogenes in selected categories of deli meats: impact of lactate and diacetate on listeriosis cases and deaths;Pradhan AK;J. Food Prot.,2009
4. The effect of nisin on Listeria monocytogenes in culture medium and long-life cottage cheese;Ferreira MA;Lett. Appl. Microbiol.,1996
5. Inhibition of Listeria monocytogenes on the surface of individually packaged hot dogs with a packaging film coating containing nisin;Franklin NB;J. Food Prot.,2004
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