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Updated: Jan 25, 2026

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria
Published on: September 16, 2013
Effect of Treatment Conditions on Nisin Inactivation of Gram-negative Bacteria
Kelly A Stevens1, Brian W Sheldon1, N Arlene Klapes1
1Department of Food Science, North Carolina State University, Raleigh, North Carolina, 27695-7624.
Abstract:
A method using nisin and a chelating agent to inactivate Salmonella species and other gram-negative bacteria has been developed. The objective of this study was to determine the effect of treatment conditions on the application of this method. Ten gram-negative organisms were used in this study, including six Salmonella species commonly associated with foodborne illness. Organisms were selected on the basis of sensitivity to nisin and a chelating agent. The following parameters were examined: (a) chelating agent, (b) nisin concentration, (c) incubation temperature, and (d) protein interference. Chelating agents included EDTA, ethylenebis (oxyethylene-nitrilo) tetraacetic acid, citric acid monohydrate, and sodium phosphate dibasic. The most effective treatment consisted of 50 to 100 μg/ml nisin applied in combination with 20 mM EDTA or citric acid monohydrate at a temperature range of 30 to 42°C. All of the chelators examined exhibited some inhibitory activity. The addition of bovine serum albumin to the treatments containing nisin and EDTA did not result in a significant decrease in inhibitory action.
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