Journal of Applied Microbiology, Vol.104, No.6, 1744-1753, 2008
Response of Listeria monocytogenes to liquid smoke
Aims: To investigate the effect of liquid smoke on growth, survival, proteomic pattern and haemolytic potential of Listeria monocytogenes. Methods and Results: Growth and survival curves were recorded in brain-heart infusion broth supplemented with three concentrations of liquid smoke. L. monocytogenes growth was inhibited in the presence of 15 mu g ml(-1) phenol while a rapid decrease in cell viability occurred in the presence of 30 mu g ml(-1) phenol. The proteome of L. monocytogenes cytosoluble proteins was slightly modified after 2-h incubation with 30 mu g ml(-1) phenol but no protein already characterized in response to other known stresses was induced, except the protease ClpP. Liquid smoke inhibited the haemolytic potential without affecting hly gene expression, showing a potential inhibition of protein activity or stability. Conclusions: The presence of liquid smoke in a rich medium strongly affected growth and survival of L. monocytogenes. Brief smoke stress affected the metabolic pathways and inhibited the haemolytic activity of L. monocytogenes. Significance and Impact of the Study: This study is a first step in the investigation of the influence of a smoked product on L. monocytogenes strains.