Researchers at University College Cork in Ireland have discovered a single point mutation in Listeria monocytogenes that helps the pathogen to grow at lower temperatures and higher salt concentrations.
The researchers have shown that the mutation affects betaine uptake at low temperatures and high osmolarity, leading to improved stress tolerance. They also observed a previously unreported “twisted cell morphology” at elevated osmolarities in the absence of the mutation. It is suggested that this adopting this shape may be a survival strategy for Listeria cells.
The food safety implications of the findings are considerable, according to the study’s authors. They observe that, “..a single point mutation with the potential to induce such dramatic shifts in cell growth and survival at low aw and temperatures – making an already dangerous pathogen even more formidable – raises significant food-safety concerns which need to be addressed.”
The findings are reported in the journal Bioengineered and the report can be found here.