The IMPACT of GROWTH HISTORY on STRESS ROBUSTNESS of Listeria monocytogenes Sharkawy Saleh, Eslam

Author(s): Eslam Saleh, Sharkawy

Environmental factors such as oxygen availability have an impact on the adaptive behavior of stress and the robustness of microorganisms. Adaptation to nonoptimal environmental conditions induces molecular changes that help microorganisms develop survival strategies toward more severe stress conditions. Listeria monocytogenes as a foodborne pathogen is regularly exposed to such environmental stresses within its natural habitat, during food processing, and throughout its infection cycle. The ability of Listeria to adapt to such changing environment enhances its ability to survival and growth in food and influences its pathogenic potential.

In this study, we will investigate the impact of oxygen availability on growth and robustness induction toward lethal oxidative and acid stresses for three strains of Listeria monocytogenes, ScottA, EGDe, and F2365. Aerobically grown cells showed higher growth rate and were more resistant to oxidative stress than anaerobically and microaerobically grown cells. However, for acid stress, anaerobically and microaerobically grown cells were more resistant than cells that were cultured aerobically.