Detection and elimination of listerial exopolysaccharide

The Gomelsky and Miller laboratories have recently discovered that Listeria monocytogenes, the causative agent of listeriosis, synthesizes a novel EPS. This EPS coats bacterial aggregates and significantly enhances listerial resistance to desiccation (dehydration) and disinfectants used in the food industry (Chen et al., 2014). At present, we don't know how prevalent the listerial EPS is in food-processing facilities and what role it plays in listerial survival. To address these questions, we intend to develop a method for listerial EPS detection and apply it to samples from listeria-contaminated facilities and from contaminated fresh produce (where EPS presence is expected). Because the likelihood that EPS enhances listerial survival in food processing facilities is high, we also plan to develop the means to degrade this EPS and prevent its formation de novo. We have identified, characterized and patented an enzyme, glycosylhydrolase PssZ from L. monocytogenes, which hydrolyzes listerial EPS. When purified PssZ protein is added to listerial cultures, it disperses pre-formed EPS-based aggregates (biofilms) and prevents new EPS formation, which makes bacteria vulnerable to disinfectants and desiccation (Köseoglu et al., 2015). For potential industrial applications, in the future we intend to identify PssZ analogs (homologs) with properties that are more compatible with sanitation solutions and/or produce washing solutions, than the properties of listerial PssZ. The Objective of this project is to develop a listerial EPS detection probe and begin determining the presence of EPS in food processing facilities with listerial contamination.