EVALUATING THE EFFECT OF ENVIRONMENTAL MICROBIOTA ON BIOFILM FORMATION AND SANITIZER TOLERANCE OF LISTERIA MONOCYTOGENES

Listeria monocytogenes is a foodborne pathogen that can survive, grow, and persist at low temperatures in produce processing facilities. One of the mechanisms that can enhance the survival and persistence of L. monocytogenes in food processing environments is biofilm formation. A biofilm represents a physical barrier that reduces the effective diffusion and antimicrobial action of sanitizers and is hypothesized to increase L. monocytogenes' tolerance to sanitizers used in food processing facilities. The role of the food processing environment microbiota on Listeria monocytogenes survival within a biofilm under sanitizer pressure is poorly understood. Hence, we propose to evaluate the ability of most relevant environmental microbiota constituents found in produce processing or packing environments (i) to form a single- and multi-species biofilms with L. monocytogenes and (ii) to measure the effect of the resulting biofilms on L. monocytogenes' tolerance to sanitizers. The outputs of this project will inform targeted and enhanced cleaning and sanitation protocols to effectively control L. monocytogenes and microbiota that can facilitate its survival and persistence via biofilm formation. We propose four objectives:Obj. 1: Isolate environmental microbiota and determine their resistance to sanitizers.Obj. 2: Characterize genomes of environmental isolates using whole-genome sequencing.Obj. 3: Characterize biofilm formation ability of bacterial families and L. monocytogenes in single- and in multi-family assemblages.Obj. 4: Characterize the effect of microbial assemblages on the tolerance of L. monocytogenes to sanitizer treatment.