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The primary objective is to determine whether protozoa isolated from meat and poultry processing industries and from fresh produce can form and release vesicles or cysts containing viable food-borne pathogens such as Campylobacter jejuni, Salmonella enterica, Listeria monocytogenes, or Escherichia coli 0157:H7, and thereby enhance survival of these pathogens in the environment.
Produce, beef and poultry were among the five most common vehicles of food-borne illnesses in the U.S. between 1990 and 2002. Little is known of how microbial communities might contribute to the persistence of human pathogens in the environment. The purpose is to learn about types of interactions between food-borne pathogenic bacteria and protozoa in order to understand how the interactions might enhance survival, dissemination, and resistance of the bacteria to harsh environmental conditions.
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Protozoa will be isolated from food processing environments and from fresh produce and will be co-cultured with GFP-labeled pathogens to determine whether pathogen-containing cysts or vesicles (released phagosomes) are formed. Survival of vesicle-bound or cyst-bound bacteria will be compared with that of free bacteria under several conditions relevant to survival in the environment or to sanitation methods such as desiccation and treatment with antimicrobials.