Title of Document : BIOFILM FORMATION BY ESCHERICHIA COLI O 157 : H 7 Karen

Title of Document: BIOFILM FORMATION BY ESCHERICHIA COLI O157:H7 Karen Suzanne Silagyi, M.S., 2007 Directed By: Associate Professor, Dr. Y. Martin Lo, Nutrition and Food Science Escherichia coli O157:H7 from cattle was evaluated for its ability to produce biofilm on food contact surfaces and quorum sensing signals in various raw meat, raw poultry, and produce broths. Generally, the strain was able to attach and form the most biofilm on stainless steel. Transfer of cells attached to stainless steel was observed onto various raw meat, raw poultry, ready-to-eat deli meats, and produce products as high as 10 CFU/cm. E. coli O157:H7 isolated from 14 animal, food, and human sources were characterized on antimicrobial susceptibility, ability to form biofilm, and production of curli fimbriae and cellulose. Strains isolated from cattle, retail chicken, and retail beef were able to form strong biofilms in addition to curli and cellulose production. Additionally, E. coli O157:H7 from retail chicken showed considerable antimicrobial resistance. This study suggests E. coli O157:H7 biofilms pose significant risk to continuous contamination of a variety of food products. BIOFILM FORMATION BY ESCHERICHIA COLI O157:H7