ABSTRACT
In their natural environments, bacteria do not exist as isolated cells but grow and survive in organized communities (1). Simplistically, biofilms are microorganisms growing on a solid surface. In practice, however, biofilms are generally defined as matrix enclosed bacterial populations adhered to a surface or to each other, producing a dynamic environment in which the component microbial cells appear to reach homeostasis, optimally organized to make use of all available nutrients (2-6). Once colonizing the surface, microorganisms form a monolayer or multilayer of cells at the interfaces between solids and liquids, or air and liquids (1,5). Biofilms are formed by almost every type of microorganism under suitable conditions, including spoilage microorganisms such as Pseudomonas and pathogens
of great concern to the food industry including the genera of Bacillus, Vibrio, Listeria, or Salmonella, (5,7,8). Throughout natural ecosystems, biofilms can be found on almost any surface exposed to water (9). In addition, biofilms are of great concern to the medical community, because biofilms play an important role in persistent human infections (4,10). In summation, biofilms can be found on almost any surface exposed to water (9) and, once established, are well documented to have a greater resistance to antimicrobial agents than free growing (planktonic) organisms (11-19). This chapter will discuss the basics of biofilm formation with an emphasis on Listeria monocytogenes.
