Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: March 1, 2009
Publication Date: May 1, 2009
Citation: Smith, J.L., Fratamico, P.M., Uhlich, G.A. 2009. Molecular mechanisms involved in biofilm formation by food-associated bacteria. Book Chapter. In: Fratamico, P.M., Annous, B.A., Gunther, N.W., editors. Biofilms in the Food and Beverage Industries. Oxford, UK: Woodhead Publishing, Ltd. p. 42-98. Technical Abstract: Biofilms are complex bacterial communities adhering to a surface, an interface, or to each other and enclosed in an extracellular polymeric matrix. Genomic studies show that gene expression patterns of bacteria in biofilms differ from those of non-biofilm cells, indicating that there is a different physiology between the two types of cells. Bacteria in biofilms are more resistant to deleterious substances (antibiotics, biocides, antibodies, etc.) and environmental stresses as compared to non-biofilm bacterial cells. Therefore, biofilms are undesirable on food and food contact surfaces or on inserted medical devices. Quorum sensing is a bacterial cell-density-dependent signaling system mediated by chemical autoinducer molecules secreted by the bacteria. When the bacterial population reaches the “quorum” level, the autoinducer molecules bind to appropriate transcription regulators resulting in the activation or repression of target genes. The effect of quorum sensing on gene expression is closely linked with biofilm formation in many bacterial species. Formation of biofilms may be either negatively or positively regulated by quorum sensing. A potential strategy to control biofilm formation is by modulating quorum sensing through the use of signal analogs or by enzymatic degradation of the signaling molecules.