Submitted to: Journal of Food Science
Publication Type: Review Article
Publication Acceptance Date: September 5, 2008
Publication Date: February 9, 2009
Citation: Annous, B.A., Fratamico, P.M., Smith, J.L. 2009. Quorum Sensing in Biofilms: Why Bacteria Behave the Way They Do. Journal of Food Science. 74(1):R24-R37. Technical Abstract: Bacteria can attach to surfaces and form biofilms, which have a characteristic structure consisting of microcolonies enclosed in a hydrated matrix of microbially-produced proteins and polysaccharides. In this complex biofilm network, the cells act less as individual entities and more as a collective living system, often with channels to deliver water and nutrients to the cells in the inner portion of the biofilm. Human pathogens form biofilms on food and food contact surfaces, which enhances their ability to survive harsh environments, to resist antimicrobial treatments, and to spread and persist in the food processing environment. The formation of biofilms is a food safety concern since persistent low-level contamination of foods can occur. Cell-to-cell signaling, known as quorum sensing, has been shown to play a role in biofilm formation in food-borne pathogens. Quorum sensing regulates bacterial gene expression through the production of chemical autoinducer molecules by the bacteria. Binding of the autoinducers to the appropriate transcription regulator(s) is followed by the activation or repression of target genes. Quorum sensing processes allow bacteria to display a unified response advantageous to the population, to tolerate stress, and to have enhanced access to nutrients and to more favorable environmental niches. It is possible that modulating quorum sensing processes, for example, by enzymatic degradation of the signaling molecules or blocking signal generation or reception, will weaken established biofilms or prevent biofilm formation and also inhibit growth of spoilage or pathogenic organisms, which would benefit food production and safety.