Cell-cell communication in food related bacteria.

Although the study of quorum sensing is relatively recent, it has been well established that bacteria produce, release, detect and respond to small signalling hormone-like molecules called "autoinducers". When a critical threshold concentration of the signal molecule is achieved, bacteria detect its presence and initiate a signalling cascade resulting in changes of target gene expression. Cell-cell communication has been shown within and between species with mechanisms substantially different in Gram-positive and Gram-negative bacteria. The identified quorum-sensing mechanisms in several food related Gram-negative and Gram-positive bacteria, including bacteriocin synthesis, luxS quorum sensing and interactions between sourdough starter lactic acid bacteria are reviewed. The understanding of extracellular signalling may provide a new basis for controlling over molecular and cellular process the deleterious and useful food related bacteria whose behaviour is mostly a consequence of very complex community interactions.