Sublethally Injured and Viable But Nonculturable Cells

The physiological state of microorganisms varies depending environmental conditions and stresses, whereby they exist in different growth phases of active replication or non-replicative yet live state. The latter state is referred to as sublethally injured and "viable but nonculturable (VBNC)" cells are of grave concern to food safety and public health, because they may be difficult to detect in food and water samples yet under some circumstances may be capable of causing disease. This article discusses the properties of sublethally injured and VBNC cells together with resuscitation methods that allow cells to recover to their normal growth properties and reliable methods for detection of the injured and inactivated bacteria. One class of VBNC cells at least has growth characteristics typically associated with sublethally injured cells and it is suggested that the condition arises from debilitation rather than being a survival mechanism. A general model for the two conditions is proposed.