Viable but nonculturable foodborne pathogenic bacteria: conceptual controversies, physiological distinctions,...

The viable but nonculturable (VBNC) state is a critical survival strategy utilized by bacteria in response to environmental stress. In this state, bacteria cannot be cultivated on media, while maintaining cellular integrity and metabolic activity and being capable of resuscitation under favorable conditions. Since its conceptual introduction in 1982, VBNC state has been extensively debated in terms of terminology and definition because it challenges the traditional notion that "viable bacteria are culturable." Studies on VBNC state have included both semantic clarification and experimental validation, ultimately establishing it as a distinct bacterial survival strategy. Under adverse conditions, bacteria may additionally present a range of intermediate physiological states apart from VBNC state, including persister state, sublethal injury state and dormancy state. These four states are fundamentally distinguished by their formation strategies, metabolic activity, membrane integrity, and resuscitation characteristics. The formation of the VBNC state is regulated cooperatively by stringent response, general stress responses, and toxin antitoxin systems. Traditional culture-based methods are inadequate for detecting bacteria in this state, potentially resulting in underestimation of food safety hazards and public health risks. Therefore, the development of effective and rapid detection methods specifically targeting VBNC bacteria is of critical importance. Currently, detection methods for VBNC bacteria are primarily categorized into quantitative and qualitative approaches. This review systematically summarizes the terminological debates surrounding VBNC state, its relationship and distinctions with similar physiological states, the formation mechanisms, and detection technologies. This review aims to provide a theoretical foundation for studies on bacterial stress adaptation mechanisms and the prevention of risks posed by foodborne pathogenic bacteria.