The viable but non-culturable state and its relevance in food safety

• Stress induces many bacteria to enter a viable but non-culturable (VBNC) state.
• VBNC cells are viable but cannot be cultivated on routine laboratory media.
• VBNC cells are highly resistant to a variety of stresses (e.g. pasteurization).
• VBNC cells can resuscitate back to the actively metabolizing state in situ, in vitro, and in vivo.
• The presence of such non-culturable cells in food presents a public health concern.

The viable but non-culturable (VBNC) state is a form of dormancy employed by many bacteria as a method of survival and can be found in nearly any ecological niche. Major characteristics that distinguish dormant cells is their ability to evade detection by routine laboratory culture, to tolerate stressful environments including food pasteurization processes and antibiotics, and to resuscitate within a host and cause disease. Given these defining characteristics, these resilient microbes raise significant concern for the food industry and for the health of those consuming foods harboring these veiled pathogens. This review provides an overview of the biology of the VBNC state, its relationship to food safety, and novel methods developed for the rapid detection and identification of VBNC cells.