## 1 Introduction
Persistence can be assessed by genetically characterizing the food plant isolates e.g., by _sig_B allelic typing (_sig_B AT) and single nucleotide polymorphism (SNP) analysis of whole genomes [10; 11; 12]. Beyond implementing the correct use of sanitizers, drainage systems, raw ingredient contamination control, and the improvement of compartmentalization in the manufacturing plant, it should be elucidated as to what extent the genotypes associated with persistence in the production environment are linked to listeriosis outbreaks and cases by making the genetic data of outbreak strains available along with the epidemiological investigation results [10; 11]. Stresses to which _L. monocytogenes_ is exposed in food, such as suboptimal pH, temperatures and osmotic pressure, heating, and smoking, induce variations in the expression of genes related to pathogenesis and virulence, such as chemotaxis, flagella motility, transmembrane receptors, and signal transduction. They can also lead to the formation of sub-lethally injured cells that are able to recover by cell repair mechanisms and/or VBNC cells that do not grow in commonly used culture media in the recommended incubation conditions [9; 13; 14]. _L. monocytogenes_ adopts different persistence strategies to tolerate food processing stressors. These are biofilm formation, the development of \"persisters\", and the transition to the viable but non-culturable (VBNC) state [10; 15; 16; 17; 18; 19; 20; 21; 22; 23]. _L. monocytogenes_ biofilms develop on the surfaces of food processing environments and withstand stressful conditions such as low temperature and desiccation [18]. _L. monocytogenes_ \"persisters\"--i.e., cells that survive cleaning and disinfection, thus reoccurring in the production plant and final products--are a subpopulation of cells that are slow replicating or non-dividing and transiently multidrug tolerant [15]. Differently, VBNC cells are in a deeper dormancy status with minimal metabolism, active transcription and translation, intact DNA and membrane, and the capacity to resuscitate in particular conditions [16]. Sub-lethally injured cells that remain metabolically active but cannot be resuscitated in the standard culturing conditions may enter the VBNC state [22]. VBNC cell formation was observed in over one hundred microbial species and may occur following starvation, exposure to extreme temperatures, oxygen limitation, high salinity, pH changes, UV light, ultrasound, suboptimal osmotic pressure, and exposure to toxic agents, varying with microbial species and strains. In addition, VBNC formation may be induced even in nutrient-rich environments such as food. The mechanisms by which bacterial cells enter the VBNC state are still largely unknown, but some studies provided evidence of the involvement of stress response proteins, transcriptional regulators, membrane proteins, proteins involved in cell division, and toxin/antitoxin systems [16]. Considering that the detection of culturable cells according to standard methods is carried out in specific culture conditions and defined time frames, nonculturability is defined as the lack of colony formation after the prescribed incubation time. This criterion can be used to distinguish VBNC cells from persister cells [16]. The detection of _L. monocytogenes_ in foods is carried out by the culture-dependent standard methods EN ISO 11290-1 and EN ISO 11290-2 [24; 25] to accomplish detection and enumeration, respectively, as specified by Regulation 2073/2005 amended by Regulation 2024/2895 for the European Union [26; 27]. These methods require several days to obtain results and are unsuitable for detecting VBNC cells [28]. Since VBNC _L. monocytogenes_ may threaten consumers' health, its reliable and rapid detection would considerably improve food safety assessment. Therefore, this review summarizes the latest findings on the factors that induce the VBNC _L.