Formation and resuscitation of viable but non-culturable Campylobacter in agri-food industry

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The presence and resuscitation of viable but non-culturable (VBNC) pathogens in the food processing environment and food products pose a significant risk to the public health. VBNC pathogens can evade detection by the conventional culturing methods, but maintain virulence and have the potential to cause foodborne illnesses when resuscitated. Campylobacter jejuni is a leading bacterial cause of human gastrointestinal disease worldwide, but the formation and resuscitation of VBNC C. jejuni and its control measures in the food industry have not been well studied. The aim of this proposal is to investigate the formation and resuscitation of C. jejuni in food processing and storage-related environment as well as in food products. In the context of C. jejuni VBNC formation, we will monitor the dynamics of C. jejuni population during the transition from the normal culturable state to the VBNC state under various stress conditions that mimic food processing and preservation. We will then apply advanced infrastructures (e.g., whole cell fingerprinting spectroscopy and RNA-sequencing analysis) to characterize the biochemical and transcriptional profiles of C. jejuni cells induced into the VBNC state. Moreover, we will develop microfluidic "lab-on-a-chip" device coupled with laser tweezers Raman spectroscopy for the simultaneous identification and separation of pure single VBNC C. jejuni cells from a mixture of different bacterial subpopulations (i.e., healthy cells, injured cells, and dead cells), followed by characterization using single-cell transcriptome sequencing. In the context of C. jejuni VBNC resuscitation, we will use metabolomics to analyze agri-food products that can promote the resuscitation of VBNC C. jejuni cells and identify the potential resuscitation-promoting molecules in foods. We will then study the transcriptional and translational profiles of resuscitated C. jejuni cells using RNA-sequencing and proteomics. Finally, we will develop intervention strategies for the reduction of normal and VBNC C. jejuni in the environment and food system. The research outcome can provide an insight to the development of rapid, sensitive and easy-to-operate methods for the detection and characterization of VBNC C. jejuni in the food industry, and mitigation strategies to reduce the prevalence of Campylobacter in the environment and agri-foods.