On-site detection of airborne foodborne pathogens using a field-deployable recombinase polymerase amplification and CRISPR/Cas12a cleavage activity assay

With the global increase in single-person households, the demand for meal kits is increasing, leading to the development of large-scale food production systems and complex supply chains. However, under the influence of global warming, these systems can be susceptible to food contamination, particularly by airborne foodborne bacteria. Conventional methods for detecting airborne bacteria involve complex, time-consuming, and labor-intensive processes, which limit their applicability for field use and rapid food hygiene surveillance. In the present study, we developed a field-deployable diagnostic platform by combining recombinase polymerase amplification with CRISPR/Cas12a cleaVage Activity (RCCVA assay) for the rapid and sensitive identification of airborne foodborne bacteria. Airborne bacteria were collected using a self-developed electrostatic air sampler and analyzed using a portable isothermal amplification device. The RCCVA assay was designed to detect four major foodborne pathogens: Staphylococcus aureus, Salmonella enteritidis, Listeria monocytogenes, and Bacillus cereus. The limit of detection was measured as 274.9, 4.5, 9.5, and 28.5 culture-forming units (CFU)/mL, respectively, within 45 min. This platform enables early on-site detection of airborne pathogens within approximately 1 h (for the analytical phase) and shows potential for real-time monitoring in food processing environments, thereby contributing to improved public health and food safety.