Abstract: In this study, a novel method for the detection of Listeria monocysteia was established using visual saltatory rolling circle amplification (SRCA). According to the hlyA gene sequence of L. monocytogenes, primers were designed. The specificity, sensitivity and detection limit for artificial contaminated samples were determined. In addition, the sensitivity, specificity and accuracy of SRCA were evaluated by applying it to detect 70 actual food samples. Results showed that the developed method gave positive results for all L. monocytogenes strains and negative results for non L. monocytogenes strains, indicating good specificity of the assay. The sensitivity of the SRCA method was 8.9 × 100 fg/μL, and the detection limit was 2.8 × 100 CFU/g, which were 1 000-fold better than those of polymerase chain reaction (PCR). Compared with the national standard method GB 4789.30-2016, the relative sensitivity, specificity and accuracy of SRCA were 100.00%, 97.01% and 97.14%, respectively. In summary, this method has the advantages of easy operation, simple equipment, strong specificity, high sensitivity, low detection limit and low cost, and can be widely used in grass-root inspection and testing institutions and small- and medium-sized food companies.

Key words: saltatory rolling circle amplification; Listeria monocytogenes; hlyA; detection; visual