Fig. 5.

Average SERS spectra (a) and PCA (b) of three L monocytogenes strains from one genoserogroup (IVb) filtered from saline solution and recorded on Ag:Au SERS platforms; PCA of two L monocytogenes strains: 16/09 and 02/07 (c). For all spectra, the excitation wavelength was at 785 nm, laser power at 0.5 mW, and acquisition time 45 s. Each SERS spectrum was averaged from at least 25 measurements at different points of the SERS platform