The effect of thin (5 nm) and thick (40 nm) silver layers and diamond like carbon nanocomposites with embedded Ag nanoparticles (DLC:Ag) against two reference strains of C. jejuni NCTC 11168 and L. monocytogenes ATCC 7644 were evaluated in this study. DLC:Ag film contained 22 at.% Ag. Silver nanoparticle size measured by transmission electron microscope was in the 5–10 nm range. Ag layers and DLC:Ag nanocomposites were deposited employing unbalanced reactive magnetron sputtering on crystalline silicon wafers. C. jejuni and L. monocytogenes numbers were counted by culture-based enumeration on selective agars and quantitative real-time PCR (qPCR) including staining with propidium monoazide (PMA). It was determined, that DLC:Ag film was the most efficient coating in the reduction of C. jejuni and L. monocytogenes numbers. Culture-based enumeration revealed that C. jejuni numbers were reduced by an average of 4.06 log10CFU/ml after 15 min and 3.61 log10CFU/ml after 30 min on DLC:Ag coated silicon wafers in comparison to control samples (P ≤ 0.05). L. monocytogenes was not detected on DLC:Ag samples after 24 h of exposure (P ≤ 0.05). PMA-qPCR showed that C. jejuni and L. monocytogenes affected by DLC:Ag antimicrobial surface showed a reduced ability to grow on culture media, but maintained viability during the whole experiment. Nonetheless, DLC:Ag antimicrobial surface could be further considered for the reduction of cross-contamination risk from food preparation surfaces due to their contamination with C. jejuni and L. monocytogenes in domestic and commercial kitchens or food establishments.