The increasing population leads ti an increasing demand for fresh produce all around the world. Making provisions for inhibiting foodborne pathogens, especially the ones producing biofilms, such as Salmonella spp., might remain impossible during the process, due to the cross-contaminations. Thus, foodborne outbreaks can be accompanied by biofilms. Chemical disinfectants are not efficient in disintegrating the biofilms since they cannot penetrate into the biofilm matrix. At this point, plant extracts with correct exposure time on fresh produce are crucial to take timely precautions against the attachment of bacteria to fresh produce. The effects of the water-soluble extract of stinging nettle were determined for biofilm formation capabilities on food product and in vitro, and swimming motilities and curli expressions of Salmonella enterica Virchow, Newport, Typhimurium, Enteritidis, Othmarschen and Mikawasima serovars. Moreover, rpoS, mlrA, ycfR, fimA, spiA and csgA, biofilm-related genes, were also screened. Results have revealed that 2 log reduction of bacterial strains named above, forming biofilm formation on spinach, have been observed by the help of the extract of stinging nettle with 1-hour exposure time. In vitro, different inhibitory capabilities of the extracts have been observed regarding the concentrations, ranging from 2 mg/ml to 20 mg/ml. The extract has significantly decreased the swimming motilities of serovars, except Enteritidis. Weak and strong biofilm producers have been observed in curli expression. In conclusion, stinging nettle extract plays an important role in eliminating biofilm formation of Salmonella enterica serovars.