Research – Combination of ultraviolet light‐C and clove essential oil to inactivate Salmonella Typhimurium biofilms on stainless steel

Salmonella typhimurium is able to form biofilms as a resistance mechanism against antimicrobials; therefore, it represents a problem for assuring food safety and highlights the importance of research on anti‐biofilm technologies. In this study, S. typhimurium biofilms were inactivated with the combination of clove essential oil (CEO) and ultraviolet light (UV‐C). The volatile composition of the CEO determined by gas chromatography showed eugenol as the major constituent (82%). A combination of CEO with UV‐C achieved a complete bacterial reduction (6.8 log/cm²) on biofilms with doses of 1.2 mg/ml and 76.41 mJ/cm², respectively. Individually, the CEO at 1.2 mg/ml caused a reduction of 1.8 log CFU/cm² of attached bacteria cells on stainless steel, while UV‐C individually used at 620.4 mJ/cm² caused a 2.9 log CFU/cm² reduction compared to control biofilms. In conclusion, this study demonstrated a synergistic effect of combining CEO and UV‐C irradiation to inactivate biofilms of S. typhimurium.