Inactivation of foodborne pathogens on stainless steel surfaces using ultraviolet light emitting diodes (UVC-LED) and ultrasonic aerosolization with GRAS agents

• UVC-LED and ultrasonic nebulization: sustainable and effective food safety methods. • UVC-LED inactivates via DNA/ROS; nebulization uses fine particles. • Both technologies significantly reduce E. coli and L. monocytogenes. • Eco-friendly methods ideal for delicate berries and leafy greens. The inactivation of Listeria monocytogenes and Escherichia coli on stainless steel surfaces was evaluated using a combination of ultraviolet light emitting diodes (UVC-LED) and ultrasonic aerosolization with generally recognized as safe (GRAS) agents: sodium hypochlorite (NaOCl), acetic acid (AA) and hydrogen peroxide (H 2 O 2 ). Stainless steel coupons (2 cm in diameter) inoculated with 6-7 log CFU/coupons of both pathogens were used as bioindicators. Coupons were treated with: UVC- LED (275 nm) at 2 and 4 cm distance for 5, 10 and 15 min; ultrasonic aerosolization with NaOCl, AA or H 2 O 2 for 5, 10 and 15 min or with combinations of both technologies. Lethality, sublethal damage and cell leakage were evaluated. Results showed that UVC-LED treatments were more effective at doses at 30.42 mJ/cm 2 (shorter distance at 2 cm and longer exposure time 15 min), achieving significant reductions in L. monocytogenes (2.27 log CFU/coupon). The aerosolized GRAS agents were also effective especially at the highest concentrations and longer exposure times, achieving complete inactivation of both bacterias. Combining UVC-LED (5, 10, 15 min) with 0.3% H 2 O 2 aerosolization resulted in a more effective inactivation at lower doses, highlighting the potential of these combined technologies to improve food safety on food contact surfaces in the food industry.