Gas ultrafine bubbles improve the efficacy of antimicrobials against eliminating fresh and aged Bacillus subtilis biofilms on various dairy processing surfaces

The objective of this research was to study the impact of incorporating gas ultrafine bubbles (UFB) on the efficacy of chlorine and peracetic acid antimicrobial (AM) solutions against Bacillus subtilis biofilms on polypropylene, silicone, and stainless-steel surfaces. B. subtilis biofilms were grown on coupons of various surfaces at 25 degrees C (for 3 and 30 days for fresh and aged biofilms, respectively) by immersing in B. subtilis inoculated brain heart infusion broth. The AM solutions (50, 100, and 200 ppm chlorine, and 20, 40, and 80 ppm peracetic acid) were prepared from the water incorporated with air, CO2, or N2 UFB. Coupons with biofilms were treated by submerging in AM solutions with or without UFB for 1 min. The AM solutions with CO2 UFB resulted in significantly higher log reductions (2.2-3.7 log CFU cm ?2) of fresh and aged B. subtilis biofilms on all surfaces compared to AM solutions without UFB (1.2-2.5 log CFU cm ?2). (c) 2024 Elsevier Ltd. All rights reserved.