Effect of gas ultrafine bubbles on the potency of antimicrobials against Escherichia coliO157:H7 biofilms on various food processing surfaces

Abstract This study investigated the impact of incorporating gas [air, carbon dioxide (CO 2 ), and nitrogen (N 2 )] UFB on the potency of chlorine (Cl 2 ; 50, 100, and 200 ppm) and peracetic acid (PAA; 20, 40, and 80 ppm) antimicrobial (AM) solutions against fresh (3 days) and aged (30 days) E. coli O157:H7 biofilms on polypropylene, silicone, and stainless‐steel surfaces. The biofilms were statically grown on polypropylene, silicone, and stainless‐steel coupons (7.62 × 2.54 cm) at 25°C for 3 or 30 days by immersing in a 3‐strain cocktail of E. coli . The incorporation of air, CO 2 , and N 2 UFB in AM solutions resulted in significantly increased log reductions (2.1–3.7 logs) in fresh and aged E. coli biofilms on all surfaces compared to solutions without UFB, except for N 2 UFB on aged stainless‐steel biofilms and air UFB on aged polypropylene biofilms, which resulted in similar log reductions as solutions without UFB (1.5–2.1 logs).