Evaluation of hydrogen peroxide foams containing surfactants for lethal activity against Salmonella enterica on stainless steel

This study aimed to identify an optimal surfactant as a component of hydrogen peroxide (H₂O₂) foam effective in killing Salmonella enterica on stainless steel. Seven surfactants (sodium dodecyl sulfate [SDS], cetylpyridinium chloride [CPC], cetyltrimethylammonium bromide [CTAB], coco betaine, lauryl betaine, Triton X-100, and Tween 80) were tested using agar well diffusion assays. Five surfactants, excluding Triton X-100 and Tween 80, exhibited antimicrobial activity. The minimal inhibitory concentrations (MICs) and minimal lethal concentrations (MLCs) of surfactant solutions were determined, with CPC (12.2 μg/mL) showing the highest activity. The antimicrobial activities of H₂O₂ (1 %) and surfactants (500 μg/mL) were tested individually and in combination for effectiveness in killing S. enterica on the surface of stainless steel coupons (SSCs). H₂O₂ treatment reduced S. enterica population from 5.6 to 4.3 log CFU/coupon. Among surfactants, lauryl betaine showed the highest activity, reducing the population to below the detection limit (1.5 log CFU/coupon). Combinations of H₂O₂ with SDS, CPC, CTAB, coco betaine, and Triton X-100 enhanced antimicrobial activity, while Tween 80 had an antagonistic effect. Foam containing H₂O₂ and surfactants (except Triton X-100 and Tween 80) exhibited enhanced activity compared to H₂O₂ alone. These observations indicate that antimicrobial activity of H₂O₂ foams varies depending on the type of surfactant in the formulation and advance the development of foam-type H₂O₂ disinfectants effective against Salmonella and possibly other foodborne pathogens on stainless steel surfaces.