Effect of surfactants on the antimicrobial activity of hydrogen peroxide and chlorine dioxide foams against Listeria monocytogenes on stainless steel

초록

This study evaluated the antilisterial activity of hydrogen peroxide (H2O2) and chlorine dioxide (ClO2) in foam formulations containing various surfactants against Listeria monocytogenes on stainless steel coupons (SSCs). First, the minimum inhibitory and lethal concentrations of six surfactants (sodium dodecyl sulfate [SDS], cetylpyridinium chloride [CPC], cetyltrimethylammonium bromide [CTAB], coco betaine, Triton X-100, and Tween 80) were determined using planktonic cells, with CPC and CTAB exhibiting the highest activity. Second, surfactant solutions (100 mu g/mL) were applied to L. monocytogenes attached to SSCs to assess surface-associated antimicrobial effects. CPC and CTAB again showed the greatest reductions, by 2.4 and 2.7 log CFU/coupon, respectively. Third, H2O2 (3 %) and ClO2 (200 mu g/mL) were tested alone or in combination with surfactant foams against the attached cells on SSCs. H2O2+CPC and H2O2+CTAB foams yielded the highest reductions (2.4 and 2.1 log CFU/coupon, respectively), demonstrating enhanced reductions by combination treatments compared with individual treatments. ClO2+CPC and ClO2+SDS foams resulted in 2.6 and 2.2 log reductions, respectively, with greater effects observed than for the individual treatments. In contrast, combinations with coco betaine, Triton X100, or Tween 80 were less effective than H2O2 or ClO2 alone. Finally, the selected foams were evaluated against L. monocytogenes biofilms formed on SSC. These findings demonstrate that the antimicrobial efficacy of H2O2 and ClO2 foams can be significantly enhanced through appropriate surfactant selection, particularly against planktonic and surface-attached L. monocytogenes, while also highlighting the need for improved strategies to control biofilm-associated cells.

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