Test methods for estimating the efficacy of the fast-acting disinfectant peracetic acid on surfaces of personal protective equipment

Aims: The work aimed at developing and evaluating practically relevant methods for testing of disinfectants on contaminated personal protective equipment (PPE).

Methods and results: Carriers were prepared from PPE fabrics and contaminated with Bacillus subtilis spores. Peracetic acid (PAA) was applied as a suitable disinfectant. In method 1, the contaminated carrier was submerged in PAA solution; in method 2, the contaminated area was covered with PAA; and in method 3, PAA, preferentially combined with a surfactant, was dispersed as a thin layer. In each method, 0·5-1% PAA reduced the viability of spores by a factor of ≥6 log₁₀ within 3 min. The technique of the most realistic method 3 proved to be effective at low temperatures and also with a high organic load. Vaccinia virus and Adenovirus were inactivated with 0·05-0·1% PAA by up to ≥6 log₁₀ within 1 min. The cytotoxicity of ricin was considerably reduced by 2% PAA within 15 min of exposure.

Conclusions: PAA/detergent mixture enabled to cover hydrophobic PPE surfaces with a thin and yet effective disinfectant layer.

Significance and impact of the study: The test methods are objective tools for estimating the biocidal efficacy of disinfectants on hydrophobic flexible surfaces.