Determining the disinfection of textiles in compressed carbon dioxide using various indicator microbes

Abstract

This paper presents a research on the disinfection efficiency of inoculated textile swatches by compressed carbon dioxide, an environmental friendly way to disinfect textiles as opposed to the conventional laundering procedures using water. The disinfection efficiency was determined by using the following microbes inoculated on cotton test fabrics: Enterococcus faecium, Enterobacter aerogenes and Candida albicans. The experiments were performed using the high pressure extraction device with a maximum pressure of 50MPa and a small extraction vessel of 500ml. Pure CO(2) and CO(2) with added disinfection agent or commercial detergent were used. The chosen disinfecting agent was hydrogen peroxide, a widespread disinfecting chemical. It was found that treatment with CO(2) for 25min at 5MPa and 40°C (313K) and the addition of 4ml of specific detergent per litre of CO(2) assures at least a five log step reduction of Enterobacter aerogenes and C. albicans, whilst treatment at 50°C (323K) with CO(2) for 25min at 5MPa is sufficient for at least a five log step reduction for Enterococcus faecium. It was also found that a 15-min CO(2) treatment at 7MPa and 20°C (293K) was sufficient for the inactivation of the yeast C. albicans, whilst these conditions were not rigorous enough for the challenge bacteria. On the other hand, the labscale treatment with CO(2) for 25min at pressure 4 and 6MPa with the addition of detergent or hydrogen peroxide only yields a log step reduction of up to 4 log steps, thus proving the slightly disinfective properties of the CO(2) treatment with added agents, but not reaching efficient results as a 5 log step reduction was not reached. Addition of heat to the compressed CO(2) treatment of textiles inoculated with microorganisms proved more effective than the addition of detergent or disinfectant with compressed CO(2) treatment at temperature of 20°C. CO(2) treatment of textiles is a promising ecological alternative dry-cleaning method for the disinfection of medical textiles.