Microbicidal Action of Heat, Detergents and Active Oxygen Bleach as Components of Laundry Hygiene

Abstract

It is known that decreasing temperatures in laundry can have a significant impact on the hygiene efficacy of laundering. This study used suspension tests to investigate the microbicidal effects of heat, detergent and activated oxygen bleach and their contributions to laundry hygiene. The results indicate that heat at 60°C contributes significantly to the microbicidal action, while detergent only has limited effects. Activated oxygen bleach strongly enhances the microbicidal action and thus has the potential to compensate for the loss of antimicrobial efficacy due to temperature decrease. This effect varied with the test strain and the temperature, and further work is needed to determine whether it is possible to achieve a hygiene effectiveness equivalent to that at 60°C across both fungal and bacterial strains.

Laundry hygiene-how to get more than clean

“…Honisch et al (2016) recently investigated laundry processes with and without detergents and found little or no effects when comparing the remaining microbial load on artificially contaminated swatches after laundering in a domestic washing machine. Only S. aureus (and to a lesser extent Enterococcus hirae) exhibited a considerably higher LR when washed with detergent compared to water alone, probably due to a better removal of bacterial cells from the fabric, since suspension tests virtually show no antimicrobial effects when detergents are added (Brands et al 2016).…”

“…Only S. aureus (and to a lesser extent Enterococcus hirae ) exhibited a considerably higher LR when washed with detergent compared to water alone, probably due to a better removal of bacterial cells from the fabric, since suspension tests virtually show no antimicrobial effects when detergents are added (Brands et al . ).…”

“…To assess the impact of mechanics on the antimicrobial efficacy of laundering, Brands et al . () performed suspension tests and compared the data with test results obtained in a washing machine using similar chemistry and temperatures. It was shown that the reduction of microbial cells on a textile surface during laundering at 20–40°C must be considered a physical removal effect rather than an inactivation by temperature or surfactants.…”

Laundry and textile hygiene in healthcare and beyond

“…The currently available standard procedures to measure the antimicrobial efficacy of laundering use artificially contaminated swatches and textiles. Most of these investigations are performed in washing machines, since alternative methods such as suspension tests do not allow for a precise simulation of washing processes due to the lack of mechanical impact [45, 46].…”

A unified framework for developing effective hygiene procedures for hands, environmental surfaces and laundry in healthcare, domestic, food handling and other settings

“…These methods can also be used to assess, for example, the separate LR contribution made by active oxygen bleach (AOB) in a laundry detergent [9]. Surfactants in soap and detergents can themselves contribute some microbicidal (bactericidal, fungicidal, virucidal etc.)…”