Level of decontamination after washing textiles at 60°C or 70°C followed by tumble drying

Infect Ecol Epidemiol. 2014 Nov 11;4:24314. doi: 10.3402/iee.v4.24314. eCollection 2014.

Abstract

Background: Several major outbreaks in healthcare facilities have occurred with the emergence of multi-resistant bacteria. A possible route for dissemination is the hospital textiles and inadequate laundering of them. The aim of this study was to develop an easy-to-use method for simulating the laundering process of hospital textiles, and thereafter apply the method when evaluating the decontaminating efficacy of two different washing temperatures.

Methods: The laundering process, including tumble drying, took place at two professional laundries. Enterococcus faecium was used as bioindicator.

Results: The results showed that a lowering of the washing temperature from 70°C to 60°C did not affect the decontamination efficacy; the washing cycle alone reduced the number of bacteria with 3-5 log10 CFU, whereas the following tumble drying reduced the bacterial numbers with another 3-4 log10 CFU, yielding the same final result independent of washing temperature. Without tumble drying, there was an obvious risk of adding non-fermenting gram-negative bacteria to the fabric. These bacteria originated from the washing cycle.

Conclusion: A simple method to simulate hospital laundering was developed. To save energy, it is possible to use a washing temperature of 60°C, but the washing cycle should be followed by tumble drying, and the whole laundering process needs to be monitored to maintain sufficient textile hygiene.

Keywords: bacterial cleanness; high temperature; laundry; textiles; tumbling.