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Key takeaways
- Healthcare textiles can carry pathogens, so laundry management is an essential part of infection prevention in hospitals and care facilities.
- Soiled and hygienically processed linen must be kept strictly separate through appropriate spatial and organizational measures.
- Chemothermal processes can disinfect textiles at lower temperatures. Their effectiveness depends on the right disinfectant, accurate dosing and reliable process control.
- Disinfectant agents differ in their spectrum of activity, compatibility with textiles, occupational safety requirements and environmental impact.
- The rules governing approved disinfectants and processes vary from country to country.
Textiles are an integral part of the hygiene protocols used in healthcare and care facilities. Bed linen, towels, curtains, mattresses, mop heads, workwear and protective clothing can transmit pathogens and pose a risk to people with weakened immune systems. The same applies to other institutions where many people live in close quarters, such as prisons and refugee accommodation. Preventive measures are therefore essential to help stop pathogens from spreading. The WHO includes the management of used and clean hospital laundry as a standard precaution in its recommendations, Minimum requirements for infection prevention and control programmes.
These recommendations are implemented internationally through national regulations. They specify spatial, technical and organisational measures to ensure that soiled, infected or infectious laundry (the “dirty” side) is kept strictly separate from hygienically processed items (the “clean” side). Procedures on the dirty side depend on the health risk posed by the laundry:
- Suspected infection: Laundry that may be contaminated with pathogens such as bacteria, viruses or fungi. The UK Health and Safety Executive (HSE) classifies these biological agents as hazard group 2.
- Infectious: Textiles known or highly likely to contain transmissible pathogens. The HSE classifies these as hazard group 3.
- Highly infectious: Laundry that is, or may be, contaminated with pathogens posing a particularly high risk of infection, for example from special high-consequence infectious disease units (HSE hazard group 4). Laundries must not accept it; it must be disposed of as special waste by the organisation that generated it.
The laundry’s role is to destroy the pathogens. In the past, textiles were boiled at 90°C for at least 10 minutes. Because this consumes a great deal of heat energy and can cause shrinkage or damage fibres, colours and finishes, thermal disinfection has largely been replaced by chemothermal processes. These use specific disinfectants at temperatures above 60°C for a prescribed time. Disinfection wash processes at 40°C are a more recent development. They save energy during heating, but the more aggressive chemicals can shorten textile life. They also require highly reliable process control, including precise dosing and temperature holding time, because the thermal component no longer provides a “safety buffer.”
Choosing the right disinfectant active ingredients is essential, and each country has its own regulations. The disinfectant list published by the UK Health and Safety Executive (HSE) classifies products by risk group. In Germany, the Robert Koch Institute (RKI) and the German Association for Applied Hygiene (VAH) classify disinfectants and processes according to their efficacy against specific biological agents:
- A. Effective against vegetative bacteria, including mycobacteria, and fungi, including fungal spores
- B. Effective for inactivating viruses
- C. Effective against spores of the anthrax pathogen
- D. Effective against spores of the pathogens that cause gas gangrene and tetanus; requires an additional sterilisation programme
Similarly, in Austria, the Austrian Association for Hygiene and Surface Protection classifies laundry disinfectants according to their efficacy against bacteria and yeasts, viruses, fungi, tuberculosis pathogens and mycobacteria.
Only a limited number of chemicals are generally suitable for killing these biological agents in a wash bath. These include peroxides, peracetic acid, sodium chlorite and quaternary ammonium compounds (QACs), which are used in commercially available detergent formulations.
- Peroxides are highly reactive oxidising agents. They destroy the outer structures of microorganisms, causing pathogens to die.
- Peracetic acid reacts with components of the cell and/or cell membrane. Because this mechanism is non-specific, the risk of resistance developing is low. Peracetic acid-based disinfectants are particularly effective in acidic conditions (pH < 3).
- Sodium hypochlorite disinfects by destroying proteins and fats, making many bacterial pathogens harmless. Chlorine’s oxidising action also breaks down chemical bonds in colour pigments, helping to remove many stains.
- Quaternary ammonium compounds are positively charged organic compounds. They interact with negatively charged cell membranes and proteins, disrupting their function and causing cell death.
The effectiveness of a hygienic washing process depends on more than the disinfectant alone. The process specified by the detergent manufacturer must be followed, including the correct temperature and holding time. Healthcare authorities around the world agree on these principles. The main differences lie in the required disinfection times, which can vary considerably, as explained in Healthcare laundry: one goal, many rules.
