Headlines about antibiotic-resistant “superbugs” have made hygiene controls and checks a higher priority throughout the laundry industry and the OPL sector is becoming more concerned about the efficiency of laundry hygiene and the effectiveness of disinfection in the wash.

News of an outbreak of infection increases customer worries and fears that this could happen in their premises, but OPL operators could do more to reassure their customers and ways of doing this range from improvements to the wash process to confirmatory checks on the cleanliness of the finished textiles.

The market leaders in care-home management and small nursing homes are now addressing both general quality and biocontamination control and are devising ways of meeting critical standards without increasing baseline costs. Improved utilities management, thermo-chemical disinfection and improved machine maintenance regimes all have their part.

Mildewed sheets and other stains

The problem of mildewed linen is becoming more common. Mildew staining is a form of vegetable dye stain that is difficult to remove and the difficulty increases with time.

The best solution is to classify rewash items with mildew stains separately and to steep them overnight in a dilute solution of cold sodium hypochlorite. Keeping the dosage below one ml per kilogram of stained textiles and steeping cold will minimise the risk of causing excessive chemical damage whilst maximising the percentage of items that can be recovered for re-use.

The linen most likely to be at risk of mildew comes from customers, especially restaurants, with only one or two collections a week. Many do not understand that storing textiles damp and cold in the dark encourages this form of organic growth. Any laundry which stores incoming work in these conditions for more than a few hours will increase the risk of mildew formation.

Protein problems

Most on-premises laundries now recognise the importance of careful washing to remove protein-based staining from human and animal body fluids.

Reliance on sodium hypochlorite bleach to remove the last traces of a protein stain is decreasing as more operators are converting to bleaches which carry a much lower risk of causing fabric damage.

As a result proteins must be softened with a low temperature pre-wash (four minutes below 40C) before passing through a vigorous high-temperature main wash with plenty of alkalinity.

Dealing with heavy staining

Many on-premises launderers struggle when they are sent heavily soiled items such as kitchen garments. Chef’s trousers with heavy blood and oily, greasy soil can be a particular problem. When such garments are sent in on a on a regular basis there is little or no point in putting everything through a medium soil process and then putting the items that need a rewash through the same process.

Heavily soiled garments need to be classified separately and given a heavy soil wash. If the level of grease and oil is high, an emulsifier will almost certainly be needed, with a main-wash which is high in alkalinity and which runs for long enough to lift all the soiling off the fabric.

Unpleasant side effects

Poor removal of protein soiling such as blood and sweat has an undesirable side-effect. These residues form nutrients for bacterial growth so even if the linen was bacteria free when it left the laundry, it will form an ideal breeding ground for any stray bacteria.

This can be a real problem in care-home and nursing home linen rooms and in small hotel on-premises laundries. The main symptom is the dank odour which assails the nose when the linen room door is opened. This is the excrement from the bacteria which are breeding on the linen surface and feeding on the residual protein soiling.

Keeping a check on bugs

On-premise launderers have neither the skills or resources to count and identify every type of micro-organism which might survive the wash.

All a small on-premises launderer dealing with healthcare, restaurant or hotel linen can be expected to do is to put critical linen from these customers through a process which includes implied thermal disinfection to assure the customer that the level of micro-organic activity at the cloth surface has been reduced to an acceptably low level.

This does not imply zero growth, which would be sterile linen, but a very low level which does not pose a significant risk to the human user.

The dipslide test

However, more and more launderers are now using a simple dipslide to verify that implied thermal disinfection is delivering the desired standard. The method is simple and cheap enough for use by even the smallest on-premises laundry.

A dipslide is a plastic “lollipop” housed in a transparent sterile Perspex tube. The lollipop is removed from the tube briefly, brought into contact with the freshly washed linen and replaced in the sterile housing for incubation at 35C.

After two days any surviving micro-organisms can be seen as scarlet colonies on the side of the slide that denotes Total Viable Count (TVC) – all organisms capable of survival. This is very much a “go – no-go test”, the desired score being zero colonies. Such a score does not mean that the textile is bug-free, as the dipslide probably only picks up one in a thousand of the organisms that are present. But a dipslide that reveals multiple colonies should merit investigation.

The problem could be that the wash is not reaching the desired temperature or that the washer-extractors are being overloaded and the allowance for mixing time is inadequate. This is a particular problem with three-and four-pocket machines.


Laundries which are part of a care-home or hotel group which operates within an ISO 9000:2000 Quality Management System will be familiar with the total quality management approach which delivers a programme of continuing improvement.

Food industry workwear OPLs have long been using HACCP principles to identify hazards and the critical control points which govern these.

The recently published EN Standard 14065 Textiles – Laundry Processed Textiles – Biocontamination Control System describes how to approach designing and installing a quality assurance system which specifically addresses surviving micro-organisms. It indicates where to look for the critical points so that these can be brought under management control.

This document is available from British Standards and is a must for those laundries which are now seeking to improve their performance in this vital area.