Moving forward on bug control

4 August 2002



Richard Neale examines developments in hygiene monitoring techniques and the increasing demand among laundry customers for putting these into practice


The increased focus on hygiene controls is changing the laundry market place.

As customers become increasingly aware of the value of disinfection - not just for linen but for laundry equipment - so launderers and textile renters who can meet this requirement are gaining a competitive edge. Further, the arrival of improved and more cost effective techniques gives the issue added impetus.

Debugging the lorry

It is neither economic nor practical for a laundry delivery lorry to handle only dirty or only clean linen. Most vehicles deliver a clean load and return full of dirty linen. So before setting out on another collection the lorry should be cleaned and disinfected.

Visible soiling on the walls of the lorry, calls for a proper clean down and flush out but in most instances it is acceptable to apply a disinfecting spray to the vehicle's interior. This will be sufficient to contain any potential colonies of micro-organisms and prevent their development.

Cages to be used for clean linen must pass through the same careful regime - vital when linen is stacked unwrapped in open cages. Cage spraying has been accepted practice for some time, but the advent of cage washing machines, which also sterilise, means that the disinfection procedure can be far more rigorous bringing much greater customer assurance.

To date, food industry customers and healthcare monitoring officers have rarely bothered to check the level of disinfection achieved in the truck or on the cage. But this is all set to change and there are now a variety of techniques for monitoring disinfection levels.

Hospitals with pathology laboratories are well equipped, in theory, to despatch skilled operatives with appropriate equipment to swab the vehicle walls and cage components. They could then grow cultures from these swabs and determine which bugs have survived and what damage these might cause.

In practice, the time and labour costs involved, make such methods unattractive for all but a few hospital trusts. So checks of this type are not undertaken on a frequent basis.

The best launderers and rental operators will arrange swab testing a few times a year, but only as a double check on their own procedures.

A much simpler though cruder technique is to use the dipslide. This comes in a sterile transparent Perspex tube and looks a bit like a lollipop with a gooey substance on both sides.

The standard dipslide in use in the laundry industry has a suitable medium for growing bacteria and viruses on one side and one for growing fungi on the other, so it can be used to monitor quickly and cheaply most types of micro-organism that might cause harm.

General monitor

It provides a general monitor of overall hygiene standards and covers millions of subspecies of micro-organism. Individual species cannot be differentiated but the test is used as a benchmark and for laundering the only satisfactory result is zero colonies after incubation.

It is important that incubation should be at a constant temperature of 30C and small incubators are available for this purpose. After 48 hours it should be possible to see colonies of any bacteria that have survived, growing as rather alarming red areas on the plain dipslide surface. Fungi tend to form fluffy white or green colonies on the other side.

A dipslide which will then measure coliforms and entero bacteria is about to be launched into the laundry processing sector.

These organisms are present in the later stages of the digestive system. Coliforms grow in the form of intense violet red clusters whilst non-coliforms differentiate themselves as colourless clusters.

Food and healthcare

For food industry and healthcare work, the dipslides should be totally clear after incubation - normally 48 hours for bacteria and viruses and up to seven days for fungi.

Most professional wash processes involve a minimum of three minutes above 71C, which is sufficient to meet Department of Health requirements for implied thermal disinfection. So how do bacteria survive on linen that has gone through a tunnel washer with three or four compartments above 71C ?

First, it is essential to sterilise a continuous batch washer used for healthcare work each morning, before processing starts. This means emptying the machine the night before and running the steam lance sterilisation cycle before work enters the rinse zone.

The worst scenario is a machine left full of work overnight as the mild conditions in the rinse zone are ideal for bacterial growth and without machine sterilisation the work will probably come out with more bacteria on it than when it went in.

Even with sterilisation, it is difficult to guarantee hygiene because the press and press tank are difficult to sterilise. Even the press membrane can transfer bacteria onto the top of the cheese for the first few batches.

Many launderers have found that chemical disinfection in the rinse overcomes this problem but the check is important and set to become more so as cross-infection claims in the NHS multiply.

So far the laundry has been regarded as a low priority but as improvements are made elsewhere so the control infection officer's remit will widen.

At present NHS trust contracts generally include a specific requirement for implied thermal disinfection and a requirement that dirty trucks be cleaned and disinfected prior to loading with clean linen. However, cross checks that disinfection is actually being achieved have not been common.

The introduction of dipslide technology is likely to make checks of this type quite routine and shrewd rental operators and launderers are anticipating the change and ensuring that their operations are prepared for stricter controls.

The opportunity for cross-infection in hotel linen is significant and, in view of the recent focus on hygiene, it is surprising that the hotel market has not tightened purchasing requirements to include disinfection of sheets and pillowcases, at least.

This oversight represents an opportunity for the textile rental sector. Pro-active launderers will be using the potential risks as part of their marketing approach and pointing them out to the customer. Infection control is one area where they can differentiate between the professional launderer and an on-premise operation, which might only be using water from the hot tap!

The laundry is often an afterthought in smaller healthcare establishments. So procedures may be poor, failing to address infection control through either ignorance or negligence.

This implications are serious. Without chemical disinfection or implied thermal disinfection, bugs could be easily transferred throughout an establishment, either through inadequate washing or via the tumble dryers. Smaller operations, such as nursing homes or hospices, have the most to gain from using a professional laundering service. The benefits have nothing to do with economics; they are geared solely to patient care.

The way ahead

At the moment developments in controlling infection are being driven forward by the Central Sterilising Club, in which representatives from the private sector, including TSA and large healthcare launderers, together with public sector hospital launderers and other public sector agency experts, pool their knowledge to produce workable improvements.

The body is an excellent example of mutual co-operation from which patient, hotel guest, laundry operative and the public in general can only benefit. An improved protocol for healthcare linen disinfection is expected.

Most meat processors and general food industry organisations are well aware of microbiological testing and have their own systems in place.

Until quite recently, few rental operators regularly checked for absence of viable micro-organisms on the surface of the clean workwear garment. This was partly because cleanroom processing of food industry workwear has only recently become the norm and there is no point in testing for bugs unless the garment has been washed and finished under cleanroom conditions.

In a normal laundry atmosphere there are plenty of bugs floating around, making testing anywhere downstream of the washing machine a waste of time.

Cleanrooms include laundry staff, so there will always be a very low level of bacterial contamination on a finished and packed garment and it is unrealistic to expect zero colonies on a dipslide test. However, it is essential to have nil coliforms and an agreed, very low level of other bacteria. The criteria should be decided in discussion with the ultimate customer.

Again the rental industry has demonstrated its ability to meet commercial requirements in respect of food industry health and safety and to incorporate these into its revised systems for cleanroom processing with dipslide monitoring.

This has been a major change over the last 20 years. In the early 1980s many launderers of food industry workwear retreated from the idea of micro-organic monitoring for fear of opening a can of worms! Now they play a major part in the concerted effort to eliminate a whole raft of pathogens that can cause food poisoning, both minor and major.

We are in the midst of change both in attitudes and controls as far as disinfection and its assurance are concerned. Rental operators are leading the way, public sector hospital laundries are also well to the forefront. A professional approach to disinfection with suitable controls to check the effectiveness of procedures is becoming an essential requirement across the marketplace.

If you are not yet up with the leaders you need to get moving!



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