Meeting the standards of hygiene sensitive industries

Launderers serving the high care sector of the food industry need to be scrupulous in ensuring that they produce hygenically clean garments.

The TSA and also the former FCRA have published excellent booklets on laundering workwear to food industry standards.

They cover not only the requirements of ISO9002 but also provide a good explanation of both HACCP (hazard analysis and critical control points) and risk analysis and biocontamination control (RABC) measures. These standards also apply to launderers serving the pharmaceutical industry and the high end of the micro-electronics industry.

Many people think of cleanliness as simply being free from soiling and staining and bright and white – coloured garments are unusual in this sector. This is no longer sufficient.

Garments used in these industries must also be free of all bacteria, other harmful pathogens and also debris, such as lint, fluff or hair, that can cause contamination. For example, the microchip industry produces thousands, if not millions, of chips for mobile telephones and computers by laminating layers of carefully prepared films over each other – building each layer with the vital electronic components.

If a single hair gets sandwiched between the film sheet layers, it can render the whole sheet of microchips faulty.

As each sheet can have a thousand or more microchips, the financial loss from such a hygiene failure can be extensive.

Stray ion

A stray metallic ion left on the fabric surface can cause damage to a single chip circuit, bridging the insulating gap or allowing a microscopic static discharge.

Similarly, particles of dust and lint will not only affect the micro-electronics industry but can contaminate a complete batch of medication or tablets. Again this will mean the whole batch has to be destroyed and the financial loss will be considerable.

So launderers processing re-usable garments for these industries must work to the same exacting standards as their manufacturing customers.

The paper disposables industry has successfully captured a large segment of the garment supply to hygiene sensitive industries by using non-woven fabrics that are sterile, lint-free and particle-free, with no stray ions or other electrical contaminants.

Single-use non-wovens can be an attractive alternative for a number of manufacturers as well as for the high-tech part of the healthcare sector, for example, in operating theatres. Some launderers have capitalised upon this and offer not only re-usable garments processed in hi-care facilities but will also supply disposable garments supported by a parallel complementary technical service.

The guidelines set out by TSA and the former FCRA will help laundries to ensure they have the correct environment for handling and processing garments for the hygiene sensitive industries.

It is equally important for laundries to specify the garments correctly and to make sure that they process such work correctly once it has been soiled and sent for laundering.

The garments’ technical specifications vary according to the industry and can range from permeability to anti-static and flame retardency but lint and particles raise other concerns.

A question of comfort

The use of 100% polyester continuous filament fibre garments can eliminate lint problems but these materials may prove uncomfortable when the garments have to be worn for eight or more hours each day.

In addition, as continuous filament fibre garments are classed as synthetic they tend to generate static. They may also be woven with metallic fibres in the warp to “earth” any static electricity build-up caused by friction during use. In this event it is essential that the correct type of metallic or carbon fibre is used as it must be highly flexible as well as being unaffected by the alkalis and bleaches commonly used in the laundry. The fibres must not corrode easily and leave unsightly residues and stains on the fabric.

Once the correct type and style of garment has been identified and approved by the user, the next step is to ensure that the processing methods will lead to hygienically clean garments.

Know your textiles

It is essential to know the type of textile used in the garment and the type of soiling that may occur when it is in use.

The garments will either be 100% polyester or a high quality polyester and cotton blend.

Any garments with a polyester content will attract oils and fats and need special washing chemistry to keep them fresh and bright.

Even if the wearer’s workplace does not use oils, fat or grease, the garments will attract body oils and fats.

The ingrained soil found inside most collars consists of skin follicles and fat from hair and skin. To add to the problem of polyester’s oil and fat affinity, such soiling will also attract hardness salts from the incoming water supply and these will form a hard shell over the surface of the fat soils.

So where there is even a trace of hardness in the water, the detergent system must not only be able to break down the hardness salts but also the extremely strong electrical bond between the oils and fats and the polyester fibre.

This will require some sophisticated chemistry and it will be essential that the chemicals are dosed correctly every time.

Mechanical action of the washing machine and process temperatures play a vital role in ensuring the garments are correctly cleaned.

Polyester needs plenty of room to move around so the garments should never be crammed into the machine and the washer should never be overloaded, otherwise this could lead to pressure, roping and thermal shock creasing.

As a guide, never load the washing machine at greater than 72g/litre cage capacity (56g/litre is ideal). The washer should be as deep as possible and the depth should be greater than the diameter.

Low temperature start

Always start the wash process at 39C or slightly less and run for at least 5minutes once the temperature and correct (medium) water level have been achieved.

Each garment in the load must be thoroughly wetted and any water soluble soiling must be dissolved. All dried-on protein soiling must be softened and ideally broken and removed.

By ensuring the correct degree of loading, polyester can be readily taken up to 71 – 80C during the main wash without causing creasing. This ensures thermal disinfection takes place so garments are hygienically clean.

The secret here is to cool down the fabrics correctly. This means that the cool water supply must be injected into the bottom of the washing machine so that the wash liquor cools first and then cools the garments.

Using the “normal” water inlet that sprays cold water into the top of the washing machine straight over the hot garments is almost guaranteed to crease the load beyond recognition.

The rate of cool down should never exceed 4C/minute and for very sensitive fabrics may need to be reduced to 2C/minute.

If there is any residual vegetable dye or protein staining, hypochlorite bleach should be used on the first rinse but this bleach will have absolutely no benefit on oils, fats, grease and carbon – so don’t waste your time and money.

With care and application of basic technology, clean-room garment processing can be a profitable source of premium revenue.