laboratory hygiene

8/8/2019 Laboratory Hygiene

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necessary, a full face shield.

For example, chemicals or bio-hazardous material can splash on your face, in your mouth or eyes.

Apart from protecting your clothes, laboratory coats help protect you from splashing.

Disposable gowns and gloves are essential when working with infectious material toprotect you from direct infection.

Use the appropriate personal protection and ensure that it fits correctly.

Working with sharps, instruments or syringes, can also present risk and requires extracare. This is especially so when dealing with infectious materials. If you cut or prickyourself under these circumstances, you should immediately report it.

When working with animal body products, faecal matter, or body fluids, it is wise toassume that they are infectious.

All of the above can be the cause of direct infection.

Always wash your hands thoroughly with the cleaning agent recommended for thework routines you are performing.

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Make sure that you keep your bench area hygienically clean. This can be a source of chemical contamination, or indirect infection if you have been working with infectiousmaterial.

The risks to your health are governed by the level of personal hygiene that you

practise. Your workplace standard operating procedures will state what precautionsyou should take when performing certain work routines.

For your own sake, and those about you, make sure that you comply with safetyrequirements.

In general, you must always:

- use the correct personal protective equipment

- keep hands and protective clothing clean, particularly at meal and toilet breaks

- wash your hands whenever you leave the laboratory and again on your return

- wash hands each time you remove protective gloves

- take steps to prevent contamination of samples

- make sure your conduct is sensible and does not cause harm to yourself or others.



Cross-contamination is the transfer of contamination from one place to another.

Your company will have procedures in place to help prevent this from occurring. Ingeneral:

- Avoid all unnecessary contact with chemicals and materials that may be

contaminated.

- Don’t eat, smoke, chew your nails or place things like pens in your mouth.

- Make sure you don’t contaminate surfaces with bacteria by transfer of materialon your hands, clothing or other personal items such as pens, worksheets,folders, chairs, safety equipment and other equipment that can come into contactwith work surfaces or other items in the laboratory.

All items in the laboratory should be treated as a potential source of contamination,even if you have cleaned it. While it is impossible to completely stop contamination,you can certainly help to minimise it.

Standards of workplace cleaning

Cleaning refers to removal of all sorts of contamination and waste materials.

Equipment, glassware, bench-tops, floors, furniture as well as people and their personal protective equipment all require specialised cleaning which depends on thepossible contamination and its properties.

Sanitising agents

You will be familiar with the role of chlorine as a germ killer. Other sanitisers commonto the domestic scene are some (dual action) detergents and hot water anddisinfectants.

Sanitising means the removal of micro-organisms using chemicals or hot water, and leaving the object in a condition which can resist further organismgrowth. The food industry uses stainless steel because the chemicals used to removefood residues and kill any organisms don’t attack this material. The microbiologicalareas concerned with testing for micro-organisms must have sterile equipment and beable to destroy any reproducing organisms. The enterprise must be able to protect itsstaff from contamination by contact with these potentially harmful micro-organisms.

Microbe destruction can be carried out with:

- chemicals (chlorine-, aldehyde- and quat-types)

- heat (flaming, wet or dry steam – autoclave)

- radiation (UV, nuclear, microwave).

Barriers such as seals and plastic wrapping are used to prevent further access. Your



trainer/supervisor will stress areas of local importance.

Disinfection of benches and other work surfaces

The general procedure for cleaning and disinfection control of work surfaces in thelaboratory are summarised below. You may use this as a guide because your

workplace will have developed its own workplace hygiene plan and procedures andyou must know them thoroughly and follow them as required.

1. Clean first with hot water and detergent to remove build up of grease and fats.

2. Rinse with water to remove traces of detergent that might reduce the ability of chemicals to disinfect the surface.

3. Apply disinfectant spray to the surface and allow it to soak. The soaking time iscalled the contact time. Contact time is important for the chemical disinfectant to beable to do its job effectively. The contact time varies with the type of disinfectantused. You should always check the manufacturer’s instructions to find out the

appropriate contact time for the disinfectant that you are using.

4. Wipe down the surface and allow to dry.

Suitable disinfectants include:

- 1% glutaraldehyde gives broad protection against microbial contaminants but itcan be irritating to your nose and throat so it should only be used in a wellventilated area.

- ethanol as an 80% v/v solution (=70% w/v ethanol)

- do not use pure ethanol because some water must be present for it to work asa disinfectant mixed with water

- be careful with ethanol because it is very flammable (even when mixed withwater)

All areas within the laboratory should be kept clean and free from dust. Dust canbecome airborne and contaminate samples and cultures. Also insects such as flies,should be kept out of the laboratory as they have the potential to contaminate testingprocedures.

laboratory hygiene

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