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lab safety

Microbiological procedures

Laboratory Safety: Good Lab Practice

Microbiological procedures

personal habit

nothing in moth

wash hands for 20 mins

contaminated

finished

disinfectant your desk

before start

finished

if spill culture

disposing used items properly

labelling

Label all cultures and solutions properly with your name or initials, date, course / lab section, and experiment information. The experiment information may include the composition of the solution, identity of the culture, or the experiment number.

Biosafety Guidelines:

Biosafety levels are determined by the National Institutes of Health and the Centers for Disease Control.

Biosafety Level 1

well-characterized agents not known to consistently cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment.

open bench tops using standard microbiological practices. Special containment equipment or facility design is neither required nor generally used

Biosafety Level 2

is suitable for work involving agents of moderate potential hazard to personnel and the environment.

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Precautions for dealing with body fluids - use Biosafety Level 2

Microbiology Safety: Aseptic Techniques

Because microorganisms are so small, large populations are generally needed in order to monitor microbial activity. Aseptic techniques help ensure that only one type of microorganism is present in a container (pure culture). These methods also ensure that the microorganisms do not escape from the container, contaminating the laboratory, and possibly causing disease.

Micro Lab Procedures: Clean Up

Items contaminated with microorganisms or body fluids must be autoclaved before disposal or washing.

Needles and syringes must be thrown into the red sharps container. Syringes without needles must be disposed of in the sharps container.

A special cart is designated in the laboratory for items that require autoclaving, including:

Glassware including flasks, beakers and other containers. Remove all marks from the glass with ethanol and place the items in the cart. Do not throw cultures down the drain. Place the containers and their contents in the cart.

Glass tubes are placed in baskets set on an angle so that the contents do not spill. Remove marks before disposal using ethanol.

Any items that are contaminated with culture or bodily fluids.

Plastic Petri plates and other disposable plastic items used to culture or contain microorganisms must be placed in the red biohazard bags for autoclaving prior to disposal.

Chemicals must be disposed of properly. Some chemicals must be placed in special containers for disposal to prevent environmental contamination. Your laboratory instructor will inform you about the chemicals you are using.

Never pick up broken glass with your hands; use a broom. Dispose of broken glass in the broken glass container. Disposable glass items that are not contaminated with culture must be placed in the broken glass container - even when they are not broken.

Paper towels should be thrown in the ordinary trash, unless they are contaminated with culture.


Protective Procedures

Read the laboratory exercise before class and plan your work.

Wear a lab coat. You should supply a lab coat and leave it in the lab.
Always wear shoes in the lab. Closed-toed shoes are required for many labs.
Tie long hair back.
Remove dangling jewelry and items such as scarves and ties.

Disinfect your lab bench before you start, if you spill culture, and before you leave the lab.

Protective Procedures for chemical hazards:

Prevent contact with the skin by wearing gloves and a lab coat.



Minimize hazards due to the formation of dangerous aerosols and splashing by wearing protective eye gear

Limit exposure to chemical fumes by working in a chemical fume hood.


Properly dispose of chemicals that pose environmental hazards.


Protective procedures for physical hazards:

Set up a Bunsen burner in the center of your lab bench in an area free of overhanging materials. Never leave a lighted Bunsen burner unattended. Keep work area clear.



Keep water away from electrical equipment.


Some procedures in the lab involve physical hazards and require special precautions, for example:


Working with hot items, either from the autoclave or heated in the Bunsen burner requires protection of your hands. Wear mitts or handle the hot item with tongs.

Using a sonicator, or sonic dismembranator, requires wearing protective ear coverings.


When working with a UV light source, wear coated UV-protective safety glasses.


Protective eye coverings are required any time that aerosols might be generated or splashing might occur.


Emergency Procedures

Report all accidents to your instructor.


familiarize yourself with the location of the eye wash station, the safety shower, the campus phone, and the fire extinguisher.


If you need to seek outside assistance for an injury or accident, call 911. Use the campus phone in the laboratory. Calling from your cell phone will connect you with the city rescue service and the city emergency services will then contact the campus police. Calling from the campus phone saves precious time.

earthquake, tornado or building fire, TURN OFF GAS JETS FIRST, then evacuate the building as directed by your lab instructor.

If a culture is spilled, cover the spilled material with paper towels and apply a generous amount of laboratory disinfectant. Let it sit twenty minutes and then clean up the towels and disinfect the bench.

Small fires should be extinguished quickly by smothering.


A fire extinguisher is ready in each laboratory.


If your clothes catch on fire "drop and roll" to smother the flames. Your lab partners should use a fire blanket or their coats to help smother the flames.

For heat burns, chill the burned area with cold water or ice and notify the instructor.


If a culture or chemicals are splashed in or near you or your partner's eyes, immediately go the eye wash station. The two of you should go together. Place your face in the eye wash station and apply water. Your partner should hold your eyes open to ensure thorough flushing.

For large spills on your body or if caustic chemicals are spilled on you, proceed immediately to the safety shower. Pull the lever, while the water floods over you, take off any clothes that are contaminated. Stay under the shower until it stops.

Laboratory Skills

Slide Preparation

Aseptic Techniques

Enumerating Microorganisms

earning techniques to make slides (wet and dry) and to stain slides with a simple stain.

From visualizing the microbes you can tell their size and shape, whether they are prokaryotic or eukaryotic, how many kinds of organisms are in the sample, may provide an idea of how to treat an infection clinically, and the smear could provide clues as to how to identify the organism.

Slide Preparation: Wet Mount

Agar Culture

Broth Culture

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medical Definition of wet mount. : a glass slide holding a specimen suspended in a drop of liquid (as water) for microscopic examination; also : a specimen mounted in this way.

wet mount

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Slide Prep: Simple Smear

Slide Preparation: Direct Stain

Aseptic techniques help ensure that only one type of microorganism is present in a container (pure culture). These methods also ensure that the microorganisms do not escape from the container, contaminating the laboratory, and possibly causing disease.

Plate Streaking

Broth Transfer

Pipette Transfer

Flaming the Loop