Glassware Cleaning for Microbiology

Glassware for Microbiology

The microbiology laboratory deals with detecting, culturing, and identifying microorganisms like bacteria, fungi, viruses, etc. Some of the requirements of microbiological laboratories are essential equipment/instruments, trained human resources, maintaining personal safety, sanitation of the working area, and regular equipment maintenance. The use of glassware is applicable for storing chemicals or performing different experiments. The glass used in constructing the glassware is either borosilicate or soda-lime glass. The soda-lime is less tolerant to chemicals and has lesser hydrolytic resistance. Borosilicate glass can tolerate chemicals like acids, halogens, and organic solvents. That is why borosilicate glass is preferred over soda-lime glass.

Equipment Commonly Used in Microbiology Laboratory

Aim to get acquainted with the different glass-wares and lab-wares used in the microbiology laboratory. A number of glasswares and lab-wares are required in the microbiology laboratory.

Test tube, culture tube and screw-capped tubes

Test Tube Holder


Volumetric Glassware –Conical flask, Graduated pipettes

Non-Volumetric Glassware -Beaker ,Petri Dishes, Stirring Rod, Glass spreader, Microscope Slide, Glass tube ,Graduated cylinders, Reagent bottle

1. Test Tubes

They are used to heat on hold reagents for observing chemical reaction.

2. Test Tube Holder:

It is used during heating of the test tube.

3. Funnel:

It is used during filtration.

4. Volumetric Glassware:

It includes cylinders, pipettes, burette & volumetric flasks. It is used in measuring accurate volume of a liquid.

(a) Dropping Bottle:

They permit the fluid to flow in a drop wise fashion.

5. Non-Volumetric Glassware:
(a) Beaker:

It is used for heating liquid and for preparing reagent solution.

(b) Petri Dishes:

The Petri dish is a shallow, circular, and transparent and used in different biological laboratories, It is used for the aerobic culture of microbes.

(c) Stirring Rod:

It is used for dissolving the solute in preparing solution.

Care of Glassware:

While working in a laboratory the technician must get acquainted with the types of glassware’s handled in the laboratory & use them appropriately. Improper use of its may lead to breakage.


There are basically 2 types of glassware:
(1) Borosilicate
(2) Soda-lime

Borosilicate is heat and chemical resistant. It can also stand mechanical stress & will not break due to sudden change of temperature. While soda-lime glass which is less resistant to mechanical shock and thermal shock. It is cheaper than borosilicate. It is easy to bend by heat.

Handling of Glassware:

It is expensive proper care and handling reduces the risk of personal injury.

General Cleaning Procedure

Dispose off any of the remaining corrosive or hazardous material used in the analysis, before giving the glassware for washing.

Empty the contents of the glassware into the washbasin. Empty any solid residues into the polythene covers for destruction of waste.

To remove any stains, marking or labeling made with a glass marking pen on the outer surface of the glassware wipe with acetone, scrub it off with a scrubber, and clean with tap water.

For difficult to clean stains or stubborn material, rinse the glassware with dilute nitric acid and rinse with tap water after 30 minutes of acid treatment.

Dip the glassware in 70% IPA for 30 minutes.

Rinse all the glassware with tap water till the solution is washed off completely.

Finally rinse with sufficient quantity of purified water.

After rinsing, dry the glassware in the hot air oven at around 85°C – 100°C.

Autoclave the glassware containing cultures in the vertical autoclave meant for disposal, and then clean as above.

Procedure for cleaning of microbiological Laboratory

Cleaning of Glassware’s:

Cleaning Procedure of Newly procured Glassware’s:

1. Soak in 2% HCl for overnight to neutralize any alkali present.

2. Wash in running tap water.

3. Boil in any synthetic detergent for 30 minutes. Rinse well with tap water and finally in distilled water.

Cleaning Procedure of Daily routine Used Glassware’s:

Boil in a detergent for 30 minutes, clean thoroughly with a brush, rinse in tap water. Dry them in the hot air oven with the temperature not exceeding 80°C.

Potassium dichromate (kMno4) cleaning solution composition

kMno4 – 25gm

Water – 25ml

Conc. H2So4 – 50ml

Preparation of Solution:

Dissolve 25gm. Potassium dichromate in 25ml of water. Add 50ml of Conc. Sulphuric acid (slowly, always add acid to water) and cool store in a stoppered bottle. Dissolve when it starts turning green.

Test Tubes:

1. Autoclave to remove infected material.

2. Boil in a detergent solution for 30 minutes. Clean with a brush.

3. Rinse in running water and finally with distilled water and place them in test tube rack upside down and dry them in an oven.

4. Cotton plugs them and sterilizes them in the hot air oven.


1. Soak in cleaning solution for overnight

2. Wash in running tap water.

3. Rinse in distilled water.

4. Dry on suction pump using spirit or acetone.

5. To sterilize plug mouth piece with cotton wool, wrap in craft paper and sterilize in hot air oven for 1 hr. at 160°c.


Pasteur Pipette:

1. Soak in 3% Lysol for 1 hour.

2. Wash it same as test tubes.

Glass Slides:

Newly received:

1. Boil in a detergent for 30 min.

2. Place in Dichromate solution for overnight.

3. Wash in running water.

4. Keep methylated spirit.

5. For using, take them out with a forceps and hold them only by the edge.

Routinely Used slidesWash it same as used 

Infected – Infected slides should be autoclaved and clean as early as possible new reuse slides used for examination of acid fast bacilli or gram stain)

Cleaning with Infected Glassware 
    • Remove the media from the container and dispose of it safely.
    • Wash the glassware in warm soapy water.
    • Rinse it with tap water. 
    • Using different methods of sterilization, like using dry heat in an autoclave. 

Contaminated material may be disposed in paper or cardboard wrappers and incinerated. Autoclave the glassware that has been contaminated. Having autoclaved, wash and prepare in the usual way.

There are many lab techniques to examine and characterize microbes, but we’ve identified five basic ones that start with the letter “I” to make them easier to remember.

The five I’s of microbiology lab techniques:
  • Inspection
  • Identification
  • Inoculation
  • Incubation
  • Isolation

1. Inspection

Inspection is also known as observation, where you look at the microorganism through a microscope, as microorganisms are too small to be seen with the unaided eye.

2. Identification

Identification is the classifying of one microorganism as different than another. There are many ways to identify them, such as their color, shape, size, and smell.

3. Inoculation

Inoculation is introducing microorganisms, such as bacteria, in a culture medium. Vaccines are also known as inoculation, as they introduce antigens into the body to stimulate a response from the immune system.

4. Incubation

Incubation is an essential microbiology lab technique. It often takes days or weeks, but one of the great things about microbiology laboratory is you don’t have to wait that length of time

5. Isolation

There are many ways to separate strains to be isolated from each other. There are two main ways to isolate bacteria: streaking on an agar plate and the pour plate method.

Isolators In Pharma Industry

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