SOP for Cleaning of Microbiological Glassware with Chromic Acid Mixture

1.0 OBJECTIVE

To lay down the procedure for Cleaning, disinfecting and sterilizing glassware used in the microbiology laboratory. If the equipment used in microbiology is not cleaned properly, the microbiological results may get affected due to contamination; it may also be dangerous to the persons handling the infected equipment and risk of infection due to potential hazards of pathogenic cultures will be very high.

2.0 SCOPE

This SOP shall be applicable to Microbiological Section of Quality Control Dept.

3.0 RESPONSIBILITY

Microbiologist

4.0 ACCOUNTABILITY

Sr. Manager Quality Assurance

5.0 PROCEDURE

5.1 Keep all the glassware, used in microbiology, in the cabinet provided for the same.
5.2 Do not use this glassware in the chemical laboratory.
5.3 Whenever glassware is used for microbiological analysis, dispose the inoculated media, at the end of the incubation period, as per the procedure described in SOP for disposal of media.
5.4 After disposal of the media, dip all the infected glassware in 3% v/v Dettol solution for 30 minutes.
5.5 Rinse with water and dip it in a 3% v/v solution of teepol for one hour.
5.6 Remove the glassware from the teepol solution and brush all the glassware.
5.7 Rinse the glassware continuously with running tap water till there are no traces of teepol solution left and, finally, rinse with purified water.
5.8 After washing, dry all the glassware in an oven at 120ºC for 60 mins.
5.9 Keep the pipettes and Petri dishes in their respective stainless steel containers.
5.10 Sterilize the glassware by autoclaving at 15 lbs pressure (121ºC) for 15 minutes.
5.11 Once in a month, dip the glassware, in the chromic acid mixture, overnight.
5.11.1 While handling chromic acid mixture, use safety goggles and rubber gloves, remove the glassware carefully from the chromic acid mixture.
5.11.2 Rinse the glassware thoroughly with tap water, as the glass tends to absorb chromic acid, and finally, rinse with purified water.
5.11.3 Check the pH of the final rinse by means of a pH paper to confirm the absence of traces of cleaning agent.

5.11.4 Preparation of Chromic Acid Mixture

The chromic acid mixture is prepared by dissolving 200 gms of Sodium dichromate in 100 ml of distilled water. Cool the solution in an ice bath and add slowly, with stirring, 1500 ml of concentrated sulphuric acid. The mixture is prepared in a hard, borosilicate glass beaker and safety goggles must be worn during the addition of acid. The mixture is extremely corrosive and is stored in a glass-stoppered bottle in a safe place. When the mixture acquires a green color, it is discarded in a continuous flow of water.
Related: SOP for Cleaning of Glassware for Microbiology

6.0 ABBREVIATION

6.1 SOP: Standard Operating Procedure

Get editable documentsView List