Equipment maintenance

For laboratory technicians

1. Equipment maintenance Dr. Hemali Parmar MBBS, M.D. Microbiology Tutor, Baroda Medical College, Gujarat

2. Equipments used in laboratory Biosafety cabinet Incubator Refrigerator Deep freeze Hot air oven Centrifuge Microscope 2

3. Biosafety cabinet 3

4. Biosafety cabinet This instrument is used to work for Sample Inoculation, Antibiotic Sensitivity Testing and Smear Preparation under sterile environment START UP : The inner surface (both horizontal & vertical) of cabinet is cleaned & disinfected with 70% Alcohol solution. Then, the shutter is closed. The U.V. light is switched on for ½ hr. The airflow is switched on for 10 min. before starting the work. The U.V. light is switched off and the simple light is switched on before starting the work. Then the shutter is opened. 4

5. contd … 5 Procedure All materials & equipments required to carry out the work are collected & checked before starting the work. : The discarding beaker containing freshly prepared 1% Sod. Hypochlorite with lid is placed inside BSC before starting the work. Only necessary items that are required for the laboratory work to be carried out are kept inside the cabinet, & no material is kept on the air holes, so that airflow of the BSC Class - II is not obstructed. It is checked that the front & the back grills are not blocked at any time during the work. Gloves, masks & cap are worn before starting the work. While working in the cabinet, the used material is discarded in the discarding beaker containing 1% Sod. Hypochlorite. The discarding container is covered properly with aluminum foil & then autoclaved. The cabinet is cleaned with 70% alcohol solution after every working session.

6. Contd … 6 SHUT DOWN : The inner surface of the cabinet is cleaned and decontaminated with alcohol or spirit solution. The shutter is then closed. The simple light & airflow are switched off. U.V. light is switched on for 10min. The U.V. (Ultraviolet) light is then switched off.

7. MAINTENANCE SCHEDULE 7 Proper cleaning of BSC is done regularly before starting the work and completing the work. Direct exposure to U.V. light is avoided. All precautions are taken to avoid cross contamination while working in the hood. Toxic, explosive or flammable substances are not used in this cabinet. The sterility is checked every fortnightly using BHI/ NA agar plates.

8. Incubator 8

9. Incubator 9 This instrument is designed to create stable, reliable environment for incubation of inoculated culture plates and biochemical tests. PROCEDURE: For the first time, switch on the mains supply and allow it to warm up to the required temperature i.e. 37 C. Monitor the incubator for temperature stability for 24 hours. Now keep the plate/ rack inside incubator.

10. MAINTENANCE 10 Place the equipment on flat surface away from direct sunlight. Clean exterior of incubator daily with a clean wet mop. Clean the interior of the incubator once a week using sterile cotton or gauze soaked in 70% Alcohol or 0.1% Sodium hypochlorite solution. Allow the interior to dry completely. Temperature of the incubator is to be recorded daily with a calibrated thermometer. Temperature chart should be maintained. Record the temperature of incubator in the morning in the temperature-monitoring sheet on the incubator by the first person who opens it. At the end of month the temperature record sheet is filed in File No D-21 Temperature record file. Any operating problem should be recorded and to be brought in notice of the Section officer concerned. Service person should be informed regarding the problem as soon as possible to solve the problem.

11. Refrigerator 11

12. Refrigerator 12 It is used to store samples, Antibiotic sensitivity discs and culture plates in follow up & reagents. Maintenance Place the equipment on flat surface away from direct sunlight. Refrigerator must be placed in such place where sufficient air can circulate to facilitate heat exchange of compressor. Always close the refrigerator door to prevent warm air from outside to enter cool chamber. Do not store eatables in refrigerator. Record the temperature of refrigerator in the morning in the temperature-monitoring sheet on the refrigerator, by the first person who opens it. Similarly record the temperature of refrigerator in the evening. Temperature should not exceed 08°C.

13. Contd … 13 Clean the cool chamber with freshly prepared 70% alcohol/ 0.1% Sodium hypochlorite once every fortnightly and wipe with sterile cloth after defrosting properly. Clean refrigerator from outside daily with a clean wet mop. Keep the compressor dust free. Clean door gasket. Record the temperature and cleaning in File No D-21 SAFETY CONDITION: Check for leakage or exhaust of gas and if found inform the Section in-charge and workshop immediately. For any problem in the refrigerator the officer in- charge must be informed immediately. Service person should be informed regarding the problem as soon as possible to solve the problem.

14. Deep freeze 14

15. Deep freeze 15 Deep freeze is used to store Antibiotic discs & sometimes stock culture. Operation: The Deep freeze is switched on. Adjustment of the required temperature i.e. -20  C is done. After the required temperature is attained, the necessary materials are put inside the deep freeze.

16. Contd … 16 Maintenance: Temperature of the deep freeze is daily recorded in the morning in the temperature monitoring sheet which is pasted on the incubator. Temperature should not exceed ­20 0C. One temperature sheet includes charts for 1 month temperature record. At the end of 1 month, the temperature record sheet is filed in File No.-BF6 ‘Temperature monitoring file’. Defrosting is done once a month. The cool chamber is cleaned with 70% Alcohol and wiped with clean cloth after defrosting properly. While defrosting, contents are kept in freezer compartments of refrigerator No.1 & 2. The deep freeze is cleaned from outside (at least once a month).

17. Contd … 17 Safety precautions: Disconnect unit from main power before attempting any maintenance to equipment or control. Do not keep the door opened for longer period of time. Check for leakage or exhaust of gas and if found inform the Section in charge and workshop immediately. Do not use metal or sharp scrapers to scrape off frost. Do not open the lid of the freezer unnecessarily or frequently. Any operating problem should be recorded and to be brought in notice of the laboratory In-charge.

18. Hot air oven 18

19. Hot air oven 19 This instrument is designed to sterilize the test tubes, or to dry the media plates before inoculation. Procedure: Switch on the mains supply and allow it to warm up to the required temperature. Start using the hot air oven after the temperature has reached the required temperature. Keep the plates/ rack inside incubator after the temperature has reached the required temperature and is maintained for 30 minutes.

20. Contd … 20 Maintenance: Place the equipment on flat surface away from direct sunlight. Clean exterior of hot air oven daily. Clean the interior of the instrument once a week using sterile cotton or gauze soaked in 70% Alcohol or 1% Sodium hypochlorite solution. Allow the interior to dry completely. Temperature of the instrument is to be recorded daily, whenever put in use, with a calibrated thermometer. Temperature chart should be maintained. At the end of month the temperature record sheet is filed in File No D-21 Any operating problem should be recorded and to be brought in notice of the Section officer concerned. Service person should be informed regarding the problem as soon as possible to solve the problem.

21. Centrifuge 21

22. Centrifuge 22 This is used for centrifugation of body fluids except for sputum. Procedure: It should be placed on flat and non slippery surface, to prevent moving away from place when in use. Its load should be balanced always, for balance dummy tube filled with equal quantity water can be placed on opposite side. Cover it with lid before using it. Turn speed control slowly up and down. Maintenance: Switch off immediately if makes abnormal noise. After use invert buckets to drain dry. After any spillage, wipe and disinfect immediately with freshly prepared (within 8 hrs.) 0.5% Sodium hypochlorite. Clean it daily. Check for brushes and bearing every 3 monthly.

23. Contd … 23 Safety precautions: Do not use without balance on opposite side Do not stop it manually. Do not use without plugging the test tube mouth. Speed should not be raised rapidly. Switch off immediately if there is breakage of tube. For any problem in the centrifuge the officer in- charge must be informed immediately. Service person should be informed regarding the problem as soon as possible to solve the problem.

24. Microscope 24

25. Microscope 25 This instrument is designed to visualize the microorganisms that one can not see with naked eye in different clinical samples as well as slides prepared from culture positive colonies. Procedure: Switch on the mains supply and then switch on the supply from base of the microscope. Adjust the objective and condenser as per requirement and place the slide on the stage. Make coarse and fine adjustment to focus the slide. After the work is over switch off the electric supply first on base and then from the mains.

26. Contd … 26 Maintenance: Place the equipment on flat surface away from direct sunlight. Keep the Microscope covered when not in use. Clean the objective lens with soft cotton cloth or tissue paper after use. Do not clean the lens with alcohol or xylene as it may damage the cement. Any operating problem should be recorded and to be brought in notice of the Section officer concerned. Service person should be informed regarding the problem as soon as possible to solve the problem.