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
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3. Biosafety cabinet
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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.
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5. contd…
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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…
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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
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 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
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9. Incubator
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 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. 370C.
 Monitor the incubator for temperature stability
for 24 hours.
 Now keep the plate/ rack inside incubator.

10. MAINTENANCE
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 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
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12. Refrigerator
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 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…
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 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
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15. Deep freeze
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 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…
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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…
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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
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19. Hot air oven
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 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…
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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
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22. Centrifuge
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 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.

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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
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25. Microscope
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 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.

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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.