Sterilization control:
· Bacterial spores: The
spore of Bacillus stearothermophilus
is used as biological
indicator is often autoclaved along with other material. After autoclaving, the
ampule is broken and the culture incubated. If the test bacterium grows in the
medium, which indicates sterilization not successful.
· Chemical indicators: Such
as pellets of sulphur in test tube or Browne's sterilizer control tubes may be
used. At 120°C
sulphur pellet gets melted red solution of Browne's tube turns red to green, it
indicates device reach the desired temperature.
· Thermocouple: It is a test article and the attached
wire outside the chamber door it connects with a potentiometer to record the
temperature directly.
Hot air oven
The instruments sterilize the
specimens and articles worked on the basis of dry heat sterilization. The materials like glasswares
forceps, scalps, scissors, throat swabs, syringes and also sterilize the fats,
oils, powder etc., which are impermeable to moisture. It works in extremely
high temperatures for adequate time to destroy microorganisms and bacterial
spores. The commonly-used temperatures and time that hot air ovens need to
sterilize materials is 170 degrees Celsius for 30 minutes, 160 degrees Celsius
for 60 minutes, and 150 degrees Celsius for 150 minutes.
The device are heated by means of
electricity, and equipped with the thermostat that controls the temperature and
the fan for the circulation of hot air inside the oven. The device has the
digital panel to control or monitor the temperature of the device. The
device is consisting of double-walled glass wool insulation that helps
to keep energy to maintain the level of heat inside the cabinet whereas the
outer layer is of metal. This device used in pharmaceutical industries to
sterilize the medical tools and instrument, inside which consist of stainless
steel double walled chamber. The hot
air oven cabinet should not be overloaded and oven should equip with the fan to
distribute the hot air eventually. After sterilization, device should be cooled
before open the doors otherwise it makes the cracks on the sterilized
glasswares.
