Procedure for autoclave validation

Title : Procedure for autoclave validation
Quality Control-Microbiology
  •          To lay down a procedure for autoclave validation.
    • This SOP is applicable for autoclave validation in microbiology laboratory .
    • Officer / Executive-QC – responsible for Implementation of SOP.
    • Manager – Quality Control
    • Method-A:
  •          Clean and load the autoclave for sterilization with accessories and glassware’s.
  •          Prepare the required number of (10ml) tubes of Soya bean casein digest medium.
  •         Take require nos. of strips of spores of Geobacillus stearothermophilus ATCC 7953.
  •          Put in petriplates and    label it, arrange the petiplates at different location no.
  •          Keep one strip unexposed for positive control.
  •         Run the cycle at 15 lbs. pressure and 121o C temperature for 15 min.
  •         After completion of cycle remove all tubes and Petri dishes.
  •         Mark location no.,date on all the SCDM  tube .
  •          Transfer strips aseptically to respective labelled tubes.
  •          Transfer one unexposed strip to one SCDM tube and label it as positive control.
  •          Keep one SCDM tube uninoculated and label it as negative control.
  •         Incubate all the tubes at 55o C ±2o C for 7days
  •          At the end of 7 days all the the inoculated SCDM tubes should show no growth.
  •          Negative control tube should show no growth.
  •         Positive control tube should show growth with in 72 hrs.
  •        The above observations will demonstrate satisfactory validation of the autoclave.
  •        Record the observation in Format-I.
  •   Method-B
  •        Validation is done by the bioindicator system consists of ampoule containing spores of    Geobacillus stearothermophillus ATCC 7953.
  •       These ampoules are stored under refrigerator when not in use. On the day of validation
  •        Take three ampoules and allow them to come at room temperature.
  •        Load the autoclave and place the ampoule in different locations in autoclave within glass beakers to avoid accidental breakage of ampoule during sterilization.
  •        Run the sterilization cycle as per procedure. (validated sterilization condition 121°C for 15 min  at 15 PSI.)
  •       Unload the chamber and remove the ampoule, mark them and incubate at 55°C ±2°C for     48 hour.
  •       The third non sterile unexposed ampoule is incubated along with the sterilized ampoule as a Positive control.
  •        At the end of 48 hour days.
  •        Positive control – Original purple colour gradually changes to deep yellow with turbidity.
  •        Exposed ampoule – The Original purple colour remains as it is at the end of incubation period.
  •       The above observations will demonstrate satisfactory validation of the autoclave.
  •       Record the result in Format-I


  •   SOP      –  Standard operating procedure
  • IPA       –  Iso Propyl Alcohol
  •   SCDM     – Soybean Casein Digest Medium
  •     FORMAT
Sr. No. Title  Format No.
Log sheet for Autoclave validation Record
Log Sheet for Sterilization load no.
Sr. No. Copy No. Department
Quality Assurance
Quality Control-Microbiology
V.P.- Plant & Operations


                                                      Format -I

  • Equipment Detail:
Name of Equipment Vertical Autoclave
Equipment ID No


  •  Detail of Test:
Sr.No Description Detail
Temperature/pressure to be achieved 121°C/15lbs
Biological indicator used  Strip/Ampoule
Name of the test organism Bacillus stearothermophilus ATCC-7953
Total population of strip/Ampoule
D value.
Media to be use Soybean Casein Digest broth
Incubation temperature 55°C  to 60°C
Duration of Incubation


  •  Details of Validation:
Details of last Validation:
Validation On
Validation Due on
Report No.
Detail of current Validation:
Date of Validation
Validation Due on
Report No.


  • Details of Observation:
Sr.No Parameters Observation Observed by
Temperature/Pressure achieved
Name of the test organism
Media used
Incubation temperature
Duration of Incubation
Lot number of Strip/Ampoule
Manufacturer of strip/Ampoule


  •  Acceptance Criteria:

There should not be any growth in form of turbidity in any of the tubes except Positive control.

  •  Corrective action if observation does not meets the requirements:
               Corrective action taken:
               Observation after corrective action:



  •  Conclusion:


  •  Approval:


Sr. No    Location Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Remark
Negative Control
Positive Control
Observed by


  •                                  Format -II

       Log Book of Sterilization(Autoclave) Load Number  

Instrument I.D.: ______________________ 

Sr.No. Date Name of Sample      Load Number Done by Checked by Remark