Effective Date: 
Wed, 06/01/2005
Wed, 08/17/2011
Mon, 03/19/2018

Test: In-house sterility testing for Autoclaves

Sterility Spore Test ampules
Ritter M11 UltraClave
Pelton and Crane Delta
Precision Water Bath Model 181


Sterility Spore Test ampules are intended for use in the monitoring of saturated steam sterilization cycles at 121ºC. Each ampule contains a spore suspension of Geobacillus stearothermophilus (ATCC #7953) within a growth medium also containing Bromocresol Purple to function as a pH indicator. The acid production associated with growth causes a change in color from purple to yellow.

Frequency of Testing: For greatest control of sterilized goods, it is recommended by the manufacturer to include sterility spore test ampules weekly.

Precautions: CAUTION: Contents of the ampule are hot and under pressure. Failure to allow sufficient cooling time (10-15 minutes) may result in bursting of the ampule. Do not use damaged ampules. Do not use after expiration date. Sterility spore test  ampules should be handled with care since they contain live cultures.

Disposal: All ampules (glass) should be disposed of in a sharps container.

Procedure: Autoclave Operator

1. Autoclave operator will include one sterility spore test ampule in different area of material being sterilized. Place ampule in the most difficult area to be sterilized.

2.  Label ampule with autoclave tape. Write the following on the tape:

  • Ritter 1 (SDC) or Ritter 2 (2nd Floor)
  • Date of spore test
  • Operator initials

3.  Document on "Autoclave Monthly Activity Log", HC: 899:  Operator's initials, date/time in,  Spore Test done

4. Sterilize according to normal procedure.

5. After autoclave is finished, remove test ampule(s) after cooling. CAUTION: Contents of the ampule are hot and under pressure. Failure to allow sufficient cooling time (10-15 minutes) may result in bursting of the ampule.

6. Return sterilized ampule(s) to laboratory.

Procedure: Laboratory

1. Place a label on processed ampule(s).

2. Place labeled ampule(s) in a vertical position in a separate container or cup into the water bath (55 - 58º C).

3. Place a non-autoclaved ampule in container with processed ampule(s). Label non-autoclaved ampule as “Control” and incubate for 48 hours (Control is an indicator of spore viability).

4. Examine processed and control ampules daily during incubation. Record observation and water bath temperature daily.

5. A failed sterilization cycle is indicated by turbidity and/or a change in color to or toward yellow. A test ampule that retains its purple color indicates an adequate sterilization cycle.

6. After 48 hour incubation, dispose of all ampules in a sharps container.

7. Negative results: The laboratory result slip is returned to Autoclave Operator, indicating “Negative X 48 hours".

8. Positive results: Lab will make stat call to the Charge Nurse indicating that autoclave spore test was “Positive at (24 or 48) hours: please repeat test, sterility not ensured." The Charge Nurse notifies a manager.  The laboratory result slip is returned to Autoclave Operator with same information.

  • Nursing staff, upon receiving positive results, will:
    • Consult "Autoclave Monthly Activity" log to identify any equipment/instruments autoclaved since the previous negative spore test run.
    • Arrange for any equipment/instruments processed in the interim to be removed from use and reprocessed.
    • Compete and submit an Incident Report via the RLS system

Quality Control: A non-autoclaved ampule is included with incubation of autoclaved ampules to ensure spore viability.

Reference: Product insert located in the Student Health Center Lab.