Autoclave Sterilizers: Testing for Effectiveness March 07 2014

In our last blog entry, we reviewed autoclave safety in the workplace and how to avoid injury when operating an autoclave sterilizer.  In our next installment of Autoclave Sterilizer Safety, we will discuss Testing for Effectiveness. 

Midmark Ritter M11 Autoclave SterilizerOver time, autoclave sterilizers can suffer from a variety of maintenance related issues. These issues can be anything from a leaky chamber seal to a clogged steam valve, and all contribute to less-than-perfect autoclave functioning. These issues could create a reduction in pressure or chamber temperature, or insufficient steam generation, which can all cause your autoclave to not fully sterilize your equipment. 

As such, Autoclaves must be periodically maintained and tested.  Always keep in mind, you should follow the autoclave manufacturer’s suggestion and your state’s guidelines for Autoclave maintenance and testing.  Below is our quick list of simple steps which should help keep your autoclave in top shape.

  • Clean your sterilizer’s chamber regularly according to the manufacturer’s instructions. The cleaner the chamber is, the less chance you will have residue buildup that clogs the various valves and degrades the internal seals. 
  • Clean gaskets on your autoclave regularly with a mild detergent. 
  • Lubricate your autoclave door hinge and any other areas where metal on metal contact occurs. 
  • Clean your tray holder and any trays with a mild detergent. 
  • Clean the safety release valve and any other steam valves, following the manufacturer’s instructions.

Keeping on top of routine maintenance should prevent issues with sterilization effectiveness. However, you should still routinely test your sterilizer to make sure Propper PASS FAIL Sterilization Integrator for Sterilizers Autoclavesthat the sterilization cycle is hot enough and the internal pressure is correct.  This requires the usage of spore tests. Spores, such as B. Stearothermophilus, can survive temperatures up to 250 degrees for short periods of time, but a full autoclave cycle should kill them.  

There are two forms of spore testing to consider.  The first being “do it yourself”.  There are spore test kits available that allow the user to test the effectiveness of a Sterilizer by utilizing a test packet and an incubator.  Always follow the spore test manufacturer’s suggested use, but basic use consists of: 

  • Placing the spore tests in your regular sterilization loads.  
  • Incubating the spores for a period of time. 
  • Checking for growth of spore colonies. 

The other option is to participate in a mail-away autoclave test program.  There are may  companies that offer a routine testing service that includes:  

  • The user purchases a starter kit based on the frequency they will test their autoclave.  (ie. Daily, Weekly, Monthly, etc.)
  • The user places the spore test packet kit in a regular sterilization load
  • Once the cycle is complete, the spore test packet is mailed to the service company.
  • The company then incubates the packet and returns a pass/fail notice to the customer. 
In either case, if spore growth is evident, you should immediately discontinue use of your autoclave and call a repair center.  Always remember that a fully functioning autoclave sterilizer is crucial to reduce the risk of cross contamination.