Biological Indicators

Biological Indicators (BIs) are a safety verification technique required to be used in compounding pharmacies around the world. They contain microbes that are typically very resistant to death-by-autoclave. They are used by lab techs verify that their equipment is operating as expected. You would put the BI into the autoclave and run it at the desired settings. After it’s finished you incubate the BI, and it will change colors if your autoclave did not successfully kill off the microbes inside.

It would be really cool to have access to these for our home labs, especially those of us using pressure cooker autoclaves. Unfortunately we’ve only been able to find them to be purchased in bulk, and they’re not cheap.

This will remain a “wishlist” item for now.

Indicator Strips

There is an alternative to biological indicators called “indicator strips” and these are much more readily available at consumer pricing. The difference is that they aren’t using actual microbes to indicate if sterilization was effective, they are instead measuring steam/heat/pressure all to certain thresholds. This is mostly adequate if your autoclave is using standard parameters. However, if you’re using something like a pressure cooker then your standard heat and pressure parameters might not get met, and instead made up for by increasing time. While this is a valid method of sterilization these strips won’t trigger as you won’t meet their parameters.

If you purchased an autoclave off ebay or something though, then these indicator strips would work great for you.