3 Tips on Testing for Fungal Control in Cleanrooms

There is a lot to consider when taking action to control fungus in a controlled environment. Make sure you know these three tips.

Recently, we posted about controlling fungus in cleanrooms.  This is a tricky subject because it depends on the form of fungus, the surface type, and environment specific to your controlled environment. We ended the series with suggestions on the kinds of test you should perform. Here is some additional information to help with that process.

Suspension tests:

It is worth noting that there are many published methods to determine fungal activity in suspension or carrier tests. You can find general test procedures to use for fungicidal activity testing in the BS EN methods (1650 and 13697) established by the European Committee for Standardization and the AOAC. However, these methods are specifically used by disinfectant manufacturers to register a product for sale. Therefore certain methods won’t be applicable or necessary to cleanroom disinfectants. Know that you can make reasonable modifications so long as they are scientifically sound.

Which fungus to test:

Wondering which fungus to use as a test microbe, like yeast or mold? Generally, you want to use fungal spore suspensions of both reference cultures and environmental isolates. Consider this example:

The AOAC fungicidal test uses Trichophyton mentagrophytes as a reference organism. This doesn’t present as great a challenge to the disinfectants as does A. niger, so it is rather misleading. It is also not as common in pharmaceutical, biotech, and medical device cleanrooms. Consequently, the procedure should include A. niger and C. albicans as reference cultures.

Your disinfectant effectiveness testing should also include the specific environmental isolates most frequently found in the facility.

A couple extra notes about preparing suspension tests:

Prepare yeast suspensions from yeast propagated on media that results in rapid growth and smooth colonies. Remember that mature mold cultures are more resistant to fungicides than are yeast cultures. Prepare molds for validation testing as conidia suspensions with hyphal fragments removed. The conidia presents the greatest disinfection challenges.

Ensure that your tests are carried out thoroughly and carefully. Document everything and make sure you are current on validation and certification. If you need your cleanroom validated or certified, contact Gerbig Engineering Company at 888-628-0056 or info@gerbig.com. Our 30 years of experience make us experts who care about your business.

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