he topic of disinfection with all its facets is playing an increasingly important role in the cleanroom industry in general, but especially in the pharmaceutical industry. Dealing with disinfection has gone from being an unloved side issue in production to an unloved important factor. More and more often, there are full-time hygiene officers in production facilities who are dedicated to the topic of disinfection and are undergoing further training in this area. The usual ‘never change a running disinfection regime’ is often impossible to maintain, especially in the era of the new Biocide Regulation, as disinfectants are withdrawn from the market or their effectiveness can no longer be proven because the tests have changed. In addition, the new Annex 1 of the EU GMP guidelines, in particular the requirement for a contamination control strategy, has significantly increased the importance of disinfection.