Biofilms are everywhere
Well hidden or sometimes visible, always disgusting, biofilms, as so well described by my colleague Rémi Charlebois, are defined as follows:
Biofilm is an aggregation of microbial cells, surrounded by a protective layer of extracellular polymeric matrix, which attaches itself to any surface found in the hospital environment and becomes a source of contamination. Formation of complex, multicellular communities by microorganisms is a natural phenomenon which helps bacteria or fungi to survive environmental stress such as cleaning and disinfection.
Warning: Graphic Content Ahead
A Biofilm looks like this:
How to remove biofilms
Here are 3 methods to eliminate biofilm:
This mehode is somewhat drastic, probably very expensive certainly mostly impractical. Some industries still proceed that way in 2016. I must say that in some cases it may be the only and best solution. For example pipe sections, filters, etc.
Strong acids and bases
Hydrochloric or Peracetic acids or strong bases such as caustic are sometimes used alternatively. However, corrosivity and danger of these chemicals can damage surfaces, individual protection equipment, storage and handling can also be a challenge . Furthermore, there is always the workplace hazards.