We explain what biofilm actually is, why standard flushing often fails to solve the problem and when professional microbiological control of the system becomes necessary.
What exactly is biofilm?
Biofilm is a complex biological structure formed by microorganisms that settle on the internal surfaces of water systems, process systems and surfaces in contact with water or the production environment.
It is not just a patch of dirt or a loose deposit.
Biofilm forms an active protective layer that, over time, adheres to pipes, tanks, valves, drinking-water systems, processing lines and hard-to-reach parts of the infrastructure.
Biofilm can harbour, among other things:
- bacteria,
- fungi,
- yeast,
- environmental microorganisms,
- pathogens responsible for secondary contamination,
- organic and mineral deposits that support the growth of microflora.
The problem is that biofilm very often develops out of sight. The system may look fine from the outside and the incoming water may meet basic quality requirements – yet active microbiological hazards can persist inside the system.
Why is biofilm so difficult to remove?
Biofilm acts as a biological protective shield. Microorganisms within its structure are far less susceptible to standard disinfectants and short-term cleaning processes.
The greatest difficulties arise from the fact that biofilm:
- adheres strongly to system surfaces,
- protects microorganisms against chemical agents,
- can re-form after ineffective cleaning,
- develops in hard-to-reach places,
- often remains invisible until quality or sanitary problems appear.
In practice, this means that one-off disinfection or standard flushing often removes only some of the contamination, leaving an active source of the problem inside the system.
Simple flushing only works on the surface
Flushing a system with water can remove loose deposits, fragments of dirt and some of the microorganisms present in the flow. However, this does not mean that the system becomes microbiologically safe.
What does flushing usually achieve?
- removes some loose debris,
- temporarily improves the system's appearance,
- reduces some mechanical contamination,
- gives a quick but short-lived result.
What does it fail to solve?
- does not remove the biofilm structure,
- does not eliminate the source of secondary contamination,
- does not effectively reach every point in the system,
- does not ensure stable microbiological control,
- does not prevent the problem from quickly recurring.
This is why many systems operate for long periods at increased microbiological risk, despite regular flushing or periodic disinfection.
Where does biofilm most commonly form?
Biofilm can develop practically anywhere there is:
- water,
- moisture,
- a flowing medium,
- organic deposits,
- areas that make thorough cleaning of the system difficult.
The problem most often affects:
- drinking-water systems,
- water systems,
- processing lines,
- CIP systems,
- tanks,
- cold stores and cooling systems,
- industrial installations,
- production surfaces,
- ventilation and HVAC systems.
Biofilm can develop in livestock production, food processing, pharmaceuticals and logistics, as well as in modern industrial installations.
How can biofilm be effectively controlled?
Effective biofilm control requires a systemic approach.
It is not just about one-off disinfection, but about a process that includes:
- risk analysis,
- identifying the source of the problem,
- selecting the right technology,
- effective biofilm elimination,
- maintaining stable microbiological conditions in the system.
Modern sanitisation and disinfection processes use technologies that make it possible to:
- penetrate the biofilm structure,
- limit its regrowth,
- reach hard-to-reach spaces,
- stabilise the microbiological safety of the entire system.
Key takeaways
Clean water at the inlet does not guarantee a safe system.
In many cases, the interior of the system itself becomes the source of recurring microbiological problems.
Biofilm:
- develops inside the system,
- protects microorganisms against disinfection,
- may cause secondary contamination,
- affects process safety,
- requires a professional approach to microbiological control.
Summary
Biofilm is one of the most frequently underestimated microbiological hazards in water and process systems. It remains invisible, is difficult to remove and can undermine process safety for a long time.
Standard flushing often removes only surface contamination without addressing the actual source of the problem.
That is why effective microbiological control requires not only disinfection but, above all, an informed and systemic approach to system safety.
