Discover why biofilms are so difficult to remove in food processing environments. Learn how the biofilm matrix (EPS) protects bacteria from cleaning and sanitising.
Introduction
If biofilms were just clusters of bacteria stuck to a surface, they would be relatively easy to remove.
But they are not.
What makes biofilms so persistent — and so problematic — is a protective structure known as:
👉 EPS (Extracellular Polymeric Substance)
This matrix is the reason why biofilms can survive cleaning processes, resist sanitising chemicals, and continue to contaminate food processing environments.
What is EPS?
EPS is a complex mixture of substances produced by microorganisms once they attach to a surface.
It is often described as:
- Slime
- Glue
- A protective coating
But in reality, it is far more sophisticated.
EPS forms a three-dimensional matrix that:
- Holds microbial cells together
- Anchors them to surfaces
- Protects them from external threats
What is EPS Made Of?
EPS is not a single substance — it is a highly complex structure made up of multiple components, including:
- Polysaccharides (sugars and glycoproteins)
- Proteins
- Lipids
- Extracellular DNA (eDNA)
Each of these plays a specific role in strengthening the biofilm.
One of the most important — and often overlooked — components is:
👉 Extracellular DNA
Unlike DNA inside a cell, this DNA acts as a structural scaffold, helping to:
- Stabilise the biofilm
- Increase its mechanical strength
- Hold the entire matrix together
Research has shown that when this DNA is disrupted, the biofilm becomes significantly easier to break down.
A Protective Barrier — Not Just a Coating
EPS does not simply surround bacteria — it actively protects them.
This matrix:
- Limits the penetration of cleaning chemicals
- Reduces the effectiveness of disinfectants
- Shields bacteria from environmental stress
Inside a biofilm, bacteria are not exposed in the same way as free-floating cells.
Instead, they are embedded within a protective environment that allows them to survive conditions that would normally eliminate them.
Why Killing Bacteria is Not Enough
One of the most important concepts in biofilm control is this:
Killing bacteria does not necessarily remove the biofilm
If cleaning processes:
- Kill microorganisms
- But leave the EPS structure intact
Then the biofilm effectively remains in place.
A useful way to think about this is:
👉 It’s like removing people from a building… but leaving the building standing and the doors wide open.
New bacteria can quickly:
- Reattach
- Recolonise
- Rebuild the biofilm
This is one of the key reasons why contamination can reoccur — even after seemingly effective cleaning.
A Complex, Multi-Species System
Biofilms are rarely made up of a single type of microorganism.
Instead, they are multi-species communities, often including:
- Different bacteria
- Yeasts and fungi
- Other microorganisms
Within the EPS matrix, these organisms:
- Interact with each other
- Share resources
- Strengthen the overall structure
This complexity further increases resistance to cleaning and sanitising.
Why This Matters in Food Processing
In a food processing environment, EPS creates a significant challenge:
- Biofilms become difficult to detect
- Standard cleaning processes may not fully remove them
- Surfaces may appear clean while contamination persists
This leads to:
- Ongoing microbial risk
- Potential product contamination
- Repeated hygiene issues that are difficult to resolve
Key Takeaway
Biofilms are difficult to remove not just because of the bacteria they contain — but because of the protective matrix that surrounds them.
👉 If the matrix is not removed, the problem is not solved
What’s Next
In the next article, we explore a critical question:
👉 Why do biofilms keep coming back — even after thorough cleaning?
When evaluating your cleaning processes, it may be worth asking:
👉 Are we removing bacteria… or are we removing the biofilm structure itself?