Biofilm – Constant source of microorganisms & potentially pathogens

What is Biofilm?

Biofilms are complex communities of microorganisms that adhere to surfaces and are surrounded by a matrix of extracellular polymeric substances (EPS). EPS plays a crucial role in the formation, stability, and protection of biofilms.

Depending on the environmental condition, biofilm can be made up of Listeria monocytogenes, Bacillus cereus and mycoïdes, Salmonella spp., Campylobacter, Pseudomonas aeruginosa, Leuconostoc or Cronobacter (Enterobacter sakazakii) building the biofilm matrix (organic polymers, polysaccharides, proteins, DNA, lipids etc.) and other (pathogen) microorganisms, phages, spoiling enzymes, spores, molds and yeast which are living inside the matrix.

Thanks to this structure, biofilms way more resistant to biocidal substances compared to the same bacteria in a liquid medium. This complex construction ensures survival even in extreme conditions.

The 3 Stages of Biofilm

1. Adhesion/Attachment

In this stage, individual microorganisms first come into contact with a surface and start to adhere to it. This initial attachment is reversible and weak. The microorganisms may use flagella, pili, or other appendages to facilitate attachment. As more microorganisms accumulate and attach to the surface, they begin to produce extracellular polymeric substances (EPS), which form a protective matrix around the biofilm.

2. Accumulation/Maturation

As the biofilm continues to develop, microorganisms within the biofilm community start to grow and multiply. The EPS matrix becomes more extensive and complex, providing structural stability to the biofilm. The microorganisms within the biofilm community start to communicate through a process called quorum sensing, where they release signaling molecules to coordinate their behavior. This communication helps regulate gene expression, leading to the formation of specialized microenvironments within the biofilm. The biofilm becomes highly resistant to antimicrobial agents and the host immune response during this stage.

3. Dispersion

The dispersal stage, where microorganisms within the biofilm detach from the biofilm, can roughly be classified in active and passive dispersal. Passive dispersal occurs when parts of the biofilm naturally slough off due to physical forces or environmental conditions. In the active dispersal stage, some microorganisms within the biofilm undergo physiological changes and initiate the process of detachment from the biofilm. It involves the production of enzymes and surfactants that help release individual microorganisms or clusters of cells from the biofilm. Once dispersed, microorganisms can go on to colonize new surfaces and initiate the formation of new biofilms.

The ability of biofilms to undergo dispersal is an important survival strategy for the microorganisms within the biofilm. It allows them to colonize new environments or escape from unfavorable conditions. So, biofilm is a constant source of contamination due to the unpredictable release of microorganisms.

Biofilm in food industry

The economic losses caused by biofilm are huge. 47% of the food recalls are linked to biofilm, 1.3 billion tons of food go to the waste because of contamination and the average direct financial impact (re-ship and lost sales) amount to 30 million Euros. In the US every week 30 recalls arise, whereby 27% are because of undeclared allergens, 27% because of salmonella, 10% caused by Listeria, 10% caused by undeclared substances and 26% because of other reasons. [1, 2, 3]

So, biofilm represents an important issue for food industries, as it has a direct impact on food safety and suitability.

Biofilm also have an impact on plant installations: it can cause resistance to the flow of fluids in the pipes and CIP, by increasing the roughness of surfaces. The slime formation reduces thermal performance in heat exchangers. Gas and odor development can also appear.

Biofilm also corrodes metal surfaces, which can lead to released microparticles and alloying elements.

Biofilm in water system

Biofilms grow easily in plant water systems, as they contain many ramifications and are difficult to clean, making it easier for the biofilm to attach itself to the wet surfaces of the water distribution system. In such circumstances, bacteria affect water quality and can also cause corrosion. To prevent their development, drinking water is treated and its quality should be monitored.

Kersia offers solutions for removing existing biofilms by applying specific enzymatic products which hydrolyze the matrix protecting the biofilm, breaking down organic materials and dissolving mineral soil and polysaccharides.

Biofilm on Farms

Biofilms can be found in various places on farms, as they can develop on a wide range of surfaces where water, nutrients, and microorganisms are present. Some common places where biofilms can be found on farms include:

  • Water Systems: Biofilms often form in water distribution systems, such as irrigation pipes, hoses, and tanks, where water flow is slow or stagnant.
  • Livestock Facilities: Biofilms can develop on surfaces within animal housing, such as feeding troughs, waterers, and walls, where organic materials provide a nutrient source for microbial growth.
  • Manure Handling Systems: Biofilms can form in manure storage areas, including pits, lagoons, and gutters, where organic matter from animal waste is present.
  • Silos and Storage Bins: Agricultural storage structures can also host biofilms on surfaces in contact with stored grains, feeds, or other organic materials.

Preventing biofilm formation is crucial to maintain animal health and productivity of the farm environment, and to avoid the introduction of (foodborne) pathogens in the food chain.

Properly remove Biofilm and control Biofilm Formation

Removing existing biofilm

Destroying biofilms typically requires a multifaceted approach, as the EPS can provide a protective barrier against chemical agents. There are several strategies and chemicals that can be employed to disrupt biofilms and degrade EPS.

1. First stage: Enzymatic degradation
Certain enzymes have shown to degrade the EPS components of biofilms. These enzymes break down the extracellular DNA and polysaccharides, destabilizing the biofilm structure.

2. Second stage: Application of a disinfectant with oxidizing agent
(such as peracetic acid) to eliminate all the contaminants.

Biofilm before treatment

1 • Enzymatic degradation

2 • Application of a Kersia disinfectant with oxidizing agent

Biofilm detection

Since the diversity of microorganisms in biofilm is very broad, the detection and even
localization is challenging.

Kersia offers audits for the detection of biofilms on the surface or in closed systems.

For closed systems, where detection is more complex: Kersia applies enzymatic products to dismantle extracellular polymeric substances responsible of the adhesion of biofilm and takes samples after the different stages for subsequent microbiological analysis. Depending on the needs of customers, the method of analysis is selected. From the total count to the identification of the micro-organism everything is possible.


[1] FDA-regulated, as reported by Swiss Re
[2] Organisation des Nations Unies pour l’alimentation et l’agriculture
[3] US Grocery Manufacturers report, Association survey of 36 international companies, 2011