Biofilms pose a serious food safety threat due to their ability to harbour pathogens and form on various surfaces in food manufacturing facilities. A biofilm protects microorganisms from chemicals and environmental stress, enabling their long-term survival and spread. Effective prevention and removal require suitable tools and cleaning methods.
According to the CDC, each year 48 million people get sick from foodborne illnesses in the U.S., with 128,000 hospitalised and about 3,000 deaths. Listeria monocytogenes and Salmonella—along with Shiga-toxin producing E. coli, Campylobacter jejuni, and Staphylococcus aureus—are key causative agents. Listeria and Salmonella account for over 40% of major FDA food recalls. All listed pathogens can thrive in biofilms.
Biofilms consist of three key elements: microorganisms, nutrients, and water. If left undisturbed, microbes secrete extracellular polymeric substance (EPS) or “slime”, composed of polysaccharides, nucleic acids, and glycoproteins. This coating protects microbes and anchors them to surfaces. Biofilms can be up to 3,000 times more resistant to disinfectants than free-floating cells, and can survive with limited nutrients and oxygen, in adverse conditions. They enable colonisation, contamination of surfaces and food, and spread via air, moisture, and human contact.
Ongoing research shows microorganisms in biofilms communicate through “quorum-sensing” to group, share resources, and provide cross-protection.
Prevention
Biofilm control begins with prevention and consistent sanitation of food facilities. Strategies to mitigate biofilm risk include:
Regulatory and standard guidance:
- Codex Food Hygiene: Basic Texts (4th ed.) recommends designing facilities and equipment to prevent harborage sites and ensuring proper cleaning/sanitising protocols.
• The Draft Guidance on Control of Listeria monocytogenes in RTE foods stresses the need to select and rotate sanitisers (e.g., quaternary ammonium, peroxyacetic acid, iodine, chlorine).
• FSIS Best Practices Guidance (2015) suggests alternating sanitisers (e.g., quats and sodium hypochlorite) and scrubbing surfaces.
• 3A-SSI Standards state that food-contact parts not suited for CIP should be manually cleaned using tools like brushes, scrapers, and squeegees.
Facilities must clean hard-to-reach and visible surfaces regularly. Risk-based hygienic zoning—such as using colour-coded tools and separating raw meat from ready-to-eat areas—prevents contamination. For example, yellow brushes for food contact surfaces and black for drains.
Biofilm removal – six-stage manual cleaning approach
Moorman and Jaykus (2019) emphasise: “one just can’t sanitise one’s way out of a persistent biofilm problem.” Eradication requires equipment teardown, deep cleaning, sanitisation, and follow-up verification.
(a) Assess your TACTER parameters
Adapted from Dr Herbert Sinner’s TACT model and expanded by Vikan:
- Use proper tools and protective clothing
• Trained personnel ensure effective cleaning
• Heat above 122°F may help but can denature proteins
• Detergents/disinfectants need adequate time to work
• Mechanical agitation helps remove soil
• Products work best at optimal pH/concentration
(b) Develop a robust cleaning and sanitisation programme
Use Vikan’s Double SAVER model:
- What type of Surface is being decontaminated?
- What is the nature of the Soil being removed or reduced to an acceptable level?
- What is the Aim of the decontamination action?
- What level of procedural decontamination Activity is being implemented?
- Is the decontamination process well Validated?
- Is the decontamination process adequately Verified?
- How Effective is the decontamination process?
- How Efficient is the decontamination activity?
- Are the processes supported by valid scientific, technical, or credible References?
- Are Remedies in place to correct or prevent anything significant that could go wrong?
(c) Have a risk-based cleaning schedule
Plan routine sanitisation of all facility elements—areas, equipment, tools—to prevent biofilms.
(d) Ensure cleaning steps are clear
- Secure/disassemble/dry-clean
- Pre-rinse top to bottom
- Apply detergent and scrub bottom to top
- Post-rinse and self-inspect
- Conduct QC post-sanitation inspection
- Sanitise and reassemble
- Dry and verify in pre-op inspection
(e) Create a manual cleaning plan & select right tools
Use hygienically designed tools—e.g., Vikan Ultra-Safe brushes, handles, squeegees, and scrapers—to clean nooks and crannies.
(f) Follow tool cleaning & maintenance protocols
Tools must be sanitised before/after use. A UK study (Campden BRI) found 47% of cleaning tools in food facilities tested positive for L. monocytogenes. Tools must be easy to clean, regularly inspected, and replaced when worn or damaged.
