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Chemicals / Infection Control

The Unseen Filth

September 12, 2012
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Although we often like to think that what we can't see can't hurt us, this is not always the case when it comes to cleaning.

In reality, many surfaces that seem clean can be teaming with microorganisms that have a natural tendency to form communities called biofilms.

Understanding biofilms, their origin and their abilities to become potentially harmful is important for maintaining a healthy building.

Once understood, a plan for controlling biofilms can be created in order to preserve your facility and protect your business.

Small But Mighty

Biofilm growth happens all around us every day — even when we can't see it.

From the plaque on unclean teeth to a slippery river rock to a floor drain in a grocery store, biofilms are present.

These communities of microorganisms quickly adhere to and contaminate surfaces, and then spread to new areas as the cells inside further disperse.

Given an environment in which to thrive, biofilms can even become visible to the naked eye.

Areas prone to biofilms are typically environments where moisture and soil are frequently in contact with a surface.

With bacteria present in water, biofilms naturally begin to form.

Drains, mop buckets, heating, ventilation and air conditioning (HVAC) systems, restrooms and kitchens are common areas prone to biofilm growth.

Within a biofilm, proteins, lipids, carbohydrates and nucleic acids are present.

Essentially, because its chemical structure is similar to soils, a biofilm can be thought of as just another type of soil that needs to be removed from a surface.

Numerous types of microorganisms also exist within the biofilm.

Although most are harmless, some are pathogens that have the ability to threaten the safety of individuals or food prepared near the contaminated surface.

For instance, Legionella bacteria may pose a problem for people working in buildings with water fountains or for people taking showers when systems are not well maintained.

Other pathogens that may be present in biofilms, such as Listeria and Escherichia coli (E. coli), pose a food safety risk.

Food contaminated by organisms that grew in biofilms not only has the potential to make customers sick, but can also have a reduced shelf life, damage company reputations and lead to a loss of sales.

A TACTic For Controlling Biofilms

In order to prevent biofilms from wreaking havoc on your facility, cleaning practices must be optimized.

Because biofilms form very quickly, cleaning should be done whenever surfaces appear soiled and at least every 24 hours — or more frequently.

For some surfaces, such as a food slicer in a deli, cleaning should occur every four hours.

The best solution for controlling biofilms is to focus on four variables during the cleaning process: Time, action, chemical and temperature (TACT).

Each can affect how much of a biofilm is removed.

• Time

Generally, the longer a cleaning chemical is exposed to a biofilm, the greater the response will be.

In the long run, rushing your cleaning or skipping hard-to-reach areas will only encourage biofilm formation.

• Action

In most cases, more mechanical action during cleaning will remove a biofilm more easily.

However, excessive mechanical action does carry risk, as it can inadvertently spread the biofilm's organisms to other surfaces.

Additionally, when too much force is applied, a surface may become damaged.

This can create scratches and dents that provide a new place for microscopic organisms and soil to dwell and will be difficult to clean in the future.

• Chemical

With chemicals, it is important to follow a manufacturer's instructions and correctly use the appropriate product for the soiled area and the surface.

Otherwise, you risk damaging a surface or leaving a film behind, such as soap scum.

Typically, when cleaning stainless steel, a broad range of chemicals can be used.

Fewer chemicals can be applied to soft metal surfaces such as carbon steel and aluminum, as they can corrode.

• Temperature

Higher temperatures usually result in greater biofilm removal.

However, when temperatures are too high, you can degrade the chemicals with which you are cleaning.

This may inactivate enzymes or drive solvents out of the cleaning solution.

Also, it is possible that soils can be baked onto a surface, thereby making cleaning much more difficult.

Best Practices For Your Facility

Once you understand TACT cleaning variables, apply the following best practices to reduce the presence of biofilms in your facilities.

1. Educate employees on biofilms

Despite increased research on biofilms in the 1980s and 1990s, it is possible that, although they have heard of them, your employees may not fully understand their impact.

Provide information about what biofilms are and their effects, in addition to training employees to better control the formation and spread of biofilms.

2. Consult with your chemical supplier before cleaning

Prior to starting your cleaning regimen, discuss which chemicals are best for your particular environment with your chemical supplier.

From acidic cleaners to alkaline cleaners, there are a variety of products that will have different effects on different surfaces and soils.

Consider selecting products that dispense the proper amount of chemical so that employees do not overuse or underuse.

Your chemical supplier can also help you understand the best way to use the chemicals so that you can get the best possible performance from them.

3. Begin with thorough cleaning before disinfecting or sanitizing

First and foremost, think of a biofilm as a microbial generated soil and create a cleaning program and schedule that adequately responds to all soils.

4. Sanitize and disinfect after cleaning is complete

Cleaning a surface prior to applying sanitizers and disinfectants removes soils that can affect the biocidal performance of these products.

On their own, sanitizers and disinfectants cannot control biofilms, but they can provide an extra measure of security to a clean surface.

Remember not to misapply or apply too much of a sanitizer or disinfectant.

5. Look for problematic areas in your facility

Because microorganisms need moisture to survive, biofilms are usually found where there is an abundance of water.

Inspect your facility for areas where water may collect, such as on floors, floor mats, counters and equipment.

Although a difficult task, try to keep the environment as dry as possible.

Biofilms, although an often unseen aspect of facilities, can easily become problematic bacteria-infested communities intent on spreading from surface to surface.

In order to limit the impact of biofilms, take measures to clean effectively.

This can be done by utilizing TACT variables and following best practices each and every time you clean.


Dr. Dale Grinstead is a Food Safety Technology Fellow with Diversey, a leader in cleaning and hygiene solutions that is now a part of Sealed Air. A food safety microbiologist with more than 17 years of research and development experience, Dr. Grinstead is responsible for leading infection control product development, evaluating potential impacts of new products and innovations and monitoring new food safety, infection control and microbiology technology trends. For more information, visit www.Diversey.com.

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