DRAIN CLEANING
Effective Procedures, Challenges and Recommendations

Often, people think that microorganisms or germs “hide” somewhere in the building environment. The truth is that microorganisms do not hide. They reside and grow anywhere you allow them to, especially where nutrients, water and air are available, such as in floor drains. Floor drains represent a favorable environment for microbial growth, especially in food preparation areas, where food, moisture and mild temperatures are readily available for their growth and multiplication.

Pathogenic and non-pathogenic microorganisms in drains typically take one of two forms. The first is free form. These are microbes that float in the drain water and are usually easier to control and destroy with traditional sanitizers. In the second form, microorganisms are embedded in biofilm.

Drain cleaning chemistry using a foaming Hydrogen Peroxide/Quat hybrid is
not only effective in removing biofilms from the visible part of the drains, it also
removes them from the underground drain pipes.

Biofilm is a protective structure formed by microorganisms in drains, when an adverse environmental condition strikes them. As the microorganisms grow and multiply, they produce a chemicalresistant polysaccharide matrix, which they use to attach themselves to the drain system surfaces. Microorganisms in a biofilm exhibit high resistance to traditional sanitation chemicals.

In most cases, biofilms can be associated with a dark or a light slime on the surfaces of the drains. The majority of the biofilm/slime is usually formed in the underground drain pipes, where cleaners and sanitizers have very limited access, making it easier for pathogenic microorganisms to reside and multiply. Therefore, when drains are not cleaned and sanitized properly and regularly, they can become a major source of microbial contamination, such as Listeria, Salmonella and E. coli.

Once in drains, microorganisms can be transferred to food processing and food service areas by different means. For example, clogged drains can sometimes cause contaminated drain water to back up from the drains into the preparation area. Blocked drains can also create positive air pressure inside the drains, which will force the air to back flow from the drains into the preparation area, dispersing microorganisms through microbial aerosolization.

Another problem occurs when drains are cleaned with brushes using an up-and-down motion instead of a circular and side-to-side motion, coupled with highpressure water to rinse the drains. This method causes all microorganisms in the drains to splash back from the drains onto the food prep equipment and food area floors.

Therefore, it is crucial to use the right tools, chemicals, cleaning procedures and frequency when cleaning drains to eliminate any microbial problems in food preparation and service areas.

Food preparation and service areas should be thoroughly cleaned at least once or twice a week to reduce
the number of pathogenic microorganisms in the drains.
This can be achieved by either of two procedures:
• Cleaning drains using detergents, brushes and sanitizers;
• Cleaning drains using a foaming hybrid of hydrogen peroxide and a quaternary ammonium compound.

Cleaning the Drains Utilizing Detergents, Brushes and Sanitizers
This is the most common procedure. It starts with brushing the drains with a cleaning solution, followed by a rinse step and concluding with a flood sanitization with a traditional sanitizer. Although this procedure is effective, it can also be detrimental to the food safety program if sanitation workers are not properly trained. There are five critical elements to this procedure.

Brush Size
The diameter of the drain brush should be at least 1/2 inch smaller than the diameter of the drain. Using a larger brush will cause microbial cells to splash back from the drains onto the food preparation surfaces when pulling the brush out of the drain.

Drain Brush Movements
As mentioned previously, brushing the drains with an up-and-down motion, instead of circular motion or side-to-side motion, will also cause microorganisms to splash back from the drains onto food preparation surfaces, contaminating them with all sorts of microorganisms.

Rinse Water Pressure
Rinsing the drains with a large amount of water at low pressure is recommended to wash off all microbial contaminants and prevent them from splashing back onto the processing equipment and food service surfaces.

Drain Brush Cleaning
Many workers place brushes on the floors when finished brushing the drains. This can contaminate the floors and surrounding area. Therefore, after brushing the drains, brushes should be placed in buckets of a strong sanitizer solution and then cleaned and sanitized in the cleaning area or janitorial sink. Drain brushes should be color-coded to separate them from the brushes that are used to clean food contact surfaces and equipment.

Underground Drain Pipes
This procedure is only effective in removing biofilm from the visible and accessible part of the drain. However, the underground drain pipes that are not touched with brushes and sanitizers are covered with large amounts of biofilm and slime that can be transferred to the processing areas by different means.

Cleaning the Drains Utilizing a Foaming Hydrogen Peroxide/Quat Hybrid
This is the most effective drain cleaning program that can be used to clean and remove biofilms from the drains. This method (known commercially as PerQuat technology) uses very powerful chemicals to clean and sanitize the drains and their underground pipe lines in one simple step.

The technology is based on a powerful chemistry between the negatively charged perhydroxide ion and the positively charged quaternary ammonium compound. When combined in one product, the two molecules form an intimate ion pair resulting in a Hydrogen Peroxide and Quat hybrid. This chemistry has a very unique cleaning ability and an antimicrobial efficacy against a wide range of microorganisms, allowing it to be used in a variety of industrial and public health environments. In fact, the chemistry is EPA-registered for the removal of biofilm from drain systems.

Drain cleaning products based on this chemistry are easy to use and can be poured or preferably foamed into the drains using a simple foaming unit that forces the product into the underground drain pipe line via a foaming attachment or assembly that can be attached to the foaming unit with a quick connection. The foam travels as far as desired in the drain pipes, depending on drain system conditions. As it travels, the foam covers all drain system surfaces, offering full 360 degree coverage. It penetrates and breaks down the biofilms from the surfaces of the drain, including the ceiling of the underground drain pipes. While breaking down the biofilm, it destroys microbial cells embedded in the biofilm. No scrubbing is required when using this technology, thus avoiding the problems associated with the previously discussed method.

The Hydrogen Peroxide/Quat hybrid chemistry is free of phosphates, acids and chlorine and helps to control and eliminate fruit flies from the drains. Products that utilize this technology are also economical and efficient. It takes only 20 to 30 seconds to foam each drain, and will reduce the amount of time and labor required to execute a complete and effective drain care program.

In summary, a drain cleaning chemistry using a foaming Hydrogen Peroxide/Quat hybrid is not only effective in cleaning and removing biofilms from the visible part of the drains, it also removes biofilms from the underground drain pipes and destroys the resistant microorganisms embedded in the biofilms and in the drain water. As a result, the total number of pathogenic microorganisms in the drain system is reduced to a minimum.

Adel Makdesi, corporate senior microbiologist, Zep Inc., for more information, visit www.zep.com.

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