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
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
Drain cleaning chemistry using a foaming Hydrogen Peroxide/Quat
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
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.
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.
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.
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
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 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.
Back to top ▲