The key difference between steril- ization and disinfection is level of bio-burden reduction. The lowest level of cleaning is sanitizing, following by disinfection, and then sterilization.
Disinfection is defined as a bio-burden
reduction of 4 to 5 logs, or reducing the number of microorganisms by 99.99% (4-log) to
99.999% (5-log). To determine the efficiency of
these levels, you would multiply your known
by the percentage. The
result is the number of
microorganisms you should
expect to survive after the
process is applied. Sterilization is defined as
the statistical destruction of all microorganisms
and their spores. This is referred to as a 6-log
kill or 99.9999% reduction of the bio-burden.
Each level can be achieved in many different ways. Typically disinfection is done
with various chemicals and applied by hand.
Sterilization requires a higher level of technology. To achieve sterilization, you would typically expect to use more high tech equipment
such as heat, hydrogen peroxide systems, and
chlorine gas generators.
WHEN IS EACH USED
“When should each be used” is a much more
difficult question to answer. Your setting and
type of work you do will typically dictate
what is required. For example, if you are
working in a vivarium you should
expect the instruments that you use for
surgery to be sterile, but it may be sufficient
for the surrounding areas to be disinfected
daily. In the healthcare setting it is sufficient
for hospital rooms to be disinfected daily and
between patients. However, the rooms that
are used for isolation of high risk patients or
transplants may require the room to be sterile.
In order to achieve a sterile room/surface
environment in any setting, you will need
to introduce some type of gas/vapor, as it
is impractical to use heat in an open envi-
ronment. Options include ionized hydrogen
peroxide (iHP), vaporized hydrogen peroxide
(VHP), chlorine dioxide (ClO2), and formalde-
hyde gas. These processes involve mechanical
controls of the air handling system and appro-
priately trained personnel or contractor to
apply them in a safe and effective manner.
Any process that is used to achieve either disinfection or sterilization should be validated.
Validation can be done in several different
ways. Swab samples done prior to the chemical application and then after the application
will show what was present prior to and
then after the process. In addition, biological
indicators populated with various spores to a
known minimum level (4-log, 5-log, or 6-log)
can be placed in the area before a process is
performed and then incubated to show total
destruction of the spores.
It is critical that you establish the required
level of cleanliness for the
process that you per-
form. This is usually
done prior to opening
a facility and all personnel should
be trained in processes that are set up
to maintain that level. The greatest
source for contamination are the peo-
ple that work in the labs and the sub-
jects of their research. It is critical that pro-
tocols are established, personnel are trained,
and processes are documented and recorded
Prior to becoming the Director of Sales at
SixLog, Steve Feinstein was the Regional Sales
Manager for Bioquell Inc. Prior to that, he
had his own company for 12 years, Medical
Repair Laboratories, which was one of the first
companies to test, certify and decontaminate
controlled-environments and critical laboratory
equipment. Steve graduated from the George
Washington University and has over 20 years of
experience within his current field of expertise.
12 OCTOBER 2014 ; ALNmag.com
OPERATIONS | Steve Feinstein
What is the difference between
sanitation, sterilization, & disinfection?
When should each be used?
The greatest source for
contamination are the
people that work in the
labs and the subjects of