Cleaning and Disinfecting the Indoor Environment: Chlorine Bleach, Quats and Phenolics
By Roger McFadden
Technical Director
Coastwide Laboratories
Disinfectants and
the Environmental Protection Agency (EPA)
In
the United States, disinfectants and disinfectant cleaners must be reviewed and registered
by the Environmental Protection Agency (EPA) before they can be offered for sale. EPA
assigns a registration number for each product and that number must be clearly displayed
on every container of the product. Companies submitting disinfectants for registration are
required to include current efficacy data to prove that their product kills ALL of the
microorganisms listed on the product label. For instance, if the product label claims to
kill staphylococcus aureus, then test data must be submitted to EPA to prove that
the product when diluted according to label directions kills the staphylococcus aureus
bacteria.
Efficacy
Tests Measure the Effectiveness of Disinfectants
The
tests used to measure the effectiveness of disinfectants on various pathogenic (disease
causing) organisms are called, efficacy tests. The EPA must pre-approve all “efficacy
test methods” used to measure the effectiveness of disinfectants against specific
microorganisms. The most common efficacy test prescribed by EPA is the Association of
Official Analytical Chemist (AOAC) Use Dilution Confirmation Test. Currently, for a disinfectant cleaner to be
registered by EPA as hospital strength, it must be effective at its recommended dilution
in killing targeted pathogens in the presence of 400 ppm hard water and 5% organic serum.
It must kill 100% of the targeted test organisms.
Ask Your Supplier
to Provide Current Efficacy Data
It is a good idea
for you to require the manufacturer and/or distributor of a disinfectant or
disinfectant-cleaner to provide efficacy data to your organization before you select it
for use in your facilities. The data should include a listing of the microorganisms it
effectively kills. Before selecting a
disinfectant product it is important to review the product label to confirm that it: 1)
contains a valid EPA Registration Number, 2) effectively kills the pathogenic
microorganisms you are concerned with eliminating and 3) clearly identifies both the
proper application and safety procedures to be followed when using the product.
What are the
Differences Between Disinfectants and Disinfectant Cleaners?
Disinfectants
require the removal of soils from a surface before they are effective. Disinfectant
cleaners combine the cleaner and disinfectant into a “one-step” process. A disinfectant-cleaner is diluted and then used to
remove soils and kill germs all in one application. One step disinfectant-cleaners save
labor time and money. Simply stated, disinfectants “disinfect” and
disinfectant-cleaners “disinfect and clean.” If you are uncertain if your
product is a disinfectant or disinfectant-cleaner, read the product label carefully. If
the label does not mention “cleans and disinfects,” then it is probably a
disinfectant or sanitizer and not a one-step disinfectant-cleaner.
Chlorine Bleach
Solutions Are Excellent Disinfectants, But Poor Cleaners
Household and
institutional chlorine bleaches contain 5.25% active sodium hypochlorite when they are
manufactured. The remaining 94.75% is primarily water. Chlorinated compounds such as
sodium hypochlorite when diluted in water form hypochlorous acid. This acid is extremely
effective against many types of microorganisms including bacteria, fungi and viruses. For
instance, the product label for Purex household bleach claims it is effective against
staphylococcus and streptococcus bacteria, Influenza A and B viruses and athletes foot
fungus. However, chlorine bleach products require that the surfaces be cleaned prior to
their use. This means doubling the time that
it takes to clean and disinfect a soiled surface.
Disadvantages of Using
Chlorine Bleach
Many institutions
do not commonly use chlorine bleach products because they:
1.
Lack
detergency
2.
react
with other chemicals to create toxic gases
3.
emit
unpleasant odors
4.
attack
hard surfaces
5.
discolor
fibers and colored surfaces
6.
damage
floor finishes
7.
lose
their strength rapidly
8.
are
expensive to use
Phenols or phenolic
disinfectant-cleaners are not as corrosive as chlorine bleach. But they aggressive enough
to attack and damage floor finishes and sensitive flooring. Phenolic disinfectants are
still the preferred product in a few health care facilities. It is used in areas where
gross contamination of blood and body fluids exist. Phenolics are effective against
pathogenic bacteria like tubercle bacillus that cause tuberculosis. Sporeforming
bacteria like tubercle bacillus are extremely difficult to disrupt because to the
protective shell which forms around the bacteria. Phenolic disinfectants are able to
penetrate this shell and kill the TB organism inside.
Iodines and
iodophor compounds can be very effective disinfectants with a broad range of killing
power. But iodophors and iodines can stain surfaces and corrode metals.
Distilled pine oil
can be formulated as a disinfectant. Pine
oils are not water-soluble. High levels (80%) of pine oil are required to kill many
pathogens. Pine oils are seldom used alone to disinfect. They are combined with alcohols
and quats to improve their disinfecting and cleaning properties. Pine Sol is an example of
a pine oil based product that also contains isopropyl alcohol and quaternary ammonium
compounds.
Quaternary Ammonium
Chlorides or “quats” as they are commonly known are based upon the active
ingredient benzalkonium chloride. These quaternary salt compounds can be formulated with a
variety of ingredients to provide a safe and effective neutral pH, disinfectant-cleaner
without damaging floor finishes or sensitive floor surfaces. In addition, quats are economical and extremely
effective odor control agents when used according to label directions.
Quats are effective
in destroying a broad spectrum of harmful microorganisms. They are effective in killing
the following microorganisms while cleaning the surfaces upon which they reside – all
in one simple step.
1.
Gram negative and
gram positive bacteria like salmonella typhi, staphylococcus aureus, streptococcus
epidermidis and pseudomonas aeruginosa,
2.
viruses
like HIV-1, Herpes simplex 1 and 2
3.
Antibiotic
resistant strains of bacteria including methicillin resistant staphylococcus aureus
(MRSA).
4.
and
fungi like trichophyton interdigitale (athlete’s foot).
1.
Does
the product have an EPA Registration Number?
2.
What
is the active ingredients? (Quats, Phenolics, Chlorine Bleach, Iodine or Pine Oil?)
3.
Is
it safe for daily use by housekeepers and custodians?
4.
Will
it damage the surfaces cleaned with it?
5.
What
germs does it kill?
6.
What
is the dilution ratio of the product?
7.
Is
it a “one-step” disinfectant-cleaner or a disinfectant?
8.
Is
it effective in hard water?
9.
Is
it effective in the presence of organic soil?
10.
What is the end-use
cost of the product?
