Farm and Home Biosecurity
Livestock/Row Crop Producer
Arkansas Farm Biosecurity Plan - Cleaning and Disinfecting
Commonly Used Disinfectants
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Important Points
Because of the outbreak of FMD in the United Kingdom in 2001, more animal
owners are looking at their biosecurity plans and how to keep contagious
diseases away from their animals. An important part of a biosecurity plan is to
effectively clean and disinfect areas where animals are housed. Disinfectants
are only one part of a complete biosecurity program and should not be relied on
as the only defense against infectious diseases.
Most disinfectants will not work if the surface is not clean. Dirt and
other organic material (feed, bedding, milk, blood and fecal material) will
inactivate many disinfectants and can protect pathogens (bacteria, viruses and
protozoa) from the effects of the disinfectant. This is particularly true for
chlorine-based compounds (bleach). Cleaning the surface physically that is to be
disinfected is very important. For large areas or porous surfaces, steam
cleaners or high-pressure washers are very helpful. Hard water can reduce the
activity of some compounds. This can be a real problem if compounds are diluted
and allowed to stand for several days before being used. If you are planning to
use a disinfectant and that compound is inactivated because of water quality,
then you will have a false sense of security. Follow mixing directions and make
sure compounds are fresh.
Know the types of organisms you are trying to remove and the effectiveness of
the compounds you are using. For example, diluted vinegar will work very
effectively against the virus that causes FMD but will not have any effect on
the bacterium that causes Johne's disease. Many bacteria will form spores that
are very resistant to most disinfectants. This includes the bacteria that cause
tetanus, blackleg, anthrax and botulism. Some compounds will require a longer
time in contact with target surfaces to remove all the pathogenic organisms.
Follow label directions to insure sufficient contact time is allowed.
Read and follow all label directions. Some compounds should not be used
directly on animals or should not be used on animals that are to be used for
food production. If you intend to use any disinfectant directly on animals or in
an area that animals are housed, make sure the label shows that compound is safe
to use. The label will have directions on how to mix the compound, what it is
effective against, and what may inactivate the compound. The label will also
have information on any possible problems with use of the compound with humans
or the environment. If you have any questions, contact the producer of the
compound directly. All chemical manufacturers maintain telephone hot lines and
most have web pages. Some compounds have very explicit mixing directions. For
example, sodium hydroxide (lye) is very caustic. When mixing this compound, use
protective clothing, safety glasses and gloves. Always add lye to water; do not
pour water over lye. Read and follow all label directions.
Commonly Used Disinfectants
Quaternary ammonium compounds (Roccal D)
These compounds work well on clean surfaces. Many compounds in this class
have some detergent activity but will often become inactive if they contact
soaps or residues on surfaces that are left behind by soaps. Any organic
material that is not removed inactivates them. If you use these compounds, be
sure to clean the surface and then rinse off any soap you may have used.
Phenol compounds (One Stroke Eniviron, Osyl and Amphyl)
These are made from coal-tar and have a very strong odor. When added to
water, the mixture often turns a white, milk-like color. These compounds are not
inactivated by hard water or the presences of some organic debris. They have a
wide spectrum and are a good general-purpose disinfectant.
Chlorine compounds (Hypochlorites) (Bleach, Halazone)
These compounds are inactivated by organic debris. They are usually more
effective if mixed in warm water. These compounds are often unstable and should
not be allowed to stand for long periods before use. They can be used with soaps
but do not mix with any acids (vinegar). These compounds can be harmful to
clothing, rubber and some metals and can irritate your eyes and nose.
Iodine-based compounds (Iodophors) (Betadine, Weladol)
These are iodine-based compounds that are combined with a molecule that
allows them to mix in water. These are very effective disinfectants but are
inactivated by organic debris, some metals and sunlight. They can stain clothing
and some porous surfaces. If mixed with quaternary ammonium compounds (Roccal
D), they are inactivated. Doctors and veterinarians have used these compounds to
disinfect surgical sites for many years.
Oxidizing agents (Virkon S)
Virkon S is a combination of an oxidizing agent, an organic acid and a
penetrating agent (surfactant). Because it is an acid, it has a low pH (2.6 when
mixed), however the label says it is not irritating to skin. It has a wide
spectrum of activity and can be effective if some organic debris is present. It
is recognized by the USDA as effective against the FMD virus. The label
indicates it can be used on livestock equipment such as grooming brushes,
saddles and buckets.
Important Points
1. Know the disease agents you are trying to disinfect and what compounds
do or do not work against them
2. Know the compound you are going to use and what the limitations of that
compound may be.
3. Read and follow all label directions. Make sure the compound you are
going to use is safe to use on or around animals and is effective.
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