The Standard Operating Procedure should always be strictly followed, and
any item listed to be cleaned should be cleaned, whether it looks like
it needs to be or not! It is important that everything be
scheduled for cleaning, including sinks, vents, lights, trash cans...
It is essential to
correctly handle the chemicals used in sanitation. They must be
stored properly and used according to label directions (don't
assume--read the label!). Never mix chemicals, unless you are
authorized to or it is listed on the label, and know the hazards to you
and the animals. A chemical must be supplied with a "Material
Safety Data Sheet" (MSDS) that details the hazards, handling
precautions and method of treating toxic reaction--read it before you
use the chemical!
Chlorine (such as
Clorox®)
is an inexpensive sanitizer that produces an excellent kill of bacteria
and viruses. It is generally used as a 10% solution, and is better
suited for use on plastic cages, as it can be corrosive to metals, such
as stainless steel and aluminum.
Phenols, including Lysol®,
are also used as sanitizers. They are slow-acting, but are
effective against the vegetative and spore forms of bacteria.
Phenols should never be used on cat cages and litter pans, however,
because they are toxic to cats.
Quaternary ammonias
("quats") are low toxicity chemicals with good detergent
action. Roccal-D®
is an example of a quaternary ammonia.
Iodine is a chemical that
is in the same class as chlorine, but is less toxic. It is usually used
as a detergent scrub or antiseptic for surgical prep and wound
cleaning. Some people, however, are very sensitive to iodine-based
antiseptics and soaps, so you should be alert to redness and itching of
your skin. Common names of iodine-based disinfectants are Betadine®,
povidine and povidone.
Some small-sized animal
facilities may hand wash cages, cage lids and racks and water
bottles. Most facilities, however, have automated equipment, such
as cage washers,
tunnel
washers and bottle washer/fillers.
Robotic systems have been developed that
dump soiled bedding, feed the cages through a cage washer and refill
the cages with bedding. Special waste
disposal units consist of a hood with negative air flow and a
dump stations for emptying cages. This helps minimize asthmatic
and allergic reactions.
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Sterilization:
Sterilization is
destruction of all living organisms on an inanimate substrate. It
can be achieved in a number of ways, depending upon the substance to be
sterilized, including moist heat, dry heat, ethylene oxide and
radiation.
Moist heat sterilization uses steam under pressure to increase the
temperature of the steam (water vapor) to above 100°
C, water's boiling point. A special machine, called an autoclave, is
used to produce this superheated steam. The target temperature,
pressure and time varies with the substance being sterilized, but in
veterinary practice the typical values are 121°
C at 15 psi (pounds pressure per square inch) for 15-20 minutes.
Autoclaving is an effective way to sterilize surgical instruments,
although it has a dulling effect on sharp tools such as scalpel blades and
scissors. It is unsuitable for heat-sensitive materials such as
plastic catheters and latex gloves.
All sterilizing systems
must be evaluated to ensure that they are functioning properly. The
autoclave can be monitored with physical, chemical and biological
indicators. The physical method is evaluation of the temperature and
pressure gauges of the autoclave, ensuring that the targets are met.
Chemical indicators include autoclave tape and strips that contain a
substance that changes color at a specific temperature. Chemical
indicators do not assess pressure, however, so changes in color do
not guarantee sterility. Biological indicators consist of
heat-dwelling bacteria (Bacillus stearothermophilus spores) that
are sent through the autoclave cycle and cultured after its
completion. If the proper temperature was attained, the bacteria
will not grow.
Dry heat sterilization is
accomplished with an oven or an incinerator. Incinerators are used
to destroy contaminated materials. Ovens provide hot dry heat.
Flash (very quick) units are available, but many ovens require one to two
hours of heating to 160°
C.
Ethylene oxide (ETO) is a
chemical that is used to sterilize many heat-sensitive materials, such as
catheters and sutures, or moisture-sensitive materials, such as electronic
equipment. ETO is a carcinogen, a mutagen and is flammable. In
other words, it's a hazardous method to use. Materials sterilized
with ETO must be aired out for several weeks prior to use, to ensure that
no residual chemical remains. Although ethylene oxide is hazardous
and the equipment is expensive, it is a reasonable option for a facility
that needs to sterilize sensitive materials.
Radiation can also be used
to sterilize heat-sensitive materials. Nonionizing radiation, such
as ultraviolet light, can be used at the entrance to an animal facility or
room. It sterilizes the surface of a substance, such as a lab coat,
drinking water or air. While not extremely dangerous to humans, it
can affect vision if you stare at an ultraviolet light for an extended
period of time.
Ionizing (ex. gamma)
radiation penetrates deeply into a substance, including an operator.
It can be lethal if direct exposure occurs. Strict safety
regulations are imposed on the use of ionizing radiation, and it is
primarily used in an industrial setting to batch sterilize catheters and
other heat-sensitive materials.
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- Vermin Control:
Vermin is any living
macro-organism (visible) that should not be present in the facility.
Fleas, ants and wild mice are all vermin.
There are two primary reasons why vermin should be excluded. They
cause direct injury, such as flea allergy dermatitis. They can also
be vectors for pathogens, introducing disease into an animal room.
The preferred method of vermin control is prevention. A facility
should be designed so that vermin cannot gain entry. Bedding and
food must be kept in vermin-proof containers. Adherence to
sanitation protocols with deprive vermin of food and shelter.
Unfortunately, prevention
is not always effective. The first step in dealing with a vermin
problem is to properly identify what species you're dealing with.
Particularly with invertebrates, the method of treatment for one species
may be ineffective against another.
After the problem has been
identified, a control procedure must be developed that will not interfere
with the experimental protocol.
-
Quality Assurance (QA):
QA is the establishment of
standards for the animal facility and all of its protocols, including
sanitation and vermin control, with the goals of ensuring high quality
research and high quality care for the animals. The Good Laboratory
Practices Act (GLP) of the Food and Drug Administration mandates specific
QA procedures for any drug experiment. All animals, facilities and
research, however, benefit from quality assurance practices.
Key to quality assurance is
the development of monitoring programs for the animals, their environment
and infectious organisms.
Isolation and quarantine of
newly arrived animals is critical to avoiding the introduction of
pathogens into the research facility. Preventative medicine programs
should be used, including vaccinations and parasite treatments. Only
animals of a defined health status should be purchased and every animal
must be observed every day.
A surveillance protocol
should be developed that includes routine monitoring of the animals for
selected pathogens. Some facilities use "sentinel"
animals--animals that are not on study, but that are exposed to the study
animals and that are more sensitive to the pathogen of concern.
Environmental factors,
including light, temperature, humidity and noise can affect the well-being
of an animal and may alter its response to an experimental variable.
All possible factors should be standardized for all animals in a
study.
The genetics of the animals
should be monitored, especially for inbred strains, so that genetic drift
and the inadvertent establishment of a new strain does not occur.
There are a number of different methods used to ensure genetic purity,
including mandible measurements, DNA fingerprinting (identification) and
tissue analysis.
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