Disinfection-Best Management Practices

Fact Sheet, Minnesota Technical Assistance Program, University of Minnesota

Using best management practices for disinfecting will help ensure that you are cleaning appropriately to kill the
bugs—the microbes—you need to kill. A side benefit is that you use only the amount of disinfectant necessary to do
the job. Ultimately, best management practices protect patients, employees and the environment.

Right Level of Clean
Different levels of cleanliness are needed for different activities.



General surface cleaning physically removes all visible dirt and organic matter, and bacteria. It is normally
accomplished with water, mechanical action like scrubbing, and detergents. Cleaning should always precede
disinfecting and sterilizing to make the processes more effective. Disinfecting or sterilizing without removing
organic matter first can inactivate disinfectants. In many cases, general cleaning is the highest level of cleaning
necessary.



Disinfecting reduces the risk of infection from microbiological contamination to a level that is not likely to lead
to infecting a patient. Disinfecting is necessary for surfaces or equipment that will come into contact with
broken skin or mucous membranes. High level disinfection is required for semi-invasive medical procedures
like endoscopy. Lower levels of disinfection are used on surfaces in intensive care wards, kennels and surgery
wards. Most chemicals used as disinfectants are corrosive, toxic, irritants or potentially carcinogenic.



Sterilizing virtually eliminates or destroys bacteria and viruses. Objects are sterilized when they will be entering
a "sterile area" such as a body cavity. Sterilization is accomplished with high heat and pressure, or toxic gases
such as ethylene oxide.

Read the Label
Review the labels of your current disinfectants. Do these solutions match the profile of the microbes you need to kill?
The labels of concentrated disinfectants also state the proper level of dilution for maximum effectiveness.

Procedures
Health care facilities, dental offices, veterinary clinics, schools, day-care centers and public buildings all use some
form of disinfecting. Often they do not have cleaning procedures. Without written cleaning procedures, procedures are
passed on verbally or guessed at based on experience with dissimilar cleaning chemicals or based on mistaken
assumptions.

Many certification programs are now requiring written procedures to ensure best management practices. Establish
procedures based on current needs, equipment and disinfectants. Clearly post the procedure at the disinfectant
dispensing station. Be sure to train all staff on the procedures. Revise procedures and update staff when any conditions
change.

Writing a Procedure
Procedures need to include information on why cleaning is done, what products and tools should be used and how to
use them. Be sure to consider the following information when writing a disinfection procedure.

1. Pre-clean
Conduct general surface cleaning to remove dirt and debris. This can remove many microorganisms and increase the
effectiveness of the disinfectant.

2. Evaluate the Need to Disinfect
Because disinfectants are designed to kill, they are toxic. Determine if a lesser level of clean is sufficient. Does an
item truly need to be disinfected or is cleaning sufficient? If the item touches intact skin, then cleaning by itself is
sufficient. General surface cleaning can be accomplished by washing with a detergent, rinsing and thorough drying.

3. Assess the Level of Disinfection
Know the target microbes you need to kill. Make a list of the specific targets like Mycobacterium or Parvo virus, and

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more general target like spores, bacilli or viruses. Items used in a semi-sterile area require different levels of
disinfecting than hard surfaces such as patient furniture or instruments in contact with unbroken skin.

4. Select an Ideal Disinfectant
Chose a disinfectant that has high efficacy and is less toxic to employees and the environment. Disinfectants that act
by oxidizing such as hydrogen peroxide or peracetic acid create fewer by-products than quaternary "quat" compounds
or chlorine. This means less toxics ultimately reach the sewer.

Hydrogen peroxide and peracetic acid are also generally more effective against all types of microbes and are not as
easily inactivated by organic matter.

5. Dispensing
To protect workers from concentrated solutions, determine what equipment is necessary to ensure proper dilutions and
easy use. Do not mix different disinfectants together or mix bleach with disinfectant. Together they may create toxic
gases, such as chlorine.

Use personal protective equipment—like goggles and gloves—for employee protection. To reduce waste, use
washable towels or applicators.

Calibrate carefully. Calibrate dispensing equipment carefully and often—at least every time a new container of
disinfectant is opened. When calibrating, check the equipment for leaks and malfunctions. Equipment can be
calibrated with water instead of the chemical to prevent waste.

Measure accurately. Concentrates need to be measured before being put in the dilution tank. All disinfectants have a
concentration at which they achieve their maximum ability to disinfect. Adding extra does not help. In fact, it
increases the likelihood of injury, damage to equipment, and contaminating groundwater, as well as increases material
cost. Follow manufacturer directions for the lowest concentration of disinfectant to achieve the highest level of
antimicrobial activity. Mix only the amount needed, do not mix a gallon if you only need a quart.

Label containers. Make sure diluted disinfectant is labeled with the name, date and initials of whoever is diluting the
solution to better track the expiration date of the dilution (outdates). Check manufacturer’s instructions for an outdate
and how to protect from inappropriate uses.

6. Use Proper Dilution and Allow Time for Disinfectant to React
More concentrated disinfectants do not necessarily react more quickly or effectively. Follow label directions carefully.
They provide information on proper dilution rate, timing and application.

Reduce volume. Use the smallest possible amount of solution—lowest possible dose—to obtain the desired level of
microbial control. This practice also reduces the potential for a microorganism to build resistance to a specific
chemical as well as reduces waste to the environment.

7. Staff Training
Train staff and clearly post the procedure at the disinfectant dispensing station.

8. Storage
Keep containers closed when not in use. Store in original container, on lower shelves. Check containers regularly for
leaks, breaks, rust or other corrosion. If a leak or break occurs, transfer product into another container with the same
labeling or to an empty container that originally held the same disinfectant and has the same label.

University of Minnesota Disinfection Procedures-Success Story
The Small Animal Hospital at the University of Minnesota, which provides care mainly for dogs and cats, was
concerned about their disinfection procedure. Chemical disinfection at the small animal hospital is critical because the
bacteria-carrying particles on the floor, cages, kennels and surgical tables could reach an animal’s open wound and
cause infection.

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In one year, the hospital received 23,342 cases and performed 4,587 surgeries. The number of cases they treat
increases every year. This increase in cases results in more disinfectant use and waste. The hospital wanted to see if
they could reduce their use of disinfectants while maintaining strict disease control.

A MnTAP intern reviewed the hospital’s procedures and evaluated their disinfection by sampling microorganisms.
She worked with the hospital staff and identified the following improvement opportunities:



More training. Proper disinfection procedures were not well understood because staff were not adequately
trained.



Post instructions. No written instructions were posted for proper procedures. Staff used their own judgment.



Proper disinfectant use. Staff sometimes used the wrong dilution and selected less than ideal disinfectants.



Understanding disinfection. Staff mistakenly believed that using a higher concentration results in more
effective cleaning.

The lack of procedures led to excess disinfectant use, costing over $5,000 a year. The clinic was not achieving its
desired level of disinfection and had increased chemical loss to the wastewater. As a result of the intern’s research, the
veterinary hospital developed and posted a written procedure, and trained its staff how to follow it. The hospital also
instituted pre-cleaning and using the appropriate dilution. No increase in infections has been noticed.

Waste

Avoid spills, clean up spills. When spills do occur, clean them up immediately. Ensure that spilled residues are
managed properly—refer to the products material safety data sheet (MSDS) for this information. Make sure
disinfectants are stored in compatible containers. For example, corrosives should not be kept in metal or stainless steel
containers. Use drip pans under spouts to catch and contain drips. Minimize transfer of disinfectants from container to
container. Use pumps and spigots instead of pouring to decrease the likelihood of spills or skin contact.

Inventory tips. Maintain appropriate inventory. Only order and stock what is needed to avoid unnecessary disposal of
excess or outdated disinfectant.

Dispose of waste properly. Unused disinfectant concentrates may be considered hazardous waste. Check with
MPCA, your county or MnTAP to see if the concentrate waste is a hazardous waste and how to properly dispose of it.

More Information

The Center for Disease Control has guidelines for levels of disinfection according to organism type. MnTAP has a
variety of technical assistance services available to help Minnesota companies reduce and manage their industrial
waste. If you would like assistance or more information about MnTAP’s Intern Program, call 612/624-1300 or
800/247-0015 from greater Minnesota.

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