The Difference Between Cleaning, Disinfecting, and Sterilizing

Disclaimer.  I am not a licensed health practitioner.  This is just another post on knowledge and understanding you might wish to acquire in advance of a disaster in case no higher care is available.  As long as our society is functioning, you should leave anything more substantial than applying a Band-Aid to the professionals.  No medication, including those available over the counter, should be taken without consulting a physician.  Information shared here is for educational and entertainment purposes only.  It is not medical advice nor a substitute for licensed medical care. 

In a situation of a prolonged collapse of society, there will possibly come a point when we need to sterilize some medical instruments or equipment.  Yeah, this is the kind of stuff we really don't want to think about, the kind of stuff we sure hope won't ever apply to us.  We certainly hope no one needs stitches or an appendectomy.  While I'm pretty confident we have stored an excess of syringes for my diabetic husband, we also have glass syringes and reusable needles just in case.

And just in case that day comes, we need to know the difference between cleaning, disinfecting, and sterilizing.

CLEANING is what we do when we wash the dishes or the laundry.  Soap or detergent and water, scrub the object clean, and hand dry it or let it air dry. Clean means there is no visible dirt or debris or food or tissue of any kind. Any gross contamination--visible blood, dirt, or debris--car harbor bacteria and viruses and protect them during disinfection or sterilization.  But there may still be all kinds of bacteria and viruses on whatever you just cleaned, because the item has not been disinfected or sterilized. 


DISINFECTING comes next.  (Actually, in the real world right now, disinfecting is the first step--it helps prevent those handling the medical instruments from picking up any diseases from the blood or debris on the instruments.  The order is switched in a more challenging environment to save time and resources.)  The disinfection process kills most of the bacteria, viruses, and fungi, but not necessarily all.  There are several different ways to disinfect instruments and other items, and each has their pros and cons.

Thermal Disinfection

• Boiling water is probably the most popular method for disinfection. Distilled or soft water is preferred to lessen the degree of rusting.  Boil instruments and other items in water for 30 minutes.  Timing does not begin until the water has come to a full rolling boil.  Instruments that have been boiled for 30 minutes are disinfected but are not considered sterilized.
• Iron textiles, like fenestrated drapes, operating room towels, and clothing with a very hot iron.  First, cover the ironing board with a clean cloth that is larger than the object to be disinfected and iron that cloth first.  Then carefully lay the object to be ironed over the base cloth.  Use several slow passes with the iron and steam well.  
• Solar power from the sun has been used for centuries to disinfect fabrics.  Simply hang the textile in full sun for at least six hours for each side.  Make sure the item is pinned to the top of the clothesline and that it is not doubled over. 

Chemical Disinfection

• Rubbing alcohol (70%)
• does not kill bacterial spores, so sterilization is not achieved;
• wipes are used to disinfect oral and rectal thermometers, scissors, and stethoscopes; small surfaces of the rubber stopper of multi-dose vaccine or medicine vials, like insulin;
• evaporates quickly, so items must be fully immersed to achieve better disinfection.
• Do not use 91% alcohol for disinfection purposes.  It evaporates too quickly and lacks adequate water to carry alcohol through cell walls to kill bacteria.
• Instruments should soak for 12 hours.
• Chlorhexidine (Hibiclens) 
• Kills some bacteria, but not spores.
• Use in conjunction with isopropyl alcohol and soak instruments for 24 hours.
• Povidone-Iodine (Betadine)
• Soak instruments in a solution of one part of a 10% solution of povidone-iodine to three parts water for 15 minutes.
• Chlorine (household bleach, 5.25-6.15% sodium hypochlorite)
• 1 tablespoon bleach to 3 cups water  OR
• 20 ml bleach to 1 liter of water.
• Make this solution just prior to use.
• Soak instruments for 15-30 minutes, no more and no less (chlorine corrodes metal instruments).

Unlike disinfection, which kills most organisms on an object, sterilization kills all microorganisms.  

STERILIZATION of medical instruments is necessary in situations of where we will be breaking skin or any time when we are going into skin that has already been broken.  Or any time we are inserting anything into the body.  Sutures, tubing, catheters, needles, scalpels, etc.  Fortunately, at the time these are purchased they generally come to us in sterile packages, so we don't have to worry about sterilizing them ourselves for the first use.  However, we could find ourselves in some interesting situations down the road with the need to re-use instruments.

The first is in an electric oven.    Two hours at 325 degrees Fahrenheit or 30 minutes at 400 degrees Fahrenheit will sterilize medical instruments.  Wrap the instruments in aluminum foil or place them on a metal tray. 

The second option is a sun oven, which  will sterilize just as well as an electric oven; however, it must be constantly monitored for temperature drops.  If the temperature drops below 325 degrees, the timing must start over.

An open flame is an option, if there is no other choice. The instrument should be held in the flame until it turns red.  And if the handle is also metal, then you'll want a clean cloth to hold it while it's being heated and sterilized.  There's no point in creating a burn victim here.  This method has the disadvantages of the time it takes for the instrument to cool down prior to use, and there is the potential for damaging delicate instruments.

Finally, there is the option most preppers have heard mentioned:  using a pressure cooker or pressure canner.  It works very similar to the autoclaves that hospitals use.  Of course, a pressure cooker or canner is not looked upon as a legally or medically appropriate option.  (So you probably wouldn't want to use it with lawyers or doctors, right?)  Fortunately, however, we shouldn't have to use this knowledge often.  And, just as fortunately, a pressure canner can achieve the requisite temperature for sterilizing equipment.  To be considered sterile, the interior temperature of the canner must reach 250-273 degrees Fahrenheit.  This is achieved at 15 psi, and that pressure must be maintained for at least 30 minutes.

By way of reminder, instruments must be clean before undergoing sterilization.  Any debris, tissue, blood, or whatever on the instrument must be removed; otherwise, it could hinder or completely prevent sterilization. Also, instruments such as clamps and scissors should be in the open position when being cleaned, disinfected, and sterilized.

Links to related posts:
Skin Preps and Washes
Betadine

For further reading:  
https://www.cdc.gov/infectioncontrol/pdf/guidelines/disinfection-guidelines-H.pdf  p 40
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2994051/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4623738/
https://www.aphl.org/programs/preparedness/Biosafety-and-Biosecurity/Documents/Practical%20Disinfection%20Guidance%20for%20the%20Clinical%20Laboratory.pdf
http://thesurvivaldoctor.com/2014/01/13/sterilize/
https://blog.gotopac.com/2017/05/15/why-is-70-isopropyl-alcohol-ipa-a-better-disinfectant-than-99-isopropanol-and-what-is-ipa-used-for/
https://activatebleach.com/docs/LINK_LIBRARY_Understanding_Bleach_Dilution_Rates.pdf
https://www.sahealth.sa.gov.au/wps/wcm/connect/d3396d00411006b8875bcf8f6fad9ea1/FactSheet-dilutions-sodium-hypochlorite_V2+2-phcs-ics-20140917.pdf?MOD=AJPERES

https://www.sunoven.com/first-aid-sterilizing-medical-instruments/
https://www.doomandbloom.net/sterilizing-instruments-in-austere-settings/
Survival and Austere Medicine, 3rd Edition, p 356.

 8.28.19