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Disinfection of a floor using disinfectant liquid applied using a mop.

Disinfectants are tissue. Disinfectants are also different from biocides — the latter are intended to destroy all forms of life, not just microorganisms. Disinfectants work by destroying the cell wall of microbes or interfering with the metabolism.

Sanitizers are substances that simultaneously clean and disinfect.[2] Disinfectants are frequently used in hospitals, dental surgeries, kitchens, and bathrooms to kill infectious organisms.

Bacterial endospores are most resistant to disinfectants, but some viruses and bacteria also possess some tolerance.

In wastewater treatment, a disinfection step with chlorine, ultra-violet (UV) radiation or ozonation can be included as tertiary treatment to remove pathogens from wastewater, for example if it is to be reused to irrigate golf courses. An alternative term used in the sanitation sector for disinfection of waste streams, sewage sludge or fecal sludge is sanitisation or sanitization.


  • Properties 1
  • Types 2
    • Air disinfectants 2.1
    • Alcohols 2.2
    • Aldehydes 2.3
    • Oxidizing agents 2.4
    • Phenolics 2.5
    • Quaternary ammonium compounds 2.6
    • Silver 2.7
    • Copper alloy surfaces 2.8
    • Thymol-based disinfectant 2.9
    • Other 2.10
  • Measurements of effectiveness 3
  • Home disinfectants 4
  • See also 5
  • References 6
  • Further reading 7
  • External links 8


A perfect disinfectant would also offer complete and full microbiological

  • Ohio State University lecture on Sterilization and Disinfection
  • What Germs Are We Killing? Testing and Classifying Disinfectants
  • Disinfectant Selection Guide
  • Disinfectant and Non-Chlorine Bleach—Office of DOE Science Education
  • The Viennese Database for Disinfectants (WIDES Database)

External links

  • Soule, H.; D. L. Duc; M. R. Mallaret; B. Chanzy; A. Charvier; B. Gratacap-Cavallier; P. Morand; J. M. Seigneurin (Nov–Dec 1998). "Virus resistance in a hospital environment: overview of the virucide activity of disinfectants used in liquid form". Annales de Biologie Clinique (in French) 56 (6): 693–703.  
  • Sandle, T. (editor) (2012). The CDC Handbook: A Guide to Cleaning and Disinfecting Cleanrooms (1st ed.). Grosvenor House Publishing Limited.  

Further reading

  1. ^ a b
  2. ^ Cleaning and disinfecting, (2009), Mid Sussex District Council, UK.
  3. ^
  4. ^
  5. ^ For a review of the early work in this field, see: Robertson OH, Bigg E, Puck TT, Miller BF (June 1942). "The bactericidal action of propylene glycol vapor on microorganisms suspended in air. i". Journal of Experimental Medicine 75 (6): 593–610.  
  6. ^ For a review through 1952 see: Lester W, Dunklin E, Robertson OH (April 1952). "Bactericidal effects of propylene and triethylene glycol vapors on airborne Escherichia coli". Science 115 (2988): 379–382.  
  7. ^ For a review of the toxicity of propylene glycol, see: United States Environmental Protection Agency (September 2006). "Reregistration eligibility decision for propylene glycol and dipropylene glycol". EPA 739-R-06-002. 
  8. ^ For a review of the toxicity of triethylene glycol, see: United States Environmental Protection Agency (September 2005). "Reregistration eligibility decision for triethylene glycol". EPA 739-R-05-002. 
  9. ^ Committee on Research Standards (May 1950). "Air Sanitation (Progress in the Control of Air-Borne Infections)". American Journal of Public Health and the Nation's Health 40 (5 Pt 2): 82–88.  
  10. ^ Lester W, Kaye S, Robertson OH, Dunklin EW (July 1950). "Factors of Importance in the Use of Triethylene Glycol Vapor for Aerial Disinfection". American Journal of Public Health and the Nation's Health 40 (7): 813–820.  
  11. ^ a b FDA/CFSAN - Food Safety A to Z Reference, "Bacteria"
  12. ^ a b Moorer WR (August 2003). "Antiviral activity of alcohol for surface disinfection". International Journal of Dental Hygiene 1 (3): 138–42.  
  13. ^ a b van Engelenburg FA, Terpstra FG, Schuitemaker H, Moorer WR (June 2002). "The virucidal spectrum of a high concentration alcohol mixture". The Journal of Hospital Infection 51 (2): 121–5.  
  14. ^ Lages SL, Ramakrishnan MA, Goyal SM (February 2008). "In-vivo efficacy of hand sanitisers against feline calicivirus: a surrogate for norovirus". The Journal of Hospital Infection 68 (2): 159–63.  
  15. ^ "Clean & Disinfect Mold, Bacteria & Viruses in any Environment". Retrieved 2010-11-18. 
  16. ^ Weber DJ, Barbee SL, Sobsey MD, Rutala WA (December 1999). "The effect of blood on the antiviral activity of sodium hypochlorite, a phenolic, and a quaternary ammonium compound". Infection Control and Hospital Epidemiology 20 (12): 821–7.  
  17. ^ "CDC - Immediately Dangerous to Life or Health Concentrations (IDLH): Chemical Listing and Documentation of Revised IDLH Values - NIOSH Publications and Products". 2009-07-31. Retrieved 2012-11-10. 
  18. ^ Omidbakhsh; et al. (2006). "A new peroxide-based flexible endoscope-compatible high-level disinfectant". American Journal of Infection Control 34 (9): 571–577.  
  19. ^ Sattar; et al. (Winter 1998). "A product based on accelerated hydrogen peroxide: Evidence for broad-spectrum activity". Canadian Journal of Infection Control: 123–130. 
  20. ^ Cochrane Collaboration: Topical silver for preventing wound infection, 2009
  21. ^ EPA registers copper-containing alloy products, May 2008
  22. ^ A. Samuel ⋅ (2011-07-22). "Chilean subway protected with Antimicrobial Copper - Rail News from". Retrieved 2012-11-10. 
  23. ^
  24. ^
  25. ^ Marino, Marilena; Bersani, Carla; Comi, Giuseppe (1999). L. Measured Using a Bioimpedometric Method"Thymus vulgaris"Antimicrobial Activity of the Essential Oils of . Journal of Food Protection (9): 1017–1023. 
  26. ^
  27. ^ Allen MJ, White GF, Morby AP (2006). "The response of Escherichia coli to exposure to the biocide polyhexamethylene biguanide". Microbiology (Reading, Engl.) 152 (Pt 4): 989–1000.  
  28. ^ Zamani M, Sharifi Tehrani A, Ali Abadi AA (2007). "Evaluation of antifungal activity of carbonate and bicarbonate salts alone or in combination with biocontrol agents in control of citrus green mold". Communications in Agricultural and Applied Biological Sciences 72 (4): 773–7.  
  29. ^ Malik YS, Goyal SM (May 2006). "Virucidal efficacy of sodium bicarbonate on a food contact surface against feline calicivirus, a norovirus surrogate". International Journal of Food Microbiology 109 (1–2): 160–3.  
  30. ^ William A. Rutala, Susan L. Barbee, Newman C. Aguiar, Mark D. Sobsey, David J. Weber, (2000). "Antimicrobial Activity of Home Disinfectants and Natural Products Against Potential Human Pathogens". Infection Control and Hospital Epidemiology (The University of Chicago Press on behalf of The Society for Healthcare Epidemiology of America) 21 (1): 33–38.  
  31. ^ Sandle T (editor) (2012). The CDC Handbook: A Guide to Cleaning and Disinfecting Cleanrooms (1st ed.). Grosvenor House Publishing Limited.  
  32. ^ Centers for Disease Control and Prevention (December 21, 2012). "Sterilization or Disinfection of Medical Devices". CDC. Retrieved July 20, 2013. 
  33. ^ Vijayakumar R, Kannan VV, Sandle T, Manoharan C. (May 2012). "In vitro Antifungal Efficacy of Biguanides and Quaternary Ammonium Compounds against Cleanroom Fungal Isolates".  
  34. ^ EPA's Registered Sterilizers, Tuberculocides, and Antimicrobial Products Against HIV-1, and Hepatitis B and Hepatitis C Viruses. (Obtained January 4, 2006)
  35. ^ "Antimicrobial Products: Who Needs Them? — Washington Toxics Coalition". 1997-09-15. Retrieved 2012-11-10. 


See also

The use of some antimicrobials such as triclosan, in particular in the uncontrolled home environment, is controversial because it may lead to the germs becoming resistant. Chlorine bleach and alcohol do not cause resistance because they are so completely lethal, in a very direct physical way.[35]

Where one does not want to risk the corrosive effects of bleach, alcohol-based disinfectants are reasonably inexpensive and quite safe. The great drawback to them is their rapid evaporation; sometimes effective disinfection can be obtained only by immersing an object in the alcohol.

Commercial bleach tends to lose strength over time, whenever the container is opened. Old containers of partially used bleach may no longer have the labeled concentration.

To use chlorine bleach effectively, the surface or item to be disinfected must be clean. In the bathroom or when cleaning after pets, special caution must be taken to wipe up urine first, before applying chlorine, to avoid reaction with the ammonia in urine, causing toxic gas by-products. A 1-to-20 solution in water is effective simply by being wiped on and left to dry. The user should wear rubber gloves and, in tight airless spaces, goggles. If parasitic organisms are suspected, it should be applied at 1-to-1 concentration, or even undiluted. Extreme caution must be taken to avoid contact with eyes and mucous membranes. Protective goggles and good ventilation are mandatory when applying concentrated bleach.

Negatives are that it is caustic to the skin, lungs, and eyes (especially at higher concentrations); like many common disinfectants, it degrades in the presence of organic substances; it has a strong odor; it is not effective against Giardia lamblia and Cryptosporidium; and extreme caution must be taken not to combine it with ammonia or any acid (such as vinegar), as this can cause noxious gases to be formed. The best practice is not to add anything to household bleach except water.

Positives are that it kills the widest range of pathogens of any inexpensive disinfectant, is extremely powerful against viruses and bacteria at room temperature, is commonly available and inexpensive, and breaks down quickly into harmless components (primarily table salt and oxygen).

[34] By far the most cost-effective home disinfectant is the commonly used chlorine bleach (a 5% solution of

Doors at the Hong Kong Museum of History with signage stating that the doors are disinfected frequently.

Home disinfectants

An alternative assessment is to measure the Minimum inhibitory concentrations (MICs) of disinfectants against selected (and representative) microbial species, such as through the use of microbroth dilution testing.[33]

A less specific measurement of effectiveness is the Food and Drug Administration (FDA). "Intermediate-level disinfection kills mycobacteria, most viruses, and bacteria with a chemical germicide registered as a 'tuberculocide' by the Environmental Protection Agency. Low-level disinfection kills some viruses and bacteria with a chemical germicide registered as a hospital disinfectant by the EPA."[32]

The standard European approach for disinfectant validation consists of a basic suspension test, a quantitative suspension test (with low and high levels of organic material added to act as ‘interfering substances’) and a two part simulated-use surface test.[31]

One way to compare disinfectants is to compare how well they do against a known disinfectant and rate them accordingly. Phenol is the standard, and the corresponding rating system is called the "Phenol coefficient". The disinfectant to be tested is compared with phenol on a standard microbe (usually Salmonella typhi or Staphylococcus aureus). Disinfectants that are more effective than phenol have a coefficient > 1. Those that are less effective have a coefficient < 1.

Measurements of effectiveness

Lactic acid is a registered disinfectant. Due to its natural and environmental profile, it has gained importance in the market.

Common sodium bicarbonate (NaHCO3) has antifungal properties,[28] and some antiviral and antibacterial properties,[29] though those are too weak to be effective at a home environment.[30]

Ultraviolet germicidal irradiation is the use of high-intensity shortwave ultraviolet light for disinfecting smooth surfaces such as dental tools, but not porous materials that are opaque to the light such as wood or foam. Ultraviolet light is also used for municipal water treatment. Ultraviolet light fixtures are often present in microbiology labs, and are activated only when there are no occupants in a room (e.g., at night).

The biguanide polymer polyaminopropyl biguanide is specifically bactericidal at very low concentrations (10 mg/l). It has a unique method of action: The polymer strands are incorporated into the bacterial cell wall, which disrupts the membrane and reduces its permeability, which has a lethal effect to bacteria. It is also known to bind to bacterial DNA, alter its transcription, and cause lethal DNA damage.[27] It has very low toxicity to higher organisms such as human cells, which have more complex and protective membranes.


[26].S. aureus and E. coli including [25]

Thymol-based disinfectant

These copper alloys were granted EPA registrations as "antimicrobial materials with public health benefits,"[21] which allows manufacturers to legally make claims regarding the positive public health benefits of products made with registered antimicrobial copper alloys. EPA has approved a long list of antimicrobial copper products made from these alloys, such as bedrails, handrails, over-bed tables, sinks, faucets, door knobs, toilet hardware, computer keyboards, health club equipment, shopping cart handles, etc. (for a comprehensive list of products, see: Antimicrobial copper-alloy touch surfaces#Approved products). Antimicrobial copper alloy products are now being installed in healthcare facilities in the U.K., Ireland, Japan, Korea, France, Denmark, and Brazil and in the subway transit system in Santiago, Chile, where copper-zinc alloy handrails will be installed in some 30 stations between 2011 and 2014.[22][23]

  • Continuously reduce bacterial contamination, achieving 99.9% reduction within two hours of exposure;
  • Kill greater than 99.9% of Gram-negative and Gram-positive bacteria within two hours of exposure;
  • Deliver continuous and ongoing antibacterial action, remaining effective in killing greater than 99.9% of bacteria within two hours;
  • Kill greater than 99.9% of bacteria within two hours, and continue to kill 99% of bacteria even after repeated contamination;
  • Help inhibit the buildup and growth of bacteria within two hours of exposure between routine cleaning and sanitizing steps.

Copper-alloy surfaces have natural intrinsic properties to destroy a wide range of E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus, Clostridium difficile, influenza A virus, adenovirus, and fungi). In addition, extensive tests on E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus, Enterobacter aerogenes, and Pseudomonas aeruginosa sanctioned by the United States Environmental Protection Agency (EPA) using Good Laboratory Practices found that when cleaned regularly, some 355 different copper alloy surfaces:

Copper alloy surfaces

A meta-analysis of 26 studies by the Cochrane Collaboration found that, most were small and of poor quality, and that there was not enough evidence to support the use of silver-containing dressings or creams, as generally these treatments did not promote wound healing or prevent wound infections. Some evidence suggested that silver sulphadiazine had no effect on infection, and actually slowed healing.[20]

United States Environmental Protection Agency classifies it into the lowest toxicity category for disinfectants, category IV.


Quaternary ammonium compounds ("quats"), such as benzalkonium chloride, are a large group of related compounds. Some concentrated formulations have been shown to be effective low-level disinfectants. Typically, quats do not exhibit efficacy against difficult to kill non-enveloped viruses such as norovirus, rotavirus, or polio virus. Newer synergous, low-alcohol formulations are highly effective broad-spectrum disinfectants with quick contact times (3–5 minutes) against bacteria, enveloped viruses, pathogenic fungi, and mycobacteria. Quats are biocides that also kill algae and are used as an additive in large-scale industrial water systems to minimize undesired biological growth.

Quaternary ammonium compounds

  • Phenol is probably the oldest known disinfectant as it was first used by Lister, when it was called carbolic acid. It is rather corrosive to the skin and sometimes toxic to sensitive people. Impure preparations of phenol were originally made from coal tar, and these contained low concentrations of other aromatic hydrocarbons including benzene, which is an IARC Group 1 carcinogen.
  • o-Phenylphenol is often used instead of phenol, since it is somewhat less corrosive.
  • Chloroxylenol is the principal ingredient in Dettol, a household disinfectant and antiseptic.
  • Hexachlorophene is a phenolic that was once used as a germicidal additive to some household products but was banned due to suspected harmful effects.
  • Thymol, derived from the herb thyme, is the active ingredient in some "broad spectrum" disinfectants that bears ecological claims.
  • Amylmetacresol is found in Strepsils, a throat disinfectant.
  • Although not a phenol, 2,4-dichlorobenzyl alcohol has similar effects as phenols, but it cannot inactivate viruses.

Phenolics are active ingredients in some household disinfectants. They are also found in some mouthwashes and in disinfectant soap and handwashes.


  • Sodium hypochlorite is very commonly used. Common household bleach is a sodium hypochlorite solution and is used in the home to disinfect drains, toilets, and other surfaces. In more dilute form, it is used in swimming pools, and in still more dilute form, it is used in drinking water. When pools and drinking water are said to be chlorinated, it is actually sodium hypochlorite or a related compound—not pure chlorine—that is being used. Chlorine partly reacts with proteinaceous liquids such as blood to form non-oxidizing N-chloro compounds, and thus higher concentrations must be used if disinfecting surfaces after blood spills.[16] Commercial solutions with higher concentrations contain substantial amounts of sodium hydroxide for stabilization of the concentrated hypochlorite, which would otherwise decompose to chlorine, but the solutions are strongly basic as a result.
  • Other hypochlorites such as calcium hypochlorite are also used, especially as a swimming pool additive. Hypochlorites yield an aqueous solution of hypochlorous acid that is the true disinfectant. Hypobromite solutions are also sometimes used.
  • Electrolyzed water or "Anolyte" is an oxidizing, acidic hypochlorite solution made by electrolysis of sodium chloride into sodium hypochlorite and hypochlorous acid. Anolyte has an oxidation-reduction potential of +600 to +1200 mV and a typical pH range of 3.5––8.5, but the most potent solution is produced at a controlled pH 5.0–6.3 where the predominant oxychlorine species is hypochlorous acid.
  • Chloramine is often used in drinking water treatment.
  • Chloramine-T is antibacterial even after the chlorine has been spent, since the parent compound is a sulfonamide antibiotic.
  • Chlorine dioxide is used as an advanced disinfectant for drinking water to reduce waterborne diseases. In certain parts of the world, it has largely replaced chlorine because it forms fewer byproducts. Sodium chlorite, sodium chlorate, and potassium chlorate are used as precursors for generating chlorine dioxide.
  • Hydrogen peroxide is used in hospitals to disinfect surfaces and it is used in solution alone or in combination with other chemicals as a high level disinfectant. Hydrogen peroxide is sometimes mixed with colloidal silver. It is often preferred because it causes far fewer allergic reactions than alternative disinfectants. Also used in the food packaging industry to disinfect foil containers. A 3% solution is also used as an antiseptic.
  • Hydrogen peroxide vapor is used as a medical sterilant and as room disinfectant. Hydrogen peroxide has the advantage that it decomposes to form oxygen and water thus leaving no long term residues, but hydrogen peroxide as with most other strong oxidants is hazardous, and solutions are a primary irritant. The vapor is hazardous to the respiratory system and eyes and consequently the OSHA permissible exposure limit is 1 ppm (29 CFR 1910.1000 Table Z-1) calculated as an eight-hour time weighted average and the NIOSH immediately dangerous to life and health limit is 75 ppm.[17] Therefore, engineering controls, personal protective equipment, gas monitoring etc. should be employed where high concentrations of hydrogen peroxide are used in the workplace. Vaporized hydrogen peroxide is one of the chemicals approved for decontamination of anthrax spores from contaminated buildings, such as occurred during the 2001 anthrax attacks in the U.S. It has also been shown to be effective in removing exotic animal viruses, such as avian influenza and Newcastle disease from equipment and surfaces.
  • The antimicrobial action of hydrogen peroxide can be enhanced by endoscopes.[18] The evidence available suggests that products based on Accelerated Hydrogen Peroxide, apart from being good germicides, are safer for humans and benign to the environment.[19]
  • Lugol's iodine solution. It is used in the poultry industry. It is added to the birds' drinking water. In human and veterinary medicine, iodine products are widely used to prepare incision sites prior to surgery. Although it increases both scar tissue formation and healing time, tincture of iodine is used as an antiseptic for skin cuts and scrapes, and remains among the most effective antiseptics known. Also used as an iodophor
  • organochlorides if treated with chlorine only. Regardless, ozone has a very wide range of applications from municipal to industrial water treatment due to its powerful reactivity.
  • catalase and peroxidase, the enzymes that break down hydrogen peroxide. It also breaks down to food safe and environmentally friendly residues (acetic acid and hydrogen peroxide), and therefore can be used in non-rinse applications. It can be used over a wide temperature range (0-40 °C), wide pH range (3.0-7.5), in clean-in-place (CIP) processes, in hard water conditions, and is not affected by protein residues.
  • Performic acid is the simplest and most powerful perorganic acid. Formed from the reaction of hydrogen peroxide and formic acid, it reacts more rapidly and powerfully than peracetic acid before breaking down to water and carbon dioxide.
  • Potassium permanganate (KMnO4) is a purplish-black crystalline powder that colours everything it touches, through a strong oxidising action. This includes staining "stainless" steel, which somehow limits its use and makes it necessary to use plastic or glass containers. It is used to disinfect aquariums and is also widely used in community swimming pools to disinfect ones feet before entering the pool. Typically, a large shallow basin of KMnO4/water solution is kept near the pool ladder. Participants are required to step in the basin and then go into the pool. Additionally, it is widely used to disinfect community water ponds and wells in tropical countries, as well as to disinfect the mouth before pulling out teeth. It can be applied to wounds in dilute solution.
  • Potassium peroxymonosulfate, the principal ingredient in Virkon, is a wide-spectrum disinfectant used in laboratories. Virkon kills bacteria, viruses, and fungi. It is used as a 1% solution in water, and keeps for one week once it is made up. It is expensive, but very effective, its pink colour fades as it is used up so it is possible to see at a glance if it is still fresh.

lysis and death. A large number of disinfectants operate in this way. Chlorine and oxygen are strong oxidizers, so their compounds figure heavily here.

Oxidizing agents

Some bacteria have developed resistance to glutaraldehyde, and it has been found that glutaraldehyde can cause asthma and other health hazards, hence ortho-phthalaldehyde is replacing glutaraldehyde.

Aldehydes, such as formaldehyde and glutaraldehyde, have a wide microbiocidal activity and are sporicidal and fungicidal. They are partly inactivated by organic matter and have slight residual activity.


[15] (coconut soap). The synergistic effect of 29.4% ethanol with dodecanoic acid is effective against a broad spectrum of bacteria, fungi, and viruses. Further testing is being performed against Clostridium difficile (C.Diff) spores with higher concentrations of ethanol and dodecanoic acid, which proved effective with a contact time of ten minutes.dodecanoic acid The efficacy of alcohol is enhanced when in solution with the wetting agent [14][13][13][12][11] Additionally, high-concentration mixtures (such as 80% ethanol + 5% isopropanol) are required to effectively inactivate lipid-enveloped viruses (such as HIV, hepatitis B, and hepatitis C).[12] A mixture of 70% ethanol or isopropanol diluted in water is effective against a wide spectrum of bacteria, though higher concentrations are often needed to disinfect wet surfaces.[11]


Although glycols are effective air disinfectants in controlled laboratory environments, it is more difficult to use them effectively in real-world environments because the disinfection of air is sensitive to continuous action. Continuous action in real-world environments with outside air exchanges at door, HVAC, and window interfaces, and in the presence of materials that adsorb and remove glycols from the air, poses engineering challenges that are not critical for surface disinfection. The engineering challenge associated with creating a sufficient concentration of the glycol vapours in the air have not to date been sufficiently addressed.[9][10]

[8][7] In the 1940s and early 1950s, further studies showed inactivation of diverse

Air disinfectants are typically chemical substances capable of disinfecting microorganisms suspended in the air. Disinfectants are generally assumed to be limited to use on surfaces, but that is not the case. In 1928, a study found that airborne microorganisms could be killed using mists of dilute bleach.[5] An air disinfectant must be dispersed either as an aerosol or vapour at a sufficient concentration in the air to cause the number of viable infectious microorganisms to be significantly reduced.

Air disinfectants


chemicals. bactericidal and worktops in the home with cutting boards rapidly. Should some bacteria survive a chemical attack, they give rise to new generations composed completely of bacteria that have resistance to the particular chemical used. Under a sustained chemical attack, the surviving bacteria in successive generations are increasingly resistant to the chemical used, and ultimately the chemical is rendered ineffective. For this reason, some question the wisdom of impregnating cloths, evolve There are arguments for creating or maintaining conditions that are not conducive to bacterial survival and multiplication, rather than attempting to kill them with chemicals. Bacteria can increase in number very quickly, which enables them to [4]

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