Disinfectant 478185 223105809 2008-07-02T16:25:03Z Biologos 3235486 /* Oxidizing agents */Statement unsourced and wrong. Catalase breaks down H2O2 into water and molecular oxygen. {{Citations missing|date=May 2007}} {{otheruses4|antimicrobial agents|the Macintosh anti-virus software|Disinfectant (software)}} [[Image:Disinfection.jpg|right|thumb|Disinfection of a floor using a [[mop]]]] '''Disinfectants''' are [[antimicrobial agent]]s that are applied to non-living objects to destroy [[microorganisms]], the process of which is known as ''disinfection''. *'''Disinfection''' may be defined as: ''Cleaning an article of some or all of the pathogenic organisms which may cause infection'' <ref>www.who.int/reproductive-health/publications/MSM_98_1/MSM_98_1_glossary.en.html</ref><ref>www.cdc.gov/oralhealth/infectioncontrol/glossary.htm</ref> <br> Disinfectants should generally be distinguished from ''[[antibiotic]]s'' that destroy [[microorganisms]] within the body, and from ''[[antiseptic]]s'', which destroy microorganisms on living [[biological tissue|tissue]]. '''Sanitizers''' are substances that reduce the number of microorganisms to a safe level.One official and legal version states that a sanitizer must be capable of killing 99.999%, known as a ''5 log reduction'', of a specific bacterial test population, and to do so within 30 seconds. The main difference between a sanitizer and a disinfectant is that at a specified use dilution, the disinfectant must have a higher kill capability for pathogenic bacteria compared to that of a sanitizer. Very few disinfectants and sanitizers can [[sterilization (microbiology)|sterilise]] (the complete elimination of all microorganisms), and those that can depend entirely on their mode of application. Bacterial [[endospore]]s are most resistant to disinfectants, however some viruses and bacteria also possess some tolerance. == Properties == A perfect disinfectant would offer complete and full [[sterilization (microbiology)|sterilisation]], without harming other forms of life, be inexpensive, and non-corrosive. Unfortunately ideal disinfectants do not exist. Most disinfectants are also, by their very nature, potentially harmful (even [[toxic]]) to humans or animals. They should be treated with appropriate care. Most come with safety instructions printed on the packaging, which should be read in full before using the disinfectant. Most modern household disinfectants contain [[Denatonium|Bitrex]], an exceptionally bitter substance designed to discourage ingestion, as an added safety measure. Those that are used indoors should never be mixed with other cleaning products as [[chemical reaction]]s can occur. They are frequently used in [[hospital]]s, [[dentist|dental surgeries]], [[kitchen]]s and [[bathroom]]s to kill infectious organisms. The choice of the disinfectant to be used depends on the particular situation. Some disinfectants have a wide spectrum (kill nearly all microorganisms), whilst others kill a smaller range of disease-causing organisms but are preferred for other properties (they may be non-corrosive, non-toxic, or inexpensive). The disinfecting properties of [[sunlight]] ([[ultra-violet]]) are powerful. Rather than total reliance on chemicals, basic [[hygiene]] - a pillar of [[food safety]] - is important in the effort to control bacteria since they generally prefer a warm-moist-dark environment. There are arguments for creating or maintaining conditions which are not conducive to bacterial survival and multiplication, rather than attempting to kill them with chemicals. Bacteria have a very rapid multiplication rate, which enables them to [[evolve]] rapidly. Should some bacteria survive a chemical attack, they give rise to the next generation. Thus they are able to develop resistance to hostile chemicals. For this reason, some question the wisdom of impregnating cloths, [[cutting board]]s and worktops in the home with [[bactericidal]] chemicals. == Types of disinfectants == [[Image:Disinfection liquid.JPG|200px|right|thumb|Disinfection liquid attached to hospital bed]] === Alcohols === [[Alcohol]]s, usually [[ethanol]] or [[isopropanol]], are sometimes used as a disinfectant, but more often as an [[antiseptic]] (the distinction being that alcohol tends to be used on living tissue rather than nonliving surfaces). They have wide microbicidal activity, are non corrosive, but can be a fire hazard. They also have limited residual activity due to evaporation, which results in brief contact times, and have a limited activity in the presence of organic material. Alcohols are more effective combined with purified water—70% isopropyl alcohol or 70% ethyl alcohol is more effective than 90% alcohol, because the higher water content allows for greater diffusion through the cell membrane. <ref name="foodsafety"> FDA/CFSAN - Food Safety A to Z Reference http://www.cfsan.fda.gov/~dms/a2z-b.html</ref> Alcohol is effective against resistant fungal and bacterial spores.<ref name="foodsafety"/> === Aldehydes === Aldehydes, such as [[Glutaraldehyde]], have a wide microbiocidal activity and are sporocidal and fungicidal. They are partly inactivated by organic matter and have slight residual activity. === Oxidizing agents === [[redox|Oxidizing agents]] act by oxidising the cell membrane of microorganisms, which results in a loss of structure and leads to cell [[lysis]] and death. A large number of disinfectants operate in this way. [[Chlorine]] and [[oxygen]] are strong oxidizers, so their compounds figure heavily here. *[[Sodium hypochlorite]] is very commonly used. Common household [[bleach]] is a sodium hypochlorite solution and is used in the home to disinfect drains, [[toilet]]s, 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. * 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. *'''[[Chloramine]]''' is often used in drinking water treatment instead of chlorine because it produces fewer disinfection byproducts, which can be harmful. *'''[[Chloramine-T]]''' is antibacterial even after the chlorine has been spent. *'''[[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 [[hospital]]s to disinfect surfaces. It 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. However, recent studies have shown hydrogen peroxide to be toxic to growing cells as well as bacteria; its use as an [[antiseptic]] is no longer recommended.{{Fact|date=February 2007}} *'''[[Iodine]]''' is usually dissolved in an organic solvent or as [[Lugol's iodine]] solution. It is used in the [[poultry]] industry. It is added to the birds' drinking water. Although no longer recommended because it increases scar tissue formation and increases healing time, [[tincture of iodine]] has also been used as an antiseptic for skin cuts and scrapes. *'''[[Ozone]]''' is a gas that can be added to water for sanitation. *'''[[electrolyzed water|Acidic Electrolyzed Water]]''' is a strong oxidising solution made from the [[electrolysis]] of ordinary [[tap water]] in the presence of a specific amount of salt, generally [[sodium chloride]]. Anolyte has a typical pH range of 3.5 to 8.5 and an Oxidation-Reduction Potential (ORP) of +600 to +1200 mV. The most powerful anolyte disinfecting solution is that produced at a controlled 5.0 to 6.3 pH where the predominant oxchlorine species is hypochlorous acid. This environmentally-responsible disinfectant is highly efficacious against bacteria, fungus, mold, spores and other micro-organisms, in very short contact times. It may be applied as liquid, fog or ice. *'''[[Peracetic acid]]''' is a disinfectant produced by reacting hydrogen peroxide with acetic acid. It is broadly effective against microorganisms and is not deactivated by [[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. Performic acid is the ultimate environmentally friendly oxidising biocide for all disinfection applications. *'''[[Potassium permanganate]]''' (KMnO<sub>4</sub>) is a red crystalline powder that colours everything it touches, and is used to disinfect [[aquarium]]s. It is also used widely in community swimming pools to disinfect ones feet before entering the pool. Typically, a large shallow basin of KMnO<sub>4</sub>/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 permanganate is a very useful disinfectant. *'''[[Potassium peroxymonosulfate]]''', the principal ingredient in [[Virkon]], is a wide-spectrum disinfectant used in labs. [[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. === Phenolics === [[Phenols|Phenolics]] are active ingredients in some household disinfectants. They are also found in some mouthwashes and in disinfectant soap and handwashes. * '''[[Phenol]]''' is probably the oldest known disinfectant as it was first used by [[Joseph Lister|Lister]], when it was called carbolic acid. It is rather corrosive to the skin and sometimes toxic to sensitive people. * '''[[2-Phenylphenol|''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 the only 100% botanical disinfectant with an EPA registration (#74771-1), Benefect. Registered as "broad spectrum," or hospital-grade, it is also the only disinfectant with a green certification, Environmental Choice. === Quaternary ammonium compounds === '''[[Quaternary ammonium compounds]]''' (Quats), such as [[benzalkonium chloride]], are a large group of related compounds. Some have been used as low level disinfectants. They are effective against bacteria, but not against some species of ''[[Pseudomonas]]'' bacteria or bacterial spores. Quats are biocides which also kill algae and are used as an additive in large-scale industrial water systems to minimize undesired biological growth. Quaternary ammonium compounds can also be effective disinfectants against enveloped viruses. === Other === 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.<ref>[http://mic.sgmjournals.org/cgi/content/full/152/4/989 The response of Escherichia coli to exposure to the biocide polyhexamethylene biguanide - Allen et al. 152 (4): 989 - Microbiology<!-- Bot generated title -->]</ref> It has very low toxicity to higher organisms such as human cells, which have more complex and protective membranes. '''High-intensity shortwave [[ultraviolet light]]''' can be used 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 fixtures are often present in [[microbiology]] labs, and are activated only when there are no occupants in a room (e.g., at night). == Relative effectiveness of disinfectants == 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. == Home disinfectants == By far the most cost-effective home disinfectant is the commonly used chlorine bleach (a 5% solution of [[Sodium hypochlorite]]) which is effective against most common pathogens, including such difficult organisms [[tuberculosis]] ([[mycobacterium tuberculosis]]), hepatitis B and C, fungi, and antibiotic-resistant strains of [[staphylococcus]] and [[enterococcus]]. It even has some disinfectant action against parasitic organisms <ref> ''[http://www.epa.gov/oppad001/chemregindex.htm EPA's Registered Sterilizers, Tuberculocides, and Antimicrobial Products Against HIV-1, and Hepatitis B and Hepatitis C Viruses.]'' (Obtained January 4, 2006)</ref>. Positives are that it kills the widest range of pathogens of any inexpensive disinfectant; it is extremely powerful against viruses and bacteria at room temperature; it is commonly available and inexpensive; and it breaks down quickly into harmless components (primarily table salt and oxygen). Negatives are that it is caustic to the skin 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 may cause noxious gases to be formed). The best practice is not to add anything to household bleach except water. Dilute bleach can be tolerated on the skin for a period of time by most persons, as witnessed by the long exposure to extremely dilute "chlorine" (actually sodium or [[calcium hypochlorite]]) many children get in swimming pools. 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 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. 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. 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. The use of some antimicrobials such as triclosan, particularly 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.[http://www.watoxics.org/homes-and-gardens/factsheets/antimicrobials] == References == <references/> == See also == *[[Antimicrobials]] *[[Antiseptics]] * [[Diethylene glycol]] - a raw material for air [[sanitation]] *[[Hygiene]] * [[Sanitation Standard Operating Procedures]] *[[Sterilization (microbiology)|Sterilization]] == External links == *[http://www.stopgerms.org Alliance for Consumer Education] * [http://www.mansfield.ohio-state.edu/~sabedon/black12.htm Ohio State University lecture on Sterilization and Disinfection] * [http://www.housekeepingchannel.com/showarticle.php?id=253 What Germs Are We Killing? Testing and Classifying Disinfectants] * [http://www.bccdc.org/downloads/pdf/epid/reports/CDManual_DisinfectntSelectnGuidelines_sep2003_nov05-03.pdf Disinfectant Selection Guide] * [http://www.newton.dep.anl.gov/askasci/chem03/chem03856.htm Disinfectant and Non-Chlorine Bleach] -- Office of DOE Science Education * [http://www.stopgerms.org Alliance for Consumer Education] * [http://www.using-hydrogen-peroxide.com/home-uses-for-hydrogen-peroxide.html Using hydrogen peroxide as a home disinfectant] * [http://www.watoxics.org/homes-and-gardens/factsheets/antimicrobials Antimicrobial Products: Who Needs Them?] {{Antiseptics and disinfectants}} [[Category:Disinfectants| ]] [[Category:Hygiene]] [[ar:ديسينفيكتانت]] [[bg:Дезинфекция]] [[cs:Dezinfekce]] [[da:Desinfektion]] [[de:Desinfektion]] [[es:Desinfectante]] [[eo:Seninfektigo]] [[fr:Désinfectant]] [[io:Desinfekto]] [[it:Disinfezione]] [[he:חיטוי]] [[nl:Ontsmettingsmiddel]] [[ja:消毒]] [[pl:Dezynfekcja]] [[pt:Desinfecção]] [[ro:Dezinfectare]] [[ru:Дезинфекция]] [[simple:Disinfectant]] [[sk:Dezinfekcia]] [[fi:Desinfiointi]] [[sv:Desinfektion]] [[tr:Dezenfektasyon]] [[uk:Дезинфікуючі засоби]] [[zh:消毒]]