FACTOID # 12: It's not the government they hate: Washington DC has the highest number of hate crimes per capita in the US.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Sterilization (microbiology)

Sterilization (or sterilisation) refers to any process that effectively kills or eliminates transmissible agents (such as fungi, bacteria, viruses and prions) from a surface, equipment, foods, medications, or biological culture medium. Sterilization can be achieved through application of heat, chemicals, irradiation, or filtration. Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Groups I: dsDNA viruses II: ssDNA viruses III: dsRNA viruses IV: (+)ssRNA viruses V: (-)ssRNA viruses VI: ssRNA-RT viruses VII: dsDNA-RT viruses A virus (from the Latin noun virus, meaning toxin or poison) is a microscopic particle (ranging in size from 20 - 300 nm) that can infect the... A prion (IPA: [1] ) — short for proteinaceous infectious particle (-on) that lacks nucleic acid (by analogy to virion) — is a type of infectious agent composed only of protein. ... In physics, heat, symbolized by Q, is defined as a form of energy whose absorption raises the temperature of a body, not existing in the transition state, and abstraction of which from the same body lowers its temperature. ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... Irradiation is the process by which an item is exposed to radiation. ... In chemistry, alchemy and water treatment, filtration is the process of using a filter to mechanically separate a mixture. ...

Contents

Applications

Foods

The first application of sterilization was thorough cooking to effect the partial heat sterilization of foods and water. Cultures that practice heat sterilization of food and water have longer life expectancy and lower rates of disability. Canning of foods by heat sterilization was an extension of the same principle. Ingestion of contaminated food and water remains a leading cause of illness and death in the developing world, particularly for children. Cooking is the act of preparing food for ingestion. ... This article or section does not cite any references or sources. ...


Medicine and Surgery

In general, surgical instruments and medications that enter an already sterile part of the body (such as the blood, or beneath the skin) must have a high sterility assurance level. Examples of such instruments include scalpels, hypodermic needles and artificial pacemakers. This is also essential in the manufacture of parenteral pharmaceuticals. Sterility assurance level (SAL) is a term used in microbiology to describe the probability of a single unit being non-sterile after it has been subjected to the sterilization process. ... A scalpel is a very sharp knife used for surgery, anatomical dissection, and various arts and crafts. ... Different bevels on hypodermic needles. ... A pacemaker A pacemaker (or artificial pacemaker, so as not to be confused with the hearts natural pacemaker) is a medical device designed to regulate the beating of the heart. ... In pharmacology and toxicology, a route of administration is the path by which a drug, fluid, poison or other substance is brought into contact with the body 1. ...


Heat sterilization of medical instruments is known to have been used in Ancient Rome, but it mostly disappeared throughout the Middle Ages resulting in significant increases in disability and death following surgical procedures. Ancient Rome was a civilization that grew from a small agricultural community founded on the Italian Peninsula circa the 9th century BC to a massive empire straddling the Mediterranean Sea. ... The Middle Ages formed the middle period in a traditional schematic division of European history into three ages: the classical civilization of Antiquity, the Middle Ages, and modern times, beginning with the Renaissance. ...


Preparation of injectable medications and intravenous solutions for fluid replacement therapy requires not only a high sterility assurance level, but well-designed containers to prevent entry of adventitious agents after initial sterilization. Fluid replacement or fluid resuscitation is the medical practice of replenishing bodily fluid lost through sweating, bleeding, fluid shifts or other pathologic processes. ... Sterility assurance level (SAL) is a term used in microbiology to describe the probability of a single unit being non-sterile after it has been subjected to the sterilization process. ... An infection is the detrimental colonization of a host organism by a foreign species. ...


Heat sterilization

Steam Sterilization

Front-loading autoclaves are very common.
Front-loading autoclaves are very common.

A widely-used method for heat sterilization is the autoclave. Autoclaves commonly use steam heated to 121°C (250°F), at 103 kPa (15 psi) above atmospheric pressure. Solid surfaces are effectively sterilized when heated this temperature for at least 15 minutes or to 134°C for a minimum of 3 minutes. However, liquids and instruments packed in layers of cloth require a much longer time to reach a sterilizing temperature. After sterilization, autoclaved liquids must be cooled slowly to avoid boiling over when the pressure is released. Download high resolution version (1255x610, 499 KB)Front loading autoclaves are very common. ... Download high resolution version (1255x610, 499 KB)Front loading autoclaves are very common. ... Front loading autoclaves are common Stovetop autoclaves need to be monitored carefully and are the simplest of all autoclaves Multiple large autoclaves are used for processing substantial quantities of laboratory equipment prior to reuse, and infectious material prior to disposal. ...


Proper autoclave treatment will inactivate all fungi, bacteria, viruses and also bacterial spores, which can be quite resistant. It will not necessarily eliminate all prions. Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... This article is about a biological reproductive structure; for the video game, see Spore (video game). ... For the bird called a prion, see Prion (bird) Prions - short for proteinaceous infectious particle - are infectious self-reproducing protein structures. ...


For prion elimination, various recommendations state 121–132°C(270°F) for 60 minutes or 134°C (273°F) for at least 18 minutes. The prion that causes the disease scrapie (strain 263K) is inactivated relatively quickly by such sterilization procedures; however, other strains of scrapie, as well as strains of CJD and BSE have shown much more resistance. Using mice as test animals, one experiment showed that heating BSE positive brain tissue at 134-138°C (273-280°F) for 18 minutes resulted in only a 2.5 log decrease in prion infectivity. (The initial BSE concentration in the tissue was relatively low). To have a significant margin of safety, cleaning should reduce infectivity 4 logs, and the sterilization method should reduce it a further 5 logs. Scrapie is a fatal, degenerative disease that affects the nervous systems of sheep and goats. ... CJD can mean: Creutzfeldt-Jakob disease chronological Julian day This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Classic image of cattle with BSE. Frantic digging going nowhere. ... Feral mouse A mouse (plural mice) is a rodent that belongs to one of numerous species of small mammals. ... Italic text // ahh addiing sum spiice iin hurr`` For other uses, see Brain (disambiguation). ... Above is the graph plots of Logarithms to various bases: is to base e, is to base 10, and is to base 1. ...


To ensure the autoclaving process was able to cause sterilization, most autoclaves have meters and charts that record or display pertinent information such as temperature and pressure as a function of times. Indicator tape is often taped onto packages of products to be autoclaved. The tape contains a chemical that will change color when the appropriate conditions have been met. Some types of packaging have built-in indicators on them.


Biological indicators ("bioindicators") can also be used to independently confirm autoclave performance. Several simple bioindicator devices are commercially available based on microbial spores. Most contain pure strains of the heat resistant microbe Bacillus stearothermophilus which are among the toughest organisms an autoclave will have to destroy. Several of these devices have a self-contained growth medium (with or separate to the spores) and a growth indicator. Bacillus stearothermophilus is a rod-shaped, Gram-positive bacteria and a member of the division Firmicutes. ...


After a run in an autoclave, the internal glass ampule in the biological indicator vial is shattered, allowing the spores into a differential liquid medium. The vial is then incubated (typically at at 56°C (132°F)) for 48 hours. If the autoclave destroyed the spores, the medium will remain its original color. If autoclaving was unsuccessful the B. sterothermophilus will metabolize during incubation, causing a color change during the prescribed period of incubation.


For effective autoclaving, the steam needs to be able to penetrate uniformly. For this reason, an autoclave must not be overcrowded, and the lids of bottles and containers must be ajar. During the initial heating of the chamber, residual air must be allowed to escape as steam enters the autoclave chamber; otherwise the final temperature will be less than that of the entering steam. Indicators should be placed in the most difficult places for the steam to reach to ensure that steam actually penetrates there.


For autoclaving, as for all disinfection of sterilization methods, the cleaning off of any biological material is also critical. Biological matter or any grime may shield organisms from the property intended to kill them, whether it physical or chemical. Cleaning can also remove a large number of organisms at once. Proper cleaning can be achieved by physical scrubbing to remove dirt; this should be done with detergent and warm water to get the best results. Manual cleaning works through agitation, where the organisms are literally brushed off using detergent. When manual cleaning instruments or utensils that have organic matter on them, cool water must be used because warm or hot water may cause organic debris to coagulate. Where it is not feasible, ultrasound or pulsed air can be used to remove debris. Ultrasound works by a process called cavitation, in which sound waves are pulsed through a water/detergent medium, causing tiny bubbles to form. When these bubbles become unstable, they implode, causing organic debris to be pulled off. Ultrasonic machines must be used with the lid in the closed position because of the creation of aerosols which can be harmful to the operator. Ultrasound is a form of cyclic sound pressure with a frequency greater than the upper limit of human hearing, this limit being approximately 20 kilohertz (20,000 hertz). ...


Food

Although imperfect, cooking and canning are the most common applications of heat sterilization. Boiling water kills the vegetative stage of all common microbes. Roasting meat until it is well done typically completely sterilizes the surface. Since the surface is also the part of food most likely to be contaminated by microbes, roasting usually prevents food poisoning. Note that the common methods of cooking food do not sterilize food - they simply reduce the number of disease-causing micro-organisms to a level that is not dangerous for people with normal digestive and immune systems. Pressure cooking is analogous to autoclaving and when performed correctly renders food sterile. However, some foods are notoriously difficult to sterilize with home canning equipment, so expert recommendations should be followed for home processing to avoid food poisoning. Foodborne illness or food poisoning is caused by consuming food contaminated with pathogenic bacteria, toxins, viruses, prions or parasites. ...


See also Food safety. Food safety is a scientific discipline describing the handling, preparation, and storage of food in ways that prevent Foodborne illness. ...


Food Utensils

Dishwashers often only use hot tap water or heat the water to between 49 and 60°C (120 and 140°F), and thus provide temperatures that could promote bacterial growth. That is to say, they do not effectively sterilize utensils. Some dishwashers do actually heat water up to 74°C (165°F) or higher; those often are specifically described as having sterilization modes of some sort, but this is not a substitute for autoclaving. Note that dishwashers remove food traces from the utensils by a combination of mechanical action (the action of water hitting the plates and cutlery) and the action of detergents and enzymes on fats and proteins. This removal of food particles thus removes one of the factors required for bacterial growth (food), and explains why items with cracks and crevices should either be washed by hand or disposed of: if the water cannot get to the area needing cleaning, the warm, moist, dark conditions in the dishwasher can actually promote bacterial growth. A Dishwasher A two drawer DishDrawer dishwasher. ...


Bathing

Bathing and washing are not hot enough to sterilize bacteria without scalding the skin. Most hot tap water is between 43 and 49°C (110 and 120°F), though some people set theirs as high as 55°C (130°F). Humans begin to find water painful at 41 to 42°C (106 to 108°F), which to many bacteria is just starting to get warm enough for them to grow quickly; they will grow faster, rather than be killed at temperatures up to 55°C (130°F) or more. Children bathing in a small metal bathtub Bathing is the immersion of the body in fluid, usually water, or an aqueous solution. ...


Other Methods

Other heat methods include flaming, incineration, boiling, tindalization, and using dry heat.


Flaming is done to loops and straight-wires in microbiology labs. Leaving the loop in the flame of a Bunsen burner or alcohol lamp until it glows red ensures that any infectious agent gets inactivated. This is commonly used for small metal or glass objects, but not for large objects (see Incineration below). However, during the initial heating infectious material may be "sprayed" from the wire surface before it is killed, contaminating nearby surfaces and objects. Therefore, special heaters have been developed that surround the innoculating loop with a heated cage, ensuring that such sprayed material does not further contaminate the area. A bunsen burner with needle valve. ...


Incineration will also burn any organism to ash. It is used to sanitize medical and other biohazardous waste before it is discarded with non-hazardous waste. This article or section is in need of attention from an expert on the subject. ...


Boiling in water for 15 minutes will kill most vegetative bacteria and viruses, but boiling is ineffective against prions and many bacterial and fungal spores; therefore boiling is unsuitable for sterilization. However, since boiling does kill most vegetative microbes and viruses, it is useful for reducing viable levels if no better method is available. Boiling is a simple process, and is an option available to most anyone most anywhere, requiring only water, enough heat, and a container that can withstand the heat; however, boiling can be hazardous and cumbersome. A prion (IPA: [1] ) — short for proteinaceous infectious particle (-on) that lacks nucleic acid (by analogy to virion) — is a type of infectious agent composed only of protein. ... This article is about a biological reproductive structure; for the video game, see Spore (video game). ...


Tindalization[1] /Tyndallization[2] named after John Tyndall is a lengthy process designed to reduce the level of activity of sporulating bacteria that are left by a simple boiling water method. The process involves boiling for a period (typically 20 minutes) at atmospheric pressure, cooling, incubating for a day, boiling, cooling, incubating for a day, boiling, cooling, incubating for a day, and finally boiling again. The three incubation periods are to allow heat-resistant spores surviving the previous boiling period to germinate to form the heat-sensitive vegetative (growing) stage, which can be killed by the next boiling step. This is effective because many spores are stimulated to grow by the heat shock. The procedure only works for media that can support bacterial growth - it will not sterilize plain water. Tindalization/tyndallization is ineffective against prions. This article is about the 19th century scientist. ...


Dry heat can be used to sterilize items, but as the heat takes much longer to be transferred to the organism, both the time and the temperature must usually be increased, unless forced ventilation of the hot air is used. The standard setting for a hot air oven is at least two hours at 160°C (320°F). A rapid method heats air to 190°C (374°F) for 6 minutes for unwrapped objects and 12 minutes for wrapped objects [1] [2]. Dry heat has the advantage that it can be used on powders and other heat-stable items that are adversely affected by steam (for instance, it does not cause rusting of steel objects).


By combining immersion in sodium hydroxide (NaOH 0.09N) for two hours with one hour autoclaving (121°C / 250°F), several investigators have shown complete (>7.4 logs) inactivation. (Note that sodium hydroxide may corrode surgical instruments, especially if the sodium hydroxide immersion and autoclaving steps are combined.) Sodium hydroxide (NaOH), also known as lye or caustic soda, is a caustic metallic base. ...


Chemical sterilization

Chemicals are also used for sterilization. Although heating provides the most reliable way to rid objects of all transmissible agents, it is not always appropriate, because it will damage heat-sensitive materials such as biological materials, fiber optics, electronics, and many plastics. Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ... This article or section does not cite any references or sources. ...


Ethylene oxide (EO or EtO) gas is commonly used to sterilize objects sensitive to temperatures greater than 60°C such as plastics, optics and electrics. Ethylene oxide treatment is generally carried out between 30°C and 60°C with relative humidity above 30% and a gas concentration between 200 - 800 mg/L for at least three hours. Ethylene oxide penetrates well, moving through paper, cloth, and some plastic films and is highly effective. Ethylene oxide sterilizers are used to process sensitive instruments which cannot be adequately sterilized by other methods. EtO can kill all known viruses, bacteria and fungi, including bacterial spores and is satisfactory for most medical materials, even with repeated use. However it is highly flammable, and requires a longer time to sterilize than any heat treatment. The process also requires a period of post-sterilization aeration to remove toxic residues. Ethylene oxide is the most common sterilization method, used for over 70% of total sterilizations, and for 50% of all disposable medical devices. The chemical compound ethylene oxide is an important industrial chemical used as an intermediate in the production of ethylene glycol and other chemicals, and as a sterilant for foodstuffs and medical supplies. ...


The two most important ethylene oxide sterilization methods are: (1) the gas chamber method and (2) the micro-dose method. To benefit from economies of scale, EtO has traditionally been delivered by flooding a large chamber with a combination of EtO and other gases used as dilutants (usually CFCs or carbon dioxide ). This method has drawbacks inherent to the use of large amounts of sterilant being released into a large space, including air contamination produced by CFCs and/or large amounts of EtO residuals, flammability and storage issues calling for special handling and storage, operator exposure risk and training costs. Because of these problems a micro-dose sterilization method was developed in the late 1950's, using a specially designed bag to eliminate the need to flood a larger chamber with EtO. This method is also known as gas diffusion sterilization, or bag sterilization. This method minimize the use of gas.[3]


Bacillus subtilis, a very resistant organism, is used as a rapid biological indicator for EO sterilizers. If sterilization fails, incubation at 37°C causes a fluorescent change within four hours, which is read by an auto-reader. After 96 hours, a visible color change occurs. Fluorescence is emitted if a particular (EO resistant) enzyme is present, which means that spores are still active. The color change indicates a pH shift due to bacterial metabolism. The rapid results mean that the objects treated can be quarantined until the test results are available. Binomial name Bacillus subtilis (Ehrenberg 1835) Cohn 1872 Gram-stained Bacillus subtilis Sporulating Bacillus subtilis Bacillus subtilis is a Gram-positive, catalase-positive bacterium commonly found in soil. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ...


Ozone is used in industrial settings to sterilize water and air, as well as a disinfectant for surfaces. It has the benefit of being able to oxidize most organic matter. On the other hand, it is a toxic and unstable gas that must be produced on-site, so it is not practical to use in many settings. It has been suggested that Ozone generator be merged into this article or section. ...


Chlorine bleach is another accepted liquid sterilizing agent. Household bleach consists of 5.25% sodium hypochlorite. It is usually diluted to 1/10 immediately before use; however to kill Mycobacterium tuberculosis it should be diluted only 1/5. The dilution factor must take into account the volume of any liquid waste that it is being used to sterilize.[4] Bleach will kill many organisms immediately, but for full sterilization it should be allowed to react for 20 minutes. Bleach will kill many, but not all spores. It is highly corrosive and may corrode even stainless steel surgical instruments. Commercial chlorine bleach To bleach something, is to remove or lighten its color, sometimes as a preliminary step in the process of dyeing; a bleach is a chemical that produces these effects, often via oxidation. ... Sodium hypochlorite is a chemical compound with the formula NaClO. A solution of sodium hypochlorite is frequently used as a disinfectant and as a bleaching agent; indeed, often it is simply called bleach, though other chemicals are sometimes given that name as well. ... Binomial name Mycobacterium tuberculosis Zopf 1883 Mycobacterium tuberculosis is the bacterium that causes most cases of tuberculosis[1]. It was first described on March 24, 1882 by Robert Koch, who subsequently received the Nobel Prize in physiology or medicine for this discovery in 1905. ...


Glutaraldehyde and formaldehyde solutions (also used as fixatives) are accepted liquid sterilizing agents, provided that the immersion time is sufficiently long. To kill all spores in a clear liquid can take up to 12 hours with glutaraldehyde and even longer with formaldehyde. The presence of solid particles may lenghthen the required period or render the treatment ineffective. Sterilization of blocks of tissue can take much longer, due to the time required for the fixative to penetrate. Glutaraldehyde and formaldehyde are volatile, and toxic by both skin contact and inhalation. Glutaraldehyde has a short shelf life (<2 weeks), and is expensive. Formaldehyde is less expensive and has a much longer shelf life if some methanol is added to inhibit polymerization to paraformaldehyde, but is much more volatile. Formaldehyde is also used as a gaseous sterilizing agent; in this case, it is prepared on-site by depolymerization of solid paraformaldehyde. Many vaccines, such as the original Salk polio vaccine, are sterilized with formaldehyde. Glutaraldehyde is a colourless liquid with a pungent odor used to sterilize medical and dental equipment. ... The chemical compound formaldehyde (also known as methanal) is a gas with a pungent smell. ... In the fields of histology, pathology, and cell biology, fixation is a chemical process by which biological tissues are preserved from decay. ... Shelf-life is the length of time that corresponds to a tolerable loss in quality of a processed food. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ... An example of alkene polymerisation, in which each Styrene monomer units double bond reforms as a single bond with another styrene monomer and forms polystyrene. ... Polyoxymethylene, also known as acetal resin, polytrioxane, polyformaldehyde, and paraformaldehyde, is an engineering plastic used to make gears, bushings and other mechanical parts ( nylon, teflon, UHMWPE). ... Jonas Edward Salk (October 28, 1914 – June 23, 1995) was an American physician and researcher, best known for the development of the first polio vaccine (the eponymous Salk vaccine). ...


Ortho-phthalaldehyde (OPA) is a chemical sterilizing agent that received Food and Drug Administration (FDA) clearance in late 1999. Typically used in a 0.55% solution, OPA shows better myco-bactericidal activity than glutaraldehyde. It also is effective against glutaraldehyde-resistant spores. OPA has superior stability, is less volatile, and does not irritate skin or eyes, and it acts more quickly than glutaraldehyde. On the other hand, it is more expensive, and will stain proteins (including skin) gray in color. o-Phthalaldehyde is the chemical compound with the formula C6H4(CHO)2. ... FDA logo The Food and Drug Administration (FDA) is an agency of the United States Department of Health and Human Services and is responsible for regulating food, dietary supplements, drugs, biological medical products, blood products, medical devices, radiation-emitting devices, veterinary products, and cosmetics in the United States. ...


Hydrogen peroxide is another chemical sterilizing agent. It is relatively non-toxic once diluted to low concentrations (although a dangerous oxidizer at high concentrations), and leaves no residue. Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in a dilute solution, slightly more viscous than water. ...


Sterrad sterilization chambers use hydrogen peroxide vapor to sterilize heat-sensitive equipment such as rigid endoscopes. A recent model can sterilize most hospital loads in as little as 20 minutes. The Sterrad has limitations with processing certain materials such as paper/linens and long thin lumens. Paper products cannot be sterilized in the Sterrad system because of a process called cellulostics, in which the hydrogen peroxide would be completely absorbed by the paper product. Endoscopy means looking inside and refers to looking inside the human body for medical reasons. ...


Hydrogen peroxide and formic acid are mixed as needed in the Endoclens device for sterilization of endoscopes. This device has two independent asynchronous bays, and cleans (in warm detergent with pulsed air), sterilizes and dries endoscopes automatically in 30 minutes. Studies with synthetic soil with bacterial spores showed the effectiveness of this device. Formic acid (systematically called methanoic acid) is the simplest carboxylic acid. ...


Dry Sterilization Process (DSP) uses hydrogen peroxide at a concentration of 30-35% under low pressure conditions. This process achieves bacterial reduction of 10-6...10-8. The complete process cycle time is just 6 seconds, and the surface temperature is increased only 10°-15°C. Originally designed for the sterilization of plastic bottles in the beverage industry, because of the high germ reduction and the slight temperature increase the Dry Sterilization Process is also useful for medical and pharmaceutical applications. The term Dry Sterilisation Process, DSP, denotes a dry aseptic sterilisation process. ...


Peracetic acid (0.2%) is used to sterilize instruments in the Steris system. Properties: CAS no 79-21-0 Synonyms peroxy acetic acid, acetylhydroperoxide, PAA Physical data Melting point: 0. ...


Prions are highly resistant to chemical sterilization. Treatment with aldehydes (e.g., formaldehyde) have actually been shown to increase prion resistance. Hydrogen peroxide (3%) for one hour was shown to be ineffective, providing less than 3 logs (10-3) reduction in contamination. Iodine, formaldehyde, glutaraldehyde and peracetic acid also fail this test (one hour treatment). Only chlorine, a phenolic compound, guanidinium thiocyanate, and sodium hydroxide (NaOH) reduce prion levels by more than 4 logs. Chlorine and NaOH are the most consistent agents for prions. Chlorine is too corrosive to use on certain objects. Sodium hydroxide has had many studies showing its effectiveness. A prion (IPA: [1] ) — short for proteinaceous infectious particle (-on) that lacks nucleic acid (by analogy to virion) — is a type of infectious agent composed only of protein. ... An aldehyde. ... The chemical compound formaldehyde (also known as methanal) is a gas with a pungent smell. ... General Name, Symbol, Number iodine, I, 53 Chemical series halogens Group, Period, Block 17, 5, p Appearance violet-dark gray, lustrous Standard atomic weight 126. ... The chemical compound formaldehyde (also known as methanal) is a gas with a pungent smell. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group (-OH) attached to an aromatic hydrocarbon group. ... Guanidinium thiocyanate is a chemical compound that can be used to deactivate a virus, such as the influenza virus that caused the 1918 Spanish flu so that it can be studied safely. ... Sodium hydroxide (NaOH), also known as lye or caustic soda, is a caustic metallic base. ...


Radiation sterilization

Methods exist to sterilize using radiation such as X-rays, gamma rays, or subatomic particles. Radiation as used in physics, is energy in the form of waves or moving subatomic particles. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... This article is about electromagnetic radiation. ... A subatomic particle is a particle smaller than an atom: it may be elementary or composite. ...

  • Gamma rays are very penetrating and are commonly used for sterilization of disposable medical equipment, such as syringes, needles, canulas and IV sets. Gamma radiation requires bulky shielding for the safety of the operators; they also require storage of the radioisotope usually colbalt60, which continuously emits gamma rays (it cannot be turned off, and therefore always presents a hazard in the area of the facility).
  • X-rays are less penetrating than gamma rays and tend to require longer exposure times, but require less shielding, and are generated by an X-ray machine that can be turned off for servicing and when not in use.
  • Ultraviolet light irradiation (UV, from a germicidal lamp) is useful only for sterilization of surfaces and some transparent objects. Many objects that are transparent to visible light absorb UV. UV irradiation is routinely used to sterilize the interiors of biological safety cabinets between uses, but is ineffective in shaded areas, including areas under dirt (which may become polymerized after prolonged irradiation, so that it is very difficult to remove). It also damages many plastics, such as polystyrene foam.
Further information: Ultraviolet Germicidal Irradiation
  • Subatomic particles may be more or less penetrating, and may be generated by a radioisotope or a device, depending upon the type of particle.

Irradiation with X-rays or gamma rays does not make materials radioactive. Irradiation with particles may make materials radioactive, depending upon the type of particles and their energy, and the type of target material: neutrons and very high-energy particles can make materials radioactive, but have good penetration, whereas lower energy particles (other than neutrons) cannot make materials radioactive, but have poorer penetration. This article is about electromagnetic radiation. ... A radionuclide is an atom with an unstable nucleus. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Albert von Kollikers hand, one of the first X-ray images. ... “UV” redirects here. ... This article or section does not cite any references or sources. ... A 9W germicidal lamp in a modern compact fluorescent lamp form factor Close-up of the electrodes and the safety warning An EPROM. The small quartz window admits UV light during erasure. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... UV light disinfects the sterile laminar flow cabinet when not in use Laminar flow cabinet or laminar flow closet is a carefully enclosed bench designed to prevent contamination of semiconductor wafers, biological samples, or any particle sensitive device. ... Polystyrene is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. ... A low pressure mercury vapor discharge tube floods the inside of a hood with shortwave UV light when not in use, sterilizing microbiological contaminants from irradiated surfaces. ... Irradiation is the process by which an item is exposed to radiation. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... This article is about electromagnetic radiation. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ...


Irradiation is used by the United States Postal Service to sterilize mail in the Washington, DC area. Some foods (e.g. spices, ground meats) are irradiated for sterilization (see food irradiation). The United States Postal Service (USPS) is an independent establishment of the executive branch of the United States government (see 39 U.S.C. Â§ 201) responsible for providing postal service in the U.S. Within the United States, it is colloquially referred to simply as the post office. ... Aerial photo (looking NW) of the Washington Monument and the White House in Washington, DC. Washington, D.C., officially the District of Columbia (also known as D.C.; Washington; the Nations Capital; the District; and, historically, the Federal City) is the capital city and administrative district of the United... The Radura logo, used to show a food has been treated with radiation Food irradiation is the process of exposing food to ionizing radiation in order to disinfect, sanitize, sterilize, preserve food or to provide insect disinfestation. ...


Sterile filtration

Clear liquids that would be damaged by heat, irradiation or chemical sterilization can be sterilized by mechanical filtration. This method is commonly used for sensitive pharmaceuticals and protein solutions in biological research. A filter with pore size 0.2 µm will effectively remove bacteria. If viruses must also be removed, a much smaller pore size around 20 nm is needed. Solutions filter slowly through membranes with smaller pore diameters. Prions are not removed by filtration. The filtration equipment and the filters themselves may be purchased as presterilized disposable units in sealed packaging, or must be sterilized by the user, generally by autoclaving at a temperature that does not damage the fragile filter membranes. To ensure sterility, the filtration system must be tested to ensure that the membranes have not been punctured prior to or during use. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Groups I: dsDNA viruses II: ssDNA viruses III: dsRNA viruses IV: (+)ssRNA viruses V: (-)ssRNA viruses VI: ssRNA-RT viruses VII: dsDNA-RT viruses A virus (from the Latin noun virus, meaning toxin or poison) is a microscopic particle (ranging in size from 20 - 300 nm) that can infect the... A nanometre (American spelling: nanometer, symbol nm) is a unit of length in the metric system, equal to one thousand-millionth of a metre, which is the current SI base unit of length. ...


References

  • Central Service Technical Manual, 6th Edition, Jack Ninemeier, PhD, Editor , International Association of Healthcare Central Service Materiel Management
  • Control of microbes
  1. ^ Mesquita, J. A. M.; Teixeira, M.A. and Brandao, S. C. C. (1998). "Tindalization of goats' milk in glass bottles.". J. Anim. Sci. /J. Dairy Sci. Vol. 76, Suppl. 1 / Vol. 81, Suppl. 1/: 21. Retrieved on 2007-03-06. 
  2. ^ Thiel, Theresa (1999). http://www.umsl.edu/~microbes/pdf/tyndallization.pdf (pdf). Science in the Real World. Retrieved on 2007-03-06.
  3. ^ Micro-dose sterilization method
  4. ^ Beth Israel Deaconess Medical Center Biosafety Manual (2004 edition)
  • Raju, G.K. & Cooney, C.L., 1993. Media and air sterilization. in Biotechnology, ed. Stephanopoulos, G., Vol 3., pp 157-184.

2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... March 6 is the 65th day of the year (66th in leap years) in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... March 6 is the 65th day of the year (66th in leap years) in the Gregorian calendar. ... Beth Israel Deaconess Medical Center, located in Boston, Massachusetts, is one of the three major teaching hospitals affiliated with Harvard Medical School. ... shelby was here 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ...

External links

  • Sterilizing symbols (D, z, F) and their meaning

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m