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Term |
Definition |
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Agar |
A derivative of marine sea-weed, used as a solidifying agent in media. |
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Acid |
A substance with a pH less than 7. |
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Aerobic |
Grows in oxygen atmosphere. |
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Alkali |
Substance with a pH greater than 7. |
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Algicide |
A chemical agent which, under defined conditions, is capable of killing algae including their spores. |
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Amphoteric |
A class of surfactant, having both anionic and cationic properties. |
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Anaerobic |
Grows in oxygen free atmosphere. |
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Anionic |
A surfactant in which the surface-active agent has a negative charge. |
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Antimicrobial |
A substance capable of killing micro-organisms. |
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Antisepsis |
The destruction or inhibition of micro-organisms on living tissues having the effect of limiting or preventing the harmful results of infection. It is not a synonym for disinfection. |
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Antiseptic |
A chemical agent used in antisepsis. |
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Bacillus |
A rod shaped bacteria. |
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Bactericide |
A chemical agent which, under defined conditions, is capable of killing bacteria but not necessarily bacterial spores. |
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Bacteriostasis |
A state of bacterial population in which multiplication is inhibited. |
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Bacteriostat |
A chemical agent which under defined conditions induces bacteriostasis. |
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Base |
Another word for alkali, i.e. pH greater than 7. |
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Biocide |
A generalised term for a chemical agent capable of killing or inactivating micro-organisms. It embraces the more specific terms algicide, bactericide, fungicide, sporicide and virucide (see also germicide).Note. Pesticides are not considered to be biocides. |
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Cationic |
A surfactant in which the surface-active agent has a positive charge. |
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Chemical Sterilising Agent |
A chemical agent which, under defined conditions, leads to sterilisation. |
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Chlorhexidine |
A bisphenol compound used as an antiseptic and disinfectant. |
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Chlorine |
A member of the halogen group of elements. Frequently, but usually, incorrectly used to define the active species in, e.g. solutions of sodium hypochlorite. |
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Coccus |
A spherical bacterium. |
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Disease |
Any change from a general state of good health. |
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Disinfectant |
A chemical agent which under defined conditions is capable of disinfection. |
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Disinfection |
The destruction of micro-organisms, but not usually bacterial spores: it does not necessarily kill all micro-organisms, but reduces them to a level acceptable for a defined purpose, for example, a level which is harmful neither to health nor to the quality of perishable goods. |
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DNA |
Deoxyribonucleic acid. Protein that contains instructions for building other proteins. |
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Fumigation |
Exposure of enclosed spaces to action of gaseous or vapour phase disinfectants or sterilants. |
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Fungus |
A group of diverse unicellular and multicellular microorganisms (pl. fungi) |
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Fungicide |
A chemical agent which under defined conditions is capable of killing fungi including their spores. |
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Fungistasis |
A state of fungal population the development of which is inhibited. |
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Fungistat |
A chemical agent which under defined conditions induces Fungistasis. |
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Genus |
A group of closely related species. |
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Germ |
A general term which should be avoided. A micro-organism which can be harmful. |
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Germicide |
A general term which should be avoided. An agent under defined conditions, which is capable of killing germs. |
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Glutaraldehyde |
A broad spectrum biocide used as an active ingredient in formulated disinfectants. |
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Gram-Negative |
Gram-Negative bacteria do not have thick cell walls, and have a lipid membrane, making them harder to lyse. Will give a negative result in a gram stain test. |
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Gram-Positive |
Gram-Positive bacteria have thick, polar cell walls that are easier to lyse. Will give a positive result in a gram stain test. |
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Gram Stain |
Stain technique used to classify bacteria into two groups: Gram negative or Gram positive. |
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Halogens |
A group of chemicals consisting of Fluorine, Chlorine, Iodine and Bromine (plus Astatine and Tennesine). Chlorine and iodine can be found in a number of disinfectants. |
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Hydrogen Peroxide |
A bleaching / oxidising agent used as a disinfectant. |
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Hypochlorite |
Usually sodium hypochlorite, but also calcium hypochlorite, solutions of hypochlorite are oxidising disinfectants producing the biocidally active hypochlorite anion and hypochlorous acid. |
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Iodine |
A halogen with similar properties to chlorine, but more stable and less reactive. |
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Iodophor |
Iodine in solution of surfactant with stabiliser. |
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Lysis |
The process of lysing a cell. |
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Lyse |
To break open a cell’s membrane. |
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Media |
A nutrient rich solid or liquid (agar or broth) used to grow micro-organisms. |
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Microbe |
An alternative expression for micro-organism. |
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Micro-organism |
A microscopic entity capable of replication. It includes bacteria, viruses and the microscopic forms of algae, fungi and protozoa. |
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Motile |
Describes organisms which can move independently. |
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Mould |
Any fungus that forms visible mycelia growth. |
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Mycelium |
A visible mass of tangled filaments of fungal growth. |
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Nucleic Acids |
An organic compound composed of nucleotides DNA and RNA. |
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Oocyst |
An oval body in the reproduction cycle of certain protozoa. |
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Pathogen |
An organism that causes disease. Can be animals, plants or micro-organisms. |
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Peracetic acid |
Acid produced by combination of acetic acid and hydrogen peroxide. A highly effective biocide. |
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Phenol |
Also known as carbolic acid, a phenyl alcohol derived from coal tar. Used as a disinfectant. |
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Preservation |
Maintaining numbers of micro-organisms at low levels i.e. low enough to make food safe to eat or to prevent spoilage. |
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Protozoa |
Unicellular micro-organisms. Classified in the Animal Kingdom. |
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QAC / Quat |
Quaternary ammonium compounds. Cationic surfactants with bactericidal but weak detergent properties. |
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RNA |
Ribonucleic acid. Involved in protein synthesis. |
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Sanitisation |
A term used mainly in the food and catering industry. A process of both cleaning / disinfecting utensils, equipment and surfaces. |
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Sanitiser |
A chemical agent used for sanitisation. |
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Sanitize |
U.S. spelling of sanitise. |
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Somatic |
Refers to the “body” or main part of a cell. Does not include reproductive structures such as spores. |
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Species |
Fundamental rank of the classification system. (Two or more species grouped together are classed as a genus). |
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Spirochete |
A twisted bacterial rod with a flexible cell wall containing axial filaments for motility. |
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Spore |
A highly resistant structure formed from somatic cells in several genera of bacteria. E.g. Bacillus. Also, a reproductive structure formed by fungi. |
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Sporicide |
A chemical agent which, under defined conditions, is capable of killing bacterial spores. |
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Sterile |
Free from all living micro-organisms. |
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Sterilisation |
A process which renders an item sterile. |
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Sterilising agent |
An agent or combination of agents which under defined conditions leads to sterilisation. |
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Sterilize |
U.S. spelling of sterilise. |
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Surfactant |
A surface active agent. |
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Toxin |
A poisonous substance produced by a species of micro-organism. |
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Vibrio |
A form of bacteria occurring as a curved rod. |
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Virucide |
A chemical agent which, under defined conditions, is capable of killing or inactivating viruses. |
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Virus |
A non-cellular entity consisting of protein and nucleic acid. Can only replicate after entry into specific types of living cell. |
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Zoonosis |
Any disease which can be transmitted from animal to man and vice-versa. |
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