Control of microbial development

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Control of microbial growth

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terms. Biocide: eliminates biologicalsGermicide: Kills bacteriaBacteriostasis: stops growthAsepsis: nonappearance of development. A few terms.. Sanitization: devastation of all lifeDisinfecting: demolition of vegetative pathogensAntisepsis: purification of living tissueSepsis: alludes to microbial contamination.Aseptic surgery procedures avert microbial tainting of wounds..

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Slide 1

Control of microbial development Some terms to begin with.

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terms Biocide : slaughters biologicals Germicide : Kills microscopic organisms Bacteriostasis : stops development A sepsis : nonattendance of development

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Some terms. Sanitization : demolition of all life Disinfecting : annihilation of vegetative pathogens Antisepsis : sterilization of living tissue Sepsis: alludes to microbial tainting. Aseptic surgery strategies avoid microbial tainting of wounds.

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Factors that impact viability Number of microorganisms Environmental impacts Time presentation Microbial attributes

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Bacterial populaces bite the dust at a steady logarithmic rate. Figure 7.1a

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Methods of Control Physical Chemical Biological Why is counteractive action best?

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Physical Controls: Not for use on living beings Somehow, adjust layer porousness and/or structure of proteins and nucleic acids

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The autoclave: Moist warmth and weight 15psi, 121'c, 15 minutes Thermal demise point (TDP): Lowest temperature at which all cells in a culture are killed in 10 min. Warm demise time (TDT): Time to kill all cells in a culture Decimal lessening time (DRT): Minutes to kill 90% of a populace at a given temperature

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Other controls Heat, dry warmth takes longer Low temperature Desiccation Osmotic Pressure Radiation Ionizing No ionizing (UV)

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Radiation harms DNA Ionizing radiation (X beams, gamma beams, electron bars) Nonionizing radiation (UV) (Microwaves kill by warmth; not particularly antimicrobial)

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Filtration Removes Microbes

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Chemical Methods of Control May be utilized on living life forms Factors that may impact sterilizing Concentration of the disinfectant What is to be purified pH Organic materials Contact with microorganism time

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Testing Use weakening test Three microorganisms are utilized Salmonella choleraesuis Staphylococcus aureus Pseudomonas aeruginosa Metal bearers plunged and dried Standard conditions 10 min at 20'C

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Disk Diffusion Method

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Types of disinfectants Phenol and Phenolics Halogens (iodine, chlorine) tie to aa of compounds Betadine iodophor (iodine bound to natural atoms)

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Types of Disinfectants Phenol Phenolics. Lysol Bisphenols. Hexachlorophene, Triclosan Disrupt plasma films Figure 7.7

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Alcohol's more often than not by protein denaturizing Heavy metals Oligodynamic activity Denature proteins

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Surface dynamic Agents (cleansers) Soap Degerming Acid-anionic detergents Sanitizing Quarternary ammonium mixes Cationic detergents Bactericidal, Denature proteins, disturb plasma layer Antibiotics Worry about resistance Not many utilized as additive (Nisin, Natamycin)

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Gaseous Chemostaerilizers Ethylene oxide denatures proteins Resistance to these techniques relies on upon the microorganism.

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Types of Disinfectants Peroxygens Oxidizing specialists O 3 , H 2 O 2 , peracetic corrosive

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Types of Disinfectants Aldehydes Inactivate proteins by cross-connecting with utilitarian gatherings (–NH 2 , –OH, –COOH, — SH) Glutaraldehyde, formaldehyde

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Types of Disinfectants Chemical Food Preservatives Organic Acids Inhibit digestion system Sorbic corrosive, benzoic corrosive, calcium propionate Control molds and microorganisms in nourishments and makeup Nitrite avoids endospore germination Antibiotics. Nisin and natamycin counteract decay of cheddar

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Resistance to concoction Biocides