Control of microbial development Some terms to begin with.
Slide 2terms Biocide : slaughters biologicals Germicide : Kills microscopic organisms Bacteriostasis : stops development A sepsis : nonattendance of development
Slide 3Some 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.
Slide 4Factors that impact viability Number of microorganisms Environmental impacts Time presentation Microbial attributes
Slide 5Bacterial populaces bite the dust at a steady logarithmic rate. Figure 7.1a
Slide 6Methods of Control Physical Chemical Biological Why is counteractive action best?
Slide 7Physical Controls: Not for use on living beings Somehow, adjust layer porousness and/or structure of proteins and nucleic acids
Slide 8The 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
Slide 11Other controls Heat, dry warmth takes longer Low temperature Desiccation Osmotic Pressure Radiation Ionizing No ionizing (UV)
Slide 12Radiation harms DNA Ionizing radiation (X beams, gamma beams, electron bars) Nonionizing radiation (UV) (Microwaves kill by warmth; not particularly antimicrobial)
Slide 13Filtration Removes Microbes
Slide 15Chemical 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
Slide 16Testing 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
Slide 17Disk Diffusion Method
Slide 18Types of disinfectants Phenol and Phenolics Halogens (iodine, chlorine) tie to aa of compounds Betadine iodophor (iodine bound to natural atoms)
Slide 19Types of Disinfectants Phenol Phenolics. Lysol Bisphenols. Hexachlorophene, Triclosan Disrupt plasma films Figure 7.7
Slide 20Alcohol's more often than not by protein denaturizing Heavy metals Oligodynamic activity Denature proteins
Slide 21Surface 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)
Slide 22Gaseous Chemostaerilizers Ethylene oxide denatures proteins Resistance to these techniques relies on upon the microorganism.
Slide 24Types of Disinfectants Peroxygens Oxidizing specialists O 3 , H 2 O 2 , peracetic corrosive
Slide 25Types of Disinfectants Aldehydes Inactivate proteins by cross-connecting with utilitarian gatherings (–NH 2 , –OH, –COOH, — SH) Glutaraldehyde, formaldehyde
Slide 26Types 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
Slide 27Resistance to concoction Biocides
SPONSORS
SPONSORS
SPONSORS