Microbiology Ch. 5
Define electromagnetic radiation
forms of energy consisting of discrete packets of energy called photons that travel in waves
Define Sterile
free of microbes
Define Viricide
inactivate viruses
Identify Sterilization Techniques
include using heat, chemicals, filtration, irradiation
Define Bactericide
kill bacteria
Examples of antiseptics
o Ethyl Alcohol o Isopropyl Alcohol
Define autoclave and describe how an autoclave functions.
o Steam first travels in an enclosed layer surrounding the chamber. It then enters the autoclave, displacing the air downward and out through a port in the bottom of the chamber.
Define Disinfection
process of eliminating most microbes associated with an inanimate object
Define Sterilization
the process of eliminating all microbes associated with an object
Minimum conditions required to achieve sterilization in an auto clave
· 121C at 15 psi pressure for 15 minutes
Items that cannot be autoclaved include:
· Acids · Explosive Material · Flammable Material · Chlorine Based Products · Reactive, Corrosive, or Toxic Materials · Radioactive materials
Identify the following as dry heat microbial control methods, describing the characteristics and use of each: incineration and dry heat ovens.
· Dry heat microbial control methods: incineration & dry heat ovens o Incineration: burns cell components to ashes o Dry heat ovens: destroys cell components and denatures proteins. Less efficient than moist heat. Requires longer times and higher temps.
Define filtration and describe the filtration of both fluids and air.
· Filtration- passage of a liquid or gas through a mesh with pores small enough to retain microbes · Filtration of fluids: various pore sizes are available; 0.2 µm is commonly used to remove bacteria · Filtration of air: High-Efficiency Particulate Air (HEPA) is used to remove microbes that have a diameter of 0.3 µm or <.
Contrast moist heat and dry heat and state the advantages and disadvantages of each as microbial control methods.
· Moist heat destroys microbes by irreversibly denaturing their proteins. o Examples of moist heat: boiling, pasteurization, pressurized steam o Advantages: relatively fast, reliable, safe, inexpensive · Dry heat o Examples: incineration, dry heat ovens o Disadvantages: takes longer than moist heat, does not penetrate microbes as well as moist heat, less efficient at killing microbes
Identify the following as moist heat microbial control methods, describing the characteristics and use of each: boiling, pasteurization, and pressurized steam (autoclaving).
· Moist heat microbial control methods include: o Boiling o Pasteurization o Pressurized steam (autoclaving)
Define the following microbial control processes and state an example where each might be used: pasteurization, decontamination, sanitization, and preservation.
· Pasteurization- process of controlled heating in order to reduce the number of spoilage microbes and destroy pathogens · Decontamination- treatment to reduce the number of pathogens to a level considered safe to handle · Sanitization- treatment used to reduce microbial populations to a level that meets accepted health standards · Preservation- process of inhibiting the growth of microorganisms in products to delay spoilage
Identify and describe the following two classes of radiation and give examples and uses of each: ionizing and nonionizing radiation.
· Two Classes of Radiation: o Ionizing - Gamma rays - X rays o Nonionizing - Ultraviolet radiation - Microwaves
Define photon
· energy content is inversely proportional to wavelength
Contributions of Joseph Lister.
· implemented aseptic surgical techniques by using Carbolic acid to treat wounds, surgical instruments, and air
What is HEPA?
High-Efficiency Particulate Air
Examples of Disinfectants
Chlorine & Lysol
Define Bacteriostatic
agent that inhibits the growth of bacteria
Contributions Ignatz Semmelweis
an obstetrician who started requiring all personnel of the hospital to wash their hands in chlorinated lime.
Define Disinfectant
antimicrobial chemical used for disinfection
Define antiseptic
antimicrobial chemical which can be used on skin or other body tissues
Define germicide
chemical agent capable of killing microbes; spores may survive