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