Alcamo's ch 7

  1. What term is used to describe a process of destroying all living microbes, spores and viruses?
  2. What does sanitation do?
    Reduces # or pathogens or discourages their growth
  3. The time necessary for killing the population at a given temp is known as the ___ ___ ___.
    Thermal death time
  4. When using a dry heat oven a temp of ___ for a period of ___ is required to kill bacterial spores.
    • 160o
    • 2 hrs
  5. How does dry heat kill microorganisms?
    Changing microbial proteins by oxidation reactions creating an arid internal environment 
  6. How does moist heat kill microorganisms?
    By denaturing proteins
  7. A change in the physical or chemical properties of a protein is known as ___.
  8. What is the most dependable method for sterilization including destroying bacterial spores?
    Pressurized steam in an autoclave
  9. In autoclaving the sterilizing agent is ___ ___ NOT ___.
    • Moist heat
    • Pressure
  10. Why is moist heat better than dry heat for sterilization?
    It penetrates materials more rapidly b/c water conducts heat better than air
  11. What is the std temp, psi & time for autoclaving?
    121.5oC @ 15psi for 15 mins
  12. Liquids and other objects exposed to 100oC for 30 mins w/an overnight incubation period at rm temp were sterilized with a process called what?
    Fractional sterilization
  13. What are 4 methods of utilizing moist heat?
    • Fractional sterilization
    • Autoclaving
    • Pasteurization
    • Boiling (unreliable tho)
  14. ____ reduces the bacterial population of a liquid and destroys organisms that may cause spoilage and human disease.
  15. T or F Spores are not effected by pasteurization.
  16. The holding method of pasteurization involves heating at what temp for how long?
    63oC for 30 mins
  17. What 4 bacteria is pasteurization aimed at?
    • M. tuberculosis
    • C. Burnetii
    • Salmonella
    • e. Coli
  18. Flash pasteurization is accomplished at what temp for how long?
    71.6oC for 15 sec
  19. Ultra high temp pasteurization method is accomplished at what temp for how long?
    140oC for 3 sec
  20. What are 3 types of pasteurization?
    • Holding or batch method
    • Flash pasteurization method
    • Ultra high temp method
  21. ___ is a mechanical method that can be used to remove microorganisms fr solution or gas.
  22. Which type of filtration consists of a pad of cellulose acetate or polycarbonate mounted in a holding device?
    Membrane filter
  23. What are membrane filters often used to purify?
    • Heat sensitive liquids
    • Bacteriological media 
    • Toxoids
    • Many pharmaceuticals 
    • Blood solutions
  24. What does HEPA stand for and how does it work?
    • High efficiency particulate air
    • A mat of randomly arranged fibers that trap particles, microorganisms & spores
  25. How does UV light control or kill microorganisms?
    Cellular DNA absorbs light & adjacent thymine molecules link together kinking the double helix & disrupting DNA replication
  26. How does ionizing radiation kill microorganisms?
    By forcing electrons out of their shells creating ions which quickly combine w/cellular water and free radicals created affect cell metabolism & physiology
  27. How does osmosis kill microorganisms?
    By leaving them dehydrated and they die
  28. Process used to destroy pathogenic organisms on or in an object or area is known as what?
  29. A disinfectant is used on what?
    Lifeless objects such as a tabletop
  30. What is an antiseptic used on?
    Something living such as tissue
  31. What word refers to a condition in which microbes or their toxins are present in tissues or the blood?
  32. A "microbial infection of the blood" is called ___.
  33. The term asepsis means what?
    Free of disease causing microbes
  34. To ___ an object is to reduce the microbial population to a safe level as determined by public health standards.
  35. Able to kill or slow growth of microorganisms 
    Nontoxic to animals or humans
    Soluble in water
    Substantial shelf life
    Useful in diluted form
    Fast acting 
    These are all characteristics of what?
    Useful antiseptics or disinfectants
  36. What chemical parameters should be considered when selecting an antiseptic or disinfectant?
    • Temp at which it is most effective
    • What pH it is effective
    • Stability or how rapid the chem reaction is
    • Type of microorganism to be eliminated
    • Surface treated
  37. Disinfectants are regulated by the ___ while antiseptics are regulated by the ___.
    • EPA
    • FDA
  38. Iodine controls microorganisms by what means?
    Reacting with proteins
  39. What 3 mechanisms does alcohol use to kill microorganisms?
    • Denatures proteins 
    • Dissolves lipids
    • Dehydrating agent
  40. What mechanisms of action does peroxide use (2)?
    • Creates aerobic environment
    • Oxidizes proteins 
  41. How does ethylene oxide kill microorganisms?
    It reacts with functional grps in proteins & nucleic acids
  42. What do surfactants do?
    Emulsify & solubilize particles clinging to a surface & reduce surface tension
  43. ___ are synthetic chemicals acting as strong surfactants.
  44. What is triclosan?
    A bisphenol, broadspectrum antimicrobial that disrupts cell membranes by blocking synthesis of lipids
  45. What is a neg side to triclosan use?
    • Bacteria develop a resistance to it
    • Can be cancer causing agent
  46. How do heavy metals kill microorganisms?
    By binding protein molecules together disrupting cellular metabolism
Card Set
Alcamo's ch 7
Chapter 7 cards