march 15 micro notes

  1. sterilization
    processes that kills living organisms including spores
  2. disinfection
    • destruction of vegatative pathogens (not spore)
    • activly growing
  3. antispesis
    destruction of vegetative pathodgens on living tissue
  4. degerming
    removal of microbes from a limited area
  5. sanitation
    lowers microbial count
  6. thermal death point
    lowest temp at which all microbes in liquid suspension will be killed within 10 min of exposure
  7. thermal death time
    minimal length of time for all bacteria in liquid culture to be killed at a given temp
  8. decimal reduction time
    time in which 90% of a population at a given temp will be killed
  9. moist heat
    • autoclave: 120-130c deg- pressure cooker
    • effect on instruments: rusts metal
    • foil or cloth wrap soild materials
    • must use on liquids that tolerate high heat
  10. dry heat
    • glassware and instruments
    • 160-170 for at least 90 min
    • usually foil wrap
    • incineration (loops and needles)
  11. pasteurization
    • milk: 63c deg for 30 min old
    • milk: 72c deg for 15 sec (new)
    • juices
  12. refrigeration
    • does not kill
    • slows metabolism, psychrophillic can still grow
    • best between 0-7
    • freeze thaw cycles can kill organisms
    • used for culture preservation
  13. lyophilization and freeze drying long term storage
    is effective in presrving foods
  14. filtration
    • used for heat sensitive liquids - seru or urea
    • .45u pores in membrane
    • often used commercially with beer, wine, and fruit juices
  15. desiccation
    • inhibits growth more than kills
    • dried meats and veggies
    • freeze dry processes in foods
  16. osmotic pressue
    • high concentration of salts or sugar
    • inhibit growth of bacteria
    • jams jellies, sugar and salt cured meats
  17. high pressure
    high pressure is transferred evenly throughout culture suspension can denature protiens
  18. radiation
    short wave (xray, gamma ray)
    high penetration power, breaks dna
  19. radiation non ionizing (UV) long waves
    no penetrating power; forms thymine dimers
Card Set
march 15 micro notes