Ch.7 Flashcards
Sepsis
microbial contamination on/in tissue
Asepsis
absence of contamination on/in tissue
Sterilization-
removing all bacterial life
Commercial sterilization
killing specific methods to kill C. Botulinum endospores (used in the canning industry)
Disinfection
removing pathogens on inert surfaces or substance (cleaning table)
antisepsis
removing pathogens from living tissue
degerming
removing microbes from a limited area (hand washing)
Sanitization
lowering microbial counts on eating utensils (to safe public health levels)
Biocide/germicide
killing microbes
bacteriostasis
inhibiting, not killing, microbes
Effectiveness of treatments depends on
Number of cells,
Environment (temp, biofilms,
Time of exposure
Specific characteristics
How are microbes damaged?
Alteration of membrane Permeability
Damage to proteins
Damage to nucleic acids
TDP and TDT
Thermal death point (TDP): lowest temp at which all cells in a culture are killed in 10 min, Thermal death time (TDT): minimum time at which all cells in a culture are killed
Moist heat sterilization
Moist heat denatures proteins, almost all viruses, fungi die in 10 min
Autoclave
is steam under pressure
Steam at 100 degrees under 15 psi above sea level gives a temp of 121 degrees
Everything is destroyed at 15 min (endospores)
Pasteurization
Reduces spoilage organism and pathogens
63 C for 30 min
High temp short-time
72 C for 15 sec used in US
Ultra high temperature
140C for <1 sec held for 3 sec in a holding tube before cooling used in europe.