Chapter 9 Flashcards
controlling microbial growth in environment
sterilization def
destruction of all microbes on an object
antisepsis def
removing most organisms from living tissue . especially pathogens
disinfection def
removing most/all microbes from a non-living surface
pasteurization def
heat to destroy pathogens and decrease spoilage microbes in food
-cidal means
to kill
- static means
to inhibit growth
is there a difference btw cidal and static
most show no difference
ideally agents for the control of microbes should be what :
harmless to humans, animals, and objects
inexpensive
fast-acting
stable during storage
Biosafety levels through what
1 to 4
BSL 1 is what
not known to cause disease in healthy humans
BSL 2 is what
associated with human disease
BSL 3 is what
potential for aerosal transmission, serious/fatal
BSL 4 is what
high risk of fatal infections, aerosal transmission in lab
–related agents of unknown risk of transmission
What are some physical methods of microbial control
Heat
Refrigeration and Freezing
Desiccation and Lyophilization
Osmotic Pressure
What are some chemical methods of microbial control
alcohols
halogens
oxidizing agents
radiation
what are the effects of high temp
denature proteins
lower integrity of cytoplasmic membrane and cell wall
disrupt nucleic acids
two types of heating methods
moist heat and dry heat
moist heat does what
autoclave/boil
disinfect,sanitize, sterilize, and pasteurize
denatures proteins and destroys membranes
what type of heat is more effective
moist heat
dry heat does what
for materials that cant withstand moist heat
requires higher temp for a longer time
Refrigeration and Freezing info
lower microbial metabolism/reproduction
some microbes can multiply in refrigerated foods
what is listeria
grows in cold places
desiccation def
drying inhibits growth due to removal of water
lyophilization def
freeze-drying is long-term preservation. it prevents formation of damaging ice crystals
