Ch 5 Microbial Control Flashcards
What is sterilization?
Killing of all living organisms
What is disinfection?
Killing or removal of pathogens from inanimate objects
What is antisepsis?
Killing or removal of pathogens from the surface of living tissues
What is sanitation?
Reducing the microbial population to safe levels
True or False: Microbes die on a positive exponential curve
Fase, negative exponential curve
What is the decimal reduction time (D-value)?
The length of time it takes a condition to kill 90% of the population
How do you preserve microbes?
Cold temperatures
How do you kill microbes?
High temperatures
How do you kill spores and thermophiles?
Combination of high pressure and temperature
High temperature in the autoclave will destroy which materials?
Polystyrene, non-borosilicate glass, and styrofoam, biological substances
Pasteurization: temperature combinations
LTLT: 63 C for 30mins
HTST: 72 C for 15secs
UHT: 135 C for 2 secs
Can you kill microbes with ultraviolet light?
Yes, but only for surface sterilization
What are gamma rays used for?
Irradiating foods and heat-sensitive items
Bacteria with greatest ability survive radiation of any known organism
Deinococcus radiodurans
What is filtration?
Filters with a pore size of .2um can remove microbes from solutions
Most effective commercial disinfectants are most active between what percentages?
60%-90%
How do you kill spores?
With bleach
What are antibiotics?
Chemical compounds synthesized by one microbe that kill or inhibit growth of other microbial species
What do antibiotics target in the cell?
Protein synthesis, DNA replication, cell membranes
What is biocontrol?
The use of one microbe to control the growth of another microbe
Example of biocontrol
Probiotics, they restore balance in the intestines
What is phage therapy?
Treats infectious diseases with a virus targeted to the pathogen
