Levels of Control
This method ensures complete removal of all microorganisms, including resistant forms.
Sterilization
This method sterilizes by combining high temperature and pressure.
Autoclave
This radiation causes DNA damage by forming thymine dimers.
UV radiation
This chemical group denatures proteins and disrupts membranes and is most effective at ~70%.
Alcohols
An agent that kills microorganisms is described as what?
-cidal
This method reduces microbial load on objects but may not eliminate endospores.
Disinfection
This method uses heat to reduce microbes in food without significantly altering quality.
Pasteurization
This type of radiation penetrates materials and disrupts DNA directly.
Ionizing radiation
This group of chemicals works by oxidizing cellular components and includes chlorine.
Halogens
An agent that inhibits growth without killing is described as what?
-static
A substance is applied to skin to reduce microbes without damaging tissue. What is it classified as?
Antiseptic
Why does moist heat sterilization work more effectively than dry heat?
It penetrates cells better and denatures proteins more efficiently
Why is UV radiation not reliable for sterilizing thick or covered materials?
It has poor penetration
This group binds to proteins and interferes with enzyme function but is not microbe-specific.
Heavy Metals
This term refers to the time required to reduce a population by 90%.
Decimal Reduction Time (DRT)
A procedure lowers microbial numbers primarily through mechanical removal rather than killing. What is this called?
Sanitization (or degerming)
A nutrient solution cannot be exposed to heat but must be sterilized. Which method is most appropriate?
Filtration
This pressure-based method is used in the food industry to reduce microbial contamination without heat.
Pascalization
Why are surfactants not considered true antimicrobial agents despite being widely used?
They primarily remove microbes mechanically rather than kill them
Why does a larger starting microbial population require longer exposure to achieve sterilization?
More reduction cycles are needed
Why must critical medical instruments undergo sterilization instead of high-level disinfection?
They contact sterile tissue and must be completely free of all microbes
An autoclave cycle fails despite correct temperature. What other variables from the lecture must be considered?
Time, pressure, and microbial load
A sealed medical device requires sterilization without heat exposure. Which method is best and why?
Ionizing radiation
A disinfectant disrupts membranes and denatures proteins but is only effective against enveloped viruses. Which group is this?
Alcohols
Name three factors that influence the effectiveness of microbial control methods.
Time, concentration, population size