Sterilisation Flashcards
What is sterilisation?
The killing or removal of all viable organisms within a growth medium
What is inhibition?
Effectively limiting microbial growth
What is decontamination?
The treatment of an object to make it safe to handle
What is disinfection?
Directly targets the removal of all pathogens, not necessarily all microorganisms
What is meant by the decimal reduction time?
The amount of time required to reduce viability tenfold
Endospores can be killed with heat. True or false?
False - can resist heat
What are the methods of heat sterilisation?
Red heat
Dry heat
Autoclaving
What is autoclaving?
Steam under pressure
Autoclaving doesn’t allow temp of water to exceed 100 degrees. True or false?
False
What is pasteurisation?
Process of using precisely controlled heat to reduce the microbial load in heat-sensitive liquids
In autoclaving - it is the pressure that kills the microorganisms. True or false?
False - it is the high temp
Pasteurisation kills all organisms. True or false?
False - that’s why it is different to sterilisation because it doesn’t kill all
UV has sufficient energy to cause modifications and breaks in DNA. True or false?
True
UV is useful for decontamination of surfaces. True or false?
True
What is ionising radiation?
Electromagnetic radiation that produce ions and other reactive molecules
Some microbes are resistant to radiation. True or false?
True
Radiation is used for the sterilisation of food both in the UK and US. True or false?
False - only in US
Filtration avoids the use of heat on sensitive liquids and gases. True or false?
True
What is the pore size in filtration?
0.22um
Filtration requires either push or pull. What can be used for push and what can be used for pull?
Push - pressure
Pull - vacuum
What is cold sterilisation used for?
Decontaminate heat sensitive materials e.g. thermometers
Cold sterilisation uses volatile, toxic, gaseous chemicals such as….
Ethylene oxidde
Formaldehyde
Peroxyacetic acid
Hydrogen peroxide