Controlling Contamination Flashcards
What are the 2 different types of heat?
Sensible - When released, there is a change in temperature
Latent - When released, it results in a change in physical state
- With no temperature change
What is air ballasting?
When small amounts of air is added to some flexible plastic products to prevent popping under external pressure
Done by creating an overpressure in the autoclave
Can cause layering of air (prevented by mixing air and steam)
What are the 2 different types of large scale autoclaves?
Gravity Displacement - Steam added to the top, with air being removed from the bottom
Best for water and non-porous items
Porous Load - Contains a vaccum pump that removes air before the steam is added
What is the difference between Quality Control and Quality Assurance?
Quality Control - Testing of the final product
Quality Assurance - Ensures that all stages of the manufacturing process contribute to the quality of the end product
- This allows parametric release of drugs (batches without testing)
Why are large scale autoclaves better than small ones?
They have shorter cycle times
This is due to having a steam generator, which allows steam to be avaliable immediately
Also often have a heated outer jacket
Ideal antiseptics will kill both transient and resisdent microorganisms…. but what are transient microorganisms?
Bacteria that can be picked up from the environment
Eg, E.coli
What is the D value, and Z value?
D value - The time needed to reduce the population size by a factor of 10
Z factor - The temperature increase needed to reduce the D value by a factor of 10
What are the 2 different ways that you can sterilise/manufacture a product?
Terminal sterilisation
Aseptic manufacturing
What are the 3 different types of steam?
And what type of heat is released?
Superheated - Water in the vapour phase that acts like a gas
As pressure decreases, as does temperature
- Sensible heat
Supersaturated - Wet steam that is in a liquid phase
Wet mist that is held in the air by convection currents
- Sensible Heat
Dry Saturated - The best type for sterilisation
If the temperature is decreased, it will condense
- Both sensible and latent heat
What are the ideal properties of disinfectants?
And what type of bacteria does this kill?
Broad spectrum
Rapid kill –> within 5 mins
Does not damage in contact material
Easy to prepare and use
Stable
Inexpensive
They kill vegetative bacteria only (actively growing)
What’s the difference between chemical and biological indicators of sterilisaiton?
Chemical - Things like autoclaving tape and browns tubes that will give a yes/no answer
Biological - The addition of spore forming bacteria to see if the sterilisation method actually kills them
- This takes time
What are the ideal properties of antiseptics?
Immediate activity –> within 1 min
Persistant/Residual activity
Non-toxic and non-irritant
Cheap
How can we ensure that water is free from contaminants?
Heat up to 80 degrees C
Use positive pressure during manufacture
Heavy cleaning of the system
What type of autoclave can cause superheating in the presence of air?
An in this, what controls it?
Jacketed autoclave
Both temperature and pressure
What is the difference between viable and non-viable contaminants?
Viable - When bacteria/fungi/viruses contaminate the product
Non-Viable - This is either particulates (each from clothes) of microbial products like toxins, metabolites and pyrogens
What are the 3 different tests we can do to see if pyrogens (LPS) have been removed?
Rabbit Pyrogen Test - Injected with a sample, and see if a fever occurs
Limulus amoebocyte lysate (LAL) - Enzymes from horseshoe crabs are mixed with the sample
- Coagulation will occur if LPS (only) are present
- Very sensitive
Monocyte Activation Test (MAT) - Monocytes are mixed with the sample, with a colour change indicating a negative result
How is an unjacketed bench autoclave controlled?
By pressure only
So any air that is present will decrease the temperature
What type of heat has rapid penetration of bacteria/fungi?
Dry saturated steam
