Controlling Contamination Flashcards Preview

PA20309 > Controlling Contamination > Flashcards

Flashcards in Controlling Contamination Deck (21)
Loading 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




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



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


Name a physical indicator that can be used to assess if sterilisation processes are functioning correctly for the following...


Heat Sterilisation

Gaseous Sterilisation



Heat Sterilisation - A digital record of the temperature at the coolest part of the steriliser


Gaseous Sterilisation - Leak and pressure tests


Radiation - Use of a dosimeter that darkens with increases radiation


Filtration - A bubble-point pressure test


What is the difference between Disinfection and Antisepsis?

Disinfection - The process of removing micro-organisms from surfaces of inaminate objects


Antisepsis - The destruction or inhibition of micro-organisms on living tissues


What is parametric release?

This is a system of release that gives us the assurance that the product is of the intended quality


Must have pre-sterilisation bioburden testing done


Only used when terminal sterilisation is done


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