In our company we have and tunnel autoclave with 10 probes. Seven of them have a fix position along the camber and the other three are “mobile” provided with a long wire so they can be inserted in a bottle in the middle of the load (coldest penetration spot)
The load, bottles filled with liquid, is inserted up to three “trolleys” through a door and discharged at the end of the cycle through a different door. This means the “mobile” probes get broken very often.
To reduce cost the Engineering department has decided to get rid of the mobile probes or to substitute them to a fix position.
My question is how could we proceed to simulate the “coldest penetration spot” and how to choose the right location. I was thinking on using bottles with a different liquid with higher specific heat
Any idea will be appreciated.
PD: substituting “mobile” wired probes by wireless probes is out of discussion due the costs and fragility of those probes.
I agree that cycle validation is the only realistic answer. I own a set of “Mobile” temperature recorders that I use for validations, but they are also available for rent from some manufacturers. Mine are from Mesa Labs.
If you don’t have any validation data, I would suggest that you start from the beginning by temperature mapping. You may find, as I have, that the center is not necessatily the “coldest” or “most difficult” position in the loaded vessel. There are a variety of engineering, loading and process material characteristics that come into play in determining this.
Usualy probes is use in Lab autoclave not in production autoclave because , if the autoclve have qualified and the sterlization cycles are validated then there is no need to use inserted probes in liquid, but it is preffer the temperature sensor probe must be present at coldest spot which must find during validation of sterlization cycle.
[quote=Timothy Barrett]I agree that cycle validation is the only realistic answer. I own a set of “Mobile” temperature recorders that I use for validations, but they are also available for rent from some manufacturers. Mine are from Mesa Labs.
If you don’t have any validation data, I would suggest that you start from the beginning by temperature mapping. You may find, as I have, that the center is not necessatily the “coldest” or “most difficult” position in the loaded vessel. There are a variety of engineering, loading and process material characteristics that come into play in determining this.
Dear elke,
You need to demonstrate in Validation that you get required temperature for desired time at the established cold point. Insertion of probes in the load is not preferred. You need to establish correlation between fixed probes and Validation probes during Validation cycles and that will be base for not placing probes in the load during routine production cycles.
For further details, feel free to contact (+91 9909985314). I have expertise in Autoclave Validation.
I believe everyones hit some part of the nail on the head.
You need to start off with Temperature mapping. This will determine your cold spots. This is basically where you would want to place your bioindicators and/or liquid temp probes.
You would then need to perform some real load configuation, you can either
a) Perform challenge validation, where you determine your maximum bottle sizes, volumes, bottle quantities, settings, etc…OR
b) determine validated load configurations.
3)If you’re consistently doing one type of liquid, with set volumes, etc, you “probably” “Could” get away with NOT inserting a probe, but it’s not advisable.
I would want to see: Liquid Probe, in a Liquid volume in the maximum liquid process volume used, + a biological bioindicator for each load.
If you are doing a variety of different liquids, with different densities, etc per load, then a load probe is a MUST.
[quote=morphius909]I believe everyones hit some part of the nail on the head.
You need to start off with Temperature mapping. This will determine your cold spots. This is basically where you would want to place your bioindicators and/or liquid temp probes.
You would then need to perform some real load configuation, you can either
a) Perform challenge validation, where you determine your maximum bottle sizes, volumes, bottle quantities, settings, etc…OR
b) determine validated load configurations.
3)If you’re consistently doing one type of liquid, with set volumes, etc, you “probably” “Could” get away with NOT inserting a probe, but it’s not advisable.
I would want to see: Liquid Probe, in a Liquid volume in the maximum liquid process volume used, + a biological bioindicator for each load.
If you are doing a variety of different liquids, with different densities, etc per load, then a load probe is a MUST.[/quote]
If I have a validated cycle then the use of probes and bioindicators is redundant. You have to validate the cycle per liquid load, it is a waste of your validation study to then release on indicators and load probes. The liquid load will react as any other thermal mass in a chamber that is uniform. Document the duration for the liquid to reach your setpoint temperture, then determine how long your soak phase needs to be. Take into account that you will have kill on the back side of the cycle as the liquid will probably take a long time to kill. I typically time off the the drain RTD as this is typically the coldest spot and last to attain temperature.
If you are 100% confident that you will always use the same load configs and stick with the validated container material, volume, etc, then a probe might be redundant.
As for bioindicator…sorry…You need one… Bio bioindicator is your last defense against any failure…or at the very least can be used to trace back any contamination problems…
Probes are Bioindicators have been longed looked at , and still are, as a pain the rear end…but are necessary in most cases…at least the bioindicator…