Number of Biological Indicators for Routine Monitoring of ETO Sterilization Cycle

[BigManP]

We are in the process of conducting an ETO validation per ISO 11135 in a 5 pallet chamber. We are a small company though, so our max load is actually only 3 pallets.

My question is, how many BI should be used for routine monitoring?

Table C.3 in ISO 11135 states "Product load volume", but in the examples below the table it says "For a usable chamber volume..." In our scenario, these two volumes are quite different - 4.12 m3 vs. 12.4 m3. Should we be using 7 BI's or 17?

Thanks!

 

[Marc]

Re: Number of BI's for Routine Monitoring of ETO Cycle

For those of us following along and learning, BI = Bioburden?

 

[BigManP]

Re: Number of BI's for Routine Monitoring of ETO Cycle

Sorry - biological indicators. These are typically spore stips placed on the outside of your pallet that are used to verify that adequate conditions existed to sterilize your product.

 

[MIREGMGR]

Re: Number of BI's for Routine Monitoring of ETO Cycle

For those of us following along and learning (...)

In an ethylene oxide gas sterilization validation, you run various tests to establish that the biological indicators you will use are assuredly more difficult to sterilize than your actual product, under conditions that amount to half the lethal-gas-exposure of your intended production sterilization cycle.

Having established this, you then can run production loads with the BIs for monitoring, without needing to do sterilization testing of actual product (which of course you want to keep in undisturbed sterile form so that you can sell it) and have good assurance that if the BIs are uniformly killed, the associated product is 10E-6 sterilized.

 

[medwise]

BigManP -

As per the standard you have to identify the cold spots (worst case position - difficult to sterilise) and place the BI there. Ideally, that will be in the middle of the pallet. Since you will have 3 pallets out of 5, I would recommned for you to have 2 BIs at the top, 2BIs in the middle and 2BIs at the bottom. Make sure that you do not place the BIs on the same side. Place the BIs in the opposite corners and alternate the position each row. To answer you the numbers of BIs you need for your load is 6 per pallet i.e. 6x3=18 BIs.

Hope it helps.

Regards
Romit

 

[SilversB]

What would be the path to move forward with product if fewer than the required number of BI's in present on the pallet for a one pallet chamber? For our process, per ISO 11135-1 Table C.3, we need to have 5 BI's per pallet. We ran 2 one pallet loads, one with 2 BI's and one with 3 BI's. Can we release the product based on historical results as well as our validation data?

 

[BigManP]

If this happened at my company, we would simply reprocess the pallets. However, we have a documented shelf life study for 2X sterilization on our packaging and 3X from a performance stand point on the product. If you don't have this, it is my opinion that someone made a very costly mistake and the product should not be released to market. Perhaps a justification could be made, but my view is that life is too short for that kind of stress. Sterility - especially documented evidence of it - is a pretty big deal. Good luck!
Paul

 

[SilversB]

BigManP - Thanks for the feedback. We have 2X validation data and are planning on sending the 2 pallets back for sterilization. It was just asked of me by others in the organization about the possibility of any other release options. Thanks again.

 

[BigManP]

Perfect. Definitely the right thing to do - in my opinion.