Hello,

I was wondering if anyone would know why plastic/paper autoclave pouches are designated as single use?

I am involved in stress testing instruments by subjecting them to repeated autoclave cycles. The instruments are placed in a pouch, and left in an autoclave for hundreds of cycles. Although the pouch is never removed from the autoclave, it is in essence, being re-used.

I'm curious if the pouches are designated as single use because the seal integrity may be compromised, or if the paper backing loses porosity and eventually fails to allow steam penetration.

Any help would be greatly appreciated.

Kindest Regards,

Brad McCloy

Good day Brad,

My understanding is that the fibers of the paper swell up in size as a result of contact with steam. The fibers in the paper do not shrink all the way back to their original size at the end of the sterilization cycle. Steam will not penetrate previously exposed paper as easily as it penetrates new paper. Each period at high heat causes additional oxidation in the paper, making it more brittle and more likely to loose its barrier properties. Because the properties of the packaging material change as a result of sterilization, to reuse the packaging would add unnecessary variables into the sterilization process.

One of the great advantages of a peel packaging system is the seal. Once the seal is broken or tampered with, this fact is clearly visible to everyone who handles the package, alerting them to the fact that the sterility of the item inside may be compromised. To reuse the packaging would mean we would have to counterfeit the original seal. The problems this would cause in the faith of the users - knowing the package can be opened, contaminated, and then passed off as a new product with an original seal - would breach the trust placed in an intact seal on the packaging.

The problems of cleaning the packaging (What is the best way to wash paper before reuse?), bringing it to a proper humidity level, inspecting the material for holes, stacking material for use, loosing the benefits of cut-to-fit roll packaging, etc. would still remain even if the other problems are solved. I think re-use is therefore impractical, so recycling the paper and the plastic might be the best solution from an ecological point of view.

Warm regards, Pete Bobb

Dear,

In addition to Mr Bobb's reply we could add the following:

Polypropylene (PP) used in paper/laminate packaging materials tends to crystallize when exposed to high temperatures during sealing and sterilizing. When PP crystallizes, the film gets brittle and breaks more easily. If re-used, the more brittle the laminate gets, the more risk for breaking and contamination. Also the heat sealing properties get weaker when re-used and hermetic closing can't be guaranteed anymore.
The process indicator changes in the first sterilization process - meaning that the packed item has been processed -. Re-using a package with already changed indicator brings a high risk for taking the packed item for use without sterilization.
Because of these factors we, manufacturers of sterilizing packaging materials, can't guarantee the product nor functionality when packaging material is re-used.

Best regards,
Anneli Haikonen
www.wipak.com/medical/