Stainless Steel Plate for Swab Recovery

Hi all

I am newly registered in this site.I have a question about cleaning validation recovery and i hope you could reply.

To check the swab recovery, what kind of stainless plate we have to use? Are there any specific dimentions for this plate? Are they commercially available?

I have no idear about cleaning validation.Kindly answer to my questions.


Dear Suri,

the stainless steel plates (called “coupons”) should mimic as exactly as possible the actual surfaces encountered in your equipment, regarding stainless steel quality and polishing. Regarding the dimensions, they depend on the surface you are going to swab; usual are 100 cm² (10x10 cm) or 25 cm² (5x5 cm), so the coupons should be slighly bigger than that (12x12 cm or 6x6 cm). This is necessary because if you swab the coupon from end to end without lifting the swab, you will get a better recovery than the actual sampling in the equipment, representing a “better case”. There are comercially available coupons, but they are quite expensive and, on top, are not the same surfaces you find in your equipment. In my opinion the best (but most tedious) way is to contact the manufacturer of your equipment for samples of the equipment surfaces, which will have the same material and polishing as the equipment, can be requested with a materials certificate, and are often supplied for free from sound equipment manufacturers, but it can be cumbersome to get in contact with the right person to get them.

Best regards


Hi Thread,

Thank you very much for your reply.It is really helped.

Thanks a lot


Hello Alfred,

Can you tell me where I can buy stainless steel “coupons”. Do you know if I can find “coupons” made in other materials like: Teflon, polyethylene, etc…

Thank you in advance for answering.

Hi Alfred

What is the acceptance criteria for microbial swab recovery? Do we have to test both bacteria and fungi?

Dimensions of a coupon depend on the required LOQ of your analytical method and is based on the carryover acceptance criteria (was MACO now MSC). Usually 5 cm x 5 cm (2 in x 2 in) is suitable and may be purchased from commercially from companies like See link below:

Hello Alfred
How much coupons will required for recovery study at a time. Please explain the procedure for swab and rinse recovery study.