Transfer from the surface to the swab and from the swab to the liquid medium used in extraction will depend on many factors. The 10% figure cited below seems unusually low. [Vortexing to remove organisms from polyester wipers, for example, has shown recoveries from 50 - 90+%.] Those who would be interested are invited to send me electronic mail with a request and their postal addresses, and I will send them: D.W. Cooper, "Using Swabs for Cleaning Validation: A Review," pp. 74-89, Cleaning Validation, Institute of Validation Technology, Royal Palm Beach, FL, 1998. Douglas W. Cooper, Ph.D. Director, Contamination Control The Texwipe Co. LLC [log in to unmask] "Sturm Pam HMR/US" <[log in to unmask]> on 09/30/98 09:26:03 AM To: [log in to unmask] cc: (bcc: Douglas W. Cooper/Texwipe) Subject: Re: [PMFLIST] Swabs vs. Contact Plates Nancy, Sorry to hear that your supplier can't meet your needs. I think if you're going to substitute swabs for contact plates you're going to have to do some in-house studies comparing recovery. My inquiries in this direction indicate that swabbing recovery is pretty poor compared to RODAC's. I know that various workers claim recovery of as much as 50%-80%, but I think they must be living in an ideal world. In my world, even if you vortex the dickens out of the swab, it still doesn't want to let go of any bugs it's picked up, and you're lucky if you get 10%. I have in the past looked for comparison recovery percentages, but the information available is somewhat unsatisfactory. I know this doesn't sound very cheerful, but that's why we only use swabs for areas that are virtually inaccessible with other sampling methods. Pam Sturm Associate microbiologist Mail: C1-M0619 Phone: (816) 966-5668 e-mail: [log in to unmask] -----Original Message----- From: Nancy Fulginiti [mailto:[log in to unmask]] Sent: Tuesday, September 29, 1998 1:52 PM To: [log in to unmask] Subject: [PMFLIST] Swabs vs. Contact Plates Hi Everyone, Recently, I had to deviate from a method that specified contact plates to be used for floor monitoring because the manufacturer was out of stock on our standing order of plates. In the deviation, I wrote that I planned to use swabs as a back up test. OF course, QA would like some documentation as to the equivalency of the two methods. Has anyone ever performed a study or can anyone direct me to a reference that compares these two methods? If I recall, the APHA might have a chapter on this. Any help is appreciated. Nancy A. Fulginiti ------------------ The PMFList (http://microbiol.org/pmf.htm) is operated from The Microbiology Network (http://microbiol.org) and supported by our sponsors (http://microbiol.org/sponsor.htm) as a service to the scientific community. ------------------ The PMFList (http://microbiol.org/pmf.htm) is operated from The Microbiology Network (http://microbiol.org) and supported by our sponsors (http://microbiol.org/sponsor.htm) as a service to the scientific community. ------------------ The PMFList (http://microbiol.org/pmf.htm) is operated from The Microbiology Network (http://microbiol.org) and supported by our sponsors (http://microbiol.org/sponsor.htm) as a service to the scientific community.