I am looking for more information on OPA and Biuret testing. What is it? How is it used? I currently use Tosi which I find efficient but would be interested in looking at other test methods to use in conjunction with Tosi.
regards, Anthony mc Loughlin

Anthony

I assume the reference to OPA is for protein residual testing as you also make reference to the biuret method. In the UK we will routinely test a washer-disinfector for its cleaning performance in two ways. Firstly there is a weekly protien residual test on real instruments. The text-book method uses ninhydrin but the biuret and OPA methods are acceptable alternatives. Refer to HTM 2030, Validation and Verification, for details. Secondly we test the cleaning performance quarterly by using an artificial test soil painted onto a test load. The recipe for the soil will depend upon the type of process being tested but further reference to HTM 2030 will define this. The TOSI test device is a similar device to test soil although the soil is already fixed to the stainless steel strip. It can be placed in a basket to represent a dirty instrument but it can't be used to soil carraiges, wheels, chamber walls as a soil can. So, you pay your money and make your choice. In the UK the sensitivities of any test method must be related back to the HTM 2030 defined method and this document would be a good place to start to understand the procedures. Look in Chapter 10 of the Validation and Verification volume.

Hope this helps - Peter Hooper

Dear Anthony,

mhp-verlag Gmbh
Address: Marktplatz 13, D-65183 Wiesbaden, Germany
Tel: +49(0)611-50 59 30, Fax: +49(0)611-505 93 11
Email:

only very recently published: "Practical Guide to Validation of Cleaning and Disinfection Processes" (Cost: 8,80 Euro).
A working group compiled this document in line with the provisions stipulated in standards, directives and recommendations. It is very useful as it describes how to perform validation and routine control in daily practice.

Best regards,
Wim Renders

Dear,

In the latest issue of Central Service, 2/04 (see the Publications page) Michels and Frister publish:
"The modified OPA method with an alternative thiol component".

Best regards,
Wim Renders