In PDA report No 49, there is a statement for biotech industry cleaning criteria about TOC, which is 5-10 ppm for upstream process, the same as you mentioned. I think I’ll use this criteria. The following questions are how to decide the sampling area ( 5x5 cm? or 2.5x2.5cm?) and swab dissolution volume (5mL?).
I saw a calculation formula about swab area and volume, do you use it too?
Limit (ppm) = MACO x (1000/C) x (D/V)
C = cumulative surface area of the equipment used
V = volume of solvent used to dispense swab
1000 = multiplication factor to convert value in mcg from mg
D = swab surface area
I am not clear the meaning of the multiplication factor “1000” . In this formula, a MACO is still needed, I don’t know how to apply this in my case. For the swab area and solvent volume, I think I can decide one variable first like the solvent volume, then calculate the swab area.
I appreciate very much you or any others who can help solve the problem.