Any microorganism that would be found on a carpet, would be very sensitive to any ph change. Microorganisms can't survive a rapid ph change, so any prespray well above a neutral ph will likely wipe out most threats. Regardless of the treatment, 24 hours later it's again covered in boogers and drool, and microorganisms will begin to thrive again. Control would require a daily application.
In reality, I think any treatment to a carpet is useless, but I am not saying don't offer it and charge for it if someone wants it. !gotcha!