Rather than use Hypochlorites, you could sterilize the stainless steel using sodium hydroxide, i.e. a weak hot solution of caustic soda, then thoroughly clean out with hot boiling water after pouring away the caustic soda solution down the drain.

You could also give the internal stainless steel of a vacuum flask or water bottle etc a couple of blasts with a Steripen just to make sure. This will kill (deactivate) all viruses and bacteria and other nasties such as crypto etc.