When pumping, blood was noticed in the parts and in the milk. We use the microwave to sterilize the parts. Are they now treif and we cannot sterilize them using the microwave? Can we use microwave if we just wash them in cold water?
The parts are still permitted to use and they do not even have to be kashered. The reason why human blood may not be eaten is not because it is integrally trief, but because human blood looks like animal blood and it is maris ayin. This maris ayin does not apply if the blood got mixed into something and it isn’t noticeable. It would surely apply to blood that got absorbed into a vessel and it isn’t noticeable at all. Therefore everything is fine.
Shulchan Aruch Y:D 66-10.