Residential refrigerator odor

[Ron MB]

How do you flush the residential refrigerator water system ie. door water, ice maker?
I have sanitized the whole coach system with bleach including the refrigerator; still getting an extremely foul odor from the door water etc.
I am getting ready to winterize with “pink” fluid; prior to this I have blown the water out and the water from the refridge stinks.
I did sanitize in the spring and there was no odor then.
How do I flush it? With what? Can I leave the bleach mix in the lines all winter?
I’ve left the pink in the lines all winter and got that odor in the spring..,,