Way too many people put way too much emphasis on cleaning/sterilizing their black tank and all the plumbing. Of course we want to keep things clean and tidy but sometimes it becomes way more of an ordeal than it should be. (Unfortunately I'm usually in line behind them at the dump station).
Most people are fine with dumping the black tank contents and then draining the gray tank contents. That gray tank dumping action is all that they feel is necessary to clean the inside of their stinky slinky.
To make yourself feel better about it, store the stinky slinky and its fittings in a plastic tub. Not exactly a completely sealed unit but makes people feel better about it.
But if you still want that warm fuzzy feeling that you get with a new hose, buy one that has caps on each end, fill it with water and detergent and bleach, cap and shake it and drain it and repeat until you feel its safe to touch.