I bring in my feeders to wash in the sink and I walk right past Monty with them and he's always been fine. I wouldn't worry too much about it - better to bring the in and clean them to prevent spread of disease anyway!
I always bring my hummer feeders in to wash and have never had any issues. Kiwi isn’t around them when I do. I am guessing she would think they were evil anyway and try frantically to get away from them - LOL. I wouldn’t worry about any airborne germs that would somehow come off the feeder.
I agree with Aqueilo and Jackie, I doubt there is anything to worry about.
Just thought I would share this. A few years back a hummingbird made a nest on my windchime. Hummingbirds were my number one favorite bird until I got a...how many guesses do you need? lol Sorry the pic is so blurry, I had a old phone at the time and had to take it through the sliding glass door.