Wash all your fruit with water very carefully, rubbing the skin with a paper towel or cloth towel. (Gets the eggs off.) Onions tend to have fruit flies, too - but I don’t use water on them. You can peel a few layers of paper off.
Pour bleach down the drain and rinse with boiling water.
Fill your garbage disposal to the top with ice. Add some bleach. Put a plate or something over the hole to avoid backsplash and turn it on, then turn on the water.
I now clean the garbage disposal every few days by grinding the ice. It works great!
Don’t forget to WASH your garbage cans, all of them - even the one in your bedroom that never gets food put into it because chances are at some point in time something remotely edible has been tossed in there and is adhering desperately under the rim. Ours get taken out onto the deck and washed out thoroughly with soap and water, sprayed with bleach, rinsed multiple times and then left out in the sun to finish drying out.
I call that game “Name That Smell” (for you young’uns, that’s a takeoff on Name That Tune). It’s especially fun to play right away when you walk in the door after being gone for a few days.
In our most recent case, it wasn’t a potato. It was a kamikaze ex-squirrel in our water heater flue.