You can certainly squirt it with star san if it makes you feel better but it it pointless. It's sanitary. So are plastic zip lock style bags. Really, beer infection can happen from wild organisms in the air, but mostly it will come from grain dust or a spot you miss cleaning over and over again that allows actual beer spoiling microorganisms a chance to set in and grow. And beer spoiling microorganisms are not on foil., or in bottled water.I serve all my beer cold.
It's like, years ago, I remember someone worried about their beer getting infected because they had a cold. I try to explain to them that beer can't catch a cold. But not sure if that really sunk in or not.